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seti

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Posts posted by seti

  1. I have a massive collection of tube rectifiers so that is what I use. Honestly I love the look of the tubes as well. I like the small MV rectifiers and the GZ34's. I even have some old ST16 bottle shape 81's. If your on a budget or space constraint I could see using SS rectifiers or if ya want dc filaments.

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  2. I wouldn't mix and match recrtumfriers as it could go south quickly. For scratch built power supples I like the tv damper diodes ike the 6DM4 as they have a slow start of about 30 seconds. There are so many great damper diodes and pretty cheap. Then there are ancient rectifiers like the 80 81 82 83. Since I have 5 81's I might do a full bridge for a DIY PP2a3 amp. For MV I really like the little 816's.

     

    Its all fun till something catches fire.

     

    1625T.thumb.jpg.0634b29e543eb2172b87b0a56a3f00d1.jpg

     

     

     

     

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  3. 4 hours ago, Travis In Austin said:

    Well the Museum has PWK's 351, Transport and mike amps on a bridge. Jim Haynes, a Charter Trustee donated two "for parts" Ampex 350 or 351 (not sure which) that we can harvest parts from. Have Jim show you the next time you are down. 

     

    The older 350 utilized metal enveloped tubes like the 12SJ7 Pentodes which were used throughout much of the electronics and only the 6C5/6J5 triode and the 6SN7 dual triode were used in the record circuit driver. The first stage playback head preamplifier tube was also indicated as a special " select" version which all had to be independently tested each for lowest noise before it was appropriate for playback purposes. It also utilized all point to point wiring in the electronics.

     

    The 351 was a huge departure, it utilized the new 12AX7/ECC83 and the 12AT7 dual triode tubes. They were much lower in noise (as all triodes are in comparison to pentodes) and were in small glass envelopes. They were also mounted on those newfangled printed circuit board thingies!

     

    Can you see what we have?

     

    I have my Dad's MR-71, an ATR 102, and a 360? (it came out of our Ampex console we had in our house from about '62 until the early 70)s. It was given to my Dad, they sold for more than most cars cost back then. 

     

    I was supposed to go down Friday morning to show Jim a new scanner I have been testing. Work got in the way. I'll maybe make it next Friday. I did some work on a Bogen DB230 for the museum and will be returning it. Nice little piece 6DW5 outputs with DC filaments.

     

    Do we know an expert Ampex restorer? These need a special touch for sure. The PWK mods should be well documented.

     

    Next time I am in Austin I would love to see your RTR stash.

     

     

  4. 7 hours ago, Travis In Austin said:

    I'm asking him to sell the horns, donate the cash, and we will get him two 403s that don't have Ron Popiel spray on hair on them. Then we can rebuild PWK's Ampex 352. 

     

    Well they would still come form the same place lol..

     

    I'll make a deal with you. You can have all my Klipsch speakers when I'm dead 8-) All donated to the museum unless Stacey wants them lol....

     

     

  5. 30 minutes ago, OO1 said:

    no one is asking you  to sell the horns , but  how about  loaning  the  horns for an  Exhibit /Event  at the  klipsch Museum .

     

     

     

     

    I don't display my k403's as they are my daily drivers. They have the driver PWK picked out the B&C DE82TN. Trust me the museum has plenty of K403's. They have some beautiful horns out of bloodwood.. I think. Then they have other examples. Have you been to the museum? They have the consumer V1. It is beautiful. Roy and Klipsch museum already has K403s... It will be fun to see the rare stuff come out for display at the museum over time...

     

    The drivers fit fine. Sound fine. Measure fine. Zako aka Maron didn't give them to me I bought them but wth in my book $500 is a giveaway.

     

    It will be fun to see where this auction ends up very strange....

     

     

  6. I have several amps that use the GZ34. It makes me wonder why could they make this killer rectifier that seems to last forever but now we have trouble just making them stable. I wonder what we are missing in tube production now. I've never killed a GZ34 and don't think I've seen one dead lol... . For DIY I love the damper diodes that are slow start like the 6dm4 or the 6AX4.

     

     

     

     

     

     

  7. 2 hours ago, Travis In Austin said:

    You need to put those on Ebay for $25,000 with an ad that says Golden Jubilee Original 403 Horns.

     

    Then in the description, put something like, "for those Golden Jubilee owners who have bass bins but are looking for the original MF/HF horns to go with them, here's your chance!" Add something that you will supply a full and complete provenance with them. 

