Twin PA mod for VJ

[mooreamps]

Twin PA mod on VJ with dual PA master volume dial controls and electronic power scaling.

Now, if you're looking at the front panel, I'll go over this.
The switch on the far left is Operate/Stand-by. In stand-by, the yellow LED glows.
This is the BITE lamp for the filament power supply. If the main POWER switch is on,
and if this lamp does not glow, check the fuse on the Orange wires from the main power
transformer.


When the switch is in Operate, this provides High Voltage to the power tubes. The
red lamp is the BITE lamp for High Voltage. If the red lamp does not glow, check the
fuse on the Red wires from the main power supply.


Above the volume knobs are the BITE lamps for the pre-amp tube and both power tubes.
The pre-amp lamp will begin to glow after the pre-amp tube warms up ; 12 seconds. The
other tube power tube lamps will glow only when the power tubes warm up and the Power
Brake is turned up. The lables on the BITE lamps match the lables next to the tubes.
If one BITE lamp fails to glow, replace that tube.



Volume. Pre-amp gain. Unchanged.
Master Body control. This is the master volume for the 6V6 power tube.
Master Sparkle control. This is the master volume for the EL-84 power tube.


Electronic Power Brake. This control , controls PA plate current for both power tubes.
Set this control at 25% for over-drive tones.
Set this control to 75% for clean tones.
Set this control to 100% for sag and compression effects.


-g

[Enzo]

Um, what is a BITE lamp?

And am I missing something? Is this a follow up to another thread? What mod are we talking about here?

[Earl]

Usually, them things are called "BIT", or Built In Test lamps/indicators.

What's the V3 mod deal?

[mooreamps]

Um, what is a BITE lamp?

And am I missing something? Is this a follow up to another thread? What mod are we talking about here?

A client in Illinous sent me a Valve Junior for the Twin PA mod and power brake. BITE means "Built In Test Equipment".

-g

[Steve Conner]

Looks nice, although I thought the BITE lamp came on to indicate lunchtime.

BTW, what is the advantage of using two different power tubes like that? Do they have two different tones? Is there one master volume for each tube?

I'm just asking because I have a similar 3 watt amp with an EL84, and I always wondered about putting a 6V6 or even a 6L6 in it.

Also, what do you do about the extra heater current? :|

[mooreamps]

Looks nice, although I thought the BITE lamp came on to indicate lunchtime.

BTW, what is the advantage of using two different power tubes like that? Do they have two different tones? Is there one master volume for each tube?

I'm just asking because I have a similar 3 watt amp with an EL84, and I always wondered about putting a 6V6 or even a 6L6 in it.

Also, what do you do about the extra heater current? :|

The 6v6 is voiced to amplify bass frequencies. The EL-84 is voiced to amplify treble. So I use the 6v6 for body and fullness, and then drive the EL-84 for presence and for some sparkle. Yes, twin master volume controls.

-g

[mooreamps]

Looks nice, although I thought the BITE lamp came on to indicate lunchtime.

BTW, what is the advantage of using two different power tubes like that? Do they have two different tones? Is there one master volume for each tube?

I'm just asking because I have a similar 3 watt amp with an EL84, and I always wondered about putting a 6V6 or even a 6L6 in it.

Also, what do you do about the extra heater current? :|

In my model-5 prototype amp, I used the 6V6. The stock power transformer wlll just barely handle the extra heater load. If not, you may have to install and additional 12 volt power transformer to drive the heater.

-g