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PostPosted: Wed Dec 27, 2017 5:19 pm 
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Mark II
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Location: West Chester, PA
DS-1 wrote:
I also tried to keep the master level as low as possible, using SEND at max and OUTPUT as needed.

I have channel 2 and 3 masters lower than 10 o clock. This because I should then put the clean master at 11-12 (and the gain clean also at 12) to match the volume and it starts to have a sort of crunchy sound.

What exactly does the cap on output?

I have a stock 3ch Triple Recto. What mod can I do to have a "2ch" similar sound?

Thanks!


Jumpering the cap on the Output pot, in practice, restores some of the low end lost when using Loop Active. IOW, it sounds a bit fuller (e.g., less tone suck). In theory I'm unsure why this is TBH. That pot has a 330K resistor in parallel tying the input to the wiper, with said cap in series. In my limited knowledge, I assumed this was a bright cap, but the opposite effect occurred when I jumpered it. It wasn't a night and day difference, but as with most things, small increments here and there contribute to the bigger picture. The brightness/fizziness is still present, but that can be dialed back with the treble/presence pots to some degree. For example, I keep the Treble at 2:00 with Loop Bypassed, but dial it back to 1:00 with Loop Active.

The only time I ever played a 2CH was waaay back in the early/mid nineties when I was just starting out on guitar. So, to answer your question, I'm not entirely sure. Search for "Pre 500 Recto" and there's a long thread about guys chasing said tone. Generally speak though, aside from those very early rectos (Rev C-E), they're all more or less the same. Sure, one small component can make a big impact, but whether or not that is "better" is entirely subjective.

_________________
Guitars:
Ibanez '98 RG7620 (EMG 81-7H, 60-7H)
Amps:
Triple Recto 3CH, Studio Preamp, 2x12 Recto Vertical cab
Past:
Mark V head, Rectoverb series 2 combo, F-30 combo, V-Twin rack pre


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PostPosted: Thu Dec 28, 2017 10:50 am 
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Mark II
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Joined: Mon Jan 30, 2006 4:24 am
Posts: 117
dtrax wrote:
DS-1 wrote:
I also tried to keep the master level as low as possible, using SEND at max and OUTPUT as needed.

I have channel 2 and 3 masters lower than 10 o clock. This because I should then put the clean master at 11-12 (and the gain clean also at 12) to match the volume and it starts to have a sort of crunchy sound.

What exactly does the cap on output?

I have a stock 3ch Triple Recto. What mod can I do to have a "2ch" similar sound?

Thanks!


Jumpering the cap on the Output pot, in practice, restores some of the low end lost when using Loop Active. IOW, it sounds a bit fuller (e.g., less tone suck). In theory I'm unsure why this is TBH. That pot has a 330K resistor in parallel tying the input to the wiper, with said cap in series. In my limited knowledge, I assumed this was a bright cap, but the opposite effect occurred when I jumpered it. It wasn't a night and day difference, but as with most things, small increments here and there contribute to the bigger picture. The brightness/fizziness is still present, but that can be dialed back with the treble/presence pots to some degree. For example, I keep the Treble at 2:00 with Loop Bypassed, but dial it back to 1:00 with Loop Active.

The only time I ever played a 2CH was waaay back in the early/mid nineties when I was just starting out on guitar. So, to answer your question, I'm not entirely sure. Search for "Pre 500 Recto" and there's a long thread about guys chasing said tone. Generally speak though, aside from those very early rectos (Rev C-E), they're all more or less the same. Sure, one small component can make a big impact, but whether or not that is "better" is entirely subjective.


Wow, this reply made my day!

I already did the "presence pot mod" on channel 3, changing the pot from stock to 25k and now channel 3 sounds very close to channel 2. A lot of fizzy is gone.

With caps mod I could improve the sound...

Is there any tutorial to do it? I believe it's a simple mod, but I want to be sure of doing the right jumper!


