Back to the big daddy Mark V

[dlpasco]

Did the loop test last night. I have a question for all of you who are trying it. Where are you setting the master when you try it?

Here is why I ask. I have read for several years, that with the loop engaged, you need the channel volumes up round noon to sound their best. That means, my master is running around 10:30 or so (that's as loud as I can get away with when the wife is home). Just turning off the loop is a big volume boost. I said this before... yeah, sounds "better" because it's way louder. But I know there are actually additional gain stages involved here, vs. the testing last week of the solo control. So when disengaging the loop, you then only control volumes with each channel volume control, so they have to be turned down or it's way loud. So I turn all three down and relatively matched, to about the volume I had before. I also have the loop volume on the back set at noon.

Just flipping the loop on and off with wherever you had the knobs set is, again (IMHO) not a fair comparison because of volume differences. So, rather than the channels around noon, master at 10:30 or so approach, I figured that to be fair I have to equal out the volumes with the loop on and off. To do this, I left the channel volumes where they were without the loop on so now roughly C1 = 11:00, C2 =10:00, C3 = 9:30 or so). Then I flipped the loop on and off a few times and adjusted the master volume when on, to match the volume levels very closely to when off.

All that for reference. Now to the results. At first I was using the JP12. Almost no difference at all in tone. Again, nothing plugged into loop or in front, guitar straight in. "Where is this tone suck from the loop I keep hearing about?" Ok, I'll get a more transparent set of pickups and try it. PRS NF3 plugged in. ON/OFF/ON/OFF repeat, repeat, repeat...

Not to be controversial or whatever. Not to be "non-critical." When the levels are carefully matched, there is almost no difference in actual tones. Certainly no "tone suck" where I sense a loss of transparency. In fact, the differences were so slight, that I basically decided I'll test it one more night ONLY because I've heard "tone suck" so many times. If I feel after the next test like I did after last night, the loop will go back on and stay on. I'll then retain the function of the master, the solo and have a usable loop. If sitting right in front of the speakers with critical ears detects almost no difference at all, then it's not worth giving up 3 functions on the amp for a difference nobody would ever notice from 20 feet away or with ANY other source of sound present. It was that slight.

So again, have any of you who felt it sounded considerably better, and have sworn off your loops ever balanced the volumes to see how much difference there really is? If so, maybe I just have a better tube driving my loop... But I'm telling you there is less difference in tone when engaging the loop, than there is moving ANY knob on any channel by even a slight amount.

Thoughts?

FYI - the call to Mesa confirmed that disabling the fx loop can improve tone, and that there should be no difference between using the solo or output controls regarding tone with the fx loop is active.

 

[IronSean]

It's slightly different between the different versions, but it's there.

In Mark V and IIC+ we've got the same 1K to ground, 47K to ground on the other size of that 120u cap, but some slight differences in the larger caps:

In the Mark V we get a two modes: In M7(Mk IIC+ mode) we have 2 2.2uF caps in parallel, or the equivalent of a 4.4 uF Cap to ground. Or in Mark IV and Extreme mode we get a 15 uF cap to ground instead.

In the Mark IIC+ There's a 0.47 uF cap on one part and a 15 uF cap on the other part. The difference between pull deep or not is the 15K resistor: With pull deep engaged, the resistor is bypassed, and you have 15 uF and 0.47 uF in parallel for a 15.47 uF capacitance. (Note that the 0.47 is only 3% variance, so not much larger than normal variance in parts anyway, and negligable). Then the Pull Deep isn't engaged, it's a 0.47 uF in parallel with a 15 uF, but with the 15K resistor on that part of the circuit. I'm fuzzy on the exact way you'd calculate that, but it would mean the signal would largely favour the 0.47 uF cap, but possibly still have affect from the 15 uF, leading to a capacitance somewhere above 0.47.

And, well, the Mark IV is a different beast. This is a perfect example of how the Mark V really is very faithful to the Mark IIC+, and the Mark IV was actually fairly different in a lot of ways, and the Mark IV mode really isn't that so much as a deeper Mark IIC+ mode.

