HiFi tube amp and homebrew guitar preamp

Non-Rickenbacker Guitars & Effects

Moderator: jingle_jangle

Re: HiFi tube amp and homebrew guitar preamp

Postby (Tube_Fan) » Wed Dec 05, 2018 7:01 pm

More tube amps
Attachments
P1010014.jpg
(Tube_Fan)
Junior Member
 
Posts: 194
Joined: Wed Jun 25, 2014 6:22 pm

Re: HiFi tube amp and homebrew guitar preamp

Postby (jps) » Wed Dec 05, 2018 8:24 pm

Fisher?
(Insert famous quote here)
User avatar
(jps)
RRF Consultant
 
Posts: 35855
Joined: Wed Feb 12, 2003 7:00 am
Location: Not of this Earth

Re: HiFi tube amp and homebrew guitar preamp

Postby (Tube_Fan) » Thu Dec 13, 2018 6:01 pm

IIRC, the one in the cabinet is a Fisher X-202-B (7591 output). The one on the top left is a Fisher 101 (el84 output). The one on the bottom left might be a Scott LK-72.
(Tube_Fan)
Junior Member
 
Posts: 194
Joined: Wed Jun 25, 2014 6:22 pm

Re: HiFi tube amp and homebrew guitar preamp

Postby (Tube_Fan) » Tue Feb 26, 2019 1:16 pm

(Tube_Fan)
Junior Member
 
Posts: 194
Joined: Wed Jun 25, 2014 6:22 pm

Re: HiFi tube amp and homebrew guitar preamp

Postby (Tube_Fan) » Sun Mar 24, 2019 7:05 pm

I got another tube amp. Its a Fisher 481a. I tried it with some speakers and it works OK.
Attachments
481a.JPG
(Tube_Fan)
Junior Member
 
Posts: 194
Joined: Wed Jun 25, 2014 6:22 pm

Re: HiFi tube amp and homebrew guitar preamp

Postby (Tube_Fan) » Sun Mar 24, 2019 7:08 pm

On the bottom, you can see the partial recapping with two long electrolytics and a 250 ohm resistor (cathode resistor) on the left wall to subsitute for the three 12ax7 filaments in series in the tuner which connects through a jack. I don't have the tuner.
Attachments
481a-bottom.JPG
(Tube_Fan)
Junior Member
 
Posts: 194
Joined: Wed Jun 25, 2014 6:22 pm

Re: HiFi tube amp and homebrew guitar preamp

Postby (Tube_Fan) » Sun Mar 24, 2019 7:12 pm

Here's the amp schematic.
Attachments
custom electra VII e49 schematic-cropped.jpg
(Tube_Fan)
Junior Member
 
Posts: 194
Joined: Wed Jun 25, 2014 6:22 pm

Re: HiFi tube amp and homebrew guitar preamp

Postby (Kiddwad57) » Wed Apr 10, 2019 5:11 pm

Hey, really fascinated by the thread. Fine looking Fishers! One time my amp was in the shop and I had a string bass jazz gig. The only thing I could do was bring my Dynaco PAS2 preamp and one MKIV mono block fed through a one fifteen cab. It sounded fantastic. The Dyna MKIVs are what Sunn used to use in their original amps, later they had their own chassis made but still used the Dyna transformers and modified circuitry.

The Dyna stereo rig is still in use, but the amps have been rebuilt with modern components to the original schematic. The PAS2 is in storage, replaced by a Fostex pc1/e passive desktop volume control, which has recently been updated with a Chinese "DACT Type" stepped attenuator. A huge improvement! Here are some pics:
Attachments
Sleeper!.jpg
Sleeper! Fostex with stepped attenuator
Dyna Stack.jpg
The Dyna stack
Source and Passive.jpg
Brains and dominator
Variac.jpg
Variac for lowering voltage
Rebuilt Dyna.jpg
Dyna MKIV
"I'm never lost because someone's always telling me where to go."
User avatar
(Kiddwad57)
Intermediate Member
 
Posts: 541
Joined: Sun Sep 25, 2011 8:59 pm
Location: Between the forest and the trees

Re: HiFi tube amp and homebrew guitar preamp

Postby (Tube_Fan) » Fri Apr 12, 2019 6:37 pm

Two more amps

The one on the left is a model B 140 The Balladier which uses two 6v6 tubes in push-pull, a 6SN7GT, a 6J5 and a 5Y3GT rectifier tube. I bought it at an antique store for $15 IIRC. The power transformer is bad, but the audio transformer seems to be good based on ohm meter readings.

The one on the right is a Hammond H-AO-39-1 which uses two 6BQ5 tubes in push-pull, a 12ax7 and a 5U4 rectifier tube.
Attachments
2amps.JPG
(Tube_Fan)
Junior Member
 
Posts: 194
Joined: Wed Jun 25, 2014 6:22 pm

Previous

Return to Forum 51 - The Quest For Tone: by Mike Snow

Who is online

Users browsing this forum: No registered users and 1 guest