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Sound of replacement parts...

ghamilton

ghamilton

Super Member
As many of you know the parts used to replace the old parts when restoring an amplifier have there own sonic signature. For instance, my AU-919 sounds different after I restored it. At this point of restoration my 919 sounds darker. This darker sound became more audible when I changed the trim pots and speaker cable binding posts. The trim pots are bourns 25 turn and the binding posts are gold plated brass. See link: http://www.superiorelectric.com/5-WAYBindingPosts.htm
Any input on what to do to reverse this darkish quality? I used a lot of elna selmic II caps in restoration.
 
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I just recapped an AU9500 with no change in sound.(Sounds wonderful!) I also used elna selmic II and changed the trim pots. I definitely wouldn't blame the caps or the trim pots. I would expect any speaker connect to be an improvement. I was going to change the speaker connects but wanted to take smaller steps for troubleshooting ease. By darker sound do you mean not as bright?
 
I guess you could say "it's not as bright". Something can sound too bright though. Turning the treble control all the way up for example would be considered too bright.
I recapped my brother's NAD 1020 preamp and Kenwood L-05M mono amps. When I put these in place of my 919 it became "clear" that my 919 was darker. The speakers did a better job of dissappearing and the image was more "3D" with my brother's stuff. My 919 should do better.:worried:
 
cravingcrave; you're the second person I've heard say that there's no change in the sound after recapping an au9500. I don't feel so bad now about having original caps in my daily driver au9500.
 
I think (PM) preventative maintenance is a big part of re-capping. Not a big change, but ready to go for the next 30+years.
 
naderpe said:
I think (PM) preventative maintenance is a big part of re-capping. Not a big change, but ready to go for the next 30+years.
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I agree. It would be nice to have all our vintage gear recapped for that reason alone. The sad reality is that most of my gear won't ever get recapped till there's a problem.
 
I hope that I didn't mis-lead you guys when I said I compaired my 919 to the kenwood / NAD combo. The darker sound was added when I changed the trim pots and binding posts. It may be more correct in sounding this way. The highs are very clear. Its just this darker and more full bodied sound.The kenwood / NAD combo has a brighter (and with that) a little more open sound.
I didn't change the trim pots or binding posts on the kenwoods.
 
Could it hurt to change out the trimpots again?? I feel that might be your area of "sound is darker". If everything else is standard, what value/type of trimpot did you put in?
 
MarkMeyer said:
Guys with 30 year old, all original amps, might want to rethink that philosophy.

http://users.trytel.com/~cmacd/CAP-exp.htm

The short story is that aged capacitors often cause damage other, more difficult to find components.
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I'm just wondering if all that nice vintage gear you have listed in your sig has been recapped?
I'd love to have all my vintage gear recapped no doubt. Recapping a speaker with no voltages present is as far as I will go. I know better than to go poking around in one of my vintage Sansui and risk ruining something. That mean paying someone to do a recap. Given the amount of keeper vintage gear I have I guess I'll have to keep playing Russian Roulette.
 
ghamilton said:
Any experenced listeners out there with any input on the darker sound of my 919? :smoke:
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Just curious, how long have you been listening to it after you completed the work. I just recapped and changed out trimmers, some diodes, and resistors in my Sansui. I have been giving it a lot of play time. I used mostly NIchicon Muse but did use some Silmic II also. I believe I hear it smoothing out, burning in, whatever it is doing it seems to be sounding better and better with more hours of play time. May be you need to just listen for a while.
 
It's broke in. Plenty of play time. I listened quite a while today and it sounds great. I heard a big krell amp and a mark levenson a while back that had this dark sound to them. The Absolute Sound & Stereophile use this term a lot.
I believe that the kenwood mono amps are a bit bright sounding. My 919 may be more correct.
 
I don't see any reason in the world that trim pots and binding posts would degrade the sound quality. New trim pots will have exactly the same resistance as what they replaced and at the risk of starting a flame war, binding posts have no sonic signature. Something else is wrong.

- Pete
 
I'd venture to say that perhaps the new caps restored the bass from it's flabby previous form due to the aging original caps. Tighter, deeper bass may easily be confused with a darker sound when comparing pre and post restoration.
 
If you guys came over to listen, you'd probably wonder what I'm complaining about. It's just a signature sound of my 919 when compaired to the L-05M mono amps. Thats my conclusion. I'm just being an audiophile I guess. Thanks guys.
And special thanks to EW for all his help in the past. :yes::ntwrthy:
 
Another possibility. When I soldered the wires to the inside of the new binding posts I had to use a wood-burning iron to get the binding posts hot enough for the solder and wire to properly melt and adhere to the posts. I first tried it with my 30 watt iron, but it wouldn't get the posts hot enough. Although it looks fantastic, I'm wondering if the wire could have been affected by this extra heat changing the balance of the sound.:scratch2:What do you guys think?
 
ghamilton said:
Another possibility. When I soldered the wires to the inside of the new binding posts I had to use a wood-burning iron to get the binding posts hot enough for the solder and wire to properly melt and adhere to the posts. I first tried it with my 30 watt iron, but it wouldn't get the posts hot enough. Although it looks fantastic, I'm wondering if the wire could have been affected by this extra heat changing the balance of the sound.:scratch2:What do you guys think?
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As long as you still have a connection, then I say no, no effect is going to be noticeable. You're talking about fairly substantial gauge copper wire, right? Copper has a melting point near 2000F -- I doubt you got it that hot, and even if you did, I'm not sure you could tell, soundwise. New capacitors, on the other hand, make a very audible difference. Larger values than original can increase bass response. Otherwise, I agree that you could just be hearing the new caps -- Aged caps have a way of rolling off the frequencies, high and low. The difference new caps makes can be startling.
 
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