Two Rock Emerald Pro

[bluesy]

.....that's way over my head. There's local guy that will probably (hopefully) understand this and can tell me if things look close to where they should be.
I just want to know if things have been monkeyed with; although his D experience may be limited. Thank you very much for the input.

[Structo]

Oh, you got that one?

I think that was one of their prototypes because it has some extra trimmers where you would expect to see fixed resistors.
Nothing wrong with it and it probably sounds great but I don't think I would mess around with those trimmers if you haven't done it before.

[martin manning]

.....that's way over my head. There's local guy that will probably (hopefully) understand this and can tell me if things look close to where they should be.
I just want to know if things have been monkeyed with; although his D experience may be limited. Thank you very much for the input.

You actually don't need to go through the procedure to find the equal signal voltage point. You could just mark the present location and then experiment with the PI trimmer (the one closest to the back of the amp of the three near the power transformer) as described in the tweak-by-ear description.

I believe the other two trimmers on that side of the board are individual bias adjustments for the two power tubes. I would set those first to match the idle current of the power tubes and then tweak the PI trimmer to get the most chimy sustain when you strum an open chord. You have to be patient as it might take some seconds after an adjustment of the trimmer for the voltages to stabilize.

The only other trimmers in the amp are the TMB for the HRM EQ, and the OD entrance trimmer, right?

[boldaslove6789]

The Emmy Pro is basically a 50w Skyliner HRM with a Fender style reverb circuit and half a Dumbleator ( 2 12ax7's for Reverb (using only 3 of the triode's), the remaining triode is used for the half a Dumbleator).

Hi, all. I have an Emmy Pro and am curious about the "half Dumbleator" thing.
If someone could explain (in non-technical terms, since I won't understand) what
the 1/2 Dumbleator is in this amp; as opposed to (I guess) a full blown Dumbleator I'd be appreciative. Also, is there recommended procedure for adjusting the four pots inside (T,M,B, and OD I believe) for getting the most out of this amp? I realize that the other three pots are for bias adjust and PI settings. Also (again) how might I "check" the PI "setting"? The manual from TR simply says not to adjust this. Since it came to me used, I really have no way of knowing if this pot has been adjusted; perhaps it's not best or optimally set.
It sounds very good, but somehow I feel there's more in there.
Sorry for the long post. I'm not a builder--but have been keen on this style of amp for quite a while. Happy New Year.

To simplify it:

The Dumbleator has one 12ax7. A 12ax7 consists of 2 triode's. Each part of the triode is a buffer to match impedance levels. A send and return.

For some reason Two-Rock only likes to use half of the 12ax7 to buffer the levels lost by interfacing line level effects.

The reverb circuit uses 1 and a 1/2 triode's, the remaining triode left is used as a Buffer (half a Dumbleator) for the FX loop.

[martin manning]

...I have an Emmy Pro and am curious about the "half Dumbleator" thing. If someone could explain (in non-technical terms, since I won't understand) what the 1/2 Dumbleator is in this amp; as opposed to (I guess) a full blown Dumbleator I'd be appreciative.

A Dumbleator and most active effects loops will have a driver (buffer) stage at the "send," and a recovery stage at the "return." Usually there is a send level control and a return level control, and the three-knob Dumbleator has a return "in" level to attenuate the returning signal before the recovery stage, and a return "out" level after the recovery stage. Reading through the TR Emmy Pro user manual, the EP evidently dispenses with the driver stage, and the send level is controlled by the master. The recovery stage has a return "out" level (after the recovery stage), which controls the power amp input level. So I guess that is pretty much a half-D'lator.

[bluesy]

To simplify it:

The Dumbleator has one 12ax7. A 12ax7 consists of 2 triode's. Each part of the triode is a buffer to match impedance levels. A send and return.

For some reason Two-Rock only likes to use half of the 12ax7 to buffer the levels lost by interfacing line level effects.

The reverb circuit uses 1 and a 1/2 triode's, the remaining triode left is used as a Buffer (half a Dumbleator) for the FX loop.

