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I finally found a TS-50B at the right price to replace the one I stupidly sold 8 years ago. Now, back then I didn't mess with the insides of amps too much but managed a 110>230v swap. Fast forward to now and I'm going to need to do it again... but I don't know what transformer I'll need.

Google has been no help at all, but there is a schematic:

BASS GO BRRRRP

Can someone with a better understanding take a look and maybe point me in the direction of a suitable replacement? Last time I used a toroidial but happy to use a traditional style as well.

That's a split-supply bridge rectifier producing +/- 35VDC. My calculation chops are rusty/confused on this sort of thing so its hard to back out the correct AC input voltage but given that the schematic says 200V I think that makes sense. It would be listed as 200V CT or maybe 100-0-100 V because it has a center tap.

Dr Tony Balls wrote: ↑

Mon Mar 11, 2024 6:55 am

That's a split-supply bridge rectifier producing +/- 35VDC. My calculation chops are rusty/confused on this sort of thing so its hard to back out the correct AC input voltage but given that the schematic says 200V I think that makes sense. It would be listed as 200V CT or maybe 100-0-100 V because it has a center tap.

Yeah, I traced the schematic to see the 200v and 35v parts but wanted to be sure.

Now to try and actually find one. Gonna be a fun evening sifting through spec sheets

Fucking hell, finding one is nigh impossible. I might have to get a custom wound one, annoyingly

Maybe I'll just run a step-down

JSett wrote: ↑

Mon Mar 11, 2024 8:18 am

Fucking hell, finding one is nigh impossible. I might have to get a custom wound one, annoyingly

Maybe I'll just run a step-down

The step down will be WAY easier.

Dr Tony Balls wrote: ↑

Mon Mar 11, 2024 9:21 am

JSett wrote: ↑

Mon Mar 11, 2024 8:18 am

Fucking hell, finding one is nigh impossible. I might have to get a custom wound one, annoyingly

Maybe I'll just run a step-down

The step down will be WAY easier.

I know. I hate having excess shit in-line though, and step downs - even the nice expensive one I bought - tend to make noise which I find distasteful.

I'll still keep an eye out. Maybe I can pick up a donor amp that's already 230v and swap them out.

I think that the 200V 8A reference is to specify the rectifier diodes. Given that this is a purely solid state amp by the looks of it, generating a split rail 35 VDC supply using two 16V Zener diodes, I would suspect that the power transformer is likely a roughly 40 VAC output.

It looks like this is the same voltage that the clone works on: Rusty Box

ryland wrote: ↑

Mon Mar 11, 2024 9:37 am

I think that the 200V 8A reference is to specify the rectifier diodes. Given that this is a purely solid state amp by the looks of it, generating a split rail 35 VDC supply using two 16V Zener diodes, I would suspect that the power transformer is likely a roughly 40 VAC output.

It looks like this is the same voltage that the clone works on: Rusty Box

This actually makes a lot more sense to me than the 200v. I have a Rusty Box actually, for a while I had one of those, a TS50 combo, TS50b head AND TS70B combo. Only the pedal remains until this arrives.

40VAC is going to be much easier to find

JSett wrote: ↑

Mon Mar 11, 2024 9:58 am

ryland wrote: ↑

Mon Mar 11, 2024 9:37 am

I think that the 200V 8A reference is to specify the rectifier diodes. Given that this is a purely solid state amp by the looks of it, generating a split rail 35 VDC supply using two 16V Zener diodes, I would suspect that the power transformer is likely a roughly 40 VAC output.

It looks like this is the same voltage that the clone works on: Rusty Box

This actually makes a lot more sense to me than the 200v. I have a Rusty Box actually, for a while I had one of those, a TS50 combo, TS50b head AND TS70B combo. Only the pedal remains until this arrives.

40VAC is going to be much easier to find

I'm glad there's some use for my mostly unused EE degree...

ryland wrote: ↑

Mon Mar 11, 2024 10:12 am

JSett wrote: ↑

Mon Mar 11, 2024 9:58 am

ryland wrote: ↑

Mon Mar 11, 2024 9:37 am

I think that the 200V 8A reference is to specify the rectifier diodes. Given that this is a purely solid state amp by the looks of it, generating a split rail 35 VDC supply using two 16V Zener diodes, I would suspect that the power transformer is likely a roughly 40 VAC output.

It looks like this is the same voltage that the clone works on: Rusty Box

This actually makes a lot more sense to me than the 200v. I have a Rusty Box actually, for a while I had one of those, a TS50 combo, TS50b head AND TS70B combo. Only the pedal remains until this arrives.

40VAC is going to be much easier to find

I'm glad there's some use for my mostly unused EE degree...

Hah! I wish I'd studied it!

This looks like it might do the trick...

https://cpc.farnell.com/multicomp/mcta2 ... dp/FF01572

Thoughts? It doesn't appear to have a center tap on second look. Gah! Obstacles

ryland wrote: ↑

Mon Mar 11, 2024 9:37 am

I think that the 200V 8A reference is to specify the rectifier diodes. Given that this is a purely solid state amp by the looks of it, generating a split rail 35 VDC supply using two 16V Zener diodes, I would suspect that the power transformer is likely a roughly 40 VAC output.

It looks like this is the same voltage that the clone works on: Rusty Box

The Rusty box works on 30V but remember that's just the preamp from a TS-50B. The 30V is functionally the same as the +/- 15V supply. The Rusty has no +/- 35V supply.

Dr Tony Balls wrote: ↑

Mon Mar 11, 2024 10:31 am

ryland wrote: ↑

Mon Mar 11, 2024 9:37 am

I think that the 200V 8A reference is to specify the rectifier diodes. Given that this is a purely solid state amp by the looks of it, generating a split rail 35 VDC supply using two 16V Zener diodes, I would suspect that the power transformer is likely a roughly 40 VAC output.

It looks like this is the same voltage that the clone works on: Rusty Box

The Rusty box works on 30V but remember that's just the preamp from a TS-50B. The 30V is functionally the same as the +/- 15V supply. The Rusty has no +/- 35V supply.

Ah, ok, I took the internet at face value

You're making me do the math, which is a good thing. For one rail (we'll double this at the end to get the full Ac voltage), we know we want 35 VDC,

adding in two diode drops at a nominal 0.6 VDC each gives us 35+1.2 = 36.2 VDC,
Dividing this by the square root of two to get the AC volatage from the transformer gives us 36.2/1.44 = 25.1 VAC.
Doubling this to get the full AC volage yields a 50 VAC transformer output rather than my earlier guess of 40 VAC.

I don't know what the transformer mounting of the TS-50B looks like, you may want to try to find something in a similar form factor when you lay eyes on it...so I don't know how a toroidal will fit...

Looking at this again, the rectifier looks essentially like two full wave rectifiers, with one being for the positive rail and one for the negative. Doing the math hre i'm coming up with a 25-0-25 transformer giving you +/- 34.25 V. So I think I concur with the 50V assessment.

legally, the only way to test one of these amps is with a travis bean bass OR a peavey t40...... those the rules.

ryland wrote: ↑

Mon Mar 11, 2024 11:00 am

I don't know what the transformer mounting of the TS-50B looks like, you may want to try to find something in a similar form factor when you lay eyes on it...so I don't know how a toroidal will fit...

I won't comment on the maths as I don't understand it, but I can comment on this. The last one I had I just drilled the chassis for the mount and stuck it in there routing the wires through one of the old mount holes. The transformer came loose with the amp.