Clean Channel...removing bright cap?

[Angle Loss]

Has anyone removed the 120pf bright cap on the gain control of the clean channel?

I've always loathed the clean channel...doesn't take overdrive pedals as well as my old Fenders. It is overly harsh and is very buzzy/shrill no matter the settings. Their "tweed" doesn't sound tweed like to me. In a fit of curiosity, I looked at the schematic and found that they had permanently wired a bright cap on the clean channel. Some may like the bright cap sound (and that is fine of course), but I do not.

I slightly modded channel 3 already (removing the local feedback on one of the tube stages as described in that old saturation thread) and really liked the results. I've modded and built amps (no need for warnings). I'm just looking to see if anyone else has done it. Did you like it? Any problems in doing it? I haven't opened it up yet to do it, but thought I'd ask.

I'm thinking it would take what is a fairly Fendery channel and make it sound more like my vintage Fenders (at least in the ballpark).

 

[Angle Loss]

Just posting an update for anyone who might be thinking of doing the same. Sounds way better now without the bright cap on channel 1. Has more than enough treble, but is able to be dialed in closer to my favorite Fender tones and takes overdrive and fuzz pedals better now.

I've removed the C39 cap (channel 3) from the Saturation Mod thread and did the jumper for the caps mentioned in it as well. The only thing left I'd like to do is figure out how to adjust the fixed "drive" control to be higher, since it is not adjustable like the earlier Marks. I think it was preset at something like 7.5, but channel 3 feels like it could use a little more.

 

[Bankim]

Thanks for the update. If I ever need a change on Ch 1 , I ll come back to this thread 8) .

I have only done a 12AT7 tube swap and I personally like it better on V6 vs being on V4. Didn't have the icepick syndrome when I bought the amp but that's just my perception. However, Whatever sounds good to me might not sound good to someone else. Did make a video using my phone couple of years back - here is the video if you are interested - https://www.youtube.com/watch?v=mDLozNfO13U. I am not an accomplished guitar player but I feel the tone comes through quite nicely in the video..

 

[Wayno]

Interesting, did you stick with the mod? How about the drive preset?

 

[batflash]

Angle,

Thanks for the insight on this one. I'm noticing that my clean channel is also harsh, fizzy, and sizzly when using overdrive pedals. Did the removal of C39 help reduce fizziness on Channel 1?

Do you have a link in regards to this mod?
Do you or have you tried other values of caps, if so, what were your findings?
Are there any other interesting mods for your Mark V that you like?


A few things I'd like to see different about my Mark V:
Volume taper on Master Volume
Correct the no-volume from the first quarter-turn on the each of the channels
Shift values of the EQ on each of the channels to my taste, such as frequency affected, Q, and even narrow cut and boost range.

I know, it sounds like I don't like the amp, however, I really do. I'm just a tweaker at heart and see a potential to improve it more towards my own tastes.


Thanks,

 

[batflash]

Just posting an update for anyone who might be thinking of doing the same. Sounds way better now without the bright cap on channel 1. Has more than enough treble, but is able to be dialed in closer to my favorite Fender tones and takes overdrive and fuzz pedals better now.

I've removed the C39 cap (channel 3) from the Saturation Mod thread and did the jumper for the caps mentioned in it as well. The only thing left I'd like to do is figure out how to adjust the fixed "drive" control to be higher, since it is not adjustable like the earlier Marks. I think it was preset at something like 7.5, but channel 3 feels like it could use a little more.

I just got around to doing this yesterday. Mind. Blown. It's sounds so much better now, and the predictability of the channel is better as well. Essentially, when you turn the gain down with the stock cap there, all highs at a louder volume are present, so the frequency response of the channel isn't balanced. It's like you're getting 90 watts of highs, but attenuated everything else. BUT, as you turn the gain up, the channel starts to balance out just past noon. Why? Because the full frequency is now matched or close to matching what was originally bleeding through the cap. I think this is why amps always sound best when you hit that noon point. You're essentially fatter, and really, balanced across the frequency spectrum.

All this to say THANK YOU ANGEL for the help on this one!

Now if only I can get the treble on channel one to sound better. Less exaggerated of Q so the extremes of the potentiometer sound smoother. Thoughts?

 

[batflash]

Just reporting back here about my Clean Channel troubles.

I removed the C7 cap AND swapped the stock 250k treble pot for a 100k linear(B) pot. HOLY SMOKES! What a difference!

