more info on Rev C/D mod for roadster

[Coker]

i read in a different post about the Rev C/D mod if anyone has performed this mod i would like some more info on how to do it. also maybe a pic or two would be awesome :mrgreen:

 

[LesPaul70]

Sorry, I hate to be a spoilsport - but why?

Even if you succeeded with the mod, you would be severely limiting the versatility of your Roadster and its usability to other purposes. Add a quality OD pedal in front of your Roadster instead, and then use your amp EQ knobs, and you will get you very close to what a C or a D sounds and feels like. Best of all, that's completely switchable. Turn off the OD, and you still have access to all those Roadster sounds, which a Rev C/D/E cannot produce.

Or if you really feel like modding an amp, buy a used (cheap) old Dual Rec. The mods, although reversible, will change the character of the amp quite a bit. Personally, I wouldn't ruin a perfectly good Roadster to get the Rev C sound. YMMV. The "Pre 500" models don't sound that much better - just very different.

 

[Shemham]

i read in a different post about the Rev C/D mod if anyone has performed this mod i would like some more info on how to do it. also maybe a pic or two would be awesome :mrgreen:

Send some good quality shots from the PCB so I can identify and mark the relevant components to be changed.

Sorry, I hate to be a spoilsport - but why?Even if you succeeded with the mod, you would be severely limiting the versatility of your Roadster and its usability to other purposes.

If you mean the ruined clean channel, that does not hold water for the Roadster as its clean channel is implemented very differently from the 2-channel model.

The 2-channel model uses some LDRs on the cathodes of the preamp to drop off the cathode bypass caps and switches some 47Kohm resistors to drop the gain for the clean mode. Lack of these LDRs is the main reason for the better attack and different distortion characteristics on the Rev C/D as they introduce some minor resistance even while open. Rev C/D did not have the 47k resistors on the cathodes to drop the gain for the "clean" mode. In order to mod the 2-channel Rectifier you'd have to remove the above mentioned LDRs and resistors which really would make the clean mode another lead channel somewhat resembling the Raw mode of the newer Rectifiers. On the other hand, Roadster, Road King and the 3-channel Rectifier models have totally different circuits for the clean mode almost separate from the lead modes. On the newer Rectifier models, the Rev E/F/G style lead mode cathodes are simulated with 100 ohm resistors that can be simply jumped to ground without any bad influence to the clean mode. Only preamp tube shared by the modes that is modified is the input tube which does not have any downsides from the mod. So the clean mode remains as clean as ever, but the leads channel gets the good sides of the Rev C/D.

So how does it sound? Not equal to Rev C/D as there are still many difference between the 2-channel and various other Rectifier models. Still, it brings more mids, reduces low end and gives more transparent feel/better attack. Whether you like the change is a matter of taste. IMO, it's definately better for solos as the tone thickens in the mids and has a better response. This mod does not make the tone shrill. That'd still require changing the presence pot.

And yeah, you can use the OD to boos the amp, but I hate what that does to clean channel as much as I hate dancing on pedals all the time :wink:

 

[LesPaul70]

Sorry, I hate to be a spoilsport - but why?Even if you succeeded with the mod, you would be severely limiting the versatility of your Roadster and its usability to other purposes.

If you mean the ruined clean channel

Actually, no - I can well believe that a Roadster would handle its clean channels differently. I was thinking more of the effect it would have on the high gain sounds.

I don't think you can easily get the more modern huge, fat and loose Recto sound from a Revision C/D. With EQ pedals, maybe, you could get something along those lines but it wouldn't sound the same. And you'd probably need two EQ pedals, one in front, the other in the loop.
I find it easier to approximate the C style sound with a newer Recto (2-chan, 3-chan, Roadster/Road King) plus a pedal in front (OD or EQ).

And to be perfectly frank, I haven't found the Rev C sound to be that exceptional in band context. You have to EQ it very carefully (and/or use Channel Cloning) or it will sound thin, piercing and brittle in the mix. I can make the fat and loose G-style Recto sound work much more easily with the band. On its own, the Rev C does sound special, though.

To the OP: I honestly would prefer the Roadster as it is, and use pedals to approximate C/D-style sound if necessary. But that's my personal stance. If you aren't afraid to change your amp, possibly for the worse, go for it. Maybe you end up with a killer amp that puts all others to shame.
Just remember to post clips if you do. :wink:

 

[Shemham]

I don't think you can easily get the more modern huge, fat and loose Recto sound from a Revision C/D. With EQ pedals, maybe, you could get something along those lines but it wouldn't sound the same. And you'd probably need two EQ pedals, one in front, the other in the loop.
I find it easier to approximate the C style sound with a newer Recto (2-chan, 3-chan, Roadster/Road King) plus a pedal in front (OD or EQ).

