Fjd
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On 3/21/2016 at 10:08 PM, WMcD said:
Power amps and the like are one subject. Not addressed here.
But I still wonder about the chain of electronics e.g. microphone amps, mixers, etc., which were used to produce recording, in history, we admire or maybe less so. This is all low level processing.
Over the years the equipment is tube or transistor, operating in Class A. The equipment uses capacitors and sometimes transformers which are subject to love and hate. But that is what we've got just before the signal is stored and distributed, by any number of means.
For example, you can say that tubes or transistors or caps are good or bad in my pre-amp. Yet the signal has probably been processed through multiple stages of equipment using the devices which are praised or vilified. That can't be un-done.
As an extension, do we really think that a pre-amp is going to do more harm or good than all the proceeding ones? It can't cure anything.
If here is one last stage of small amplification using similar devices and topology in our living room, how much can we hope to accomplish?
WMcD
To borrow an iconic phrase from Ten Bears, "there is iron in your words." Yep, I just got done watching the movie "The Outlaw Josey Wales" and decided to read a little.
You sure outlined way too many variables to even think about all of the potential impacts when considering the audio reproduction chain as the initial capture of the performance all the way to the output from the speaker in a home listening environment.
In my experience at the “home” level, for a well-implemented system, well-engineered circuits constructed into amplifiers with quality parts of the appropriate specifications, whether tube or solid state, will appear to exhibit more similarities than differences on my Klipschorn implementation.
Of course, I try to select components that are actually capable of doing the job asked of it in that I would never ask my two watt single-ended triode amplifier to drive the Klipschorns to levels that can fill Carnegie Hall.
I do find many things about the “music simulation” experience very interesting and I do firmly believe that the ear (even an “untrained” ear) can detect very small differences that seem very inconsequential on the surface; and I certainly cannot find fault with those that just use their ears and go with what provides the listening experience they are looking for.
However, from another perspective, although the ear can detect very small differences, the brain may NOT exactly know what aspect of the music simulation experience to attribute the difference. While my ears may make judgments based on my “feelings” during the music simulation, I expect my brain to reason from principles the specific, as best as I can determine, “why” rather than immediately jump to a poorly reasoned anecdotal view.
Lately I’ve been trying to match components (whether tube or solid state) that have very low noise floors and low distortion levels, specifications not solely achieved through high levels of negative feedback; and have as much of the gain up front as possible and the less gain at the end of the audio gear chain in order to try to maximize the S/N of the system and avoid attenuating amplified "noise" and “distortion” at the end of the audio gear chain. Of course, all of this on highly efficient Klipschorn speakers.
Although I’m still a few months away, next on deck is what appears to be a well-engineered line stage developed on the DIYAudio forum using a 4P1L tube that is actually a pentode tube but has direct heated filaments and wired as a triode resulting in a very linear tube with very low noise levels for the line stage circuit.
The 4P1L tube line stage will provide 7dB of gain and I plan to see how it matches up with my First Watt F3 amplifier that has 12.5dB of gain. This line stage is not necessarily an easy implementation as the 4P1L can be very microphonic, but once the various “triggers” that cause a tube to ring are engineered out of the implementation and the 4P1L is wired as a triode, it looks like it will be a line stage that meets the current criteria of low noise and low distortion.
Just because one tube amplifier in one system resulted in “big-old-fat-tubey” bass, regardless of what my brain may initially try to tell me, it doesn’t mean that every tube amplifier will result in the same experience. With a well-engineered circuit, it may just be a crappy transformer was used in the build that saturates too quickly on low frequencies.
In the same manner, just because one tube amplifier in one system resulted in a “surreal, emotional” experience, doesn’t mean in another system that experience can be duplicated. The same thing appears to go for solid state too.
Yep, most of us want it all, but sometimes decisions about trade-offs and compromises can be very insightful.
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well bad news.... bad news indeed!
I am truly broken hearted!
one amp works ( dead silent & sounds good) , the other hums and does not. ( It does play music for a second after being turned off)
I just got off the phone with Mike from quicksilver. He gave me a few ideas of things to check, nothing seems wrong. He has no clue as to what the problem is. But it does not play and has 60 cycle hum.
I was so looking forward to this! I will spend a few hours comparing one side to the other with a DVM. I swapped tubes, different sockets, power cords, receptacles etc. No villain has been found. DAMN THE LUCK!