The lower value pot narrows the range of the treble, making the twist of the knob more forgiving and easier to dial in. I am of the opinion that anything after 2 o'clock on that knob was useless and nasal. I think this treble knob and funky cap is what made this amp difficult to dial in for a lot of people, particularly those that played with the GAIN set before 1 o'clock.

Now you can dime the treble, still rip heads off, but it's just bright, rather than harsh and nasal. AND now you can set the GAIN to 9 to 12 o'clock and not have to compensate back pulling back on the treble or add mids and bass. It's such a different channel now. I'm gonna say that I'm in love with it.

Side note, I'm playing through 2 - 1x12 oversized Stagecraft cabs, small opening on the back, loaded with Eminence DV77. I've gone through at 10 other speakers of varying flavors, too. This modification was really what this amp and I needed.

Alright, done typing here. I'm gonna shut up and play my guitar! Cheers!

 

[rarebitusa]

Congrats sounds like those changes are working for you. Curious how do these mods effect the voicings of Chan 1? Tweed mode has always been a big change WRT Clean/FAT. Also does the normal/bold switch respond differently?

 

[batflash]

Congrats sounds like those changes are working for you. Curious how do these mods effect the voicings of Chan 1? Tweed mode has always been a big change WRT Clean/FAT. Also does the normal/bold switch respond differently?

The BOLD still responds like it typically does with that extra low mid girth. The Clean and Fat channels also play a lot better, in my opinion. They've always been lower gain and volume, so I had a tendency to push the gain on those past noon anyway. Remember that pushing the gain past noon, you start approaching that balance I was talking about earlier; where the signal flow now goes through the pot rather than the bright cap and the response of the bass and mids catch up with all the mostly unattenuated highs. BUT, if you play the FAT and CLEAN on lower gain settings, this MOD will help balance out those voicings too.

The mod has no affect on CH2 or CH3. From what I can tell though, there isn't a cap on either of those channels that affects them the way the cap on CH1 does.

 

[shredgd]

I've always loathed the clean channel...doesn't take overdrive pedals as well as my old Fenders. It is overly harsh and is very buzzy/shrill no matter the settings. Their "tweed" doesn't sound tweed like to me. In a fit of curiosity, I looked at the schematic and found that they had permanently wired a bright cap on the clean channel. Some may like the bright cap sound (and that is fine of course), but I do not.

I slightly modded channel 3 already (removing the local feedback on one of the tube stages as described in that old saturation thread) and really liked the results. I've modded and built amps (no need for warnings). I'm just looking to see if anyone else has done it. Did you like it? Any problems in doing it? I haven't opened it up yet to do it, but thought I'd ask.

I'm thinking it would take what is a fairly Fendery channel and make it sound more like my vintage Fenders (at least in the ballpark).

I’m glad I’m not the only one who wonders why they made the decision to make the bright cap fixed. Yours is exactly the same comment I had for this extraordinary amp: compared to a Fender blackface circuit, it doesn’t eat pedals as well because of the fixed bright cap. I must keep the treble and the presence quite low and the mids quite high, still overdrive/distortion pedals sound strange because of that “scooped” quality of the circuit.
They probably favored the “Petrucci clean” presuming people wouldn’t use overdrive pedals with it that often.

Now I’m very tempted to perform the mod as well! (I’m an amateur DIY builder and modder, so no concerns here as well)

Giulio

 

[DECEMBER]

Yes, overdrive/distortion pedals sound horrid into the clean channel of the Mark V. But the clean tone is perfect. It's perfectly bright and detailed without being harsh, but this is why gain pedals sound so harsh and buzzy into it.
I think the amp has plenty of overdrive options already, so it doesn't need to be able to take pedals. Why use a solid-state gain pedal with an amp that has 7 preamp tubes and 9 preamp voicings, 4 of which can do low-gain overdrive? (6 if you include the power tube overdrive you can get with Clean and Fat set on 10W).
But, yeah, the only distortion pedals I can use with the Mark V are the kind that are designed to work as preamps and plug straight into the FX return, bypassing the amp's preamp. The Solar Chug sounds very similar to channel 3 when used as a preamp into the FX return.
The Badlander 50W has a more pedal-friendly clean tone, but as a clean tone, if I put the treble, presence, and bass at max, it's still not near as bright and thumpy as the Mark V clean. I just got the Badlander and I like it a lot more for high gain, but I've been trying to justify selling the Mark V and I just can't part with that clean tone. So I'm using an A/B switch with both amps for 3 channels: Crunch & Crush on the Badlander, and Clean-Bold on the V, stereo FX return to both power amps.