     

     

    Hell no! I will only part with my K403s on death 8-)

     

     

     

     

  8. 12 hours ago, Islander said:

     

    Is that what you meant, or were you referring to the 403 in the first sentence?  Or did you think I was saying that the 403 was the better horn, because that’s not what I said.  I believe that the 402 is the better horn.

     

    There are different horns with slightly different goals. The k403 needs a little less eq but with the jubilee having a dsp that is a moot point. I like em both. K402 is now on Klipsch state of the art Jubilee is all that needs to be said.

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  9. 1 hour ago, Islander said:

     

    From everything I've read on the Forum, the 402 is the better horn, which is why so few 403s were made.

     

     

    I wouldn't say better as it is hard to beat the k402. Think of the K403 as a k402 with collapsing verticals. The reason I love the horn is it sounds great and has Roy and PWK's hand in the design. Pretty cool. When you hear the new Jubilee it is undoubtedly the state of the art in sound. I've never heard anything better.

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  10. That isn't exactly what happened 8-) 

     

    Klementovich was gifted the Golden Jubilee's by Valerie. They had K403's. There were two pairs made she had the other pair. Klementovich didn't like the "plastic" K403's so he replaced with martinellis. He also didn't like the crossover so he moved it to 750hz which was an odd thing to do. Klementovich sent the K403's to Maron Horonzack. I had happened to contact Maron to talk horns when I had mentioned how much I would love a pair of K403's. Maron said "How bad do you want them?" I was joking and said something like $500 and he said $550 and I'll ship them to you..... Next thing I know I have a pair of unobtanium K403's and I have been listening to them ever since. They are amazing as they are the combinitation of wills and compromises of PWK and Roy. It has Roy's flair and PWK's collapsing verticals. They are my favorite audio item.

     

     

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  11. 7 minutes ago, mike stehr said:

    I have a Lambda C-281M. 325 volts at 200ma maximum operating voltage. The Hewlett Packard 712A would be nice to have...

    A retired EE friend had a tube power supply he picked up when he was an employee at Magnavox...it was older looking unit that uses 6550 for pass tubes.

    600 volts at 200ma. I'd always tried to talk him out of it to no avail. 

     

    I also have a Lambda LA-100-03BM. Switchable up to 35 volts at 10 amps. An 80–90-pound tank...

     

    It was really a case of paying too much attention to the images I took to reference for rebuilding, and not enough attention to the schematic.

    I wouldn't be surprised if these are the original tubes that came with the unit. 

     

    That is cool.. It would be hard to build a tube amp power supply as good as HP or Lambda... Great stuff.

     

    My second hobby is restoring test equipment.

     

     

     

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  12. 20 hours ago, captainbeefheart said:

     

    I know all too well many amplifiers on the market aren't designed great either.

     

    I never said anything about his amps being noisy with hum, my point was he clones a lot of WE91A circuits and from experience if you just copy the schematic you will have stability issues with the positive feedback. Those amps aren't easy for a novice to build optimally.

     

    That and many errors in his wording like him saying "input sensitivity is 300mA" instead of 300mV. Little things like that tells me a lot. 300mA across even an input impedance of 50k is 15,000 volts. I highly doubt the amplifier requires 15000v to be driven to full power 😂

     

    There isn't much required for good sound. I have had many borderline stable amps with high distortion and other gross discrepancies still sound good enough to use. But by no means does it imply they are great amplifiers. For that we would need some specs and measurements of his builds which he doesn't provide.

     

     

    I'm not telling people to not purchase his amps, I'm only putting things into perspective. He is a clone builder with no knowledge of electronics, he sadly focuses on brand name parts instead of the circuits themselves which is a bad sign in my book. Some of his other builds are much more forgiving circuits which won't have the troubles of say a WE91A but from someone with a ton of experience with electronics I'm here to tell you those amps are not for the faint of heart to clone if you want optimal results. Does his amps function? Yes of course but I'm certain that most of his WE91A clones are going to be unstable and ring like a bell.

     

    I'm only saying I won't go to a dentist that his day job is an electrician and just because he has a pair of pliers and has successfully pulled teeth before doesn't make him an actual dentist.

