Opinions on a relay activated volume boost

[daz]

I have done this for years by putting a pot near the effects loop and taking the return signal to a relay which either sends it to the destination or to a pot which is used as a variable resistor to ground. So one lug to ground, the other to the relay and in one position of the relay it sends a wire to the return hot. It works fine and unlike using a second master it''s much simpler and doesn't pop. My question is, does anyone see a issue with this affecting the tone at all? I only ask after doing this for years because i now have an amp that sounds so good i want to be sure i don't compromise the tone even slightly. I figure it' better then a switched second master because that way you change the series resistance and therefore the tone a bit, not to mention the pop. But if anyone has thoughts about a better way than i am doing it or any other thoughts that may be helpfull, please speak up, i'd be very interested.

[olddawg]

I have done this for years by putting a pot near the effects loop and taking the return signal to a relay which either sends it to the destination or to a pot which is used as a variable resistor to ground. So one lug to ground, the other to the relay and in one position of the relay it sends a wire to the return hot. It works fine and unlike using a second master it''s much simpler and doesn't pop. My question is, does anyone see a issue with this affecting the tone at all? I only ask after doing this for years because i now have an amp that sounds so good i want to be sure i don't compromise the tone even slightly. I figure it' better then a switched second master because that way you change the series resistance and therefore the tone a bit, not to mention the pop. But if anyone has thoughts about a better way than i am doing it or any other thoughts that may be helpfull, please speak up, i'd be very interested.

Seems like to me it's no different than plugging a volume control pedal or a passive attenuator footswitch into the the effects loop.

[daz]

Well, it is because it's not being used as a voltage divider. It just places more load on the signal to ground.

[Richard]

So you're effectively placing a variable resistance from your signal to ground whereas a traditional volume control would also have a resistance in line with the signal. Am I understanding this correctly? How does the response differ from a traditional voltage divider? I would imagine the rolloff would be much slower but I've never wired one up like that. I'm sure that the impedance of the effects loop also has an effect.

[J M Fahey]

Agree and add.
IF therevis a capacitor in series with loop send ,you are adding low resistance value afterit (so you can attenuate) and it mightcut a lot more bass than expected.

Of course actual frequency and severity depend on the circuit feeding it.

Try to post a partial schematic showing that area.

[Enzo]

Does the amp already have an FX loop? If so, dummy this pot up on a plug and plug it into the loop and then you tell us if it affects tone. Certainly a lot faster than a debate here.

[daz]

I have used this in the past a lot, and if tone is changed i never noticed. But i ask because tone is tricky and often you will not hear the difference right away or under certain circumstances like different volumes etc. I just thought maybe someone might had a black and white answer.

So you're effectively placing a variable resistance from your signal to ground whereas a traditional volume control would also have a resistance in line with the signal. Am I understanding this correctly? How does the response differ from a traditional voltage divider? I would imagine the rolloff would be much slower but I've never wired one up like that. I'm sure that the impedance of the effects loop also has an effect.

Yes. Never noticed any bass rollvoff so i guess it's probably fine. In any case, i only use this setup to drop the volume a tad so that for solos or places where i need a but of a volume boost it's there. If i were using it as a full range volume like a master that of course would not work and id' use a voltage divider.

[olddawg]

I have used this in the past a lot, and if tone is changed i never noticed. But i ask because tone is tricky and often you will not hear the difference right away or under certain circumstances like different volumes etc. I just thought maybe someone might had a black and white answer.



Yes. Never noticed any bass rollvoff so i guess it's probably fine. In any case, i only use this setup to drop the volume a tad so that for solos or places where i need a but of a volume boost it's there. If i were using it as a full range volume like a master that of course would not work and id' use a voltage divider.

I have a similar result using a Weber Mini Mass attenuator with a bypass footswitch option. The unit cost $125. The attenuator is barely on then I bypass it for a lead volume boost. The advantage is I can use it on any stock amp. Works very well when I'm miked.

[Chuck H]

I'm sidin' wit da dawg

An attenuator will change the tone a little, but no more, and probably less than adding/subtracting resistive elements between the preamp and power amp. I like attenuators and endorse their use at every opportunity. Moving on...

The load you intend to use is still comprising part of a voltage divider. Otherwise it wouldn't reduce volume!!! It's just that other resistors or the tubes internal resistance are acting as the series resistor instead of a dedicated series resistor. And Juan is right about the change in tone. Which, while it would be greater with a dedicated series resistor added, will still be there in either scenario.

As mentioned, a schematic would be nice. What I'd be interested in is whether the stage in question uses a fully bypassed cathode resistor. If it does you can have 5dB to 6dB adjustability from a very low impedance source to run cable, skip fussing with a relay circuit and suffer almost no change to the signal other than gain.

[daz]

I'm sidin' wit da dawg

The load you intend to use is still comprising part of a voltage divider. Otherwise it wouldn't reduce volume!!! It's just that other resistors or the tubes internal resistance are acting as the series resistor instead of a dedicated series resistor. And Juan is right about the change in tone. Which, while it would be greater with a dedicated series resistor added, will still be there in either scenario.

As mentioned, a schematic would be nice. What I'd be interested in is whether the stage in question uses a fully bypassed cathode resistor. If it does you can have 5dB to 6dB adjustability from a very low impedance source to run cable, skip fussing with a relay circuit and suffer almost no change to the signal other than gain.

It's basically in the effects loop, so right between the master and PI just like a JCM for example. tone stack>master>send>return>PI. I tack the load on right at the return jack before the .022 that goes into the PI.

The reason i asked this question because when you use adjustable simple load liek this rather then a VD that does the same thing but also imparts a series resistance to the signal, to get the same degree of volume attenuation a VD would give you have to reduce the ground resistance till it's far closer to ground than a VD would be at that level. Thats and the series resistance it would seem would cause a tonal difference besides just a volume difference. But the reason i asked is that i am of the belief that very subtle differences you may not notice outright when listening for it may in the long run degrade your tone enough that you don't like it as much as you did. It's tricky. So rather than try and A/B it ad nausium and still wonder if i might have a lesser tone w/o being able to hear it during listening tests, i asked the question to see if there aws a definitive answer. But so far the only negative i have heard is less bass. But thats one thing i can say i never had a problem with something that doesn't worry me.

At this point i no longer worry about it, if for no other reason that since i decided to build it into a outboard box i can easily A/B it if i feel at some point my tone isn't quite right or i can just remove it altogether. I asked because i was considering the fact that I was going to build it into the amp i coudn't easily test it if i'm feeling something is not perfect at some point.