MechEngVic
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Posts posted by MechEngVic
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On 8/19/2020 at 10:59 AM, iaRIVR said:
Are the inductors and other components considered an upgrade over stock or more of a direct replacement?
Debating whether to go with just caps or the full board.
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They look great! I wonder how they'd look with the motorboard stained instead of black...
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3 hours ago, RandyH000 said:
that's very good news for sure -- the Assembly line missed a crucial step , with covid 19 , and all that is happening , workers are making mistakes -
Yeah, like ordering take out food. Getting a correct order has been next to impossible.
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51 minutes ago, ferpromo said:
Need to replace the EL34 tubes on the ST-70
That's a great looking ST-70! It looks like the driver tubes are the original 7199's. It they work, keep them. NOS 7199's are going for 40$+ per tube. If they are bad, you might consider buying and installing adapters on the sockets and use 6GH8's. The 6GH8 measure just as good or better than the 7199. Used 7199's are hit or miss.
If you're not sure of the condition of the rest of the circuits, they might need to be gone over. Capacitors and carbon composition resistors go bad over time.
I recommend new production Mullard or Tung-Sol EL-34's. If you want the best, NOS Mullard Blackburn XF2,3, or 4's, they start at about 400$ a quad.
The rectifier tube is the most tricky one. If it needs replacing, try to get a NOS Mullard GZ34/5AR4, they go for over 100$ but they are worth it. New production versions don't last very long.
The guys over at the Dynaco forum can help you with everything you need for this amp.
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1 hour ago, JL Sargent said:
And if you like baseball, how bout a good curve. I've found that caps with higher ESR can sound better than those with lower ESRs. Paul put some magic mouse pee in those old oil cap cans he used back in the day.
I believe you. A higher ESR cap can improve the overall impedance of a crossover. They can also open up frequency ranges that may be lacking in the existing crossover. The problem with a cap that begins increasing in ESR is, it will eventually allow DC current to move across it and that's when it can become destructive. In speakers you really don't have to worry about it, in amps you do.
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5 hours ago, ferpromo said:
I'll post a few pics later , do you think the ST-70 is a nice match for the Cornwalls ?
In my experience, push-pull, class A amps powered by EL-34 tubes are some of the best to combine with horn speakers. Tube amps create specific harmonic distortions that work well with horns, and in turn, the horns seem to work better in the rooms they're in.
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5 hours ago, carlthess40 said:
Has anyone used any of these Soviet made caps ?
Yes I bought a few of them and have not tried them. I did put my tester on them and the Measure within specs and have a very low esr .
Last week I bought a single Klipsch H1 from Emile, I think I’ll pull the crossover and give them a try
Capacitor PIO OMBG-1 ОМБГ-1 400V 2uF 10% Ussr Soviet Military Rhombus
Sent from my iPhone using Tapatalk
I used these 6uf caps in my KLF-10's. Both tested exactly 6uf and had next to no measurable ESR with my cheapy ESR meter. They are paper in oil, metal foil caps. These upgraded crossovers yielded a significant change in sound quality from the original crossover, and since my KLF's are less than 20 years old, I don't think the original caps were that worn out.
In regards to ESR: My cheap tester seems to work pretty good. I've tried it with old caps and it shows increased ESR, and new caps test low.
Another interesting thing I'm finding is that the leads of a capacitor have a lot to do with ESR. The way that the leads are attached to the cap and also the way cap makers choose to "terminate" the wound materials can affect performance. Some more simply finished caps will show increased ESR after several hours of use, whereas caps that have better materials and termination methods show no changes in ESR even after hundreds or thousands of hours of use. Also, with cheaper caps, if you wiggle the leads, you'll get changes in ESR. The ClarityCaps I tested didn't show changes in ESR with lead wiggling. ClarityCap touts a high quality method of end termination.
While my simple and limited experiments are by no means conclusive nor applicable to all capacitors (because I only tested a few brands/types), they may help explain differences in price and performance of capacitors. And it may help explain sound differences in caps that initially measure the same.
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On 8/22/2020 at 9:00 AM, ferpromo said:
Thanks for the tips !
How about pics of the rest of your setup? Especially the ST-70.
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You want to eliminate the influence of room on your listening experience? Sit right in front of your speakers!🤣
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If your speakers had consecutive serial numbers, I'd return both for a new set with consecutive serial numbers. That is actually quite the alarming defect.
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In very general terms, The bigger the horn, the better. If you want to establish a design goal, as Preston Tom says, then a good simple goal would be to incorporate the biggest mid horn you can, then tune it to work well with the woofer and tweeter. It sound like that was your informal goal to begin with.
The mic you ordered, DATS V3 (parts express), REW, Audacity, and X-Sim will give you what you need to make meaningful changes to the crossover to help you achieve your goal.
The mike and REW will allow you to make frequency response and impedance measurements for the whole speaker as it sits (this will show you what you're hearing). The DATS V3 will allow You to get FR and Z measurements for the individual drivers (plus many other things). Audacity will allow to convert the individual driver graphs into .frd and .zma files for X-Sim (DATS may also let you do this). X-sim will let you plot the driver graphs together and virtually install the crossovers so you can see their effect on FR and Z curves (and compare to REW measurements). Then you make adjustments from there and measure again with REW as you go.
Use what you see together with what you hear. You'll learn to hear with your eyes and you'll learn to measure with your ears.
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5 hours ago, AnotherKlipschGuy said:
Ah, how embarrassing. After some trial and error (and soldering) I finally found what the issue was. At the same time I changed my Klipsch Reference R-8SW Subwoofer from "on" to "auto." That pop was the sound of the subwoofer turning on
That's the best kind of problem to have!
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8 hours ago, geoff. said:
KPT-904
KLF-10s and RF-82s are bookshelf speakers, LOL!