If anyone wants to call and see if we can fix this that would be great. If not they go back on Monday.......and I save up for a pass labs 30.8.
I'm sure there will be others that come along that are well-versed in troubleshooting and can outline various steps; however, I bought a used tube stereo amplifier about three years ago that demonstrated similar symptoms out of one channel where I got a loud hum and no music. In my situation I took the bottom off the amplifier and noticed that during shipping one of the leads of a capacitor had broken off from the solder joint. I soldered it back together and both channels worked fine.
Just never know how shipping will impact an amplifier. In another instance I bought a used solid state amplifier and during shipping, one of the MUR860 bridge rectifiers broke connection with the circuit board, although it may have been related to the small heat sink becoming unattached too. I replaced the MUR860 diode and attached the heat sink properly and the amplifier checked out and worked fine.
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There is no counting the number of the old but very good NE5532 op amps the sound is mixed with in the studio.
A couple of years ago I posted several of these projects to the forum; however, I had bought a parts kit and modified my Creek OBH-11 headphone amp and replaced the NE5532 with the LME49720, upgraded a few of the coupling capacitors and resistors and I was somewhat caught off-guard with the results in how significant of an improvement. It seemed like the noise floor was lowered and a 'veil' of haze was lifted from the music.
Sadly, the LME49720 was also on this list of parts, along with the LM3875, scheduled for obsolescence and to be discontinued. I know that I have a few other pieces of gear with the NE5532; therefore, I guess that I need to start thinking of experiments that I may want to try and buy a sleeve of each discontinued item.
Given the experience with the Cheek OBH-11, along with a schematic and a basic understanding of how a circuit works, I think there is a lot of opportunity to take some of these types of parts and upgrade some of the lower-tier audio gear that can be picked up for a few dollars on the used market and pennies on the dollar of the cost when new.
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I've built a Aleph 30 which can be converted fairly easily to the Aleph J by changing the front end transistors to the jfets. It is a very nice amplifier with some outstanding treble. It was the first FW clone I built. It is a good choice with our horns.
The way you have been cranking out the builds, it may not be too long before you have sampled the entire portfolio of amplifiers.
Of course, my thought is that a person can never have too many amplifiers. With that said, have you given any thought to building a F4 at some point and drive it with one of your single-ended tube amplifiers or even using a bi-amp set-up as Nelson Pass describes in the schematic below where the single-ended tube amplifier drives the mid/tweeter directly and drives the F4 that in turn drives the woofers?
A single F4 will give 25 watts (50 watt peak) per channel into 8 ohms and 40 watts into 4 ohms. However, wired as a mono block the F4 will give 100 watts. Essentially, one way to think about the F4 is as a refined power follower, it will essentially push the same voltage out that you send into it, but it will feed much more current through the load than the SET amp, if, or when, needed.
I see this same concept of tube for voltage gain and solid state (usually mosfets) for current used in some of the high-end headphone amps too.
In another set-up I have I essentially use my DHT SET amplifier as the "voltage gain stage" directly into the F4 and because the F4 is such a simple Push-Pull circuit with no feedback, very low distortion levels and only a miniscule 50uV noise level, a lot of the characteristics of the DHT SET amp that I find very favorable will come through. I like to think of it kind of like a "SET on steroids" in some ways, but also noting that it looses only some very small aspect of that intimacy that DHT SET can provide in those near-field lower-level listening sessions.
On an important side note, there are various implementations of "adaptors" out there as the DHT SET output will need to be adapted to the RCA input of the F4. Also, due to the F4's high input impedance (47,000 ohms), a resistor (~ 20 ohm, 5 watt resistor, but some have used anywhere from about 15 ohm - 22 ohm depending on how they like the sound) is needed across the SET outputs since the SET only "sees" the F4 and not the speakers. On DHT SET amps with multiple taps (i.e. 4, 8 or 16 ohm) there seems to be some diversity on which tap sounds best; however, I suspect that is more related to system synergies.
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While I suspect some can hear the noise in certain situations, I’m sure others cannot (especially that person that lives in a city apartment where the ambient noise levels tend to be much higher). In comparing the M2 with the J2 (I purchased) using my Klipschorns, while I did not experience any annoying hum, I had suspected that the level of noise may have been part of what I perceived as a slight masking of the musical detail as opposed to listening with the J2 that had the type of liquid clarity in the very fine musical details that was more in line with what I was looking for.
