Beefing up my Madamp.

polifemo

I´m very happy with the sounds I´m getting out of my Madamp A15Mk2!!!
Instead of buying a bigger high end "Bootheek-amp" I might as well upgrade my Madamp. (The sound is VERY good!)

I´m thinking about getting bigger transformers and go for 2xEL34 instead. (This will give me a 50 watt amp)

I´ve been in touch with Jan Philipp Wuesten who is willing to wind me a custom PT, BUT I need to solve the following problem:
In the A15Mk2 the switching system is powered from a 28V (or something) tap on the stock OT.
Could MAD maybe give me some hints about how to solve this little problem/function on a new PT!?

How should I specify this new PT in order to have it work with the switches?
Would the switching system work with a higher voltage?

I´ve modified my amp quite a bit o suit my needs, and I must say that the sound I´m getting is on par with MUCH more expensive amps!
I just need a louder clean sound, thats all.

Thanks for a great kit Martin

antissime

perhaps you just need an additional small transformer on the inside for the switching.

polifemo

Zitat von antissime;249761

perhaps you just need an additional small transformer on the inside for the switching.

Yes, I´ve been recommended this before but I´d love to hear what thougts MAD might have.
There IS some space for a small transformer inside the chassies but if I could have a PT with this feature I´d prefer that.

eBernd

Hi,

First: I hope you know how to change the bias section of the power supply for the different power tubes you want to need.

Because in the original footswitch application the bias section - especially the 20 Vac winding of the PT - is used for both the bias voltage generation and the 12 Vdc to run the foot switch option.

If you want to supply the -original - footswitch by a separate winding it should deliver 12 Vac @ 0,2 A.

Bernd

MAD

Hi polifemo,
as Bernd said, the footswitch option needs 12V DC (so 12V AC is fine) and for larger power tubes (e.g. EL34 or 6L6) you need more BIAS voltage.
Regards,
Martin

polifemo

I´ve realised that this will be to troublesome...

I´ll leave the Madamp as it is and build a Hiwatt clone instead.
THAT will give me headroom!

EdwinSteenstra

Maybe it is an idea to build only a poweramp, when my a15 lacks power (rarely) I plug it through to a 4x12 stack in which i built a 100W transistor poweramp, for that i've created a line-out from the 8 ohm speaker-out with a few resistors (as seen in MAD's galerie).

Jetzt mitmachen!