Matchless DC30 preamp

[Rafael Puyol]

Hi guys Im not around here very often cos Im just starting with tubes (Ive built several transistor stompboxes). The thing is that I want to build the Matchless DC30 preamp (only the one that uses 12ax7)
The schematics Ive found are these:
http://mywebpages.comcast.net/jabiga...s/dc30_ch1.gif
and here the power supply:
http://mywebpages.comcast.net/jabiga...s/dc30_pwr.gif

Or this one:
http://heysam.com/schem/matchlessdc30.jpg

They look very similar but are they accurtae?
If you guys think this is not the best project to start please tell me I also thought about the hotbox which there is more info available but I was told its more fuzzy, and perhaps in the future I could build the dc30 power amp and had it complete.

Cheers
Rafa

PD: Out of topic: Is it difficult to wind my own output transformers?

[Smitty]

Yeah, they're close enough. The big thing is that the first tube is parallel for lower noise and that its plate voltage is around 130 to 135. Pretty low. The node feeding the direct coupled cathode follower should be around 300 to 305.

The tone stack is right.

No need to wind your own transformers unless you want to. Getting setup to do it is expensive unless your time is worth nothing. Don't do it to save money. There are so many good ones out there.

Smitty

[Rafael Puyol]

Thanks a lot Smitty
The problem with output transformers is that here in uruguay were i live they are not available and buyign the trough internet is very expensive. I must sum the price of the transfmormer and the shipping and then multiply it by 1,6 because of import taxes.
So winding my own would be the best, time is not really important as now Im on holidays.
It shouldnt be very complicated as I would need only 8 ohm output.
Sorry for my english
Cheers
Rafa

[Albert Kreuzer]

Hi Rafa,

more than you ever wanted to know about winding transformers:

http://geek.scorpiorising.ca/windingtransformers.html

Hope this helps!

Cheers,
Albert
www.albertkreuzer.com