You are correct sir, and this best sums up my thoughts... I can hear the amps if they are on and the room is quiet and I am right up with my ear in the horn. However, I like so much of the other things about the M2 that this is insignificant to me at this time. However, I have read exactly what you have written about the J2 vs the M2 and I would be curious to hear one in my setup.
It does seem that mine is quieter, I have to climb right into the horn to hear anything, and I agree that's probably due the larger case and better separation. When I say climb into the horn, these are K402s so I am being literal.
That's great and "needing to climb into the horn" to detect the noise (I understand the literal aspect you outline because I've had my Jubilees for five years now, Khorns for a much longer time) was essentially what I was trying to describe with my mathematical analysis of 500uV of noise, also outlined in that post; and how the noise level generated (at the speaker, not the listening position) from that level of voltage was already much lower than the typical day-to-day noises that already contribute to the ambient noise level in many houses and apartments.
Since there had already been a couple of comments regarding the noise level of the amp that people had read about on other forums, I tried to put it into some context in relation to the various noise levels that most people are familiar with and demonstrate how little noise is actually there through mathematics, without suggesting specific conclusions, but thinking that the readers questioning the noise level would come to the realization that at the listening position, any noise from the amp is essentially non-existent. I hope that the analysis hasn't been misunderstood by those reading the thread and further contribute to some of the confusion where people have been thinking the amp is too noisy for horns.
Now that you have built one First Watt clone (since we all like to spend other people's money on this forum), if, or should I say when, you are up for a "different" build, I would suggest the Aleph J in order to sample a First Watt single-ended class-A two stage design that will match up very nicely to a larger variety of speakers as opposed to one of the other more esoteric single-ended, single gain stage designs where it becomes very difficult, if not impossible, to source certain parts.
The "hard to get" Aleph J parts (circuit boards; transistor kit including 8 - IRFP240 N Channel Mosfets, 2 - ZTX550 & 4 - ZTX450; and 2 matched pairs LSJ74 JFETS for the differential amplifier gain stage) all can be bought at the diystore, there is a well-documented "6L6" build guide for the Aleph J on the diyaudio forum (at link below), and in some respects, the J2 is kind of like the JFET output transistor update of the Aleph J design.
http://www.diyaudio.com/forums/pass-labs/241729-aleph-j-illustrated-build-guide.html
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I realized that my few previous interactions with Canada have been to either make the drive and pick up the item or the seller has used Canada Post, and sending to Canada has been USPS resulting in none having gone through customs. I don't have my notes with me, but I had tried to verify the various charges to figure out exactly who got what, and I had the same $48 for customs and brokerage, but I was only charged the standard $25.95 by UPS upon delivery (not sure the exact reason for the additional $41 you were charged over the $26). I tend to believe that UPS automatically sends everything to customs in order to charge $25.95 for brokerage, somewhat similar to how they often refuse to insure something unless you let them toss it in their box of peanuts and pay an additional $20 - $30. Overall, still an excellent deal over what I've seen available on the use market and still substantially cheaper than the $1,000 "c-stock" example currently on eBay.
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I was extremely fortunate to get the only unit that was basically new. Fjd, I feel even more so now that I've heard your story.
I've never had an item take so long to clear customs, especially since I couldn't find any signs that the box was actually opened and content inspected. However, the aspects that I find most important are that it did arrive safely and appears to be in working order with minimal cosmetic wear.
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So, i hope I get some free coffee around here ... in 10 years, i’ve got my first thread locked.
I could use a nice garage door.
Since the thread title wasn't about garage doors or multiple birthdays on the same date, when reading the title of this thread, I initially felt bad for BigStewMan since I thought maybe he got his second thread locked in 10 years and "locksmith" was a new euphemism.
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First Watt Clone - The DIY M2 is a class A amp that follows Nelson Pass's design and tries to clone his work. NP is a big supporter of DIY and released this schematic recently. As I already own 2 M2s, I built this to run my center channel K402 bi-amped.
The completed tested and working AMP:
I have never built anything like this before and if not for Wdecho, not sure I would have attempted to. With his guidance and help in parts selections and oversight during the build he managed to help me build this from afar without me electrocuting myself. I want to share my experience with you, to encourage you to try and build a SS amp or tubes or line stages whatever. If I can do it, so can you. To start I suggest having a nice soldering iron. I bought a Hakko for this build and have no regrets, part of my success is good clean soldering.