But in the Mark IV, there's a 2.2 uF cap associated with the Mid Gain mode, and a 15 uF cap followed by a 22K resistor that can be toggled out somehow. The circuit entering into this stage is actually fairly different, and there's things going on with the different channels that I can't make sense of since I haven't studied the IV schematic much. Also, just looking at the manual, there's no Pull Deep in the Mark IV, so suddenly this makes more sense. R2 basically has Deep on, Ld has it off, but with Mid-Gain on you get a 2.2 uF cap instead. But the Mark IV has major circuit and layout differences which could account for the deepness even without the exact pull deep circuit present.

TL;DR: The MarkIIC+ mode seems to approximate pull deep off, the Mark IV mode approximates Pull Deep engaged. The Mark IV was totally different and didn't have this option and got it's depth somewhere else.

 

[Bullen]

Cool! Thanks fot clarifying the deep function on the different amps. You learn something new everyday.

But what about the Mark III? On my red stripe the deep function is not subtle at all. It adds a really deep and at times an almost overpowering bass boost, especially if the 80hz slider is up a bit. Neither my old Mark V or my new JP2C is anywhere close to that. My IV is closer, but the III seems to go both deeper and louder. The III's deep function seems closer to the deep on my 2:90 actually. Really powerful.

I thought that the deep on the Mark III was similar to the IIC+, but if the V and the JP is to judge from, my III is different. My Mark III is in need of some servicing right now, so it might be a case of bad caps or pots or something else wrong with it ( it's gotten a pretty bad hum lately). Maybe the deep on my amp isn't supposed to behave like it does.

 

[IronSean]

Looking a schematic (Not sure which stripe version it applies to, or if it's ever changed) it seems identical to the IIC+ schematic.

I know on my Quad it felt more prominent than on the Mark V. I'm not sure if part of that is that it's dampened on the Mark V with the effects loop on (As on the V, the loop was moved from right before the pull deep and master volume, and instead is after the GEQ and has a gain makeup stage and the output knob it has to pass through too). Or maybe the Power amp is the difference. I've heard people saying running through their IV power amp brought back the massive life they felt the V lacked, and I know the V simulClass power amp is different than past designs, the tubes run hotter, more wattage is squeezed out, Obviously the circuitry for the 10 watt mode is different, the transformer would be a different spec too I'm sure.

I'll have to play around with it some this evening.

 

[dlpasco]

Cool! Thanks fot clarifying the deep function on the different amps. You learn something new everyday.

But what about the Mark III? On my red stripe the deep function is not subtle at all. It adds a really deep and at times an almost overpowering bass boost, especially if the 80hz slider is up a bit. Neither my old Mark V or my new JP2C is anywhere close to that. My IV is closer, but the III seems to go both deeper and louder. The III's deep function seems closer to the deep on my 2:90 actually. Really powerful.

I thought that the deep on the Mark III was similar to the IIC+, but if the V and the JP is to judge from, my III is different. My Mark III is in need of some servicing right now, so it might be a case of bad caps or pots or something else wrong with it ( it's gotten a pretty bad hum lately). Maybe the deep on my amp isn't supposed to behave like it does.

I think it's a Mark III thing. Deep on my blue stripe III is like a kick in the face. You definitely notice it and it's overwhelming if the bass knob or 80 Hz slider are very high at all.

 

[IronSean]

The other thing to remember is the pull deep just acts as a low filter, removing low end content when not engaged, and leaving it in the signal when pulled.

chipaudette posted this great image in another thread:
Frequency Response of "Pull Deep" by chipaudette, on Flickr
http://www.flickr.com/photos/50442673@N03/4629417552/

So the difference might come down to the IIC+ being a relatively tight, mid focused sound, where the III and IV might have more low end content hitting that stage, making the difference between in and out more prominent.

 

[Bullen]

Cool! Thanks fot clarifying the deep function on the different amps. You learn something new everyday.

But what about the Mark III? On my red stripe the deep function is not subtle at all. It adds a really deep and at times an almost overpowering bass boost, especially if the 80hz slider is up a bit. Neither my old Mark V or my new JP2C is anywhere close to that. My IV is closer, but the III seems to go both deeper and louder. The III's deep function seems closer to the deep on my 2:90 actually. Really powerful.

I thought that the deep on the Mark III was similar to the IIC+, but if the V and the JP is to judge from, my III is different. My Mark III is in need of some servicing right now, so it might be a case of bad caps or pots or something else wrong with it ( it's gotten a pretty bad hum lately). Maybe the deep on my amp isn't supposed to behave like it does.

