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Will caps alone improve a preamp?

Ken Boyd

Ken Boyd

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I own a tube preamp from Hong Kong mostly point to point wired and was think of changing out all the caps to better ones thinking it will improve the quality of the unit. The power supply is pretty hefty, a decent sized choke, all point to point, other than what looks to be a little phono amp on a PC board. With good tubes loaded in and replacing all the caps I would think it might benefit a bit. I don't know why it couldn't be made to be better with just that or does replacing all the resistors with better ones need to be done as well?
 
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Don't think I've heard of a preamp made in Hong Kong before. Would be interested to see a few pics. How old is it? Do you have a schematic?

Jack
 
Ken, It's a definite maybe...
Sometimes, the new item simply needs some time with music passing thru, in order to "break-in" all of the parts.

Modern, metallized caps do need more than a few hours of music passing thru, to "settle in."

My 1938 theater amps need at least 10-12 minutes before the sound really "opens up."

You can install higher quality parts, but, then the "settle in" time starts again.

When your sound system has high resolution, plus your ear to brain system (psycho-acoustics) is well developed, recognizing how musical instruments sound live, you will know which type caps and resistors you prefer. However, you cannot forget to let the units and parts warm up and settle in...

After replacing parts, the resulting sound may not be to your liking. For example, if I try polypropylene caps and the sound is too brittle or forward for my ears, I then try mylar, polyester or even "paper in oil" caps. Sometimes, the Vitamin Q type caps really help.
Other units might sound better with the propylene, or even Teflon caps.

I use my favorite acoustic guitar or piano recordings as my reference. Your favorite music is very important to evaluate the changes.
 
It depends? There is some nice audio equipment being built in Hong Kong.
Expensive too. Remember Hong Kong is, or was different from the rest of China.
For me replacing the caps would depend on whether they're the real deal or not, like Nichicon, etc. There are a lot of Chinese counterfeit parts.
 
ASL preamp, the AQ-2006, I have owned one for a long time, and just picked up a second one as the price was right. Yeah guess it wasn't made in Hong Kong looking thru the paper work seems it is a Hong Kong based company with Chinese manufacturing.

I do have the schmetics. and here is a photo of under the chassis.




WIN_20260801_10_32_37_Pro.jpg

WIN_20260730_20_48_51_Pro.jpg
 
Guess my question relates to what makes one preamp great over another being so, so? If you used good componets, and good tubes what would make one so much better over another.

I wouldn't say these sound bad, I think they sound good considering how inexpensive they are compared to some of my other preamps like the VAC, Cary, ARC's and others. I just think it might come down to less expensive caps and possibly resistors. It is quiet, just not the same separation of instruments, and a bit more what sounds like distortion. I really wouldn't have known better as my old one was my long-time preamp in my system. It wasn't until I replaced it with a Cary, and also the VAC that I noticed it just wasn't as good sounding.
 
Ken Boyd said:
I own a tube preamp from Hong Kong mostly point to point wired and was think of changing out all the caps to better ones thinking it will improve the quality of the unit. The power supply is pretty hefty, a decent sized choke, all point to point, other than what looks to be a little phono amp on a PC board. With good tubes loaded in and replacing all the caps I would think it might benefit a bit. I don't know why it couldn't be made to be better with just that or does replacing all the resistors with better ones need to be done as well?
Click to expand...
Define "better".
 
I'm not that good at putting it to words, a bit tighter and more crisp impact on the bass notes. A bit more definition on the instruments and vocals.
 
Ken Boyd said:
Guess my question relates to what makes one preamp great over another being so, so? If you used good componets, and good tubes what would make one so much better over another.

I wouldn't say these sound bad, I think they sound good considering how inexpensive they are compared to some of my other preamps like the VAC, Cary, ARC's and others. I just think it might come down to less expensive caps and possibly resistors. It is quiet, just not the same separation of instruments, and a bit more what sounds like distortion. I really wouldn't have known better as my old one was my long-time preamp in my system. It wasn't until I replaced it with a Cary, and also the VAC that I noticed it just wasn't as good sounding.
Click to expand...
VAC and ARC at least are likely to have extensive and sophisticated regulation and power supply separation.

Not sure what the design is of the pre in question but unlike power amps, output transformers are unlikely to be part of the equation (but possible...) with preamps. If the circuit is simple it's possible that some component upgrades will give a different presentation. They won't change the design to that of the other preamps, and I doubt one would find a sophisticated, regulated design at a low price point. Which is not to say that some might prefer the simpler design, but if you consider the VAC and ARC as reference sound, I doubt you'll prefer a different approach.
 
Selmerdave said:
VAC and ARC at least are likely to have extensive and sophisticated regulation and power supply separation.

Not sure what the design is of the pre in question but unlike power amps, output transformers are unlikely to be part of the equation (but possible...) with preamps. If the circuit is simple it's possible that some component upgrades will give a different presentation. They won't change the design to that of the other preamps, and I doubt one would find a sophisticated, regulated design at a low price point. Which is not to say that some might prefer the simpler design, but if you consider the VAC and ARC as reference sound, I doubt you'll prefer a different approach.
Click to expand...

It might be the case at least with the VAC, and the Cary, and even my Luxman as they all have a remote power supply, but the ARC doesn't.
 
Ken Boyd said:
With good tubes loaded in and replacing all the caps I would think it might benefit a bit. I don't know why it couldn't be made to be better with just that or does replacing all the resistors with better ones need to be done as well?
Click to expand...
One thing you prolly already know, there is a small percentage of cases where changing things can make it worse. And returning everything to the way it originally was sometimes doesn't get you back to where you started.

It's more true with analog. There is a little Juju magic that can be lost in these contraptions.

:)
 
Ken Boyd said:
I own a tube preamp from Hong Kong mostly point to point wired and was think of changing out all the caps to better ones thinking it will improve the quality of the unit. The power supply is pretty hefty, a decent sized choke, all point to point, other than what looks to be a little phono amp on a PC board. With good tubes loaded in and replacing all the caps I would think it might benefit a bit. I don't know why it couldn't be made to be better with just that or does replacing all the resistors with better ones need to be done as well?
Click to expand...
Is this a new preamp or used. If used, how old do you think it is? I get tube rolling, but I find it hard to believe one would need to replace the caps and/or resistors on a new (or relatively new) unit unless it sounds bad.
 
When I see this, @Ken Boyd :

1785599982802.png

I say again : "if it works don't fix it" ! Don't mess with this : it will take you hours and money, you may make mistakes and damages, plus "modded" doesn't imply "better"...

How many tubes amps and preamps "modded" I had to return to their original circuits (as best and when feasible) to make them operate as they should ? If you want pics, I have some... Be wise : if one day you want to resell it, usually "unmodded" sells better than "modded" !

But it's me, OK ? :biggrin: ;)

T
 
eiraved said:
Is this a new preamp or used. If used, how old do you think it is? I get tube rolling, but I find it hard to believe one would need to replace the caps and/or resistors on a new (or relatively new) unit unless it sounds bad.
Click to expand...
These are all older preamps at this point, thinking maybe 20 years old. What my thinking is even when new they were Chinese made caps, and the quality might be an issue, and now they are older. There isn't much in here if you eliminate the little phono section, so improving the quality of what is there might be a nice improvement.
 
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