     

    Not all his clones are going to be as troublesome of a build, it was just an example and I'm certain a broken clock is right twice a day so yea I'm sure some of his amps he has produced sounds fine. But again I personally would want someone that knows what they are doing. A backyard mechanic might be able to slap some brake pads on your Toyota but do you want him putting a timing chain on a near 500hp S58 engine inside your lovely M3?  I doubt it.

     

    It might just be me, but if I'm going to spend thousands of dollars on an amplifier I'm going to want something designed by someone competent. I have given multiple examples of why just cloning a circuit many times isn't enough to achieve optimal performance no matter how many expensive boutique parts you throw at it. Any amplifier with a decent amount of feedback will need to have compensation networks worked out, it's something you cannot copy from a schematic unless you build the exact same amplifier with the same exact chassis, layout, and parts. I don't expect the average person to know this stuff which is why I'm taking my time to explain it to anyone willing to read it.

     

    This isn't art, it's not a painting that is subjective. Amplifiers are technical devices bound by the laws of physics. Yes anyone can make an amplifier that produces sound but is it optimal? That takes someone with knowledge and experience, sheer will won't get you there no matter how hard you pray to your gods. If I'm going to fork over thousands of dollars for a piece of technical equipment I'm not going to trust someone doing it by the seat of their pants that mixes up mA with mV, I want someone that knows what they are doing. That's all.

     

     

    Yeah he is a clone builder 1000% and a bloody good one. Not really gonna argue.

     

     

  13. 11 hours ago, captainbeefheart said:

     

    I suppose if you stick to cloning a known simple no feedback circuit he will do fine but he admits he has zero electrical engineering background and his portfolio is all clones of circuits.

     

     

    This worries me in a few ways, firstly if the amplifier has feedback you can't just copy the compensation networks and expect fantastic results unless you copy the EXACT layout/chassis and EXACT  same parts and transformers used. For example anytime I clone a Mullard 5-20 type circuit I have ended up with very different lead/lag compensation network values. Output transformers will have the biggest impact on this and the layout will also change parasitic properties.

     

    If you have a simple, zero feedback design that you want him to clone I'm sure he'll do fine, as he states in his website that pretty much anybody can clone circuits and build tube amplifiers that have already been designed from an engineer.

     

    Just a note of caution. Personally I wouldn't want a food biologist fixing my car or making me an amplifier as it's not their area of expertise, it's just a hobby to him.

     

    I also looked through his portfolio and gut shot images of soldering and layout and he doesn't seem to follow any guidelines. For example he has a large coupling capacitor where he extended the leads of the cap to reach where he needed to go. On any build I have looked at I can see many bad decisions made which are all rookie mistakes. That's fine if you are building yourself an amplifier but if you are shipping amps across the country you should at the very least take some time to study MIL Spec soldering requirements for different component types to learn how to build a rugged piece of equipment. For what he is doing (cloning) that will improve his amps significantly. It would also help if he did take some electrical engineering courses to not just clone but improve upon older designs and make certain the amp is as good as can be.

     

    I don't see any specs or measurements. I guess just another fly by the seat of his pants clone builder selling amps that know nothing about electronics. Sorry it just irks me. Any hack that jumps into something head first with zero background knowledge just doesn't sit well with me. I suppose many of the builds he is making are very simple zero feedback old designs.

     

     

    I've actually heard two of Min's amps on horns. They were free from hum and sounded fantastic. The look is advanced DIY. I've heard his SET amps not push pull a 45 and 300b. If you look at the shear number of amps he has built and his feedback that says a lot. The list on his website is not all he as done. He has been building for many years. I would trust him over much of the stuff out there. He is a good and honest builder. A direct coupled SET amplifier is not rocket science. If I can do it as a first amp build someone with 100's of builds under their belt will not find it problematic.

     

    If I had to list all the cottage industry audio companies not run by audio engineers you would be shocked... Well likely you would not be but a few of them are actually good.

     

     

     

     

     

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  14. 6 minutes ago, captainbeefheart said:

     

     

    Each unit is two LND150 depletion mode FET's  with their gate, drain, and source pins tied to grid, plate, and cathode pins. There isn't a "dummy" load for the filaments which is good and bad. Good that it saves energy and bad in that with less current draw on the heater winding voltage will increase possibly stressing the other tubes in the circuit.

     

    It will have a completely different distortion profile compared to a true 6SN7 so I don't see the allure either.

     

    Those whacky engineers. If they can do something do they ask themselves if they should do something.

     

     

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