Sick of the trebly ice-pickyness on my Mark V. Suggestions?

Another thought on the ice pick tone...... :|

I was looking at the schematic to better understand how the EQ effects tone of the amp (Also compared to the Mark IVB schematics). You have to consider that the EQ circuit is last tone control of the signal path before the phase inverter. Also, the EQ is not tube driven, it is solid state (considering the matrix of NPN and PNP transistors along with the passive components of inductors and capacitors that make up the filters). Once the signal enters the EQ the distorted signal will gain some higher order harmonics of the input signal which adds to the ice pick effect. Two things, shape your overall tone of each channel with the tone, gain and presence controls with the EQ turned off, and then use the EQ as the final shaping tool. Since the EQ circuit is effectively the front end of the PI, select a tube that has good low end and improved high frequency roll off for the phase inverter. The exception here is, if you are using the FX loop for the master volume control, half of V6 will insert another tube driven gain stage used as a return to shift the voltage level back to the amplitude of the EQ signal. In essence, V6 could be used to tone shape the EQ signal as well as V7 (PI). For some time I have battled the ice pick tone but did not realize I was actually making it worse with different preamp tubes. I finally abandoned my tone quest with the Mark V and resorted back to stock tubes and could not be happier. Since the phase inverter circuit is not fully balanced (due to the Simul Class and 10W circuit which is class A) there is an offset so using a matched triode tube probably will not make any difference. I found the Mesa 12AX7A (current production) serves the PI position quite well. For some time I have been using a matched triode Sovtek LPS for the PI position of all of my amps. I tried one in the Roadster and discovered it brightened the amp up too much. After that, I am no longer using the Sovtek LPS and much prefer the Mesa 12AX7A as the PI tube. My Mark V was an ice pick from the start so I thought changing preamp tubes would be the way to go. I could not be so wrong. Power tubes and speakers can also enhance the top end too. I had found the Tung Sol 7581 and Svetlana 6L6GC increased the ice pick tones, even the SED =c= 6L6GC did the same thing to the point it was intolerable. Going back to stock preamp tubes for me was the cure. Now I can enjoy the SED =C= tubes and retain my hearing. I am one that is hyper sensitive to high frequencies. For me, if the amp sounded like thin window pane glass shattering in my ears (and the Mark V did just that) just no point in going any further. It will make a difference what type of speakers, size of the cabinet, and their characteristic at high volume vs low volume that could make or break your desired tone and or gain characteristic. The presence controls are very influential to the overall tone of the Mark V. Going back to stock Mesa tubes in the preamp, I can now raise the treble and presence controls in all three channels and most of the voice configurations (except tweed and edge which require major adjustments in order to sound good and keep them out of the brittle zone). Extreme and the EQ preset is no longer an issue for me with the Mark V. I generally play at elevated levels and want to feel it as well as hear it and enjoy it at the same time without wads of cotton in my ears. Changing speakers may help but it will not cut the high frequency out unless it has a considerable drop in frequency response. EV, Celestion (V30, MC90) and others can be bright, but what matters most is to remove the undesirable top end in the signal before you convert it to mechanical energy (speaker).

Wow, thanks so much for all of the suggestions! I am going to try some of the suggested trouble shooting because I'm not ready to give up on this one yet.

The curse of the mark. Mesa and a lot of high gainers suck out the high and then try to compensate later in the circuit it leads to unatural highs which fatigue your ears quickly. I always struggled with this when I had my mark IV. It's the nature of the beast. Some say a bogner ecstasy suffers from the blanket over the speakers again just what bogner diid to handle all the extra gain IMHO some mfg handle this problem better then others but it's a problem IMHO

Since I was in Nashville, went to the local Mesa Boogie dealer, World Music. I have to try out the Mark V head sitting on top of a 2x12 cab. I could not get the ice pick tone out of it. Sounded a bit different than mine at home, but was close. Actually I like the way mine sounds in combo form with extension cab (both having EV speakers).

OK, I just wanted to report that I sold my Rectifier 2x12 Horizontal cab with V30s, and bought a Mesa Widebody Closed-back 1x12 with a C90 and it COMPLETELY SOLVED THE PROBLEM.

There is no ice-picky harshness at all there any more. I can now even use the EQ presets and they sound great.

What a relief.

WOOWOO \o/

Thanks for the data point (seriously)

My experience is with the MkIII, not V, but the ice pickiness is a Mark series family trait. And I spent decades working that out of my tone. Here's how...

Going with my green stripe MkIII and 2x12 halfback cabs, I swapped speakers numerous times, with mixed results, swapped preamp tubes, and considered circuit mods, but here are the only things that really worked: changed cabs...a PRS pine 2x12 w/ V30s, and replaced the V1 12ax7 with an NOS Mullard. The tube swap made the biggest difference. It's the secret to the Marshall midrange honk and it completely revoiced the MkIII. Keeping the 2.2kHz slider down on the GEQ, treble down, volume down and cranking the master in class A mode yielded another big difference. Eventually, when played by itself, it sounded much more treble-tamed, but in a live band setting, it lost its mix cut. It sat heavy against the other guitarist and I struggled to keep volume down and still get heard for solos. Eventually, I switched to a different PRS amp for my classic rock gig and kept the MkIII for more modern stuff.

Today, it's back to complete stock. I use it mostly on ch3 and roll off the tone control on the guitar to compensate. It works perfectly and if I need to step out more, I turn the guitar volume and tone controls. Embrace the Mark for what it is. 8)

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If you have adjusted your presence and treble settings and are still getting the ice pick sound, lower the pickups on the guitar, a common mistake is that players adjust their pickups as close to the strings as possible, this is not correct as everyone plays different. Swapping tubes won't fix your issue, different speaker cabs won't fix the issue(you will be chasing your tail)The mark v is all about response, this is why if you have played on other amps you have not experienced the ice pick issue.

Changing tubes does make a difference as different tubes emphasize different things and change response. But changing tubes or even cabs will not fix the issue but maybe not emphasize it as much. The Mark V is fully capable out of the box to sound awesome with no ice pickness, the issue is not with the amp, it's tubes or cab. The issue is: the type and gauge pick, pickup height, settings. I have owned several Boogie's. When I got the Mark V:25 i had ice pickness that I did not have on my roadking, Electra dyne, Hughes and my diezel Little Fokker, I lowered my pickups problem solved.

tptb73 said:

OK, I just wanted to report that I sold my Rectifier 2x12 Horizontal cab with V30s, and bought a Mesa Widebody Closed-back 1x12 with a C90 and it COMPLETELY SOLVED THE PROBLEM.

There is no ice-picky harshness at all there any more. I can now even use the EQ presets and they sound great.

What a relief.

Click to expand...

V30s sound great in a band mix but often sound harsh on their own. The C90 is a balanced speaker that always works well with the MkV.

Before throwing money at the problem, I should think the first question would be, "How far away are your ears from the speaker?"

I just changed the stock preamp (JJ) tubes in my Mark V with old Mesa labelled Russian 2 (EHX) and it seems to have cured most of the ice pickiness I noticed in the amp. It made the amp sound a lot closer to my Mark III and IV, witch also has the russian preamp in them. The amp became more chunky and open. More balanced in the frequencies but with bigger bottom end and more detailed highs. Worth a try if you are having some issues with the sound.