Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on December 20, 2017, 10:14:34 am

Title: Conversion of a small SS Combo - GA-5T Skylarc or Same amp modded ?
Post by: kagliostro on December 20, 2017, 10:14:34 am

I don't know who planned the modded version, here are the two schematics

(https://i.imgur.com/CdoOujg.png)

(https://i.imgur.com/IYot8XR.jpg)

I recovered a PT an OT, 1 x ecl82 (6bm8) and 1 x ecc83 (12ax7) and have a pair of small SS combo that can be converted (Ibanez IBZ3B - Samic Smart 2)

I'm a bit confused from the high value of the resistor on the plates of the ecc83 tube, on the modded version the values are more standard ...

Someone knows something about the modded version ? I would like to decide which version to build

Thanks

Franco

Title: Re: Conversion of a small SS Combo - GA-5T Skylarc o Same amp modded ?
Post by: VMS on December 20, 2017, 11:36:38 am

NFB might be wrong in the modded circuit, looks like it's bypassed by the cathode cap.

Title: Re: Conversion of a small SS Combo - GA-5T Skylarc o Same amp modded ?
Post by: sluckey on December 20, 2017, 11:40:54 am

Take a look in Hoffman's schematic library. You'll find 3 more GA5-T schematics to chose from.   :icon_biggrin:

Title: Re: Conversion of a small SS Combo - GA-5T Skylarc or Same amp modded ?
Post by: kagliostro on December 20, 2017, 11:48:29 am

@ VMS Thanks

I didn't noticed that

Ciao Steve

I'll go to give a look, but if I remember correctly only one GA-5T Skylarc 1961 uses an ecl82 tube  :icon_biggrin: 

BTW, I've draw the ecl82 version of the schematic that now is on the archive (starting from GA-1RT-1) because other versions were not very readable  :wink:

Franco