2 Channel and 3 Channel Presence Pots: Reversed?

[cardinal]

Sorry for all my Recto questions. I have a 3 Channel Triple Solo head and a Rev G in the mail to me. I'm looking at the part numbers of the presence pots and I'm confused:

2 Channel Part 3 Channel Part
Orange Channel: 592151 (100K) 590737 (25K)
Red Channel: 592737 (25K) 590151 (100K)

Are they really swapped from the 2 channel to the 3 channel?

Lately, on the 3 channel Solo, I seem to prefer the Modern mode in the Orange Channel rather than the Red Channel. I assume that's because of the value of the presence pot. Looks like the Rev G already matched the 25K presence pot to the Red Channel. Is that right?

Thanks!

EDIT: on my screen that Table is laid out so nicely, but it doesn't post right. In any event, it looks like the 2 Channel Orange Channel gets a 100K presence pot, while the 3 Channel uses that for the Red Channel. And the 2 Channel Red Channel gets a 25K presence pot, while the 3 Channel uses that for the Orange Channel.

Is that right? If so, why the switch?

 

[Silverwulf]

Don't let the colors confuse you. You can't compare the Orange and Red channels of the 2 amps. People oftentimes get confused when talking in reference to the colors, so I prefer to speak in reference to the channels. Essentially, Channel 2 (what you're referring to as "Orange") on the 3 channel model is closest to Channel 2 (the "Red" channel) on the 2 channel model. Channel 3 ("Red") is a little different than anything you'll find on the 2 channel.

Long story short (too late), if you like Channel 2 Red on the 2 channel model, then you'll like Channel 2 Orange on the 3 channel more. Channel 3 Red is a little different and a little more aggressive.

 

[cardinal]

if you like Channel 2 Red on the 2 channel model, then you'll like Channel 2 Orange on the 3 channel more.

Now I'm really confused. This hopefully will all be addressed once the new amp gets here.

Why do you say that? I've never played a 2 channel Recto before. I bought one blind because it was very very cheap. I may end up preferring the 3 channel Solo that I already have, but Im curious why you think that I'll prefer the 3-channel orange to the 2-channel red.

On the 3-channel amp, I can get the Vintage mode to sound essentially identical on either the red or orange channel, but I only really like Modern mode in the orange channel (which you say is like the 2-channel Red, but better).

To what channel of the 3-channel does the 2-channel orange compare? In other words, if the 2-channel red is closest to the 3-channel orange, what is the 2-channel orange closest to on the 3-channel?

 

[Silverwulf]

I think we've got some wires crossed here. I much prefer 2 channel Rectos to 3 channel Rectos - hands down. There's nothing on a 3 channel I like better than what the 2 channel does. That being said...

I think we need to stop referring to colors altogther in order to avoid confusion. I was simply trying to say that Channel 2 in each amp is very similar. Channel 3 in the 3 channel is a little different. You won't find anything in the 3 channel model that is comparable to Channel 1 on the 2 channel model. It's slightly different.

 

[cardinal]

Got it. That makes much more sense.

But, I'm still confused on the value of the presence pots. From that monster "pre-500 mod" thread, it seems that the value of the presence pot is pretty important.

From the part numbers listed in the respective manuals, on Rev G: they presumptively matched Vintage Mode with a 100K pot and Modern Mode with a 25K pot (I say "presumptively" because Channel 1 by default is Vintage Mode and Channel 2 by default is Modern Mode). But on the 3 Channel, they presumptively matched Vintage Mode with a 25K pot and Modern Mode with a 100k pot (again, I say "presumptively" because from the manual Channel 2 was optimized for Vintage Mode and Channel 3 was optimized for Modern Mode).

So it looks like they switched the value of the presence pots to the modes that they'd go with. That just seems strange to me.

 

[Setherial]

Got it. That makes much more sense.

But, I'm still confused on the value of the presence pots. From that monster "pre-500 mod" thread, it seems that the value of the presence pot is pretty important.

From the part numbers listed in the respective manuals, on Rev G: they presumptively matched Vintage Mode with a 100K pot and Modern Mode with a 25K pot (I say "presumptively" because Channel 1 by default is Vintage Mode and Channel 2 by default is Modern Mode). But on the 3 Channel, they presumptively matched Vintage Mode with a 25K pot and Modern Mode with a 100k pot (again, I say "presumptively" because from the manual Channel 2 was optimized for Vintage Mode and Channel 3 was optimized for Modern Mode).

So it looks like they switched the value of the presence pots to the modes that they'd go with. That just seems strange to me.

