Is there an EL84 type tube with lower gain?

[kiteman]

Just like replacing 12AX7 with 12AT7 or 12AY7?

It's for my Kustom Defender 5H head. I can lower the gain in the preamp but it makes it sound cold. How about lowering the gain in the power tube? It's easier to swap tubes rather than messing with the circuitry.

Such a beast exist?

[jim p]

You could get some drop in power by connecting the speaker to a lower impedance jack 8ohm speaker to 4 ohm jack. A factor of two will not harm the amp and you bass response should be a bit better. To actually lower the gain of the output tube you would need to lower the plate supply voltage or the screen voltage or both. Usually people install a VVR variable voltage regulator for this. On the Kustom people have been replacing the output transformer for a much better sounding amp. There is also a simple tone control mod just replacing a resistor in the amp with a pot. Look over at Sewatt to see what is posted http://www.sewatt.com/node/20385

[kiteman]

Thanks jim, some good ideas there but I don't really want to mess with the circuitry. How about the volume knob? Will a higher value pot give me more range? The way it is, as soon as I turn the knob it's blasting already.

I have a 75 watt 16 ohm 1x12 cab and this 5 watter make that speaker dance.

[Justaguyin_nc]

You might want to google "L-PAD" and see how 10 bucks can make a nice cheap attenuator. Might color your sound, but for 10 bucks it might be worth a shot.

Justa thought

[kiteman]

You might want to google "L-PAD" and see how 10 bucks can make a nice cheap attenuator. Might color your sound, but for 10 bucks it might be worth a shot.

Justa thought

Damn, I forgot. I have an attenuator, a Weber MASS200. It's buried somewhere in the closet. I forgot I used it when I biased my Alchemist the first time.

I guess it'll work with a 5 watter.

[deeaa]

Yep, I guessed it'd sound cold...l-pad or mass brake will work well. Tranny change does also improve at leat the epi 5watter clearly, but also makes it even louder.

[jim p]

Looking at the schematic there is a zero ohm resistor (R3) in series with the volume pot if you change that to 470k to 1 Meg that would reduce the sensitivity of the volume pot. You can also try lowering the value of R15 the 100k resistor say 47k instead. Down side of an attenuator or L-pad is if you use it for an overdriven sound it will shorten the life of the EL84. Another thing about an L-pad is it is a resistive load so you highs will not be the same as if you were driving a speaker. The Weber attenuator maybe a voice coil with no cone so it will be a similar tone to driving a speaker.

[kiteman]

Looking at the schematic there is a zero ohm resistor (R3) in series with the volume pot if you change that to 470k to 1 Meg that would reduce the sensitivity of the volume pot. You can also try lowering the value of R15 the 100k resistor say 47k instead. Down side of an attenuator or L-pad is if you use it for an overdriven sound it will shorten the life of the EL84. Another thing about an L-pad is it is a resistive load so you highs will not be the same as if you were driving a speaker. The Weber attenuator maybe a voice coil with no cone so it will be a similar tone to driving a speaker.

Yes, it have a speaker coil inside and supposed to be one of their best attenuators. It also have a treble compensator.