[/quote]

Thank you for that simplified explanation!

[bluesy]

[

I believe the other two trimmers on that side of the board are individual bias adjustments for the two power tubes. I would set those first to match the idle current of the power tubes and then tweak the PI trimmer to get the most chimy sustain when you strum an open chord. You have to be patient as it might take some seconds after an adjustment of the trimmer for the voltages to stabilize.

The only other trimmers in the amp are the TMB for the HRM EQ, and the OD entrance trimmer, right?[/quote]

Yes in regard to the other (TMB/OD) trimmers.
So once the power tubes are matched up bias wise, adjust the PI trimmer from a reference point for the above chime. Will the other trimmers have an effect on that? IE: should the TMB/OD trimmers be "set-up" prior to any PI adjustment?
Or after. Or does it matter?
Thank you all for the input.

[martin manning]

I believe the other two trimmers on that side of the board are individual bias adjustments for the two power tubes. I would set those first to match the idle current of the power tubes and then tweak the PI trimmer to get the most chimy sustain when you strum an open chord. You have to be patient as it might take some seconds after an adjustment of the trimmer for the voltages to stabilize.

The only other trimmers in the amp are the TMB for the HRM EQ, and the OD entrance trimmer, right?

Yes in regard to the other (TMB/OD) trimmers.
So once the power tubes are matched up bias wise, adjust the PI trimmer from a reference point for the above chime. Will the other trimmers have an effect on that? IE: should the TMB/OD trimmers be "set-up" prior to any PI adjustment? Or after. Or does it matter?
Thank you all for the input.

Yes, bias first, then set the PI trimmer, independent of the HRM EQ and OD entrance, as long as they are some where close. Those later two are related, as the amount of drive you put into the OD will likely affect the EQ that works best with it. I'm not expert with the TMB, someone else will have to give you recommendations there.

[Decko]

The Emmy Pro is basically a 50w Skyliner HRM with a Fender style reverb circuit and half a Dumbleator ( 2 12ax7's for Reverb (using only 3 of the triode's), the remaining triode is used for the half a Dumbleator).

Hi, all. I have an Emmy Pro and am curious about the "half Dumbleator" thing.
If someone could explain (in non-technical terms, since I won't understand) what
the 1/2 Dumbleator is in this amp; as opposed to (I guessH) a full blown Dumbleator I'd be appreciative. Also, is there recommended procedure for adjusting the four pots inside (T,M,B, and OD I believe) for getting the most out of this amp? I realize that the other three pots are for bias adjust and PI settings. Also (again) how might I "check" the PI "setting"? The manual from TR simply says not to adjust this. Since it came to me used, I really have no way of knowing if this pot has been adjusted; perhaps it's not best or optimally set.
It sounds very good, but somehow I feel there's more in there.
Sorry for the long post. I'm not a builder--but have been keen on this style of amp for quite a while. Happy New Year.

To simplify it:

The Dumbleator has one 12ax7. A 12ax7 consists of 2 triode's. Each part of the triode is a buffer to match impedance levels. A send and return.

For some reason Two-Rock only likes to use half of the 12ax7 to buffer the levels lost by interfacing line level effects.

The reverb circuit uses 1 and a 1/2 triode's, the remaining triode left is used as a Buffer (half a Dumbleator) for the FX loop.

Hi Bold, TAGers,

So the compliment is as follows:

V1 Rhythm (as modeled after Skyliner)
V2 Lead (as modeled after Skyliner)
V3 Reverb (circuit?)
V4 Reverb and 1/2 Dumbleator "return out" section
V5 PI (as modeled after Skyliner)

So, without a one to one schematic, I am attempting to piece this project together.

I have the Skyliner schematic which shows everything but V3 and V4.

Questions:

1. What reverb circuit is being used here? And how is it tied into the Skyliner schematic? I assume after V2...

2. I would like to understand how and at what point the 1/2 Dumbleator is integrated in the circuit? Why not just integrate the complete Dumbleator circuit?