I should've emphasized that the mod does not make the amp brighter nor do I consider it to make it thinner. Most of the brightness associated with the Rev C seems to come from the presence pot value and some other changes that remained up to the Rev F model. This mod only reverses the cathodes to Rev C/D (as well as to SLO) specs. It changes the nature of distortion removing some of the low-end giving a better overall response. While some of the low-end is gone from the earlier circuit, they seem to be compensated by some more mids making single notes to have fuller body to them. If I compared it to external devices, you could say this mod equals to using EQ in front of the amplifier boosting some mids and slightly cutting the low-end. It'd still lack the EQ in the loop to cut some low-end.

So why would I make the mod if I can use an EQ or a decent boost pedal to approximate the difference? One reason is that the mod does not boost the noise level with signal as most of the pedals do. Other than that, it's a matter of preference whether you like the change.

Another reason I encourage people with newer Rectos to try the mod is that it's very easy and fairly safe to perform. You only need to solder few wires to jump three 100ohm resistors to ground on the cathodes. It's even easier to remove if you don't like the change.

 

[Coker]

one of the questions i had is does this effect all channels i was only hoping it affected channel 4. i currenty use a ts9 but i am trying to get rid of he tap dance.

 

[Shemham]

It'll affect channels 3 and 4. It can also have very slight effect on the feel of channel 1 and 2 modes.

 

[2kutzmalone]

Send some good quality shots from the PCB so I can identify and mark the relevant components to be changed.

If you mean the ruined clean channel, that does not hold water for the Roadster as its clean channel is implemented very differently from the 2-channel model.

The 2-channel model uses some LDRs on the cathodes of the preamp to drop off the cathode bypass caps and switches some 47Kohm resistors to drop the gain for the clean mode. Lack of these LDRs is the main reason for the better attack and different distortion characteristics on the Rev C/D as they introduce some minor resistance even while open. Rev C/D did not have the 47k resistors on the cathodes to drop the gain for the "clean" mode. In order to mod the 2-channel Rectifier you'd have to remove the above mentioned LDRs and resistors which really would make the clean mode another lead channel somewhat resembling the Raw mode of the newer Rectifiers. On the other hand, Roadster, Road King and the 3-channel Rectifier models have totally different circuits for the clean mode almost separate from the lead modes. On the newer Rectifier models, the Rev E/F/G style lead mode cathodes are simulated with 100 ohm resistors that can be simply jumped to ground without any bad influence to the clean mode. Only preamp tube shared by the modes that is modified is the input tube which does not have any downsides from the mod. So the clean mode remains as clean as ever, but the leads channel gets the good sides of the Rev C/D.

So how does it sound? Not equal to Rev C/D as there are still many difference between the 2-channel and various other Rectifier models. Still, it brings more mids, reduces low end and gives more transparent feel/better attack. Whether you like the change is a matter of taste. IMO, it's definately better for solos as the tone thickens in the mids and has a better response. This mod does not make the tone shrill. That'd still require changing the presence pot.

And yeah, you can use the OD to boos the amp, but I hate what that does to clean channel as much as I hate dancing on pedals all the time

Shemham hello sir I am picking up a roadster this weekend. Is there a way to make channel 3 like a rev c and keep channel 4 a stock roadster?

 

[Shemham]

Shemham hello sir I am picking up a roadster this weekend. Is there a way to make channel 3 like a rev c and keep channel 4 a stock roadster?

Already pm'd you, but I'll leave my reply here as well in case someone else will be inquiring about it later.

The short answer is: no, you can't make Rev C mod only to channel 3 except for the presence potentiometer value.

Channel 3 and 4 are in essence the same. They are only distinguished by their own separate potentiometers and presence circuits. Otherwise the two channels are effectively the same.

Rev C mod is essentially jumping three 100ohm resistors on preamp cathodes located between cathode 1uF cathode caps and the ground. The mod allows the cathode resistor bypass cap to operate to its full capacity so to speak, which the 100ohm resistor is hindering. Those cathodes are shared by channel 3 and 4 so the mod will affect the operation on both channels. There is no practical way around this. In any case, the mod is fairly easy to do even and even easier to revert back.

The first two jumped resistor are also shared by channels 1 and 2. However, the mod should not have any adverse effect on those channels. Channels 1 and 2 will regardless switch a separate cathode bypass capacitor in parallel to the ones used on channels 3 and 4, which totally swamps the impact of this mod on channels 1 and 2. In other words, the mod should affect mainly channels 3 and 4, while channels 1 and 2 remain effectively the same.

What you can do, though, is play with different presence pot values for channels 3 and 4. You could try the 250k linear presence pot (the one used on Rev C's Modern Red ) to one of the higain channels to see if you liked that more than the original value.