Has anyone undone the "volume mod" and liked it better?

[lockbody]

So, I've read two posts now linking the DC volume mod to a big difference in volume between the two channels so I decided to undo the mod on my DC-5. Sure enough, the volume mod creates a "gap" between the volumes of the two channels.

Before, with both gains on "7", I would need to keep the clean channel volume around "3" and the dirty channel around "8" for the volumes to match. Also, the amp just didn't feel very loud. Nice for noodling, not so much for my power trio.

After undoing the mod, the volumes are definitely more balanced. Now I can run the clean volume on "4" and the dirty volume on "5.5" and they pretty much match. The amp is also louder up to around "5" on the output knob, and anything after that makes no difference in volume, just power amp saturation.

However, my DC-5 feels tighter and seems to have less apparent gain than before. Not that there isn't a boatload of gain on tap, there just seems to be less of it. There definitely seems like the amp has a more solid low-end now, too. Probably due the increase in "tightness". I run a 12at7 in PI slot, so that may have something to due with the amp feeling so much tighter post, post-mod, too. Of course, output knob taper goes from "0" to "whisper" to "WHOA NELLIE!!!".

I'll need to see how it all works with the band before I decide to undo my undoing, but for now it stays un-modded.

 

[MusicManJP6]

Let us know what you think of it un-modding after the band test. I've never heard mine stock because I bought it with the volume mod already done... I'm curious!

 

[edward]

I won't "un-mod" mine for the simple reason that it is more usable to me with the "modded" master vol pot. The taper is smoother and the low-volume (no, not bedroom volume levels but usable low-vol even with band) tone is better w/o the resistor in the circuit, IMHO. The numerical disparity between channels to me is irrelevant ...nor is the difference as great as yours: mine is like 1.5 to less than 2 number difference. Maybe something is awry with yours??

Nor did I hear any "looser" or "less tight" bottom end when I did the mod. FWIW, I like a good, focused bottom end, and I listen for it ...I definitely would have noticed had I lost any or had it gone flabby.

Edward

 

[lockbody]

Alrighty. I had the boys over last night and had a chance to crank the ol' DC-5 up and put it though its paces at volume.

Bottom line, I like it better with the volume mod undone.

First of all yes, the taper of the output knob sucks. The knob acts like it goes from "0" to "8" instead of to "1". "2" now is equal in volume to "4" with the mod. "4-ish" is where I usually need to run my DC-5 to keep up with my drummer and bassist (Most of the time, our bassist is asking me to turn up.). I feel at that point, my DC-5 starts to lose definition a tad as the power amp saturates. To me, it get a little muddy in the low-mids, and doesn't seem very crisp, either (I'm using both the internal speaker and my 4x12 halfback.). "2.5-3" seems to be this amp's sweet spot with the volume mod.

After undoing the mod, I set the output knob to "2" and it was almost too loud. I'm not sure exactly what that resistor is doing to the amp, but while it was loud, the power amp didn't seem to be saturating as much, leading to a crisper, tighter sound. My bandmates noticed a difference, too. My bassist even asked if I had retubed my amp. I found myself actually dialing back the treble over my normal settings. Turning the amp to "4" didn't make that big of a difference in volume, but re-introduced the little bit of muddiness in the low-mids that I don't like. As it's been mentioned on the forum before, anything past "3" on the output knob is pretty much the same with or without the mod. There's just something going on at "2" without the mod that my ears find pleasing with my particular equipment.

The only thing I haven't done is try a different power tube beside my normal =C= SEDs, but I've never really heard them described as particularly "muddy" tubes as they saturate.

So overall, unmodded is best for me and my band's style. If we played a bit quieter, and/or something besides late sixties and seventies hard rock, or I was a bedroom/basement rocker I would stay with the mod, as it's definitely easier to to get a better sound at lower volume levels.

I also think if I had a DC-3 or 10 I would leave it modded too. The DC-3 because of the intended audience for a 30w amp is more about singing tones at lower volumes, and the DC-10 simply because you generally don't have to turn 100w amps up very far before you drown everything else out. You need that control the volume mod gives you.

So for now I going to keep it with no volume mod. YMMV, of course.

 

[eschoendorff]

Hmmm.. I clipped the leg of the doohickie when I did the volume mod... now I have to "thread a needle" to get the solder iron in there under the big bad blue capacitor to undo the volume mod. Maybe I'll just leave it like it is for now. :wink:

 

[Johnny Load]

Would it be possible to install a push-pull pot for the Master Volume that when pushed in would use the resistor for the "factory" volume taper, and when pulled out would bypass the resistor for the "volume mod" taper? It seems like this would allow you to have it both ways, in case there is an actual difference in tone from one method to the next. Just a thought.

