Marshall 2525

[akkar]

Hello everyone,

does someone has a Marshall 2525 schematic?

Thanks

 

[Printer2]

Something similar?


http://www.guitarampsusa.com/Documentation/2525.jpg

 

[akkar]

I don't know honestly

Looking at the original manual, I see it features High/Low output switching (20 Watt to 5 Watt) that I don't see in the Ceriatone version.

Ceriatone has bright, rhyhtm clip, channel select switches that the original one doesn't have

 

[Printer2]

So modify it for whatever you want.

 

[akkar]

I'm interested in how actually they designed that, in particurarly the power control switch.

Thanks for the suggestion though

 

[leadbelly]

I believe the 2525 is based on the 2555, whose schematic can be found. Of course, it will take a little work to go from 4xEL34 to 2x6V6.

 

[Printer2]

It's a type of power scaling on the mini. The plate voltage is about 280 on 20 watts and about 175 on 5 watts. On the 2555x and the original series the low power was pentode triode switching. The power scaling approach doesn't change the tone much, but triode sounds different from pentode.

Mini Jubilee 2525h | Page 2 | MarshallForum.com

 

[akkar]

Mmmm so they use a different technique than the pentode/triode of the 2555

 

[JonSnell Electronic]

The 2555 uses a Triode/Pentode switch, nothing else so it only reduces the gain but achieves a similar power output when over driven into class AB2.
The 2525 uses a reduced HT switch. That's it.
I will not share a schematic as I am a Marshall repairer and agreed to keep their copyright material confidential.

 

[Printer2]

Not really sure how the 2555 can get driven into AB2, the PI is capacitor coupled. Maybe the triode switch?