Changing to fast diodes in a bass amp

[Bob M.]

Hi,

I have a low-powered (tube) bass amp that I'm trying to increase performance on. As an experiment, I thought I'd try fast diodes for the rectifier. I know some say they cannot hear a difference and others say it does increase performance somewhat. But anyway, I have them here and I thought I'd give it a go.

But my question is this: I have some of two types of fast diodes here: Vishay UF 4007 and Vishay BA 159. Both diode types are rated at 1.0 amp at 1000 volts. Can I mix these diodes (some of each) or should I just use one type or the other?

Thanks in advance for your on-point replies,

Bob M.

[alexradium]

Hi,

I have a low-powered (tube) bass amp that I'm trying to increase performance on. As an experiment, I thought I'd try fast diodes for the rectifier. I know some say they cannot hear a difference and others say it does increase performance somewhat. But anyway, I have them here and I thought I'd give it a go.

But my question is this: I have some of two types of fast diodes here: Vishay UF 4007 and Vishay BA 159. Both diode types are rated at 1.0 amp at 1000 volts. Can I mix these diodes (some of each) or should I just use one type or the other?

Thanks in advance for your on-point replies,

Bob M.

i would use one type only,whatever it is.
Increase performance,which way?

[Bob M.]

For the better, of course. Amps come from manufacturers trying to be all things to all players but sometimes players want their equipment pointed toward the particular musical jobs they are asked to perform. This is the case here. I've changed some filter caps, fooled with some of the coupling caps so the amp is voiced a little closer to my liking, a tweak here, a mod there. I had these diodes lying around so I thought I'd give them a try. I'm on the sidelines on the UF 4007 /1N 4007 rectifier debate. As I said in my original post some say it helps, other say there is little to no difference but I thought of this as an experiment. I like experiential knowledge.

Bob M.

[Chuck H]

Here's a discussion where Randall Aiken responds to the matter. Apparently someone took something he wrote out of context and that may be how this rumor got started. But in a nutshell, no. Fast diodes won't improve or change the audio signal in any way. The tubes run off the DC provided by the power supply via the capacitors charge. Any diodes are amply fast enough to maintain this charge. Ultra fast diodes can be of benefit where rectifier switching noise is a problem. I've been using plain Jane 1n4007's forever and haven't had a problem yet. If I ever come across rectifier induced buzz I'll try some ultra fast diodes. Or maybe just snubber the regular diodes. It'll depend on which is faster or cheaper.

https://www.harmonycentral.com/forum...r-impact-tone/