 

[Monsta-Tone]

On my 5, and on my 10 for that matter, the channel volume difference is not the same as yours.
I usually run my gain at 7-9, so this may be a factor and may be why I don't experience the same things as you.

My clean channel's Master is at 5 and my lead channel's Master is at 3 and they are fairly equal in volume.
I also run my clean channel's Gain at 5-7 depending on whether or not I want some grit.

Alot of the differences may be EQ settings too.
I run my lead channel's EQ all on 6 or 7 (bass, treble & middle).
I run my clean channel's EQ - Treble 6 - Mids 5 - Bass 7.
Clean Presence 10
Lead Presence 10

Output at 3 for practice (with the MV mod).
Graphic EQ in a mild upside down V for solo boosts.

The push/pull pot is an excellent idea. I think I'll do that with mine and experiment a little.

 

[photogold]

Johnny,

IMO, there's no need or benefit to adding a push/pull pot to have volume mod/factory taper. All the volume mod does is change the taper, so instead of pushing the knob, you can get the same effect by just turning the knob one number.

I studied the schematics, and from what I see, the effect of removing the resistor is completely confined to the pot. The rest of the amp doesn't know and doesn't care if the resistor is removed or not. With the volume mod, the only thing that should change is the number on the knob for a particular volume setting. I know some people have reported a change in the tone. Different people say it is "tighter", "smoother", "warmer" with (or without) the mod. Other people say that there is an imbalance between the volume of the rhythm and lead channels with the mod. But on paper, I don't see how any of this is possible.

I did the volume mod on my DC-3 last weekend and I didn't find any change in tone or an imbalance between channels. I was checking to see if I could notice a change, but then again, I was predispositioned to not expect a change.

What I did find was a slight change in the taper of the output volume. It was less of a change then I expected. This amp still gets very loud, very fast. It does make adjustments a little easier at practice volume. At very low volume, about 1/3 of the current would go through that parallel resistor. And the effect becomes less as you increase volume. I find that my bedroom setting is 1-1.3 instead of 0.8-1, and my practice setting is 1.6-2.2 instead of 1.2-1.5.

I admit that I'm new to tube amps, but I do have an extensive background in electronics. That's how I pay the bills. I'm sure there are many people here with a better ear for tone changes, but from looking at the schematic, I don't see how that is possible.

Adding the push/pull pot would make it convenient to test for tone and imbalance though.

 

[lockbody]

I'm thinking of re-modding mine this weekend to test if I really heard what I thought I heard. Right now, I still say my DC-5 is brighter and tighter now than its been in the past year that I've had it modded. I'm not beyond saying I had a preconceived notion that it would sound different and that affected what I "heard". But my bandmates heard enough difference to think I had re-tubed it, and I hadn't told them I was going to do anything to the amp beforehand. So there! :lol:

This will be interesting... One member of the board is in a band with two DC-10's. :twisted: One has the volume mod and one doesn't. He says the one with the mod sounds "crappy" compared to the other one and is looking to un-mod it. It will be interesting to see how the two compare after un-modding his.

 

[kartoffel]

I did this on my DC10 and heard no change. The only change was that I had to go and redo my channel volumes and messed with the ratio between channel and master. This is where I think the change in sounds come from. Sometimes I run my channels at .5 and my master at 4-6 and adjust the channel volume to get to the desired volume level. This give an entirely different sound than running the master at .5-1.5 and the channels somewhere from 4-7. IMHO I think the change is just because you have to turn the knobs after you do the mod, but that's just my .02. Also at low volumes I cant get the clean channel to get to the lead channels volume it's entirely too quiet because I play the lead with the V on the eq so it acts as a volume boost. This only happens when I play at quiet quiet practice volumes. When I turn it up it's very easy to balance the two channels.

 

[Johnny Load]

From what I've read, it does sound like the resistor is only affecting the volume pot and not any other component of the amp. I have no real idea, though. I'm actually still trying to find a DC-3 to buy (in my budget...that's the kicker). DC-2's and DC-5's seem readily available, but the -3's are nowhere to be found!!!

 

[Monsta-Tone]

The 3 is a strange duck, in the sense that it has a completely different Phase Inverter circuit from the 5 & 10. I could definitely see where there may be more changes in the mushy or tightness department with the 3.

All in all, I've modded over 20 DC's and just don't see a difference in tone, other than the difference you would normally see with the Output Volume in a different place.

I think that I will try running my channel Masters down a little and the Output up to see if it does get mushy, but it's 100 watts of kill yer mama, so I don't think my DC can get mushy, not even with the extreme gain mod!