Excellent job on the M2 build. At some point, the M2 is on my “audio bucket list” to build. I heard one briefly when I bought my J2 so I picked up the boards and autoformers during the group buy to add to my parts bin. Interesting concept applied with the M2 using the input autoformer as the gain stage in that it seems like Nelson does something similar to the step-up transformer used as a gain stage for a moving coil cartridge. I see he gets 15dB of gain using the autoformer.
Not to argue but what I read on audio asylum - quote from NP "M2 is definitely the noisiest available from FW at 500uV. Put this amp on 100db speakers and you will hear it". It was that comment only that had me re-think the purchase.
He goes on to talk about the effect autoformers has on this in picking up field noise from a near transformer.
Cantilope did say in one of his conversations with me that he thought maybe the M2 he just built is quieter than the 2 production ones he bought. It may be because of the size of the case. Perhaps the Firstwatt case is a little bit smaller making the input transformers closer to the PS transformer. I have LaScala's that are like 103db speakers and my M2 is quiet. Nelson may just being safe in case someone does complain about a touch of noise when you are a foot from the speaker with no music playing. I can stick my ear right on the horn, nothing, but I am almost 67 and I am sure my hearing is not as good as my Grandsons. I have one that complains that the dog whistle hurts his ears every time I use it. Most hear nothing from a dog whistle.
The M2 is considered one of the best sounding FW amplifiers with horns along with the F3 and newer SIT amplifiers.
I have heard Nelson say the F5 with bright speakers is like instant coffee in the microwave in the morning but there are members here that like the F5 with their horns. A lot depends what you are expecting from your speakers. The F5 probably has more detail, I have not heard one. I have not considered building one because of what Nelson had to say about it but then I may like the F5 if I were to build one. The F6 is a very revealing amplifier with some of the best detail you will find in an amp. It is not my favorite amp with my horns in my room A very good amp but not my favorite. The M2 has a more SET sound that I find attractive.
I have to think in most situations the level of noise will be inconsequential. At 500uV the amplifier is injecting 500 microvolts (or ½ millivolt) of noise into the speaker. With 103dB speakers, one watt into an 8 ohm load is 2.8 volts. The math will show that 500uV is 75dB below 2.8 volts. Therefore, the amplifier would introduce approximately 28 dB (103dB – 75dB) of noise (SPL) from your speakers.
In a quiet room with no music playing, one of those rooms where you can hear 10dB of noise from a pin dropping, using very high efficiency speakers greater than 100dB I can see how some people can probably slightly hear the amplifier. However, there are many things that impact ambient noise levels in a house or apartment that are louder; such as someone starts to whisper (30dB), the refrigerator kicks on (50dB), someone starts taking at a conversational level (60dB), among many other things that impact the ambient noise levels.
While I suspect some can hear the noise in certain situations, I’m sure others cannot (especially that person that lives in a city apartment where the ambient noise levels tend to be much higher). In comparing the M2 with the J2 (I purchased) using my Klipschorns, while I did not experience any annoying hum, I had suspected that the level of noise may have been part of what I perceived as a slight masking of the musical detail as opposed to listening with the J2 that had the type of liquid clarity in the very fine musical details that was more in line with what I was looking for.
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Here are the specifications for the DE-5000 in case anyone is interested in the comparison of accuracy and precision.
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Speaking of hurricanes, a little bit of nostalgia. When Marshall was changing out his vintage Sansui integrated amplifiers to vintage McIntosh, I bought one of his restored Sansui AU-11000 integrated amplifiers to go along with my Sansui TU-9900 tuner (modified by Radio X Tuners).
The AU-11000 is a beautiful piece of 1970s nostalgia, was dead quiet, gotta love the massive power supply in these old Sansui integrated amplifiers, headphone jack, features and knobs everywhere you look, and, of course, a MONO switch when it’s time to critically compare stuff.
Now, of course, his packing skills were so exemplary too, as I thought he had either packed the Sansui in order to withstand a hurricane or maybe he had mistakenly packed two integrated amplifiers, given how big and heavy of a box.
On a side note, I had always thought he left the forum when the old spam patrol uniforms were introduced.
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I received the crossovers Monday in a very smooth and easy transaction. Great communication and crossovers in nice shape. Now, just where did I put that schematic on modifying the crossover network circuit and installing the battery to convert to battery biased capacitors?
