Mulling a clean master volume on non-HRM -what value to use?

[titser_marco]

Hi! I've tested the ODS style amp I built last weekend and now I understand what most of you say about the weakness of this design, i.e. the clean channel generally overpowers the OD side.

I was thinking of a master volume pot that only was active when the clean side is switched on, and is bypassed when OD mode is on. What value would you guys recommend? Thanks!

[martin manning]

I don't understand your problem. Non-HRM amps usually have one master and a balance (ratio), HRM's usually have two masters. Either way you can balance the channels or not as you desire. You could convert yours to separate masters if you prefer that arrangement.

[aflynt]

I've usually had the opposite issue, at least with the stock 102 circuit. With my preferred gain settings, I need to turn the ratio control down to around 2 1/2 - 3 to get the OD level to balance with the clean. With low plates and treble bleed, they seem more balanced to me however; in both timbre and volume.

-Aaron

[titser_marco]

I don't understand your problem. Non-HRM amps usually have one master and a balance (ratio), HRM's usually have two masters. Either way you can balance the channels or not as you desire. You could convert yours to separate masters if you prefer that arrangement.

Essentially what happens is this: say we have our clean volume at max, and the OD level at max as well. At least to my ears, the OD volume is still lower than the clean volume when you switch between the channels. What I was thinking is that the master volume for clean is only put in the circuit during clean mode, and bypassed when in OD mode. That way, I can still use the clean section's full level (in our scenario) to drive the two gain stages of the OD.

Clearly, this is not possible if I put the master volume just at the end of the clean section before the switch, since I will effectively be lowering the gain going onto the OD section if I turn the clean master down.

In any case, I guess I go back to my original question, with a bit of modification: what value is typically used for a clean master volume in an ODS type build?

[ToneMerc]

In any case, I guess I go back to my original question, with a bit of modification: what value is typically used for a clean master volume in an ODS type build?

It's not really typical, but In reference two the two separate masters, you can use 1M.

TM

[martin manning]

Essentially what happens is this: say we have our clean volume at max, and the OD level at max as well. At least to my ears, the OD volume is still lower than the clean volume when you switch between the channels.

Is the Ratio control all the way up too?

[JD0x0]

No real issues here, I can set the OD amount to '1' and still get the OD channel louder than the clean. With the OD set higher I can match/boost/cut volume perfectly with the clean channel.

IIRC 100k L for both ratio and level.

[Guy77]

Hi! I've tested the ODS style amp I built last weekend and now I understand what most of you say about the weakness of this design, i.e. the clean channel generally overpowers the OD side.

I was thinking of a master volume pot that only was active when the clean side is switched on, and is bypassed when OD mode is on. What value would you guys recommend? Thanks!

Hi, what you could do is get a "1MA-Dual-Stacked-Concentric-Potentiometer" .
It would just replace your current Master volume pot and it could control clean and OD volumes independently.
I ordered these from mojotone in the past (they are currently out of stock) but if you Google it there should be others selling them.
I might do something similar to my ODS amp in the future.

Cheers
Guy77

[ayan]

I think if one will be doing any rewiring, what makes sense is to have completely independent master controls. Look at any HRM schematic for the wiring. The tremendous benefit that brings about is that then one will have a dedicated master for the clean where a nice, large bright cap can be used without fearing negative side effects on the overdrive side.

By the way, regarding the first post in this thread, I can relate to the OP's point with some caveats. The bottom line is that if we want the preamp volume high, the clean channel will have a lot of volume. In some cases with this setting, the OD "channel" may not be sufficiently louder than the clean channel for this to work well. I don't know about you guys, but I like my OD to be quite a bit louder than my clean. If in addition to having the preamp volume high one wants very little overdrive, then the OD channel will not be as loud as the clean, period.

Gil

Hi! I've tested the ODS style amp I built last weekend and now I understand what most of you say about the weakness of this design, i.e. the clean channel generally overpowers the OD side.

I was thinking of a master volume pot that only was active when the clean side is switched on, and is bypassed when OD mode is on. What value would you guys recommend? Thanks!

Hi, what you could do is get a "1MA-Dual-Stacked-Concentric-Potentiometer" .
It would just replace your current Master volume pot and it could control clean and OD volumes independently.
I ordered these from mojotone in the past (they are currently out of stock) but if you Google it there should be others selling them.
I might do something similar to my ODS amp in the future.

Cheers
Guy77

[Structo]

On my ODS I have my preamp vol about 1:00

In fact, just about all controls except the tone controls are around 1:00

I use the Dumbleator output pot for the overall master.

If you have bright caps on the vol or master, having the pot turned up a bit keeps the bright caps from having too much effect on the tone.

I have a 120pf on the volume and I think a 30pf on the master.

[Guy77]

I also run my preamp vol at 1:00 and master at 1:00. My non-HRM really starts sounding big and beefy when almost everything is at 1:00! And of course using the dumbleator as a master is the way to go, I will never play again without the dumbleator especially with a 50 watt amp, it really makes the 50 watt amp sound much bigger tone wise.

[norburybrook]

If I played my 100w BM through the EV with volumes set at 1 o'clock people would be running for the hills

And I'd have no hearing left in a very short time......



Dumbleator is a necessity to keep levels down


Marcus

[Structo]

titser_marco,

What do you have your OD trimmer set at? (usually located inside the amp)

[titser_marco]

titser_marco,

What do you have your OD trimmer set at? (usually located inside the amp)

I actually don't have a trimmer, so I used a regular pot mounted on the front panel, LOL. In any case, I have it at around 22-30k resistance against ground as that is what I've read around the forums and found to be a very useful ballpark figure for setting the OD trim entrance.

[Guy77]

Here is the Dual-Pot Master vol installed in my 50 watt 124 high plate non-HRM with reverb.

I really love this mode. I can now have a separate bright cap on my OD and Clean channels and I can really balance the tone between the 2 channels.
I used 30pf on the overdrive and nothing on the Clean for now, I may change these later once I play it more.
I did notice a slight increase in hiss on the overdrive channel with this pot. I may need to run a shielded cable from the pot to the relay to remedy this.

I installed another relay and now when I engage the OD pedal it also switches the Dual Master volume pot to the Overdrive side and back to the clean side. My amp also has 2 tube reverb and the same relay turns off my reverb when I engage the Overdrive channel. I like my overdrive channel much better when there is no reverb.
I have pictures below of the dual pot. I need to buy knobs now that can fit this pot since it needs 2 knobs that can turn independently. The adventure continues!

Cheers

keep the iron hot
Guy