Master Volumes Types

[ampdoc1]

I never tried to figure out the right or wrong,..it just seemed to me it would work. You might try to get ahold of the TUT where it was shown.

The single 1M audio taper pot worked fine for me,...no problem with the taper,...but I wouldn't expect it in to to work any differently than when used as a volume control elsewhere..

[Structo]

Thank you

[Structo]

While researching this I came upon some interesting attenuation circuits.

This has probably been covered here in the past but I thought it could be revisited.

It's the Full/half/1/4 power cathode switching idea.

Pretty simple really and according to the forum posts I read it works well on any cathode biased PP amp.

I'm going to try it on my amp.

[Markusv]

I just implemented the single audio taper 1 meg pot on the LTPI in my KT 66 rocket.

Thus far I like it.
I feel it allows me to run the gain at or above the 9 o'clock position, where the amp starts to behave in a very pleasing fashion. For instance I feel the tone stack and cut control really come to the fore
However, at very low mv settings, with the gain cranked, you should not expect great sound. It is just thin and fizzy sounding
Leads me to believe that this amp requires the optimal signal trough the LTPI to make the Power tubes really shine (DOH!)

Fun amp
Very easy to tweak and so forgiving compared to a Liverpool!

Thanks for all the great info!

Markus V

[Stanz]

I have found the same thing with the Rocket. I will back off the bootstrapped MV just a bit, 3 o'clock or so. It seems the PI is just a tad too overdriven, but that is enough to drop the signal into a cleaner range and I can bring the volume up as high as 12 o'clock. Great overdrive sound with the volume somewhere between 9 o'clock and 12 o'clock. Start dropping the cut control and you can get some fantastic distorted sounds.

[Markusv]

Great advice!
I'll try your approach-
Am also considering a 500k resistor between wiper and grid and then use a 500 k pot.
That way it should be impossible to dial MV into the shitty sounding range, -no?

Markus V

[Stanz]

Great advice!
I'll try your approach-
Am also considering a 500k resistor between wiper and grid and then use a 500 k pot.
That way it should be impossible to dial MV into the shitty sounding range, -no?

Markus V

yeah, it'll make it a 500k - 1M pot, which for a 1M audio pot would limit it to the 7 - 10 range, since 500k falls past the mid point. That makes sense though, limit the range of the pot to the part that is actually useful.

[Alexo]

Check out the "volume" control on this schematic:

[img808]http://www.moonguitaramps.com/images/ta ... ematic.png[/img]

Moon Talon Link

[Structo]

I guess there are many ways to skin a cat!

That's slang for, many ways to do the same thing.

Anyway I installed that power switch yesterday.

It is a full/ half/ 1/4 power switch. I installed separate cathode resistors and caps.

Surprisingly enough, the perceived volume drop is not that great.
I know there is something like only 3db difference with half power, I guess I was expecting more.

It works but not that much difference in volume and a little change in the character in tone.

Next will be a cut control. This little amps is ending up with a lot of switches and dials!

Here is the diagram again, I think they must have switched servers yesterday because the files are gone.

[drz400]

Check out the "volume" control on this schematic:

[img808]http://www.moonguitaramps.com/images/ta ... ematic.png[/img]

Moon Talon Link

That is the Mojave powerdampening control , is is covered in one of the tut books and has some nasty noises when turning the pot. Doesn't sound that great, at least didnt in my Coyote.

[jjman]

I guess there are many ways to skin a cat!

That's slang for, many ways to do the same thing.

Anyway I installed that power switch yesterday.

It is a full/ half/ 1/4 power switch. I installed separate cathode resistors and caps.

Surprisingly enough, the perceived volume drop is not that great.
I know there is something like only 3db difference with half power, I guess I was expecting more.

It works but not that much difference in volume and a little change in the character in tone.

Next will be a cut control. This little amps is ending up with a lot of switches and dials!

Here is the diagram again, I think they must have switched servers yesterday because the files are gone.

At 1st glance it looks like that cathode cap switcher circuit would reduce the AC signal significantly when switched to the lowest power setting. The problem is that the AC signal can also pass thru the “bias resistors,” albeit with some “resistance.” Even with the cathode caps completely removed I don’t think it would be adequate to function as any type of significant volume reducer.

[Alexo]

Check out the "volume" control on this schematic:



Moon Talon Link

That is the Mojave powerdampening control , is is covered in one of the tut books and has some nasty noises when turning the pot. Doesn't sound that great, at least didnt in my Coyote.

Ah ok... yes, it does seem weird to me, since it's just cold-biasing the phase inverter, which I would expect to be far from a transparent way to reduce the volume.

[KennyB]

I use a 50k NFB shunt resistor to reduce the volume in my amp. This is with a 100k feedback resistor.
Besides being part of the feedback ratio, I would be interested in knowing how this affects my phase inverter?

I tried the power dampening mod with the bias resistor, and didn't like it.
But this seems to give me better distortion and thickens up the tone.
It's not adjustable like a master, but seems to tame the amp.
- Ken

[Colossal]

Check out the "volume" control on this schematic:

Moon Talon Link

That is the Mojave powerdampening control , is is covered in one of the tut books and has some nasty noises when turning the pot. Doesn't sound that great, at least didnt in my Coyote.

Ah ok... yes, it does seem weird to me, since it's just cold-biasing the phase inverter, which I would expect to be far from a transparent way to reduce the volume.

I read a thread by Ken on AX84 about the Talon in which he said that while that schematic had the (Mojave) pre-PI MV, that he too found that he didn't care for the tone with it in that position. It was just an option that he tried in the original Talon design.

[Structo]

I guess there are many ways to skin a cat!

That's slang for, many ways to do the same thing.

Anyway I installed that power switch yesterday.

It is a full/ half/ 1/4 power switch. I installed separate cathode resistors and caps.

Surprisingly enough, the perceived volume drop is not that great.
I know there is something like only 3db difference with half power, I guess I was expecting more.

It works but not that much difference in volume and a little change in the character in tone.

Next will be a cut control. This little amps is ending up with a lot of switches and dials!

Here is the diagram again, I think they must have switched servers yesterday because the files are gone.

At 1st glance it looks like that cathode cap switcher circuit would reduce the AC signal significantly when switched to the lowest power setting. The problem is that the AC signal can also pass thru the “bias resistors,” albeit with some “resistance.” Even with the cathode caps completely removed I don’t think it would be adequate to function as any type of significant volume reducer.

This was the final design from the guys at EL34 world forum (Hoffman).
It does drop the gain quite a bit without the caps on the cathode.
Not as much as it does on a preamp tube but it does work.

But like I said, half power is only going to be 3db lower in sound level.

The 100K resistors are simply anti pop resistors.