My KLF's are my desk monitors!
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Sounds interesting,
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On 8/20/2020 at 10:27 AM, jjptkd said:
I'd probably go for the KLF-10's myself as they have the larger cabinet, larger woofers and larger horn. They should play louder and have more bass. Plus they have real wood veneer instead of the cheaper vinyl wrap.
All good points in favor of the KLF-10's. The only plus for the RF-82's would probably an improvement in high end extension due to the titanium tweeter. But for about 60 bucks you can buy titanium diaphragms for the KLF's from Bob Crites. I got them for my KLF-10's, and liked them, but I felt that the horn lens had more to give and ended up attaching FaitalPro drivers to the KLF-10 horn lens, and along with crossover updates and 6" stands, really took them to another level. In other words, I think the KLF-10's have more potential than the RF's.
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10 hours ago, VDS said:
yes, i feel the harshness is gone. the sound loses all "dimensionality" but i suppose that is the lack of high frequency? putting my ear 12'' straight out from active tweeter i hear some simbelence? harshness? hissing?
Sibilance takes place between about 5000 and 8000 hz, and is your problem if it's coming from the tweeter. But your mid horn can make a lot of noise at the lower range of that too. Testing and attenuation at that frequency range can do wonders. I wouldn't listen to your speakers with a driver disconnected. Do frequency sweeps and look for the peaks. You already know the crossover frequencies. If the peaks are high enough, it's the tweeter.
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9 minutes ago, Lbk said:
Actually they are about the same age, the Dayton being only slightly.older. It should be fun to hear if any difference, will find out tomorrow.
Re-read your comment, I see you weren't talking about the original electrolytic, but the Crites one. Let us know how it turns out!
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6 hours ago, Mighty McIntosh said:
I looked up what L-pads are, and I am intrigued, b/c it looks like these regulate -- impedance? -- do I have that right? One measure so far that made a significant impact was changing from 4 ohms to the 8 ohm taps: BIG improvement from washy to focused sound. Is it possible L-pads could tame mid frequencies in the 1500-4000 Hz range?
Horns in general, and Klipsch horns in specific, tend to accentuate the frequencies between about 1500hz and 3500hz. That is what you're hearing as harshness. It's about the most common complaint about Klipsch speakers. It is a feature of horns, they naturally amplify those frequencies and PWK figured out that if you work carefully with that range, you can bring out a liveliness of sound that gives us the addictive midrange bloom that we all love, and why "the music lives in the midrange". It's a fine line and can become harsh with wear and tear combined with our aging ear sensitivities. Plus no speaker is perfect.
Using an L-pad on the mid horn would attenuate the horn's entire frequency range (around 800hz to 6khz I think). If you want to tune just the "harsh" range, you'll have to make changes that affect impedance (modifications to the impedance curve are like changing the volume of a specific frequency range). You want that. What you don't want to do is to change the frequency response curve, that will change the sound signature. You just want to drop that range down in volume a bit. You can do it using resistors of specific values along specific spots in the midrange circuit, either in series or parallel, or both. IMO, it's better than changing capacitor or inductor values.
L-pads can definitely help get you in the neighborhood, but i'd use them temporarily as they are mostly lower quality.
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1 hour ago, Lbk said:
Do you think there is any advantage in the Dayton over the electroytic? I am happy with the bass and would hate to screw it up. Alot of this is over my head but I am learning,thanks.
There is an advantage, it's a newer capacitor. An electrolytic is used only for cost savings. It would be hard to hear a difference between the two caps in this position if they were new. Focus on the caps in the signal path. Stick to film and foil or paper in oil caps for best sound.
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Just now, Lbk said:
Ok thanks! I have no way to measure but speakers sound fine so tomorrow I will change out the 6uf and 2 2uf.
Klipsch uses electrolytics in less critical positions and they calculate the higher ESR of those caps into the overall impedence of the circuit. The dayton will have a lower ESR initially but the circuit will be fine even after that cap drifts.
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7 minutes ago, Deang said:
A good cap for sure, but the values are limited.
You'd think with as many caps as Solen whips out for themselves and other companies, they'd produce the full complement. They are no doubt capable of making caps better than most and cheaper than most.
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2 minutes ago, Lbk said:
Finally pull 1 xover from a chorus II. In Bob's kit the 68uf is electrolytic, the former ownet replace it with a Dayton audio 68uf. (Huge compared to the elec.). I like the bass and was wondering if the Dayton 68 uf would affect the testing if replace just the 1 6uf and the 2 2uf and keep the Dayton 68uf in the woofer section.
Since the highs are in question l am thinking it should be ok.? Opinions, let me know so I can exchange the xover caps. Thanks!
Since the 68uf cap is not in the signal path, as long as it measures well, it's fine
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8 hours ago, RandyH000 said:
which caps do you use --- I have 2 pairs of scala 80's - 2 pairs of heresy 77s and 1 pair of cornwall 78 , all are needing caps ------Carl likes Audyn , there is a Solen factory Store pretty close to us-----so that's option 2 -
The Solen tin foil and film caps are great. Super low ESR values and great bang for the buck.
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On 8/14/2020 at 6:16 PM, Cornwall-Sweden said:
Maybe i should use som felt pads, to avoid scratches on the floor?
If you mean putting felt pads under the spikes, the spikes will go right through them. You can get feet for the spikes.
Small tear in chorus II radiator
in Technical/Restorations
Posted
Thin layer of titebond on inside only, thin strip of paper towel on top of glue, thin layer of glue on top of paper towel. Press with finger so glue enters void of tear but not so it overflows to outside. Nothing bonds paper (shredded wood) better than wood glue. Thin strip the length of the tear and just a fraction wider.