Need Advice...Gut it or Mod it?

[Blindog]

I have a KMD XV100SD amp from the late 80's that I picked up for 100W HRM BM ODS build. I'm trying to figure out a way to modify without hacking up the front panel look. Am I crazy for thinking like this, or should I just gut it and start over? Or do I just gut the preamp and mod the output section and PS? This thing has got some beefy iron. I've got the schematic and some pics below.

Also, I'm trying to figure out what exactly IC 2 is doing. It's a dual JFET opamp. Then there's the 2 effects loops. I've never seen a design like that. I'm just trying to figure out what to keep and what to trash from the original circuit if i attempt to mod the pre. Obviously the solid state clipping between V2b and V3b.

I'm totally open to any ideas you all may have, even if it means calling me crazy

Mark

[heisthl]

should I just gut it and start over? Or do I just gut the preamp and mod the output section and PS? This thing has got some beefy iron. I've got the schematic and some pics below.
Mark

Depends on how much money you have in it - if not much steal the transformers and make a new amp otherwise repair it and sell it for enough to make a new amp. IMHO modding stuff like this thinking you're going to create a masterpiece is a waste of time and effort, it's never going to be better than something from scratch.

[Bob-I]

Personally I love taking old amps and turning them into something special. That said, modding an amp like this is sometimes more effort than it's worth and the results can be less that simply gutting it and using the chassis and iron to as a platform.

Gutting it and drawing up a layout using the existing chassis and iron would be my approach. Also notice that there's one control missing, the clean master or Ratio as HAD called it sometimes.

Good luck with the project.

[butwhatif]

I like challenges, but trying to make this into an ODS etc might be just that.
Depends on how close to a particular sound you want to go. And, the outside lane might be that it's unachievable. But then again, it might become something way nicer than it is, if you're up to the task.

[Blindog]

Depends on how much money you have in it -

Got $225 invested in it (about what a decent set of new tubes would cost ) So I'm totally Ok with gutting it and starting over.

Personally I love taking old amps and turning them into something special.

Same here. But, after some thought and reading the comments, I think I'd like to do this...Keep the power supply and output pc board intact, and remove the preamp and start from scratch. After studying the schematic and the layout, everything logically connects to the preamp from that board. Basically I'd be doing a preamp transplant I could then fill in any unused front panel holes and come up with a new faceplate, like I did on my Bassman 10 conversion.

The only challenge, for me anyway, is coming up with a layout for the preamp taking into consideration where the preamp tubes are mounted now. If I chassis mounted them, I'd have to use those octal adatper plates for the sockets. The holes are about 1 1/4. I don't have any layout drawing skills

Anyone see any issues with this idea?

Thanks for all the input.

Mark

[heisthl]

Might be easier to just abandon the chassis and do it in a different one with a more conventional layout. Some amps are easier to push in the Dumble direction than others - here's a clip of a Carr Slant 6 with a modded lead channel:

[Blindog]

Might be easier to just abandon the chassis and do it in a different one with a more conventional layout

I agree. But where do I get a decent chassis? I've not heard good things about the Natch chassis, and the other option would one from Nik. I'd like to get one screened (like Brandon was selling) I missed the boat on those. Plus, I was trying to save some time and $$ by re-purposing the old chassis. I guess If i completley gutted it it would probably be easier to do a more traditional layout.

[Bob-I]

The only challenge, for me anyway, is coming up with a layout for the preamp taking into consideration where the preamp tubes are mounted now. If I chassis mounted them, I'd have to use those octal adatper plates for the sockets. The holes are about 1 1/4. I don't have any layout drawing skills

Anyone see any issues with this idea?

Thanks for all the input.

Mark

No issues with the idea at all. Now's the time to work on your layout skills.

[pamaz67]

from a 50w kmd ( don't remember the model though) and it turned to be a killer ods non hrm amp
Such a killer one that now belongs to one of the most appreciated italian guitar player. he gave me a fuchs in change of it!

Ciao

Paolo

[Blindog]

from a 50w kmd ( don't remember the model though) and it turned to be a killer ods non hrm amp
Such a killer one that now belongs to one of the most appreciated italian guitar player. he gave me a fuchs in change of it!

Paolo, that is very encouraging indeed! Did you do the mod yourself? Would you mind sharing your layout? Very nice looking amps on your web site, by the way!

Mark