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I just received the last one complete with the box, paperwork and cord for 516.97 US Dollars.
I inquired back in December and didn't get one because of the lack of box, plus these units were 8 years old... I got interested again when I found out the price listed was CAD. So, I emailed the seller a couple of weeks ago and he said: "Turns out you got lucky – you’re getting the last one we have, which has been designated as a “spare” all its life. It’s still got its original packaging and it’s not unlikely that it’s never even been plugged in."
It is spotless! No doubt about it looks and smells brand new!
I was one of the people that got one of the units without the original box and just received it last week. Ordered it in February not long after Chris posted, but it seemed to disappear for a while during the process of clearing customs somewhere in Pembina, ND. I never had to wait this long on anything international coming through New York, but maybe they move much slower in North Dakota as opposed to New York.
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It looks like this has a really crude routing job for the ports on the horn...
Bruce
It looks like this has a really crude routing job for the ports on the horn...
Bruce
Nothing wrong with using cardboard either.
Since I have essentially no experience in building horns, you both got me worried about what I'm planning with my old ALK/Martinelli trachorns.
Are these issues you both point out really that detrimental to the synergy design using the standard DIY-type tractrix horn base similar to my trachorns and similar to the other wood tractrix horns people are using on Klipsch speakers, which from my read of the thread, seems to be more of a “proof of concept build” he did in 2014 rather than a finished product ready to sell?
I guess that I looked at both of the threads and it seems to me that the 2016 Faital Pro LTH142 tractrix horn with all of the 3d printing is a type of "evolution" or "progression" of his take on the tractrix-synergy concept that he started with the wood tractrix horn (similar to the wood horn many use on Klipsch) in 2014.
I was actually very impressed that the measurements in that thread of the "Trynergy" with only an 8.5" X 13" mouth, supported horn loaded gain down to 350Hz, along with a very nice response curve, all using inexpensive drivers. I couldn’t determine if directivity narrows like the traditional tractrix curve, but I suspect it does since I didn't see any changes in the horn to address that aspect.
However, now I’m worried that since I may not be able to make my trachorns very pretty converting them to the synergy design, especially like the 3d printed pieces from his 2016 synergy build using the Faital Pro horn as a base.
From everything I have read on the DIYAudio forum, the forum where Patrick Bateman posts his car synergy horns, and in the “K402 synergy” that Chris is building, while there are complex aspects to the build, each example also seems to indicate that the design results in fairly forgiving builds.
Since this will be my first attempt, maybe before I cut into my trachorns, please expand on these issues you guys are seeing and help me better understand the actual impact of these issues on the horn loading, response curves and measurements for this design? How would you do it differently to mitigate these impacts, what materials should I use and what type of tools should I try to find access in order to give my build a better chance of success?
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These horns would suffice for a bookshelf-sized multiple entry horn design, sort of like this one but with an updated and better horn for purpose: http://www.diyaudio.com/forums/multi-way/285030-bookshelf-multi-way-point-source-horn.html
I had been following the little synergy horn builds for his car that Patrick Bateman was making and documenting on various forums; however, I see that xrk971 has now started several very interesting threads. I like how he started with the Faital Pro LTH142 waveguide and is incorporating the use of 3d printing with the woofer to waveguide adapter and 3d printing for the woofer chamber volume reducer plug.
The other that I found interesting was his take on the “tractrix-synergy” horn that he calls the “Trynergy” at this thread below. It might not be a perfect fit in the stock Klipschorn top hat; however, for the group that enjoy the traditional tractrix curve, it sure seems to solve the problem of finding a 1” throat compression driver from needing to go down to 400 Hz. I keep eying the old pair of Martinelli/ALK trachorns I have and thinking I need to find access to some woodworking tools.
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Not to complicate the discussion but you DO NOT need a digital processor/active crossover to use the 510 and 402 horns.
I have the system in my avatar running the very complicated dual digital processors/crossovers setup and 5 amplifiers........Excellent in all regards. Love it. Uses 402 and 510 horns.
I also have a PURE ANALOG system on the other side of the room with passive crossovers and tube preamp and amps using 402 and 510 horns as well. The ONE THING YOU MUST HAVE in this setup is an EQ. I use a DBX analog graphical EQ that can take care of EQing the 402/510 setup just fine (used on the tape monitor loop of the preamp).