 

[scottcrud]

I have a DC10 with the volume mod, and there's another DC10 in our jam room that's stock. There is a absolute difference in tone and volume between the two amps with the same setting.
My amp has brand new Ruby 6L6's, the other one has stock Boogie 6L6's. The two biggest differences is mine isn't as loud and mine has too much low end, a lot more than the other DC10. Oh, and mine has a tiny bit less gain. The other one sounds better.

 

[edward]

I have a DC10 with the volume mod, and there's another DC10 in our jam room that's stock. There is a absolute difference in tone and volume between the two amps with the same setting.
My amp has brand new Ruby 6L6's, the other one has stock Boogie 6L6's. The two biggest differences is mine isn't as loud and mine has too much low end, a lot more than the other DC10. Oh, and mine has a tiny bit less gain. The other one sounds better.

I am highly suspect that the volume mod is the difference. I am not doubting that you hear a difference. But I cannot believe that the difference in tone (bass), volume, and gain you perceive is due to singular resistor designed (I surmise) to simply affect the taper of one volume pot. Too simple a circuit (and "far away") to cause all that. I am willing to bet that if you bring the resistor back into the circuit that you'd still hear the same difference between the two "identical" amps.

BTW, did you check all the normal stuff like same speakers, same cab, same cable straight in (no fx in line), plugged into the same tap, and using the same guitar with exact same settings? That said, the differences in preamp tubes and pwr tubes can even make the difference.

Edward

 

[eschoendorff]

This thread has me riveted. Please keep us updated... I have been going back and forth on my volume mod and would love some conclusive findings.

 

[scottcrud]

I am highly suspect that the volume mod is the difference. I am not doubting that you hear a difference. But I cannot believe that the difference in tone (bass), volume, and gain you perceive is due to singular resistor designed (I surmise) to simply affect the taper of one volume pot. Too simple a circuit (and "far away") to cause all that. I am willing to bet that if you bring the resistor back into the circuit that you'd still hear the same difference between the two "identical" amps.

BTW, did you check all the normal stuff like same speakers, same cab, same cable straight in (no fx in line), plugged into the same tap, and using the same guitar with exact same settings? That said, the differences in preamp tubes and pwr tubes can even make the difference.

Edward

Same settings, same guitar, same cabinet etc. Just different tubes. 3 people in the room, all guitarists. Everyone noticed the same thing, so I no it's not my ears! LOL.

 

[lockbody]

So I just re-modded the vol pot, and sure enough... the lead channel just doesn't seem as tight as it was un-modded. Seems gainier and looser. More modern, if you will.

I know that resistor should not be making that much of a difference, but it does. while I can get the same volume out of the amp by simply turning it up, I cannot get the same the same feel out of it not matter what. The feel of "2" un-modded is simply not the same as "4" modded even though the volumes are roughly the same.

Next step, pull the chassis, solder a short jumper to each leg to make it easy to go back and forth, and break out the recorder.

 

[kartoffel]

I have a DC10 with the volume mod, and there's another DC10 in our jam room that's stock. There is a absolute difference in tone and volume between the two amps with the same setting.
My amp has brand new Ruby 6L6's, the other one has stock Boogie 6L6's. The two biggest differences is mine isn't as loud and mine has too much low end, a lot more than the other DC10. Oh, and mine has a tiny bit less gain. The other one sounds better.

The difference is the tubes though not the volume mod. The tubes would account for the low end and gain. Probably even the volume, but that could be subtle differences in age and use.

I still stand by my prior post that I heard no difference except for the fact that I moved knobs after I did it and that's where all the difference came from. Proportion of channel to master volume makes a big difference and you will surely need to adjust that after you do the mod.

 

[kekam35]

The only thing I'm getting out of this thread is that I should just leave my amp alone.

 

[lockbody]

I did this on my DC10 and heard no change. The only change was that I had to go and redo my channel volumes and messed with the ratio between channel and master. This is where I think the change in sounds come from. Sometimes I run my channels at .5 and my master at 4-6 and adjust the channel volume to get to the desired volume level. This give an entirely different sound than running the master at .5-1.5 and the channels somewhere from 4-7. IMHO I think the change is just because you have to turn the knobs after you do the mod, but that's just my .02.

So, if the resistor only changes the taper of the output knob, why is this? Why would you have to change the balance between the channel volumes and the output knob to get the sound back the same? Why not simply turn the output up?

It is possible I could replicate the sound my DC-5 un-modded by backing down the channel volume, but I already run the output around 4. If I back down the channel volume from its normal 7, it would make the lead channel a lot quieter than the rhythm and make it hard to hang with the rest of the band. I will try this tonight, though.