Why is a single channel amp inherently better than a multi?

[Structo]

On his 25th Anniversary model, there is a control called "Wattage".

This is the description of that control:
Wattage: This six position switch acts as a voltage divider in the phase inverter to incrementally
reduce the drive signal going to the power tubes. The last position disconnects the switch from
the circuitry, leaving the stock values unaltered. When running the amp wide-open, it is suggested
to select the second position (one degree of attenuation) for extended tube life. Do not adjust the
wattage control while playing guitar though the amp at high volumes because of potential volume
spikes between switch positions.

Anybody know how that is constructed?
Six way switch and resistors?

[Structo]

Not sure which amp this is other than it is a two channel.
Doug Sewell designs PRS amps.

[M Fowler]

Not much different then the watts control I use on my Reverb Rocket but I use 25kL pot to control the PI. It really work well in the Rocket not so well in an Express based on my experience.

[John_P_WI]

On his 25th Anniversary model, there is a control called "Wattage".

This is the description of that control:
Wattage: This six position switch acts as a voltage divider in the phase inverter to incrementally
reduce the drive signal going to the power tubes. The last position disconnects the switch from
the circuitry, leaving the stock values unaltered. When running the amp wide-open, it is suggested
to select the second position (one degree of attenuation) for extended tube life. Do not adjust the
wattage control while playing guitar though the amp at high volumes because of potential volume
spikes between switch positions.

Anybody know how that is constructed?
Six way switch and resistors?

I have not been inside one but I would guess this method is an attempt to circumnavigate a patent or existing design. Best guess, similar to a Mojave scale control where the PI bias resistor value is changed, in this case instead of a pot, a voltage divider ladder setup is used. This would certainly lead to "thumps" as the dc is being interrupted during switching.

Of course the plate voltage on the pi could be changed, or the grid leak values too.

IMHO, it is a worthless design if you can not adjust on the fly. The "do not adjust at high volumes because of volume spikes" could also suggest that this may play with the grid leaks, similar to KOC's improved bootstrapped Master, instead of a pot, they are using a switch. When the switch is in between positions the grid leaks are temporarily out of the circuit causing volume spikes....

Finally, I would also argue that this has less effect on tube life than power scaling / VVR in which the plate and screen voltage of the output tubes are varied. If this method reduces the drive, it may limit the screen grid current resulting in some extension of tube life.....

Stick with VVR and PPIMV, tried, true and proven. Just my 2 cents...

[Joost]

Back on topic. What's your opinion of adding a dumbleator to the chain?

[SoundPerf]

IMHO, it is a worthless design if you can not adjust on the fly. The "do not adjust at high volumes because of volume spikes" could also suggest that this may play with the grid leaks, similar to KOC's improved bootstrapped Master, instead of a pot, they are using a switch. When the switch is in between positions the grid leaks are temporarily out of the circuit causing volume spikes....

Finally, I would also argue that this has less effect on tube life than power scaling / VVR in which the plate and screen voltage of the output tubes are varied. If this method reduces the drive, it may limit the screen grid current resulting in some extension of tube life.....

Stick with VVR and PPIMV, tried, true and proven. Just my 2 cents...

You can switch it "on the fly". It's just suggested not to do it at full bore. If you played these amps you would understand why doing it at full volume is not reccomended. They're really peeling paint at full volume. I can say that it is not a "worthless design".

I've been to the last 3 PRS open houses and have followed the amps pretty closely. They have evolved pretty extensively the past two years. It's important to know what each design and line is and meant for. I've hesitated to bring up these amps here because of the possible conflict of interest. But, I can tell you they are awesome amps. In fact probably some of the best built and bang for the buck around.

It's also important not to confuse the SE line with the higher end stuff. And yes, they're not single ended, but named after the other overseas built line of guitars that PRS has. But the truth is the SE line of amps are quite killer for the price.

Paul and Doug Sewell are really smart and nice guys and willing to take the time to talk shop with anybody. Even me...

To sort of get back to topic. The earlier single channel PRS amps are quite nice and in many ways superior. But like most things it's really what best fits your needs. It seems that most those designs are being relegated to the "Custom Shop" department.

[SoundPerf]

Back on topic. What's your opinion of adding a dumbleator to the chain?

