Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Jim Nasium on August 01, 2021, 02:48:06 pm

Title: Transformer Help
Post by: Jim Nasium on August 01, 2021, 02:48:06 pm

I am wanting to go ahead and get some spare parts on hand for the Gretsch 6159 Dual Bass(1966-67).

Please help me specify a suitable replacement for the transformers.

The PT configuration presently looks as it is pictured.
Two black wires go to the main switch circuit.
Two red wires go to the diodes.
Two green wires go to V6.2, and V6.7 (power tube)
One green/yellow wire goes to the ground lug on the V6 (power tube).

Title: Re: Transformer Help
Post by: Jim Nasium on August 01, 2021, 02:50:24 pm

Here are pictures of the OT.

Title: Re: Transformer Help
Post by: Electron Tornado on August 01, 2021, 05:02:44 pm

This might help:

Title: Re: Transformer Help
Post by: sluckey on August 01, 2021, 08:04:57 pm

Quote from: Jim Nasium on August 01, 2021, 02:48:06 pm

Please help me specify a suitable replacement for the transformers.

For starters, measure all the secondary voltages, ie, red wire to red wire, green wire to green wire.

Title: Re: Transformer Help
Post by: PRR on August 02, 2021, 12:50:30 am

280VAC >200mA, 6.3VAC >2.7A

5K CT 20-30 Watts to whatever speaker impedance

Title: Re: Transformer Help
Post by: Jim Nasium on August 02, 2021, 07:40:38 pm

Quote from: PRR on August 02, 2021, 12:50:30 am

280VAC >200mA, 6.3VAC >2.7A

5K CT 20-30 Watts to whatever speaker impedance

Hi PTT, thank you for the response. I am a super newbie. Could you please break down your comment to me to a beginner level?

Title: Re: Transformer Help
Post by: Jim Nasium on August 02, 2021, 08:02:00 pm

Quote from: sluckey on August 01, 2021, 08:04:57 pm

Quote from: Jim Nasium on August 01, 2021, 02:48:06 pm

Please help me specify a suitable replacement for the transformers.

For starters, measure all the secondary voltages, ie, red wire to red wire, green wire to green wire.

Thank you for the response. Since I am waiting on replacement capacitors to arrive before changing them out, I do not want to supply power to them. If I removed the two 6L6 power tubes, could I safely perform the measurements without charging the amps capacitors?

Also, what needs to be checked in order to cross reference the Output Transformer?

With the head removed from the cabinet, the speakers are not connected, so no load there. Is that okay to do, or should I connect them first?

Title: Re: Transformer Help
Post by: sluckey on August 02, 2021, 08:07:02 pm

Just disconnect the red wires to test for voltage. PRR already covered the OT.

Title: Re: Transformer Help
Post by: j_bruce on August 03, 2021, 06:48:08 am

the one i used:

http://www.classictone.net/40-18103.html (http://www.classictone.net/40-18103.html)


worked fine.