Diode rectifier vs Weber Copper Cap

[Greg_L]

I'm building a 6G6B Bassman clone into an old SS combo amp I had laying around.

https://www.gad.net/Blog/wp-content/...-Schematic.jpg

I have the diodes to make the rectifier bridge, but I also have a GZ34 equivalent Copper Cap and an extra tube socket. My PT does not have a 5v rectifier heater winding, but the Copper Cap doesn't need that.

I'm trying to fit all of the filter caps inside the chassis instead of externally under a doghouse, like Fenders usually are, so space is a bit of an issue. Can I use that Copper Cap instead of building the diode bridge? I'm thinking I'd just need to run the PT secondaries to the Copper Cap socket as if it were an actual tube rectifier and then take the B+ off that.

Sorry if this is a dumb question, I'm just trying to learn as I go.

[Helmholtz]

Please post your PT specs.

A bridge rectifier is different from a full wave/2-phase rectifier and needs a different PT secondary.

[Greg_L]

Please post your PT specs.

A bridge rectifier is different from a full wave/2-phase rectifier and needs a different PT secondary.

40-18005.pdf

That's my PT

[Helmholtz]

[ATTACH]n957127[/ATTACH]

That's my PT

PT should work fine with the copper cap and should give around 420V B+.
Or just use 1N4007s (2 per side) for maybe 15V higher B+.

[Greg_L]

PT should work fine with the copper cap and should give around 420V B+.
Or just use 1N4007s (2 per side) for maybe 15V higher B+.

The schematic shows three diodes per side. Why is that?

[Helmholtz]

The schematic shows three diodes per side. Why is that?

Probably because Leo didn't have 1000V diodes then.

[Greg_L]

Probably because Leo didn't have 1000V diodes then.

Ah, yeah that makes sense.

So I could use just four 1N4007s. I also have some beefy 1N5408s.

[Helmholtz]

4x1N4007s or 4x1N5408s, makes no difference here.

[tedmich]

The schematic shows three diodes per side. Why is that?

OMG, Leo was making a "Triple Rectifier Amp" way back then! Truly a pioneer, I hope Randall Smith doesn't sue

Seriously though, make sure to explore the vibrant Bassman community!
http://fenderguru.com/amps/bassman/

[Greg_L]

OMG, Leo was making a "Triple Rectifier Amp" way back then! Truly a pioneer, I hope Randall Smith doesn't sue

Seriously though, make sure to explore the vibrant Bassman community!
http://fenderguru.com/amps/bassman/

Haha cool thanks I'll check it out.

[Chuck H]

My reservations for using the copper cap would be:

1) What if the amp isn't always yours (things happen) and someone tries to plug an actual rectifier tube into it.?. The worst case here is just that the amp won't work. So that's not a big deal, but still a little off from an idealistic perspective. ie: If a tube socket is included in the design said socket should operate a tube. But small taters.

2) It seems to me that the socket and wiring take up just as much space as a diode rectifier. Maybe more or at least more inconvenient depending on overall design considering that it needs to occupy a hole in the chassis. And on that note...

3) You need to cut a hole in the chassis. Why trouble if you can avoid it. Make it easy on yourself because life will be hard enough at times when you may not even expect it. (this is a philosophy I've found it necessary to adopt )

4) What if Weber Copper Caps become unavailable? The amp would be non operational for the novice or, at the very least you would need to wire a diode rectifier on the socket pins anyhow. And,..

5) The Weber Copper Cap is a diode rectifier with a series resistance for sag in a copper bottle. If you use a diode rectifier you can choose your own series resistance that suits the design as you see fit.

JM2C

[Greg_L]

My reservations for using the copper cap would be:

1) What if the amp isn't always yours (things happen) and someone tries to plug an actual rectifier tube into it.?. The worst case here is just that the amp won't work. So that's not a big deal, but still a little off from an idealistic perspective. ie: If a tube socket is included in the design said socket should operate a tube. But small taters.

2) It seems to me that the socket and wiring take up just as much space as a diode rectifier. Maybe more or at least more inconvenient depending on overall design considering that it needs to occupy a hole in the chassis. And on that note...

3) You need to cut a hole in the chassis. Why trouble if you can avoid it. Make it easy on yourself because life will be hard enough at times when you may not even expect it. (this is a philosophy I've found it necessary to adopt )

4) What if Weber Copper Caps become unavailable? The amp would be non operational for the novice or, at the very least you would need to wire a diode rectifier on the socket pins anyhow. And,..

5) The Weber Copper Cap is a diode rectifier with a series resistance for sag in a copper bottle. If you use a diode rectifier you can choose your own series resistance that suits the design as you see fit.

JM2C

All valid points. Some I've already considered, some not so much. I forgot that the Copper Cap has "sag" built into it. Very good point, and not a "feel" I'm interested in exploring for this particular amp.

Since this was a solid state chassis it had no tube socket holes and I've already cut the four 9-pin and two 8-pin socket holes. One more wouldn't be a big deal, but I think you're right about not bothering.

Diodes it shall be. I was on the fence, but now I've fallen off of it.

[Chuck H]

Always take the path you see as best for you. I only offer my input when it's solicited

[Greg_L]

Always take the path you see as best for you. I only offer my input when it's solicited

Haha and I appreciate all advice. I got no ego. I'm just a guy trying to learn this craft as I go. This site - all of you - have a been a tremendous help to my growth and understanding of tube circuits. My only regret is that I can't help other people as well as you guys help me. Maybe one day...

[Leo_Gnardo]

Probably because Leo didn't have 1000V diodes then.

My understanding is 600PIV was considered max for rectifiers "back in the day" late 1950's.

There's no harm running a string of 3 x 1000V rated rectifiers. Cheap insurance. 1N4007 cost pennies.