I have been collecting parts for a spud amp and have a PTX with 6.3v and 5v but the two 380v legs are not center taped. So, can this be used in an amp? I've not seen a scheem without a center tape on the main primaries.
OK, I just whipped this up in PSU II with the two chokes I have and it looks a little low for the tubes I am using. They are the 6LR8. I need to think about 1. if this is enough voltage and 2. do I have room for 2 rec tubes.
Are there any rectifier tubes that have 4 elements in them?
That is an interesting idea J. I don't know why it wouldn't work. I don't think I can modle it in PSU but maybe a little bench testing would be in order.
OK, I just whipped this up in PSU II with the two chokes I have and it looks a little low for the tubes I am using. They are the 6LR8. I need to think about 1. if this is enough voltage and 2. do I have room for 2 rec tubes.
Are there any rectifier tubes that have 4 elements in them?
Go for it! It is not something I have tried either, I just remembered reading about it, so found the website for you. Let me know if it flies. DIY at its finest is just trying it, right?
More then just four diodes in one envelope, you need to find a rectifier that does not have a shared cathode. The bridge needs to look just like in the PSU II diagram, four plates and four cathodes. Two "normal" tube rectifiers can't work
If the voltage is low use SS diodes
Thanks Doz. This amp chassis is a work of art (I am a metal sculptor) so it is pretty much set up for a tube rec. I think I should just wait for a CT PTX of the approp. voltage. The tubes really can't go that high anyway so I would have to knock it down....to much trouble.
Do we get to see pictures?? Sounds great.
I've used Hybrid rectifiers in a small pre-amp when I lacked the appropriate transformer. Worked well enough.
I must rather lash something up on the bench than model, but I'm just like that... I spend 70% of my waking hours pushing buttons on a keyboard, so I'd rather spend the other 30% with an iron in one hand ... and the warm smell of tubes![]()
Yep, me too..click click click all day long. Nice to melt solder at night.
Here is the amp all painted up. the rec tube goes in back on the tube and the 6LR8s go up on the twin peaks.
This worked like a charm for me - I built several little mono block pairs and stereo EL84 amps at least 5 yrs ago with a similar implementation in the power supply. Choke filtered supplies with Solen film caps and reclaimed iron from several vintage large console radios, etc.
They've seen pretty much constant daily use since then, with nary a problem.
Astute surfers might recognize the audio portion of circuit
First, are the transformer and choke resistance values close? If not, adjust to match reality and model it with 4 vacuum rectifiers, then with 4 solid state ones. Average the two to see what you'll have with the hybrid bridge. BTW, I'd look for a HV secondary with less than 150 Ohms DCR for 100 mA.