Express mod to lower gain

[sniffyduke]

I was curious if you guy's may know of a mod to lower the gain a little refering to the Francesca Layout.

I'm kind of a newbie. I'm assuming It would be a resistor?

thanks

[M Fowler]

Instead of reworking the circuit just try 6V6s rather than EL34 or change the V1 to 12AT7 and change to 5751 in V2.

In other words if you have different types of 12A_7 tubes given them a try in one or two positions its your choice.

[sliberty]

I like the split plate load resitor mod that has been discussed here many times. I have it installed on my UniWreck, and it does a nice job of taming the beast a bit.

I also really like using a 12AT7 in V3 (PI) instead of a 12AX7. This also takes off just a little bit, and for me, creates the perfect amp.

[M Fowler]

I keep the 12AX7 in V3 and use the 12AT7 in V1 and V2 on my one Express but the latest build using Pacific tranny set I keep all the 12AX7s in and man she is nice. Oh and plenty of bass so transformers do make a difference.

[roberto]

I will 12ay7 V1, because 12at7 has too different working conditions and sound.

[JamesHealey]

You can change the 150k Grid Leak resistor to 56k this was seen on some wrecks and helps bring the gain down.

I also changed my feedback resistor to 47k.

very simple doesn't ruin the tone or feel but makes it a bit tamer.

very cheap to do also!

but try the valve compliments first!

[geetarpicker]

You can get a pretty drastic gain reductions with simple tube swaps. Plus the good thing is it's quick to undo. I've done full on country gigs with my Express, running the amp almost totally clean and then using a pedal board in the very traditional way. Kind of the anti way to run these IMHO but it works surprisingly well with a 12AU7 in V1 and a 12AY7 in V2. At that point I can get the amp almost half the way up before it breaks up even running a Keeley compressor set above unity gain.

[JamesHealey]

thats pretty cool to know Glen..

[M Fowler]

Glen do you always run NOS tubes or do you try current production tubes?

[Ron]

I'm wondering whether anyone has installed the TW master volume and, if so, does it maintain the core sound?

(The TW master volume is a dual 1M potentiometer that controls the level of the input to the output tube grids from the phase inverter plates. A standard MV simply reduces the input to the phase inverter.)

[paulster]

I'm wondering whether anyone has installed the TW master volume and, if so, does it maintain the core sound?

It's been well discussed, and, no, not really. The key to the Express sound is getting the power tubes working hard as well and the PI and the preamp clipping.

Even if you take out the power tube clipping you want the power stage to be pulling lots of current to get the compression in the power supply that gets that clean to scream sound without a big volume increase.

If you want to see how much compression there is set the gain up to noon, listen to the ambient hiss level and then hit an A chord and then mute it. The hiss volume will have dropped dramatically and then will quickly ramp up as the power supply gets back up to full voltage.

A master volume will lose this aspect.

Attenuators are the way to go with these, I'm afraid.

[rawnster]

If you want to see how much compression there is set the gain up to noon, listen to the ambient hiss level and then hit an A chord and then mute it. The hiss volume will have dropped dramatically and then will quickly ramp up as the power supply gets back up to full voltage.

A master volume will lose this aspect.

Attenuators are the way to go with these, I'm afraid.

Are you sure it's not your inner ear's cochlea bowing down and then recovering?

[bgkyt1]

Hello everyone. I'm new here and am interested in a TW-type amp.

I'm wondering whether anyone has installed the TW master volume and, if so, does it maintain the core sound?

It's been well discussed, and, no, not really. The key to the Express sound is getting the power tubes working hard as well and the PI and the preamp clipping.

Even if you take out the power tube clipping you want the power stage to be pulling lots of current to get the compression in the power supply that gets that clean to scream sound without a big volume increase.

If you want to see how much compression there is set the gain up to noon, listen to the ambient hiss level and then hit an A chord and then mute it. The hiss volume will have dropped dramatically and then will quickly ramp up as the power supply gets back up to full voltage.

A master volume will lose this aspect.

Attenuators are the way to go with these, I'm afraid.

How much worse is the effect of a MV on a Trainwreck compared to other amps?
thanks...

[geetarpicker]

Hello everyone. I'm new here and am interested in a TW-type amp.

I'm wondering whether anyone has installed the TW master volume and, if so, does it maintain the core sound?

It's been well discussed, and, no, not really. The key to the Express sound is getting the power tubes working hard as well and the PI and the preamp clipping.

Even if you take out the power tube clipping you want the power stage to be pulling lots of current to get the compression in the power supply that gets that clean to scream sound without a big volume increase.

If you want to see how much compression there is set the gain up to noon, listen to the ambient hiss level and then hit an A chord and then mute it. The hiss volume will have dropped dramatically and then will quickly ramp up as the power supply gets back up to full voltage.

A master volume will lose this aspect.

Attenuators are the way to go with these, I'm afraid.

How much worse is the effect of a MV on a Trainwreck compared to other amps?
thanks...

It's been my experience that a Wreck with a master looses some of the compression effect. The net result is the volume difference between clean and distorted isn't as even. It seems without the power stage (and power supply) being hit hard the full distorted tone doesn't have as much compression and get's too loud compared to the clean tone. The reason is a master volume circuit will keep the current draw on the power supply lower than normal, and less power stage compression will occur. I guess this happens on any amp with a master, compared with cranking it up. It's just that on a wreck the clean to scream potential is so nicely usable and even it's a shame to loose it to a master. I think cranking the amp with an attenuator is a much better solution. I believe attenuators these days are much better (and getting better all the time with new advances in such devices) and the trade offs are less than with a master volume circuit IMHO.

[bcmatt]

How much worse is the effect of a MV on a Trainwreck compared to other amps?
thanks...

I understand it that a TW is the most important amp in the world to NOT have a Master Volume on. No amp depends on having no Master Volume more than a TW. It still might sound better than lots of other amps, but it really depends on that Power tube push to get the TW sound.
I'm being totally redundant because Glen has a great explanation but I just felt like typing...