Pro-10 Blue + Green = Muscle Milk

[jeffwhitfield]

I think it’s the PDR. It was the last resistor off the output which I believe is the PDR. In this case, a 470R was called for. I had a 570K in there instead. Big difference and caused higher frequencies to get carved off. Now I’m left wondering how it happened. Was I drunk?

 

[Feral Feline]

Ahh okay, R41 is the culprit.

My limited understanding of a PDR, in the usual context of stompbox effects, is it provides a path to ground for capacitors’ stored energies, the PDR usually at the front end of a circuit, though sometimes at the end — it reduces the popping when engaging or bypassing the pedal.

A large value keeps it from influencing the tone while still providing an escape route for the stored energy differential that would otherwise cause a pop.

The PDR in the Andromeda DLX is R2 (1M), there is no PDR on the output.

There are other uses for pull-down and pull-up resisters in other general circuits of which I have no ken, but you can search online if it interests you. I’m mainly interested in pedals, and other more knowledgable people can explain it so much better than I… for example:

Pedal pops even with a pulldown resistor

Pedal pops even with a pulldown resistor

www.diystompboxes.com

 

[jeffwhitfield]

Ahh okay, R41 is the culprit.

My limited understanding of a PDR, in the usual context of stompbox effects, is it provides a path to ground for capacitors’ stored energies, the PDR usually at the front end of a circuit, though sometimes at the end — it reduces the popping when engaging or bypassing the pedal.

A large value keeps it from influencing the tone while still providing an escape route for the stored energy differential that would otherwise cause a pop.

The PDR in the Andromeda DLX is R2 (1M), there is no PDR on the output.

There are other uses for pull-down and pull-up resisters in other general circuits of which I have no ken, but you can search online if it interests you. I’m mainly interested in pedals, and other more knowledgable people can explain it so much better than I… for example:

Pedal pops even with a pulldown resistor

Pedal pops even with a pulldown resistor

www.diystompboxes.com

Ah, good info! Thx for sharing!

 

[HamishR]

If it was a 470R it wasn't a pull-down resistor! They're usually 1meg or more.

I really like the Protein Blue - the Green doesn't really excite me so much. But the Blue is one of the few 3-knob ODs where I could almost use it without adding a bass control. Almost...

 

[jeffwhitfield]

If it was a 470R it wasn't a pull-down resistor! They're usually 1meg or more.

I really like the Protein Blue - the Green doesn't really excite me so much. But the Blue is one of the few 3-knob ODs where I could almost use it without adding a bass control. Almost...

The Green is more or less a standard ODR-1. It could use a Bass Cut control for sure.

The Blue doesn’t really need much but a Presence control could add some extra flexibility. Might even consider adding an extra clip option.

The magic happens when you stack them. The whole Blue/Green stack is quite different than a KoT, which is just two Blues really. I added an order switch and that really changed things. The stacking is just incredible.

 

[jeffwhitfield]

Ok, so I have a few mods I’m doing…

First one is a simple one: a Presence pot for the Blue channel. Basically, just do the following:

1. Remove the 10n capacitor on C7
2. Using a B25K pot, add one leg of the 10n cap to leg 1 of the pot,
3. Jumper legs 2 and 3 on the pot
4. Jumper the other end of the cap to the outside hole of C7.
5. Jumper leg 3 of the pot to the inside hole of C7
6. Mount your pot to your enclosure however you wish

The Presence pot is nice cause it gives you some extra tone shaping with the higher frequencies. What's nice is that you can turn Tone pretty much all the way off and then add back in some higher frequencies with Presence. It also allows for adding a bit more sparkle when Tone is set higher. Basically gives you more range with various amps, especially those that tend to be more mellow.

 

[jeffwhitfield]

Next one I tried was a Bass Cut pot on the Green channel. I added it to C5 by removing the positive leg and jumping a C50K pot to it. It worked...sort of. Just way too subtle to make much difference. I might have done it to the wrong cap. Could be that it needs to be done to C6. Will have to trace it a bit more to figure out the best spot.

In fact, I might be able to borrow off the Andromeda Deluxe and do it in a way that can be jumpered in without any component removals. All it's really doing there is adding a couple of 220n caps off the clipping stage with a 25kB in-between to control how much bass is being cut.

Last one will be a Mids pot. That one is a bit more involved. Requires a small circuit be injected between where the circuit breaks off into the Spectrum stage and the second op-amp stage. Fortunately, none of the components have to be removed. Just straight jumpers from a small PCB...which will require some sort of mounting into the enclosure. Could combine this and the Mids mod into one little PCB.

Without the schematic, I'm finding it a bit hard to figure this out. Kinda making my way around the circuit...but still would be easier with a schematic in hand (cough! hint! hint!)