Hi Cardinal

So, you really have to forget about these colors. As Silverwulf already said, Ch.3 is totally different, and has by itself nothing to do with "especially modern", it is from the circuit a totally different design. Vintage or modern are chosen with the little switches in each channel (on the 3-ch, each can switch to vintage or modern, additionally also to raw, and on the 2-ch you can switch ch1 to normal, vintage or modern, and ch2 to modern or vintage. I also like the 2-ch recto better than the 3-ch, soundwise ;-) ).
The values of the pots match, so to show it with your table (simply shift the right part of the table one line downwards):

2-ch recto has (a) channel 1, and (b) channel 2
3-ch recto has (c) channel 1, (d) channel 2, and (e) channel 3

so your table
100K on (a), compares to none on 3-ch
25K on (b) and (d)
100K compares to none on 2-ch, but on (e)

So the "modern" channel on the 2-ch is like the 2nd channel on the 3-ch, so they also have the same pot-value (25K). Channel 3 is an own design, so they put in 100K.

Another idea how to look at it: on the 2-ch, ch1 in normal (clean) mode is like ch 1 on the 3-ch, the 2-ch channel 2 is like ch2 on the 3-ch, and channel 3 on the 3 channel is a new and different channel.

Hope this helps, and does not make more confusion ;-)

 

[cardinal]

^ Thanks, that is helpful, but I see what I think is causing the confusion.

Using your nomenclature, what makes (e) so different that (d) other than the presence pot? As far as I can tell, they are suppose to be identical. Switching to Modern mode in either (d) or (e) kills the negative feedback (as evidenced by a massive volume jump when switching from raw/vintage to modern in either (d) or (e)). According to the manual, they are the same except for that presence value.

If that's true, then what makes (e) in Vintage mode such that it's uncomparable to (a)? I get that there are differences inherent in the differences between the 2-channel and 3-channel amps, but if (d) is roughly equivalent to (b) (both with the 25 K presence pots); why do you say that (e) is not roughly equivalent to (a) (both with 100 k presence pots)?

Also, by default (a) was matched with Vintage High Gain and (b) was matched with Modern, though they can obviously be cloned, etc. But this is their default position, so I would think that Mesa believed that the respective presence pots were best suited for each mode.

And according to the manual, (d) clearly was intended to be used with Vintage Mode by default and (e) to be used with Modern mode by default. They of course can be used the other way around (and that's how I do it), but the manual indicates that by default (e) was "optimized" for Modern mode (Mesa's own wording). But (e) uses the 100 k presence value, significantly higher than the 25 k value used in (b). So Mesa's "optimized" Modern mode in the 3-channel Solo heads (e) has a significantly higher presence value than (b). That just seems odd to me. But, I've read that some of the earliest Dual Rectifiers used high values for the presence pots (I think I've read as high as 220 k?), so maybe the high value for (e) was intended to shift that Modern mode back to those really bright, earlier Rectifiers?

Oh well, I guess I'm just hopelessly confused over the "why," but at least I know that I can make the 3-Channel Solo sound fantastic, so I'm happy.

My 2-Channel Rev G was suppose to have been delivered last Friday, but UPS lost it I think once I can play them back to back, I'll start to figure out what's going on.

EDIT: just to be clear, I actually prefer the Vintage mode with the 100k pot and the Modern mode with the 25 k Pot, which is how the 2-channel Rev G orange and red channels seem to be set up, respectively.

 

[JCDenton6]

Hope they find your amp duder, I remember the story of the Mesa cab :?

 

[cardinal]

I may start insisting on a different carrier from UPS. Earlier this year, they lost a 4x12 (!) that was shipped to me. Sounds like you had the same thing happen? Seriously, how do you "lose" one of those? Especially in my case, since it went "out for delivery" and then disappeared for a month. Like it accidentally fell into the seat cushions or something. I thought it was almost hilarious.

 

[cardinal]

Finally got the amp after UPS had their way with it. :x Roughed it up pretty good. But after playing it a bit, I have no concerns with the value of the presence knobs. :lol:

 

[JCDenton6]

Nice, glad you got the amp and are enjoying it!
2 channels rule! :mrgreen: :twisted:

 

[cardinal]

:twisted:

 

[Setherial]

Cool, this looks very good!

Glad, that you finally got the amp.

So for your questions about the channels...
To be short: Of course, mesa do their description about how the channels should be supposed to sound very simillar, as they all are dual rectifier solo heads. And a description is done on the computer, and about the specific amp, and (mostly) not in comparison with other products.

But in fact, not only the presence pots are different, and are also not the only part in the circuit, that are responsible for the sound.
I.e. you wrote:" why do you say that (e) is not roughly equivalent to (a) (both with 100 k presence pots)? " Well the pots may be the same resistance, but the tubes are driven totally different, so (e) drives the tube "harder" than (a), so it gets a more "modern" sound ;-)
So if you look at the schematics, you can see that there are many slight differencies, i.e. slightly different resistor and cap values, slightly different voltages of the tubes, and so on.
This makes a slightly different sound, even if for most common audience, a rectifier sounds like a rectifier ;-)

You shurely already heard the differences by yourself?!

Well, the main thing is, that despite of what is inside or how it is set up, if you like the sound/it sounds great for you, all is fine!
(But nevertheless it is good to know, what happens inside ;-) )

So have fun with your amps!