Output transformer needed for Marshall Studio 15

blackba said:
I have a Marshall studio 15 on the bench with a bad output transformer. The power transformer was already replaced with a mercury at some point.

Mercury does not have a bobbin to make one for me. They can rewind The current transformer, but it’s very expensive.
I don’t need the balanced di tap, just something that will work.

https://schematicheaven.net/marshallamps/jcm800_studio15_15w_4001.pdf
I appreciate the help.
Click to expand...
Hammond maybe? Heyboer? What tubes does the studio 15 use, 6v6? Maybe a lunchbox amp donor that has the appropriate primary impedance?
Crazy longshot…but maybe reach out to Marshall?
 
blackba said:
I have a Marshall studio 15 on the bench with a bad output transformer. The power transformer was already replaced with a mercury at some point.

Mercury does not have a bobbin to make one for me. They can rewind The current transformer, but it’s very expensive.
I don’t need the balanced di tap, just something that will work.

https://schematicheaven.net/marshallamps/jcm800_studio15_15w_4001.pdf
I appreciate the help.
Click to expand...

I see it’s running 6V6 in push pull class AB

The datasheet I found for a typical PP AB 6V6 arrangement calls for 8K ohm primary impedance at around 320 on the plates.

I checked Mercury’s site and the O18RS-L
OT calls for 8K CT and is rated for 18W

I’d call Mercury for confirmation but I think this is the one I’d use personally if I were in your shoes. It can do 4/8/16 but I’d probably just wire up the 16/8 and forget the wonky 4 ohm wiring. Tie it off and double shrink wrap it,

https://www.mercurymagnetics.com/pr...8-watt&filter_product-type=output-transformer
 
glpg80 said:
I see it’s running 6V6 in push pull class AB

The datasheet I found for a typical PP AB 6V6 arrangement calls for 8K ohm primary impedance at around 320 on the plates.

I checked Mercury’s site and the O18RS-L
OT calls for 8K CT and is rated for 18W

I’d call Mercury for confirmation but I think this is the one I’d use personally if I were in your shoes. It can do 4/8/16 but I’d probably just wire up the 16/8 and forget the wonky 4 ohm wiring. Tie it off and double shrink wrap it,

https://www.mercurymagnetics.com/pr...8-watt&filter_product-type=output-transformer
Click to expand...
The Tweed Deluxe I just built has an almost perfect OT if I have it right.

I used the FTDO-59. It has just the 8ohm secondary (8k primary) and self-lead but they have multiple versions of that OT wrt secondaries and probably self lead if that matters.
 
glpg80 said:
I see it’s running 6V6 in push pull class AB

The datasheet I found for a typical PP AB 6V6 arrangement calls for 8K ohm primary impedance at around 320 on the plates.

I checked Mercury’s site and the O18RS-L
OT calls for 8K CT and is rated for 18W

I’d call Mercury for confirmation but I think this is the one I’d use personally if I were in your shoes. It can do 4/8/16 but I’d probably just wire up the 16/8 and forget the wonky 4 ohm wiring. Tie it off and double shrink wrap it,

https://www.mercurymagnetics.com/pr...8-watt&filter_product-type=output-transformer
Click to expand...
I think an output transformer for a Marshall 18W like you are thinking is the ticket. Mounting is different, but I can make it work.

That also opens up other options like Heyboer and Hammond. Leaning toward the Heyboer from Mojotone at this point.

https://www.hammfg.com/part/1750PA
https://www.mojotone.com/British-Style-18-Watt-Output-Transformer
 
You must log in or register to reply here.
Back
Top