Channel Switching Mod-on a JCM 800?

[syscokid]

I think this a pretty cool mod for this type of amp. I tried to contact the amp tech responsible for this mod. I offered to pay for his knowledge for this mod, or even ship the chassis to him to get the mod done. I think he was surprised by my first request, and hasn't responded to the second request. He's either really busy, or I might have pissed him off!

Anyone familiar in what needs to be done to accomplish this mod? I thought this would be a fun project to try myself, but maybe it's way over my head!

[youtube]http://www.youtube.com/watch?v=Ow3KchaiWVo[/youtube]

[herbvis]

For a simple channel switch option

http://skipzcircuits.com/CHSW.html" onclick="window.open(this.href);return false;

[joey]

Which part of the mod? In either case both are an incredibly easy thing to do.

[HTH]

We should have a sticky here with a JCM800 channel switching mod for 2203 amps, or anyone wanting to bypass the cold-biased (10k cathode) stage for a plexi kinda tone for their 'clean' channel.

[syscokid]

Which part of the mod? In either case both are an incredibly easy thing to do.

Just the channel switching, as shown in the video with the added volume control. I have a Metro fx-loop board ready to go for install...which I've had the experience of installing on another 2204 project...at least that was easy

We should have a sticky here with a JCM800 channel switching mod for 2203 amps, or anyone wanting to bypass the cold-biased (10k cathode) stage for a plexi kinda tone for their 'clean' channel.

That's a great suggestion...



Thanks for the Skipzcircuits link!

[joey]

Which part of the mod? In either case both are an incredibly easy thing to do.

Just the channel switching, as shown in the video with the added volume control. I have a Metro fx-loop board ready to go for install...which I've had the experience of installing on another 2204 project...at least that was easy

Okay, when time allows ill post something up. It's very easy

[syscokid]

...Okay, when time allows ill post something up. It's very easy

Thanks...especially the "easy" part!

I'm assuming the added volume control acts as a circuit with only one volume control...no preamp volume or master volume? Or in other words, on a stock 2204 it would be like plugging into the Low Input with Master Volume at 10, and then adjusting the volume with the Preamp Volume?

[RussB]

subscribed

[Holgar]

In the 80s I have payed 50$ for the channel switching mod. So it must be easy. Too sad, that I have sold these amps and cannot make a shem or layout.

[syscokid]

I have ordered and received the channel switching module from Skipz Circuits. But I have been too busy to install it. Skip has sent me a schematic/drawing of the switch adapting to the 2204 circuit. If it works out well, I'll ask Skip for permission to post it.

On the other hand, I'm pretty sure I'm going to have a huge volume difference between the 2 channels. There's probably a way to pad up the signal, but I'm clueless here. I would like to incorporate an added volume control as demonstrated in the video, too.

Hopefully somebody will chime in soon... ... ...

[mxr2000]

Any update about it?

[syscokid]

Any update about it?

Nothing yet. I'm going thru some major procrastination on this project...

I would be more motivated if anybody with more knowledge can guide me thru this...

[Janglin_Jack]

I have ordered and received the channel switching module from Skipz Circuits. But I have been too busy to install it. Skip has sent me a schematic/drawing of the switch adapting to the 2204 circuit. If it works out well, I'll ask Skip for permission to post it.

On the other hand, I'm pretty sure I'm going to have a huge volume difference between the 2 channels. There's probably a way to pad up the signal, but I'm clueless here. I would like to incorporate an added volume control as demonstrated in the video, too.

Hopefully somebody will chime in soon... ... ...

I bought a Marshall 4010 combo that a switching mod on it. It used some vactrol, (relays) and was a pretty clever switching design, but it needed a small trasformer and a tag board, etc. The mod was done clean and easy to reverse. The part I liked was they used some dual concentric pots for the volume and gain. This way you can set the gain/master how you like it for each channel.

I reversed the old mod and the amp is basically stock. Ditched the treble peaking circuit, and a few other small odds and ends. I ended up using a Skipz input switch. As I remember it was easy to install. I'll have to see if I can post a picture.

Mike

[Jd267]

Has anyone figured out how to do this ? I built a 2203 clone and would love to add a clean chan .

[herbvis]

Yes, its not to difficult to do. Colossal amps sells great Reay kits with excellent customer support. Skipzcircuits also has a nice little kit with some example instuctions. With the Skipzcircuits kit you can install it in place of the low input(2203 style). It will allow you to switch between the high and low. I used a collosal amps kit to make my 2203 have 3 channels with independent gain poys amd a seperate clean volume. Just takes some good planning.