For the Amp and kit builders

[Darg1911]

Probably not the best forum for this question but I'll give it a shot anyway. I could use some input / advice. Thinking about a JTM45 "clone". If I do it, I'm going to definitely want to add a Master volume. Looking over a bunch of the different kits, the layouts are all pretty similar. I think I only came across one with a master volume and it was installed in one of the input jacks. Not something I want to do. It seems that most people pull one of the speaker out jacks and install a MV in it's place. I'd rather not do that unless I had to. Other than that, it looks like the only space on the back of the chassis would place it between a couple of the 9 pin sockets. My concern really is about avoiding noise issues. Do you think a MV (either pre or post PI) would be more susceptible to inducing or picking up any noise if it was located on the back of the chassis between two of the preamp tubes?

Thanks

 

[Surgeon]

Re: For the Amp and kit builders

Well, it would all be dependent on your routing of the wires but I'd steer clear of adding something this close to the preamp stages. That being said, I added a MV on my latest buid between the power and preamp tubes and it works just fine so if you do it carefully you could still be ok.

Question: if we're talkin about a kit or a diy build, why not just drill an extra hole on the front panel? Much more practical from a player's perspective and further from the tubes too. I did that on my jcm800 kit and you wouldn't know it's an add-on, lomks just as food as the rest.

 

[Edgecrusher]

Re: For the Amp and kit builders

There are a number of ways you can do it. Surg has the right idea I think in saying just drill another hole. There is ample space to do so.

If you want the type that the later 2203's and 2204 became famous for you could just remove one of the JTM45 channels and cascade it like Marshall did. In this way you wouldnt have to drill holes it would look like a JTM45 you would just lose the ability to jump channels.

Theres a bunch of ways it can be approached. Ceriatone has layouts for a ton of modded circuits you can dig through.

 

[Darg1911]

Re: For the Amp and kit builders

I'll check out Ceriatones pages for the mods. Just ran across a youtube video of a scratch build. The guy had a PPIMV with pot installed between two of the 9 pins. He used shielded cable so I feel OK about that being a possible option. Aside from one of the input jacks, I'm not really seeing where I can install another pot with it not looking out of place, unless I punch/drill a blank chassis which I'm not up for. But it's not like I have a chassis sitting in front of me. It's not even in the planning stages at this point, just in my head (especially now that we just had to replace the damned refrigerator) but I thought I would ask for some input anyway. Thanks.

 

[Edgecrusher]

Re: For the Amp and kit builders

You can use one of the jacks. No one uses the low input for the b channel that ive ever seen. I'm not fond of it being on the back though. Its work able I just wouldnt like it. I would prefer to move the prescence knob to the rear and put the master on the front. But thats just me. I sometimes have to adjust volume on stage its pretty rare that after sound check i move the prescence. But thats up to you if you can live with it on the back have at it.

 

[Darg1911]

Re: For the Amp and kit builders

You can use one of the jacks. No one uses the low input for the b channel that ive ever seen. I'm not fond of it being on the back though. Its work able I just wouldnt like it. I would prefer to move the prescence knob to the rear and put the master on the front. But thats just me. I sometimes have to adjust volume on stage its pretty rare that after sound check i move the prescence. But thats up to you if you can live with it on the back have at it.

That's a good idea ... moving presence to the back. Thanks.