The Amp Garage

I didn't like how the tone controls worked with that jumper, so I removed it. I found the PAB worked better after that too.

I am having a great time setting that trimmer at the entrance to OD1. Every time I settle with a setting, I find a better one! Maybe I should have put it on the front panel.

Thanks Heisthl

I am trying to figure a way to make this loop provide a parallel option.

I have two amps with parallel effects loops and IMO there is nothing better. The amp tones stay completely untainted and there is so much more control over the effects mix.

Where is the Schematic for this??

I would figure you would need to incorporate the NORMAL channel tube and make circuit changes following one of the many schematics.

Did HAD ever do this type of mod before he went into production??
Does anyone have some documentation of doing this type of stuff?

Thanks!

Nice clean work. Labeled and ready to sell?

Is the D'lator a series/parallel loop?

I only learned this studd by looking at the published layouts and schematics.. Here is a snip from two layouts. The one on the right comes from a layout that is labeled BASSMOD.

Here I am again posting to myself... Sorry guys, it's just not a clone but IS the circuit. Here is an update... I played the amp with the switching and found to get a good clean or OD sound I had to compromise the other sound. IMO It appears the best Dumbles have footswitchable (PAB and BRIGHT) stuf...

Nice work!!! Can't wait to see how you build the speaker cab.

Just noticed.. You don't have any relays in that amp. Are you just using the panel switches?

Thats a high pass R/C filter. Fun to play with changing the R and the C to shape things. A good example of this filter is where HAD uses a 220k/500pf (or 220k/330pf on some schematics) to feed V1B, something that you never see in Fenders, but is essential to the Dumble tone. Although very popular i...

I have major tweakitis! I've had to stop myself many times. Now I make a small change and wait for weekly band practice. That's where I listen. Another great thing to do is add a small switch to the amp. I'll add one to the chassis on the top (or bottom for you tube hangers) or on a push/pull pot. I...

Structo wrote:From what I remember a typical Fender bypass was 25uf/1K5 and 100K plate loads.
Don't see much of that in Dumbles unless I misunderstood your meaning.

Okay, darn close.. 5uf bypass cap cuts off a bit higher (~40hz) than the 25uf (~9hz) but most guitar speakers don't reach that low anyway.

Interesting to me is the totally standard (Fender) plate and cathode resistor values. After looking at so many schematics of these amps and implementing the circuit this appears to be unusual. (?)

I guess I am used to the Fender style tone controls. This tone control works a lot different.

I am using the ODS - non hrm schematic without the bass mod. It appears the MID control does not do much, if anything, when the BASS control is full off. I do have the MID cap as a 47n but I have noticed the ODS has a 10n. Will this make much of a difference? I did notice how the tone controls effec...

Question about the tone controls:
I tried the Bass mod which made the bass control and PAB not very effective.
I changed it to not the bass mod but the midrange does not work with the bass turned down. Not very useful.

What seems to be the best tone control option?