Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: pepparspray on December 09, 2008, 07:59:13 AM

Title: Gretsch tubeamp transformer
Post by: pepparspray on December 09, 2008, 07:59:13 AM
Hiya!
Me and a friend is talking about building a tubeamp with som minor solid state addon and we were wondering if someone could help us with parts.

Our fysics teacher told us that we needed a special kind of transformer because one of the tubes were strange. Since our teacher is the strangest person we've met we don't exactly trust him. Could someone help us figure it out?

Here's the schematics: http://www.2shared.com/file/4423507/b4ecf2e4/gretsch6150a.html

So if someone understand what the schematics mean by this please reply :)
Title: Re: Gretsch tubeamp transformer
Post by: teemuk on December 09, 2008, 09:06:20 AM
Looks like a pretty standard setup for tube amps. You need two transformers:

1 x Power transformer with three secondary windings:
- HT/B+ winding ??? Volts
- 6,3V filament winding with proper current carrying capability for 1x6V6GT and 1x12AX7
- 5V filament winding with proper current carrying capability for the 5Y3GT rectifier tube
Get the datasheets and see how much currrent the filaments of these tubes will draw.

1 x SE-audio/output transformer:
This will convert the 8-ohm secondary impedance to a proper primary impedance
(I believe) the right primary impedance for a 6V6GT should be about 5K - 7.5K, so something like a Hammond 125CSE might be allright for this amp.

Tube experts, plese correct me if I'm wrong.
Title: Re: Gretsch tubeamp transformer
Post by: Jack1962 on December 17, 2008, 07:16:59 AM
Teemuk is dead on , for these transformers for the output transformer use a Hammond P-T1650E (15 watts (that's all you really get from to 6v6's)) for the power transformer use a Fener Champ replacement Xformer #125P1B.022772 . This is just an old 15 watt(if bias hot and pushed real hard 16-18 watt) 6V6 Valco amp , they are ok if you like thee Fender tones.