Rocktron Plexi afterburner feature - Tried something new

[mourguitars]

I spent a lot of time yesterday with the Plexi, i put a MXR 10b EQ after it and it brought it to life...also Boosting it with a Timmy...i dialed them in pretty good with all my guitars thru the Intellifex....

Still havent played the Blackplate much...i just roll down my guitars volume for the clean parts i play...but i gotta say, my rack sounds very sweet now...pretty happy with it, plug and play... i like that after all these decades

Mike

 

[mouzer]

I spent a lot of time yesterday with the Plexi, i put a MXR 10b EQ after it and it brought it to life...also Boosting it with a Timmy...

Might have missed this in the rest of the thread, but what are you using for monitoring/amplification? Just curious.

 

[mourguitars]

Might have missed this in the rest of the thread, but what are you using for monitoring/amplification? Just curious.

At the moment a TS100 Carvin in stereo, Intelifex and 2 2x12 cabs with G12H/V30 speakers

Mike

 

[mouzer]

Cool, thanks! I had good experiences with the TS100 about 10 years ago. Sounds like a great setup.

 

[mouzer]

The first triode of V4 (Pins 1-2-3) is for the afterburner. But the second triode of V4 (Pins 6-7-8) is the output stage for the complete preamp (impedance converter high to low).

Has anyone tried something like the JJ 12DW7/ECC832 in V4?

Looks like one triode has the gain level of a 12AU7 while the other has the gain of a 12AX7. Sounds like an interesting way of reducing the Afterburner's drive while retaining the gain of the output stage.

Vacuum Tube - 12DW7 / ECC832, JJ Electronics, Dual Triode | Antique Electronic Supply

In the 12DW7/ECC832, Section 1 of the tube (pins 6, 7, and 8) is the high gain 12AX7/ECC83 spec (gain factor 100) and Section 2 (pins 1, 2, and 3) is the low gain 12AU7/ECC82 spec (gain factor 17).

www.tubesandmore.com

Thoughts, guys?

 

[DirtyHarry]

Has anyone tried something like the JJ 12DW7/ECC832 in V4?

Looks like one triode has the gain level of a 12AU7 while the other has the gain of a 12AX7. Sounds like an interesting way of reducing the Afterburner's drive while retaining the gain of the output stage.

Vacuum Tube - 12DW7 / ECC832, JJ Electronics, Dual Triode | Antique Electronic Supply

In the 12DW7/ECC832, Section 1 of the tube (pins 6, 7, and 8) is the high gain 12AX7/ECC83 spec (gain factor 100) and Section 2 (pins 1, 2, and 3) is the low gain 12AU7/ECC82 spec (gain factor 17).

www.tubesandmore.com

Thoughts, guys?

Sounds good. I didn't know about that.

 

[mouzer]

Sounds good. I didn't know about that.

Interesting tube, I think. I'm not sure if you noticed that there are 2 variations of the tube on that page, where the gain factors of the triodes are reversed. In the interest of clarifying which of the two would be ideal for V4, would you mind naming which variation of the tube you'd find to be 'correct' to this situation?

You mention:

The first triode of V4 (Pins 1-2-3) is for the afterburner. But the second triode of V4 (Pins 6-7-8) is the output stage for the complete preamp

I think my suspicions are probably correct, but which of the two would you pick?

ECC832 (T-12DW7-JJ-X)​
​	Section 1​	Section 2​
Pins​	6, 7, 8​	1, 2, 3​
Gain​	Factor of 100​	Factor of 17​
Spec​	12AX7/ECC83​	12AU7/ECC82​

ECC823 (T-ECC823-JJ)​
​	Section 1​	Section 2​
Pins​	6, 7, 8​	1, 2, 3​
Gain​	Factor of 17​	Factor of 100​
Spec​	12AU7/ECC82​	12AX7/ECC83​

Thanks for all your invaluable information!

 

[DirtyHarry]

Interesting tube, I think. I'm not sure if you noticed that there are 2 variations of the tube on that page, where the gain factors of the triodes are reversed. In the interest of clarifying which of the two would be ideal for V4, would you mind naming which variation of the tube you'd find to be 'correct' to this situation?

You mention:



I think my suspicions are probably correct, but which of the two would you pick?

ECC832 (T-12DW7-JJ-X)​
​	Section 1​	Section 2​
Pins​	6, 7, 8​	1, 2, 3​
Gain​	Factor of 100​	Factor of 17​
Spec​	12AX7/ECC83​	12AU7/ECC82​

ECC823 (T-ECC823-JJ)​
​	Section 1​	Section 2​
Pins​	6, 7, 8​	1, 2, 3​
Gain​	Factor of 17​	Factor of 100​
Spec​	12AU7/ECC82​	12AX7/ECC83​

Thanks for all your invaluable information!

Well, with my bright mod in the afterburner stage I am good with the original tube. But to keep the gain in the output stage (pins 6-7-8) and to experiment a different gain in the afterburner stage (pins 1-2-3) ECC832 (T-12DW7-JJ-X) will be the right choice (as you allready suspected).

 

[DirtyHarry]

BTW: The mentioned gain factors of 17 or 100 are only given in a basic kathode circuit (for example V4a).
As V4b is a kathode follower circuit, there will be some gain differences with different tubes, but not really that much. The purpose of V4b is to change impedance from high to low.

 

[mouzer]

Well, with my bright mod in the afterburner stage I am good with the original tube. But to keep the gain in the output stage (pins 6-7-8) and to experiment a different gain in the afterburner stage (pins 1-2-3) ECC832 (T-12DW7-JJ-X) will be the right choice (as you allready suspected).

Thanks DirtyHarry. Much appreciated. Did you find that your bright mod opened up the sound of the afterburner? I think the afterburner feature has a lot of potential but things can get really muddy real fast for me.

 

[DirtyHarry]

Thanks DirtyHarry. Much appreciated. Did you find that your bright mod opened up the sound of the afterburner? I think the afterburner feature has a lot of potential but things can get really muddy real fast for me.

I think after my bright mod the sound character keeps nearly constant with afterburner on, which wasn't without. It was indeed muddy before because of the missing treble frequencies. Just give it a try - it's only 2 components.

 

[mouzer]

I think after my bright mod the sound character keeps nearly constant with afterburner on, which wasn't without. It was indeed muddy before because of the missing treble frequencies. Just give it a try - it's only 2 components.

Thanks again, DirtyHarry. Your help is much appreciated.

 

[mouzer]

Finally got around to trying out this mod on my VS Plexi. Thanks DirtyHarry!

The Afterburner is much better now, totally usable. Hard to find a bad sounding setting!

I wonder if it'll be equally effective in the Black Plate+, since the circuits are basically the same..?

Edit: Flipping back through the thread it seems like you had a few ideas for mods on the Black Plate+. Curious about your findings!

 

[DirtyHarry]

Finally got around to trying out this mod on my VS Plexi. Thanks DirtyHarry!

The Afterburner is much better now, totally usable. Hard to find a bad sounding setting!

I wonder if it'll be equally effective in the Black Plate+, since the circuits are basically the same..?

Edit: Flipping back through the thread it seems like you had a few ideas for mods on the Black Plate+. Curious about your findings!

Did you get my Black Plate schematic with my mods some time ago?
I remember I wasn't able to post it here at this site.

 

[mouzer]

Did you get my Black Plate schematic with my mods some time ago?

I don't think I've seen these yet! Thanks for sharing, I'm excited to try this one out too.