3. What is the function of the board which is piggy backed on top and toward the front of the main D board? Is this board in the Skyliner schematic? I notice the relays so, I can assume we are switching between rhythm and lead channels as well as bypassing the tone stack? Yes? I also see the mid, bass and treble trimmers. This would be the fixed eq? Jason's build has another pot "trim"... What is this trimmer adjusting?

4. The power board has another node that is not present in the Skyliner schematic. I assume this is to feed voltage to the reverb and effect loop. Yes? Assuming that it is what I think it is, can you point me to a schematic that shows how the additional node is integrated and what r values are used?

Sorry for the many questions but I am most intrigued with this side of the forum and this style of amplifier. The excitement is driving me to want to understand the circuit!

Regards,
Decko

[boldaslove6789]

It has a Skyliner and HRM overdrive (that's the board with the 3 trim pots and 2 relay's on it.) The trim pots are Treble, Middle, and Bass controls for the Overdrive.

The reason Two-Rock doesn't use the other half of the D-Lator is because Bill Krinard doesn't like to use the other half of the circuit cause of the tonal properties it has.

I'm not sure about the Verb circuit.

[brentm]

I wonder if the verb circuit would be documented in the schematics for the Two Rock CRS. I'd imagine this is pretty close to the mark. Difficult to read in spots, but not impossible.

https://tubeamparchive.com/files/two_ro ... em_667.pdf

There is another version of the schem (green paper) about 6-7 pages on the forum somewhere that might be a better example. Can't find it ATM.

[boldaslove6789]

You might be better off using the 2 Tube "Redplate" reverb Henry H. Posted a while back. That way you could use the full Dumbleator Circuit.

[Decko]

You might be better off using the 2 Tube "Redplate" reverb Henry H. Posted a while back. That way you could use the full Dumbleator Circuit.

Hi Bold,

I decided to breadboard this Emmy Style build rather than committing full bore to a design. I can explore and play with different circuits including different reverb circuits and the Dumbleator circuit. Then, implement one that I like. As far as reverb circuits, is there a clip that I can hear the 2 tube red plate? I have been considering using 6SN7's for the reverb tubes. The tube is fat and and bold for a dual triode. I also hear much about stand alone reverb cuicuits such as Fender or Ampeg.

Regards,
Decko

[bluesy]

Not wanting to twist this thread any farther; but with all the expertise on this site, what do you think those "tonal properties" would be? Would a full blown Dumbleator add or subtract from the "D" sound? (In this amp) Thinking RF here.
I did mark all the trimmers, checked the bias, moved the PI trimmer slowly and slightly in either direction of my mark ~ ended up sounding best where things were originally.

The reason Two-Rock doesn't use the other half of the D-Lator is because Bill Krinard doesn't like to use the other half of the circuit cause of the tonal properties it has.

[martin manning]

Not wanting to twist this thread any farther; but with all the expertise on this site, what do you think those "tonal properties" would be? Would a full blown Dumbleator add or subtract from the "D" sound? (In this amp) Thinking RF here.
I did mark all the trimmers, checked the bias, moved the PI trimmer slowly and slightly in either direction of my mark ~ ended up sounding best where things were originally.

The reason Two-Rock doesn't use the other half of the D-Lator is because Bill Krinard doesn't like to use the other half of the circuit cause of the tonal properties it has.

I think the reason for the half-D'lator in the EP might just as likely be that K&M didn't want to add another socket and the associated components for the buffer stage, and end up wasting an extra triode somewhere. Since the reverb uses a tube-and-a-half, it leaves one triode available for the loop, but adding another tube means adding two more.

The stand-alone D'lator allows plugging-up to use the driver stage, the recover stage, or both, so I tried it just now. With both stages in, and nothing in the loop, I think there may be a bit of swirly-phasy stuff that isn't as evident with just the recover stage in, but it is not that different really, and I can see making the decision to leave the send buffer out and keep costs down. The send level can be controlled by the amp's master volume, so you still have that feature, but you do lose the low-impedance drive that would be useful if FX and long cables are in the loop.