Roy Delgado tested this exact setup for many of us to hear in Hope. It works and it is easy to use. Saves a lot of money on processors and multiple amplifiers. It also saves money on your passive crossovers because there IS NO EQ IN THE CROSSOVER. You set the EQ yourself.
I highly recommend this FIRST for those interested in the 402 and 510 horns but not yet experienced in active crossovers.
My source equipment feeds both of these systems I mentioned so I can easily A/B test between them and while they do not sound exactly the same, it is hard to tell the top ends apart. Using a microphone and RTA the curves are virtually identical. In fact I used the curves from my big MCM setup to adjust the EQ on the analog system.......until they were the same. Simple to do. 20 minute job with an RTA. This setup WORKS GREAT.
JWC has been over and listened to this many times. Perhaps he will comment if he sees this. I would put this setup up against anything in a room and I'm sure it would do just fine.
I don’t remember the model number, but I think I’ve read where your model DBX is one of the 1/3-octave models of equalizer that they sell where the center frequency of its filters are spaced one third of an octave apart, or three filters to an octave.
The 1/3-octave equalizers on the market today are really nice and, I know this is oversimplification, but somewhat like having 30 separate “volume controls” per channel to adjust the amplitude of very specific audio frequencies.
Last year I was looking for a nicer 1/3-octave equalizer and I was surprised how many hit the used market regularly and at decent prices. Of course there is additional risk buying used vs. buying new; however, with a little patience and research it isn’t too hard to find a nice deal on used equipment if someone doesn’t want to buy new.
Here is the general list of my focused searches and where the majority of the selling prices seemed to end up. Of course, there are outliers to the ranges and with a little patience and time, it can be fairly easy to find a nice example below the range I listed. I found a very nice Klark Teknik DN360 with the factory installed balanced transformers for $229 shipped.
XTA GQ600
List: ~ $1,575
Used: ~ $300 - $450
Klark Teknik DN360
List: ~ $1,299
Used: ~ $250 - $400
Ashly GQX-3102
List: ~ $620
Used: ~ $150 - $300
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Thanks Fjd -- wasn’t sure how many people paid attention, and thanks for the cool video. Tennessee and Bullwinkle are my favorites.
On the thermos thing, I just picked up a stainless steal Stanley. We will give it a chance.
Congratulations on the Stanley; however, I'm sure that along with myself, BigStewMan might also be slightly disappointed you did not go with Bullwinkle or Foghorn Leghorn.
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I have 2 brothers that use this old school thermos….http://www.amazon.com/Stanley-Classic-Vacuum-Bottle-Hammertone/dp/B000FZX93K/ref=sr_1_3?ie=UTF8&qid=1458755018&sr=8-3&keywords=stanley+thermos+cup
I have one just like that, it was hard to find in the 2 quart size, but will last forever, I hope.
I had the old glass models, and like many it broke, so it was replaced with the new model with SS insides. Probably not the best for keeping temps but there tough.
I think in the 1950s and 1960s that my Dad preferred the glass because creating enough vacuum wasn’t really that well perfected yet and without enough vacuum between the stainless steel, coffee just didn't stay hot as long as the glass liner, especially in the Northern winters working outside. Of course, the new vacuum technology is not indestructible either as I dropped my thermos once and it broke the vacuum seal and without that layer of insulation created by the vacuum, the coffee no longer stayed hot for very long. Had to replace the entire thermos, no replacing just a liner.
I was looking for a coffee maker with an insulated carafe instead of the hot plate at one of those coffee forums and was amazed at how several posting in the threads would continually whine that they didn’t want to “pre heat” the carafe for best performance. In that respect, although the level of vacuum today is much better creating a better layer of insulation, nothing has changed in pre heating stainless steel and as a reminder the instructions to pre heat were stamped on the bottom of the thermos too. The thermos even had a reminder to wash the cork with boiling water after use.
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Any coffee thermos recommendations? I have business Law II again this evening and if its like last week, I am going to need a lot of coffee. I don't need whole lot, but enough to get me through a couple hours. I always like the old Stanley ones. Are they still any good, last I had seen someone with one, they complained about it leaking.
I remember that my dad would have a glass lined thermos bottle in his lunch box for years and occasionally, he would come home pissed because his thermos suffered a broken “filler.” However, in those days the glass filler was replaceable and it was off to Sears that evening for a replacement filler.