First, I like to use effects. So, the D-lator makes for an important part of my setup I haven't played tons and tons of amps, but, I have owned a few Boogies, and many Fenders. I've always had a hard time dealing with FX loops, but also hate certian/most effects in front of the amp.

The most important thing to remember is the signal and tone is only going to be as good as the worst sounding device in the chain. IMO, the Dlator is not a weak point.

[Structo]

As far as my Dumble clone and Dumbleator goes, I like to put the time based effects in the loop.
Reverb, delay, modulation.
The exception is my Wah Wah pedal and my Trem/ Rotary TR-7.

When I rarely use a dirt pedal it goes into the front as well as my Wah.

[groovtubin]

As far as my Dumble clone and Dumbleator goes, I like to put the time based effects in the loop.
Reverb, delay, modulation.
The exception is my Wah Wah pedal and my Trem/ Rotary TR-7.

When I rarely use a dirt pedal it goes into the front as well as my Wah.

I don`t mind the Dator here at the house, and some verb/delay practicing @ 2-3AM in the morning! BUT, i find live, that running a small solid state amp with a line out from the stereo of my FX unit, fills out the room nicely, and adds ALOT of dimension to the tone esp at lower volume`s like at church!. Use ta run the amp on dator alone w/4x12 marshall , and line out of amp into fx into a stereo cab/power amp, now THAT was a HUGE sounding rig! Currently a rocktron stero rampage is used, and the stereo chorus in is is nice! Gets me into the Eric J side of the house! How do you like to run your`s?

jim

[pamaz67]

the reason I subscribe to the assumption that a single channel' amp is better than multi channel, is that in a multi channel amps the voicing and dynamic beahviour of the power amp is a compromise between what ideally a clean and an od channel require. This is more true considering hi gain amps.
In a single channel there are simply no compromises between channels to achieve, therefore the "tuning" between preamp and power amp can be perfected.

[groovtubin]

the reason I subscribe to the assumption that a single channel' amp is better than multi channel, is that in a multi channel amps the voicing and dynamic beahviour of the power amp is a compromise between what ideally a clean and an od channel require. This is more true considering hi gain amps.
In a single channel there are simply no compromises between channels to achieve, therefore the "tuning" between preamp and power amp can be perfected.

I`d def agree, i tuned one of my friends bandmaster D channels clean channel ONLY w/6550`s , we were shooting for a more CONVINCING SRV tone and def achieved it! But this new tweak would KILL a nice fat OD sound!

jim

[thyx]

Anytime you have more than one channel in an amp, you've had to compromise something, somewhere. You can't optomize two different channels at the same time. One, or both, must suffer.

Try an ODS. Which channel on the ODS do you think was compromised on? Not that it sounds bad...but that's not the point. The point is, the ODS clean could sound better. Enter the SSS. Even Dumble knew it.

[diagrammatiks]

Anytime you have more than one channel in an amp, you've had to compromise something, somewhere. You can't optomize two different channels at the same time. One, or both, must suffer.

Try an ODS. Which channel on the ODS do you think was compromised on? Not that it sounds bad...but that's not the point. The point is, the ODS clean could sound better. Enter the SSS. Even Dumble knew it.

this is a bunch of crock.

The SSS has a completely different power amp topography then the ODS.

[Structo]

Anytime you have more than one channel in an amp, you've had to compromise something, somewhere. You can't optomize two different channels at the same time. One, or both, must suffer.

Try an ODS. Which channel on the ODS do you think was compromised on? Not that it sounds bad...but that's not the point. The point is, the ODS clean could sound better. Enter the SSS. Even Dumble knew it.

As I understand it, the ODS amps are not really two channel amps.

That is, the OD circuit cascades from the clean circuit giving the illusion it is a two channel.
With this type of amp it is a compromise to tune each circuit, especially the OD circuit since it doesn't have a tone stack.
Anything you do will affect the OD side.

Most likely this is the reason Alexander changed it to HRM, to have better control over the OD.

It would be fun to mess around with the preamp circuit and make it a true two channel.

The ODS amps uses four stages for the OD, so you would have to add another 12ax7 tube, to make it equivalent.

This doesn't really mean anything, I was just thinking out loud.