Pacific TW xformers used in a different topology (ie Plexi)?

[Axeplyr]

Hi all,

I've been lurking for awhile, and I'm getting ready to build a 1x12 nmv combo. I was leaning towards a trainwreck express, but now I'm on the fence and may go the plexi route. But the 30w nmv is where I want to stay.

Will the Pacific trainwreck trannies serve me well with a Marshall Plexi preamp circuit? My gut feeling is yes... but maybe someone has used these trannies in a different topology and can share the experience? Thanks!

[RJ Guitars]

Axe,

Look for a post in the Trainwreck Files by a guy named "Rawnster" - using "Rockster" as a key word. I think he used this output tranny on an iteration of my "Rockster" amp. This amp is something sorta like a cross between a Trainwreck Rocket and a 59' Bassman and uses KT-66 tubes in the output section. If I recall correctly this build sounded awesome. You'll find a lot of similarities in the Marshall plexi and the 59 Bassman schematics... which might imply this a good tranny for your project.

I'll be curious what kind of results you get if you move forward on this build. I have a JTM45 that needs transformers. The transformers have always been a fragile yet critical part of the Marshall sound. Many of us would welcome a great option for an output tranny in these amps.

BTW - The Pacific 6.6K output tranny for an Express appears to be a knockoff of the Stancor A3801. Most Trainwreck savvy guru's agree with this piece of legendary history.

The 35 watt rating is pretty conservative and you might actually find the Pacific a bit more Beefy than a 50 watt Marshall output tranny.

Good luck and let us know what happens.

rj

[Axeplyr]

RJ,

Thanks for the reply!

I found the post you specified. Mouthwatering! Nice work indeed.

I will very likely be moving forward with this build. There is a bit of research I'll need to do, but I like the idea of buying the set and being able to possibly build both circuits around it and switching back and forth as a tone experiment sounds really appealing.

And I'm not sure I'm man enough to handle the Trainwreck circuit.

[paulster]

One of the big differences between Marshalls and the Express is that where Ken used a 6600ohm primary for a pair of EL34s, Marshall used 3500ohm.

If you don't have any 16ohm speaker cabs then you could always deliberately 'mismatch' the Wreck OT and label the secondary taps as 2ohm, 4ohm and 8ohm, which will give you a 3300ohm primary.

It's still quite a different transformer than a Marshall OT in terms of its construction but that may give you something useful in terms of getting a more plexi-ish sound out of it.

Then again you may prefer the plexi front end with an Express power section.

[Axeplyr]

Thanks Paulster. I was planning on using a 16-ohm cab. There won't be issues will there? Or tone degradation due to the different impedance?