Caswell #39 Question

[Mark]

A nice set of photos and thanks for sharing these shots with us. What was wrong with the amp and how did it sound after you repaired it?

[dorrisant]

Nothing wrong with the amp. It is for sale:

http://www.mooremusicev.com/products/ma ... aswell-mod

The store lost the footswitch, so I am trying to make the one they bought work.

It sounds like Slash dropped his amp off at my house! You have to crank it to get it to play right. Kinda like a Ferrari... Sure it can go 30 mph in town but it begs to hit 200!!!
This thing is smoking hot! It seriously feels like you get up on top and ride it. Back off the guitar volume and it is a hissing mess, but that is why the footswitch is needed for playing live I suspect. It really does cover the Appetite For Destruction sound, no pedals really needed.

Tony

[Mark]

I played a clone that didn't have hiss issues and I didn't think it had that much gain, but it did sound good.

I dare say it is official the circuit diagrams of the Caswell amp are incorrect.

I've had a quick look at it the input is slightly different. I don't know why he didn't have a whole board made up to replace the circuitry as the wiring has to go back and forward across the amp.

[dorrisant]

Its here for now if you guys want to trace it out to a schematic.

The highest gain settings give up some of the best tones I've heard from a JCM 800. With the footswitch you can change the settings of the amp back to stock, so with that in mind, you could avoid hearing most of the hiss with some thought and practice.

I will try to post some voltages if you guys want them. I would most likely not build one of these but would be more than glad to cough up the goods for those who do.

Tony

[M Fowler]

How is this different from all the work the guys on Metroamp did with the DBM #39?

My version kicks butt we put it up against a couple Splawn amps.

Mark

[Mark]

http://forum.metroamp.com/download/file.php?id=7024

Is this the circuit you put into your amp?

This circuit doesn't have the mid boost etc. The amp I heard sounded nice but it certainly didn't copious amounts of gain. I'd say it had a bit more gain than your typical Marshall but a lot more focused.

I had a look at one of the cathode resistors I thought it was 1K but it might have been 10K.

[M Fowler]

Yes there is a mid boost.

[Mark]

Hi Mark

What circuit diagram did you use for your amp?

I'm not sure if we are talking about the same circuit.

My feelings about the circuit I posted the link for were that it could have used more gain at the input stage and a larger cathode bypass cap.

[M Fowler]

Hi Mark

What circuit diagram did you use for your amp?

I'm not sure if we are talking about the same circuit.

My feelings about the circuit I posted the link for were that it could have used more gain at the input stage and a larger cathode bypass cap.

Here is my thread https://tubeamparchive.com/viewtopic.ph ... fowler+hrp

And the thread where I got the info from on Tag. https://tubeamparchive.com/viewtopic.ph ... sc&start=0

[Mark]

Okay I found the circuit, I thought I would have used two triodes for the first stage. One to provide fatter clean tones and the other to provide more gain for the overdrive channel, I think I would have used a larger cap than 0.68uF as I like fatter tones.

[Mark]

Okay I found the circuit, I thought I would have used two triodes for the first stage. One to provide fatter clean tones and the other to provide more gain for the overdrive channel, I think I would have used a larger cap than 0.68uF as I like fatter tones.

http://caswellamps.studioelectronics.co ... agram.html

The mid boost is going to be a larger cap, but there appear to be three gain boost switchs on this amp, one may well be a tone control lift.

[M Fowler]

I sold my HRP based on AFD #39 by Darkbluemurder so I started on another build.

I'm using a chassis from ValveStorm.com a 1969 Chassis 100 watt but with an undrilled front panel. I didn't want to drill all those holes.

Very nice chassis, got the back panel from them and using my own HRP front panel.

https://tubeamparchive.com/download/file.php?id=29896

[mhartman]

I sold my HRP based on AFD #39 by Darkbluemurder so I started on another build.

I'm using a chassis from ValveStorm.com a 1969 Chassis 100 watt but with an undrilled front panel. I didn't want to drill all those holes.

Very nice chassis, got the back panel from them and using my own HRP front panel.

Nice, that should be a fun build. I just spent the last few weeks tweaking my ceriatone AFD#35 to get it closer to SIR#36 specs. I'm loving it now.

[M Fowler]

Sweet I've eye balled that #35 amp as well plus all the info on Metroforum, enjoy.

[mhartman]

Sweet I've eye balled that #35 amp as well plus all the info on Metroforum, enjoy.

Talk about a novel of a read. Since those guys clammed up about their tweaks, it has been rather cryptic over there.