Filmosound guitar amp conversion

[mozz]

Filmosound guitar amp conversion. Model 179. Before i finish the build, i finished the schematic, stealing a couple parts from other amps and some original to the Bell and Hollow filmosound model 179. I need opinions, corrections, etc.

Now with actual working voltages, some voltages are from original schematic (110-117v) power supply. Originally was cathode bias, changed to fixed bias. It has a few less tubes than stock and my wall voltage is 122 today, so i expect it to be high. I can get 17 watts output clean, plate voltage 410 and tube current 25ma each. 73% dissipation or close. (jj6v6s) I may drop the B node down a bit, i have a 1k in there now. No sound checks until the wife goes out saturday. No oscillation of hum, which is a good sign.

[Tony Bones]

I've heard a couple of Filmosound conversions that sounded great! The nice thing about using those old projectors is that (1) there are thousands of them sitting in high school store rooms etc (though probably most have been disposed of by now) and (2) nobody will ever want them! So it's cool to ravage and reuse the parts.

I have a Filmosound booster amp that I picked up cheap. It even came with a gently used P12Q speaker. Unfortunately it's not like the common model 179 projector amps. There's a pair of 6L6 and a single 6SL7; not quite enough gain for a guitar amp, so it sits quietly until I figure out something to do with it. I might need to cut a hole for another tube...

[chardbou]

Hello mozz

I have a Filmosound model 179 amplifier.
I want to convert it into a guitar amplifier.
I would like to know if you had to make corrections to your shemat and if it operates property in its current version.

Thank you

[mozz]

Here is the build thread.
Filmosound Model 179 Conversion | A Guitar Forum

[zipgun]

Have you ever made a layout for this? I'm a newbie. I have a 179. I've put 5f2a into different filmosounds before but I'd love to try yours out.

[mozz]

There is not really a layout, you have only a small area to work with under this chassis. I did a point to point and added standoff's where needed. Even though the website "a guitar forum" was bought out, my thread is gone. I don't know if i have any pictures from this build, i may. I do remember saying that if anybody besides me ever has to work on this, i will be getting bitched out. I think i did the bias and power sections first. When i have to sleeve resistor and cap leads, it's getting tight.

[zipgun]

If you ever get a pict, I'd love it. If not, I'll play around. I brought my first build to a buddy with a variac to check out my first build and I got chewed out pretty good.

[MMcK]

There is not really a layout, you have only a small area to work with under this chassis. I did a point to point and added standoff's where needed. Even though the website "a guitar forum" was bought out, my thread is gone. I don't know if i have any pictures from this build, i may. I do remember saying that if anybody besides me ever has to work on this, i will be getting bitched out. I think i did the bias and power sections first. When i have to sleeve resistor and cap leads, it's getting tight.

Hello Mozz, your old thread thanks to the heads up from Willard
https://web.archive.org/web/20170815...version.95617/

Know this is an old thread but hope it helps someone.

[mozz]

Yes, the Wayback machine prevails. I probably have all the original pictures on a IDE drive here somewhere.