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PostPosted: Wed Jan 03, 2018 8:21 pm 
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Mark II
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Joined: Tue Feb 26, 2008 2:23 am
Posts: 62
Location: West Chester, PA
I recommend learning a bit more about tube amps and electronics in general before you attempt to mod your amp. No offense, but if you're unsure of what to jumper, that suggests you lack the basic knowledge of reading schematics and signal tracing the PCB. It's not hard to learn, but it's essential for your safety. YouTube has everything you need to know.

_________________
Guitars:
Ibanez '98 RG7620 (EMG 81-7H, 60-7H)
Amps:
Triple Recto 3CH, Studio Preamp, 2x12 Recto Vertical cab
Past:
Mark V head, Rectoverb series 2 combo, F-30 combo, V-Twin rack pre


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PostPosted: Thu Jan 04, 2018 5:31 am 
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Mark II
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Joined: Mon Jan 30, 2006 4:24 am
Posts: 117
dtrax wrote:
I recommend learning a bit more about tube amps and electronics in general before you attempt to mod your amp. No offense, but if you're unsure of what to jumper, that suggests you lack the basic knowledge of reading schematics and signal tracing the PCB. It's not hard to learn, but it's essential for your safety. YouTube has everything you need to know.


Yes, you're right!

I'd like to learn more about it, because i want to experiment before sell it to get a 2ch...that's why I want to know how the 3ch sounds with these mods. I can solder, but I need to improve my learning about electronics.

Do you think that it's possible to do a tutorial to make these mods easier?


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PostPosted: Fri Jan 05, 2018 11:10 am 
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Mark II

Joined: Sun Sep 30, 2012 4:40 pm
Posts: 128
Location: Finland
DS-1 wrote:
I have a stock 3ch Triple Recto. What mod can I do to have a "2ch" similar sound?
Thanks!

3-channel Rectos have 20uF filtering at the parallel power supply nodes of the preamp while 2-channels models have 30uF in these positions. Swap the two pairs of parallel 10uF electrolytic filter caps in the power supply with 15uF caps with similar (or better) specs. This task is not that simple as you have to lift the circuit board in order to work with the caps.


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PostPosted: Sat Jan 06, 2018 6:29 am 
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Mark II
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Joined: Mon Jan 30, 2006 4:24 am
Posts: 117
Shemham wrote:
DS-1 wrote:
I have a stock 3ch Triple Recto. What mod can I do to have a "2ch" similar sound?
Thanks!

3-channel Rectos have 20uF filtering at the parallel power supply nodes of the preamp while 2-channels models have 30uF in these positions. Swap the two pairs of parallel 10uF electrolytic filter caps in the power supply with 15uF caps with similar (or better) specs. This task is not that simple as you have to lift the circuit board in order to work with the caps.


Very cool mod! Have you tried It? How the sound changes?

Instead what about the 100ohm resistor to jumper?


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PostPosted: Sat Jan 06, 2018 2:07 pm 
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Mark II

Joined: Sun Sep 30, 2012 4:40 pm
Posts: 128
Location: Finland
DS-1 wrote:
Very cool mod! Have you tried It? How the sound changes?

Instead what about the 100ohm resistor to jumper?

Not on an actual Rectifier, but I've compared between 10uF, 20uF and 30uF caps on my SLO/Recto-clone I've built. In my experience, the higher you go, the more punchy, bigger and less compressed the amplifier feels. It feels as if the amp slightly cleans up. The lower value caps provide slightly less bottom-end and make the feel more compressed.

IMO, the 100ohm resistors on cathodes have somewhat unique effect. They slightly reduce the gain boost that the cathode caps provide and flatten the frequency response. This seems to result in a slightly more pronounced lowend with less upper mids and treble. This in turn increases the hair and grind when e.g. playing power chords which is one part of the Rectifier trademark tone. The price is paid in somewhat dampened attack. If the 100ohm resistors are jumped, there is slight gain increase in the mids and treble.


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