HiFi tube amp and homebrew guitar preamp

[Tube_Fan]

More tube amps

[jps]

Fisher?

[Tube_Fan]

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]

Expanders and compressors
http://antiquesci.50webs.com/CompExp.htm

https://web.archive.org/web/20140717051 ... opic=41150

[Tube_Fan]

I got another tube amp. Its a Fisher 481a. I tried it with some speakers and it works OK.

[Tube_Fan]

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.

[Tube_Fan]

Here's the amp schematic.

[Kiddwad57]

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:

[Tube_Fan]

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.

[Tube_Fan]

I bought this book years ago.

https://www.amazon.com/Search-Musical-E ... 1884250017

http://www.meta-gizmo.org/

http://www.meta-gizmo.org/tri/index1.html

https://od.lk/s/OV8xNjQ4NjE5OTdf/HiFiNews1994-r.pdf

[Tube_Fan]

A better copy

[Tube_Fan]

Where has all the Good Stuff Gone?
Electronics Now Oct 1996

[Tube_Fan]

Good tube literature
https://audiokarma.org/forums/index.php ... ure.71504/

[Kiddwad57]

"Where has all the good stuff gone," was a good but frustrating read. Thanks man! The same concepts can be applied to the guitar and amp market as well. At one time this really bothered me but I don't know how I feel about it now. Does it matter where the wealthy buyer lives? That hifi/guitar/amp is probably out of my reach anyway.

It mostly feels bad that younger players don't have quality used items available to them in the way many of us did growing up. Princeton amps, even Champs, are getting hard to come by, when back in the day they were cheap as dirt.

I've had to teach students how to turn on a silverface Bassman!

[jps]

I've had to teach students how to turn on a silverface Bassman!

I can see it, now. Someone getting into a car for the first time to learn how to drive.

N@@ß: Hey, how do ya' boot this thing up?