I think it's a Mark III thing. Deep on my blue stripe III is like a kick in the face. You definitely notice it and it's overwhelming if the bass knob or 80 Hz slider are very high at all.

Yeah, it's really powerful on the III and since the deep on my 2:90 is similar, I thought all deep functions acted the same.

 

[Bullen]

The other thing to remember is the pull deep just acts as a low filter, removing low end content when not engaged, and leaving it in the signal when pulled.

chipaudette posted this great image in another thread:
Frequency Response of "Pull Deep" by chipaudette, on Flickr
http://www.flickr.com/photos/50442673@N03/4629417552/

So the difference might come down to the IIC+ being a relatively tight, mid focused sound, where the III and IV might have more low end content hitting that stage, making the difference between in and out more prominent.

Yeah, that could be it. So I guess the deep on a real IIC+ is more similar to the V and the JP2C then?

 

[Nicklotsaguitars]

So the difference might come down to the IIC+ being a relatively tight, mid focused sound, where the III and IV might have more low end content hitting that stage, making the difference between in and out more prominent.

Yeah, that could be it. So I guess the deep on a real IIC+ is more similar to the V and the JP2C then?

Gotta say, I had pleasing results yesterday using mark4 mode. Thinking about it differently.
Instead of being on mark2 mode and fighting a losing battle to calm down the mid attack that seems to eat up the whole frequency range. Using mark4 and increasing that modes mid attack, which in turn calms the bass end down. Works a lot better.

 

[Dreamtheaterrules]

FYI - the call to Mesa confirmed that disabling the fx loop can improve tone, and that there should be no difference between using the solo or output controls regarding tone with the fx loop is active.

I saw that. Was asking in real world terms, how much difference it makes. It's way too to easy to perceive any change in volume as a big "improvement." When careful level matching, I found it wasn't enough of an improvement to give up 3 features on the amp for. If anyone else wants or needs these features, please do the test I suggest above and let me know what you think. I've got stock tubes in the amp and the difference was so small it was not worth giving up the loop, master and solo for.

I will only temper this with this remark though. What you posted is not "news" and neither is what I posted. I've seen this debate before, (and before I had one to try myself) at The Gear Page. Some guys swearing the loop was a significant tone sucker, and some guys swearing that with matched levels and proper loop volume setting, the differences were very small. I'm discussing this here to see what you guys find in actual testing. There may be something else at play here, or maybe we solve another thing that has been an issue for some.

I tend to be curious about this stuff. I'm fully aware that tones one guy doesn't like another will love. That's all understandable and expected! But "the loop sucks tone enough that I leave it off" vs. "it doesn't make a significant difference".... well, when both parties can hear and seem critical of such things, I get more curious about the difference of opinions because this is not a debate of tonal preferences, this is more a factual statement of "yes it makes a big difference" vs. "no it doesn't make a big difference." So, Mesa can say the tone can be improved with the loop switched off. But if the differences with proper settings are small enough to be inconsequential in any gigging situation or mix, then there are probably some guys who didn't like the loop, who'd like to know that. I'm anxious to hear what you guys think if you try it.

 

[Nicklotsaguitars]

How should we conduct the test?
I'm a strong believer in perceived volume being a huge effect on the sound of an amp. Will the amp balance volume wise between loop on and off?
And the loop itself. Do we test with a patch cable joining the sockets? Do we test loop disabled against loop off on the footswitch. Or loop on. If on with a patch cable or without?

I ask because I had an old 2210 some years back. I was having the shell recovered and using the chassis. Consequentially the reverb tank wasn't connected. Once, out of habit I hit the reverb switch turning it on and got a huge volume boost. I suspect because of the reverb recovery circuit not suffering loss from the tank. Now I've no doubt this amp won't be subject to those vast differences. The 2210 was Marshalls first channel switching amp. It had severe bleed through on the tone controls between both channels.
But I'd like to rule it out to make a fair test

 

[Dreamtheaterrules]

Loop knob at noon. When I was using it on all the time, I had channel volumes near noon per what I had read about them sounding better turned up at least around there when using the master. I had the master between 10:00 and 11:00 depending on how loud I wanted it. Turning off the loop means turning the channel volumes way back. Even 10:00 can be loud depending on channel. Set them at the desired level, and then since they are down, your master will have to go up from where it was. I found that once I set all three volumes pretty close (Fat/Crunch/II or IV) the balance point between on and off, was almost exactly noon on the master. I flipped it many times until I couldn't hear a volume difference when the loop was on vs. off.

