Tube Amp Archive

So, I'm going over the layout verifying the NFB circuit and lo and behold, the 390 ohm resistor after the NFB resistor was bypassed with a 22uf electrolytic for some reason.

Removed the cap and all is good in OTS land.

Can you explain why someone would do this?

It does not appear to be functioning...

NFB resistor?

The NFB circuit is a little strange on this thing, just looking at the layout.

I'm sure the answer is obvious and I'm brain farting but, I've acquired a Ceriatone OTS that sounds beautiful (clean) on the 16 ohm tap running into a 16 ohm load or any load but distorts on either the 4 or 8 ohm tap running into any load. The distortion isn't necessarily unpleasant but definitely u...

Alright, apparently there's a few versions of this head. This one is a DSL copy.

I think I talked him into getting on the forum and found out he is not opposed to starting from scratch to build the simple hand-wired high gain unit.

We'll see if he gets on.

Chris, I hate to be harsh, but if your friend is a business person, he will know that he doesn't HAVE TO spend a lot of money trying to make an amp that nobody is in love with, just because he bought the company. Hopefully, he got something other than this amp "design" for whatever he spent. But th...

The more I look at this amp, the stupider I get.

roberto wrote:That chip is taken from the Marshall 2000 series.
It's a fixed depth.

Ah! I see what looks to be the NFB now.

This schematic is a little confusing.

It's a mess, but you can follow it through. I'm surprised at how much preamp is still there if you made this OD channel only. Going around clockwise - Preamp across the top, with the (only one!) extra OD gain stage in the middle between RL1 and RL5, separate normal and OD tonestacks in the right to...

I don't want to seem a pita, but if the owners of the company can't even read a schematic, how they think to manage the aftersales? Just sell some copies made by someonelse and then disappear? I wouldn't be part of that... Hey roberto. I know it's a lot of reading to go back through the whole threa...

Lol. Come on, that tone kills;-) I too need Advil to look at the schematic. Let me begin by stating I don't have a lot of inside info. I met my colleague when I was trying to find some tolex locally for a rush job a few weeks back. Madison Amps was, for all intents and purposes, dead. He's was an ow...

This is just my opinion but instead of trying to remove all the extra, I'd start with the output section and build a pre-amp that suited my tastes. Well Jim, I'd do the same thing if it were my project but, my friend bought this amp company because he loves the high-gain tone of this particular amp...

John_P_WI wrote:I doubt it will sound the same without the interaction of the trimmed fat...

Well, you're right obviously. But, hopefully, once the fat is gone, it'll sound better and if not, tweaking will commence.

Lol. There's a lot of fat to be trimmed. I guess I should have stated the plan- Ditch the; reverb, effects loop, switching, clean channel, everything that isn't the overdrive channel and power section. Controls-gain,TMB, level. Understood. Good call. Determine what positions you prefer for the vari...

Lol. There's a lot of fat to be trimmed.

I guess I should have stated the plan- Ditch the; reverb, effects loop, switching, clean channel, everything that isn't the overdrive channel and power section. Controls-gain,TMB, level.

Here is the schem.

I tried pm-ing it to you but apparently, it's too large.

Now, nobody steal the circuit, go into mass production and take away all the profits;-)