How about a "Bullwinkle in Space" thermos or maybe a "Flintstones" thermos?
Given all of those great selections above, I actually have a couple of sizes of this thermos with the vacuum insulation between the double-wall of stainless steel and liked them so well, I bought the vacuum insulated travel mug too.
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If you confused copper for gold, you need to get your eyes checked.
I confused it for gold (even though I knew it was copper and I have been a member here for quite sometime) not to mention that I have been wearing glasses since I was 2yrs old. Not everyone is blessed with 20/20.
One in eight males have some level of color vision deficiency (color blindness), female ratio is one in 200; therefore, statistically, it would appear that the forum could have over 2,800 registered members that may not be able to distinguish copper.
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I know this can be fairly common issue, along with being tackled many ways. But I thought I would check here first, doing so always saves me money. Like the title says, when I turn on my receiver Integra DTR 40.2 I have the 12 volt trigger line out to a Niles APC-3 trigger. I used this with my McIntosh MC2100 with no problems. Now with the Bryston 2b's, I get a very loud pop/thump when powering on and off. I will note I am running a 2 way active system, using MINIdsp for the crossover. I get this thump on both the mid/hi horn as well as the bass bin.
One of the ideas is to solder a cap across the mains at the switch. But I have no idea what kind or value of cap to do. Another idea is a delay box/gadget/do hicky of some sort. Could a different pro crossover take care of this? So what do you guys do that have this issue?
Thanks
I’m aware of the following potential causes for the loud thumps.
1. Spark or brief electric arc caused by main power on/off switch of power amplifier. Each time the amplifier is switch on or off, a spark jumps across the gap. It can get pretty loud, especially if you are not expecting it.
2. Inrush current surges where there is an instantaneous input current draw by the transformer when the amplifier is first turned on. When an E-core transformer is first energized, the transient current can increase up to 15 times larger than the rated transformer running current. Toroid transformers can have up to 60 times inrush to running current.
3. DC offset at the output of your power amplifier, which is typically not nearly as loud of a thump (much more mild) as the spark/electric arc thump. If you have DC Offset voltage issues, the addition of an output relay with a delay will eliminate the thump sound on power up. However, this only removes the “sound” and does not solve any potential amp issues if the DC Offset is actually too high at the output.
In relation to the spark/electric arc and inrush current surge issues, you will notice in the pictures below that the First Watt clones use CL-60 negative temperature coefficient (NTC) thermistors as in-rush limiters and X1/Y2 safety capacitors to suppress the spark or electric arc at the amplifier on/off switch. One CL-60 thermistor is wired in series between each of the AC mains from the IEC switch and connecting with each of the two transformer primary windings. The X1/Y2 safety capacitor wired in parallel to the main input, along with the switch and fuse.
I believe many of the builders use the X2, which is fine; however, I have been using the following X1/Y2 safety class Murata ceramic disc capacitor (3300pF 250Vrms) in my amplifiers.
This link has a section regarding the various classes of safety capacitors and how they are used.
http://www.justradios.com/safetytips.html
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That Jensen woofer has P15P stamped in ink on the basket perimeter. Interesting to note that the first Cornwalls used P15LL Jensen woofers and they are somewhat prized. That tweeter horn looks pretty interesting also.
The Jensen P15LL (P = Alnico magnet) is really nice and more of a bass woofer and, in addition to those early Cornwalls, can also be found in the Jensen Imperial, the bass woofer in various Leslie organ speaker cabinets, in addition to the “legendary and mythical” Western Electric 753C broadcast/monitor loudspeaker.
Although, many of the Western Electric 753A through the 753C series speakers had a “rebranded” Jensen called the Western Electric KS 12004. I believe that in early versions the 753 model was a rebranded Jensen A15PM (predecessor to the P15LL).
The Jensen P15LL is one of the really desirable woofers for the Leslie speaker cabinet and has a double roll suspension, while models such as the P15Q and some P15N's are single roll suspension and both are more in the full range driver classification. The P15N and the P12N both tend to be really desirable to guitar players.
Given there were so many made, the Jensen P15LL seems to be rather common and I see them selling on eBay for about $75 - $150 each; however, in many instances the cones look pretty worn out and tend to need re-coned.
Even the old field coil Jensen F15LL and F12N are fairly common. I have two of the F12N field coil drivers that I plan to install in a pair of Heresy cabinets that I saved from destruction (someone sold the guts and tossed the cabinets).