It was fairly loud for home. Loud enough to clearly hear any tonal shifts, loss of transparency or other changes. Once you get the volumes really balanced on or off, the difference in actual tone is pretty small. In may amp, it was nowhere close to enough to worry about or to give up the features of the loop, master and solo controls for. Any small improvements you make would more than offset it. Example, I almost always hit my amps with a boost. Turning off the boost alone lost more tone than turning on the loop. Way more in fact (and yes I readjusted the volumes without the boost). I'm a fairly critical listener. In my amp, the difference in the loop on is not an issue. I listened on all three channels as well, so I've tested from squeaky clean to high gain. I will test this one more time and unless I hear something significantly different, my loop won't ever go off again. I am ready to try some pedals in the loop, plus it's just too easy to turn one knob to crank everything when the wife is gone, and turn it all back down to loud home volumes when she's there or lower than that when she's there but it's later in the evening.

 

[Nicklotsaguitars]

Yes mate that's some of what we need, definite settings to compare to.
Because, absolutely no funny stuff intended, we all hear and interpret things differently. Aside from that, we all have different hearing ability. Mine changes throughout the week if I've been gigging on a Saturday. Sunday/Monday I can barely have a conversation, by Friday I'm back on form.

So what I propose is that we set up a specific neutral list of settings. That we can all go to. Then decide how we should conduct our own individual tests. For which I propose we test the amp first at the footswitch function of the effects loop. loop off/on without the send/return sockets connected with a patch cable. Then test loop on/off with a patch cable connecting the send/return sockets.

Then make a comparison of the loop with patch cables against the loop switched off at the back of the amp. So it can't be activated and you lose the master volume and solo functions. And once again without the patch cable.

I really do think that something like that would be the only fair way.
I mean, I read so much about 'tonesuck' and half of it I think is nonsense. It's always portrayed negatively. When in some instances, the slight dumbing down of high frequencies and rounding out of the mid range, which is what I associate with the word. Can be an improvement.

So if we get a clear set of parameters with which to conduct the test. Get a few owners to participate. We'll get a much more accurate idea of what people are hearing, if nothing else. Because at the end of the day, it's all speculative. You may prefer your amp facing the wall and stood upside down. No one can tell you you're not allowed to like that.

 

[SamuelJ86]

If I'm understanding you correctly, you're saying just to match the volumes with the fx on to the same as when it's off. So when you flip the bypass switch the volume is the same. If that's the case I tried it out. And I still heard a difference. It's not huge but it's definitely there. After playing for a while with the loop on though, I don't really notice it much anymore. You add circuitry when the loop is active, so I'm not suprised there's a difference. But I agree that it's not as big a deal as some make it out to be.

 

[Dreamtheaterrules]

Yes, you're adding two gain stages, so of course it's not completely imperceptible. In my amp though, it's very minor. Honestly, some may perceive it as an improvement. But, last night I took the knobs off my "matched" settings and if you don't have the loop knob in it's best spot, for example, you can make it much more "different."

This conversation sparked another trip to the manual over the weekend, and I re-read the comments about turning the loop on and how it makes it closer to the old models, with regards to control over gain staging. Many cite the lack of two gain controls as a big difference between the V and older models. Once I've put this topic to rest to my own satisfaction, the next one I'll mess with is using the some experimenting with the loop volume AS that second gain stage control as the manual indicates. Another thing you can't do with the loop off.

 

[dlpasco]

Still losing my mind over how brutal this amp is. Consistently amazed by how much BETTER it sounds than the tone in my head that I'd been chasing for the last few years.

 

[Dreamtheaterrules]

Have you been experimenting with mids knob vs. 750 slider much?

 

[dlpasco]

Have you been experimenting with mids knob vs. 750 slider much?

I've been diming the mid knob and then scooping the bejesus out of the 750 slider. YMMV.

 

[APEMAN]

-

 

[bdubbs]

I do find turning the loop off can help you get channel volume the way you like. My clean channel is always slightly quiet where i run my master where i have to turn the channel volume up so much that i get slight breakup that I don't want.

With loop off I can get my clean channel at the volume I like without sacrifice. Just a note from a live player.