Hammond AO-43 Guitar Amp Build Options with Amp Layout

[Yamariv]

Eeek, sorry about my newb reply but I'm not too sure where the choke is inserted in the layout :S I'm planning on using this Stew Mac Layout with the original Hammond Choke

https://www.stewmac.com/Pickups_and_Ele ... p_Kit.html

I checked out the Duncan software but it's a little complicated for my knowledge of schematics I'm going to have to brush up a little more on my theory knowledge..

[sluckey]

Eeek, sorry about my newb reply but I'm not too sure where the choke is inserted in the layout :S I'm planning on using this Stew Mac Layout with the original Hammond Choke

https://www.stewmac.com/Pickups_and_Ele ... p_Kit.html

That StewMac instruction manual is very detailed. Page 22 and 23 (step 39) show you exactly how to connect the choke. Refer to the schematic on page 47 to see how it actually fits into the circuit.

Keep in mind that this layout is for a JCM 800-2204 high gain amp. It's NOT the same as a Plexi. If you are really interested in a Plexi using a StewMac layout you you would want this one...

https://www.stewmac.com/freeinfo/i-1073 ... ctions.pdf

Also, there will be some minor circuit tweaking, mainly in the power supply and power amp, to adapt this layout to use 6V6 tubes. And if you want to actually build the StewMac 50W amp the iron on that AO-43 chassis is not usable.

Here's a link to my 6V6Plexi that uses all the iron from the AO-43 amp. All the little tweaks are already worked out. Use it freely as you see fit.

http://sluckeyamps.com/6v6plexi.pdf

[Colossal]

This is a little off topic but, the layout drawing and instructions have you soldering a ground bus wire across the pots. That is a bad practice and antiquated. The layout includes this as keeping with the original JCM800. Since your amp will be repurposed, there is no reason to repeat the mistakes of the past.

EDIT: I was posting as Sluckey was. Definitely use his layout and see how the ground scheme is laid out.

[Yamariv]

Sorry guys, I should have clarified..Yeah I definitely want to do the JCM800 high gain 6V6 conversion of the A0-43 as I'm lucky enough to already have a Plexi

So what is the issue with the common ground bus wire across the Pots, never heard of that issue?

[sluckey]

If you can read the schematic and follow the layout in those instructions you should not have any problems doing this conversion. Of course there will have to be adaptations to the layout if you use the AO-43 chassis. Reading the schematic will keep you straight on this. Let us know how this turns out. Post some pics too.

[pompeiisneaks]

Sorry guys, I should have clarified..Yeah I definitely want to do the JCM800 high gain 6V6 conversion of the A0-43 as I'm lucky enough to already have a Plexi

So what is the issue with the common ground bus wire across the Pots, never heard of that issue?

Basically it can be harmful to pots to have to scratch away surface coatings, and get an iron that's got enough heat to adequately solder to the back of the pots. That much heat can and does occasionally harm the pots themselves. Many builders (myself included) now will use a bus bar that runs along the back of the pots with a soldered jumper wire between any grounds on pots and then connect it near the input jacks so that all of the preamp signal path is grounded far away from the higher current sources.

~Phil

[Yamariv]

Yeah, I'll definitely post some pics of the build when I get started. So in my case with the 6V6's would you guys just go with 32uf across the board for filercaps? Or should I lower the later ones to 16uf to get more of a squishy vintage sound?

Phil, would you by chance be able to post a pic of an amp where you did this ground bus so I can visualize what you mean? I might as well do it this way on my amp if it's better..

[sluckey]

This is what Phil is talking about...

[pompeiisneaks]

Yes exactly, thanks sluckey!

~Phil

[Yamariv]

Wow, that's some nice work on that amp! Thanks for the pic, totally see what you mean about the bus wire now

BTW, what the trick to getting all the resistor and cap wires so straight?? Looks awesome

[dorrisant]

High plate voltage... Hear me out, JJ6V6S will handle it. That is the reason I switched to them for my Silver Jubilee conversion... that and the breakup.