However, the Western Electric parts just keep rising in price as just this past September 2015, one of the eBay tube sellers sold a single new in box Western Electric 713C compression driver for $12,966.
A Leslie organ speaker with the Jensen P15LL in action.
Western Electric 753C
Jensen P15LL
Leslie organ speaker with Jensen P15LL
Western Electric 753 broadcast monitor
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If the network is any indication, this speaker is a University/DIY product/kit.
At first a quick scan of the pictures I was thinking an EV "kit" build (many brands sold the speakers as kits in the 1950s and 1960s) of the Aristocrat or Baronet. However, the crossover sure looks like the University and I agree with you that it is most likely a University kit speaker build or a DIY build from just a set of plans. You never know what drivers will be in a cabinet so it pays to inspect. It seems that University drivers were used as OEM drivers by other speaker builders too. Not that it is worth much to me, if it is a three-way speaker, even if not a kit and built from a set o plans, that cabinet may have University drivers too and if not, I've seen a couple of these DIY-looking speakers with a 15" Alnico magnet Jensen woofer, an Alnico 8" mid-driver, and the old Calrad tweeter.
For those that may not be familiar, here are a few close ups of the University N-3 crossover; along with pictures of the speaker pulled from the advertisement link.
Pictures of the speaker pulled from the advertisement link.
Of course, my thought is that a person can never have too many amplifiers. 
maybe tubes are not that great? I do not know! HELP!
in Talkin' Tubes
Posted
This thread from 1999 at the link below is the first DIY build that I’m aware of using the same LM3875 chip that the 47 Labs Gaincard amplifier used. I still remember that initial “fanfare” of the 47 Labs "chip amp" because I have associated it with a point later in my life during the period between 1995 – 1998 where I had went through another corporate downsizing, a divorce, completely restructured my life yet again, then proceeded to put myself through college.
At that point in my life I couldn't afford a Gaincard and didn't really care, but it seems that the fall out to the Gaincard appeared when many were “disappointed” in how less than $100 in parts could have this type of impact and a manufacture would actually charge $3,300 for less than $100 in parts (not surprising since there are some that are upset with the price of a K402 over the cost of the materials). The big gainclone threads on the DIYAudio forum that Peter and others started really put this chip on the map from a simple DIY project perspective.
http://www.audioasylum.com/cgi/t.mpl?f=general&m=29634
Since I’m more of a builder rather than engineer, when these chips presented themselves for things I wanted to explore, I focused on what people were doing with the LM3886 given it was an upgraded version of the “classic” or “infamous” (take your pick since it went against conventional wisdom at that time) LM3875.
The LM3875 came after the LM1875 and is actually the most basic of the “higher power” chip amps of this series by Texas Instruments, with the more advanced designs being the LM3886 and LM4780 (essentially two LM3886 dies inside the larger package). The LM3886 has higher current handling (in theory should make it more capable of handling 4 ohm impedance loads) vs. the LM3875 and added mute functionality.
On a side note, Peter of AudioSector has a LM4780 Amplifier Kit for sale, in addition to his LM3875 kit, but I haven’t worked it into any of my audio budget to experiment.
http://www.audiosector.com/lm4780.shtml
However, as with anything in audio, these chips will still involve trade-offs and compromises. The video of the Harman Kardon AVR with the LM3886 seems to confirm my suspicions that the LM3886, even with the higher current handling capabilities, shows excellent specifications in power output and shows very low distortion and noise levels, but will tend to have difficulties with high volume levels or difficult loads; and in certain situations it does not appear to be able to handle running into both situations simultaneously (regardless of the capacitance or heat-sinking).
Given the above with the Harman Kardon AVR implementation, as I referenced earlier about consumer audio gear with potentially poor implementations of traditional amplification, I still believe that there are real opportunities to upgrade some of the cheaper amplifiers out there. I picked up an old Harman Kardon AVR 345 for pennies on the dollar that will be slated for LM3886 chips at some point.
Another “chip amp” blast from my past, is my “McGainclone” that is based on an un-restorable McIntosh MC250 amplifier and a couple of the assembled LM3886 modules. While I have not compared this amplifier to a properly restored McIntosh MC250 amplifier, I like this modification a lot as this amplifier helps provide a very pleasing listening experience.
I don't know for sure, but just maybe, it's about those Mac transformers?
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