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Discussion for the new Mark V

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APEMAN
Mark III
Posts: 309
Joined: Tue Nov 08, 2011 10:48 am

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Post by APEMAN » Sun Apr 09, 2017 11:17 am

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Last edited by APEMAN on Fri Feb 28, 2020 10:28 am, edited 2 times in total.

Wayno
Mark III
Posts: 357
Joined: Sun Sep 27, 2015 2:50 pm
Location: Good ole England

Re: Mesa MarkV / Saturation 'mod'

Post by Wayno » Sun Apr 09, 2017 3:55 pm

Hi,

That's very interesting. The ice pick highs are the nemesis of all Mark V owners I reckon. Especially in iic+ mode I find. I've tried all sorts of things to eliminate it, different combinations of channel and Master volumes, presence and EQ setting etc. I even tried a bigger coupling cap soldered in place of the small one for iic+ mode after the EQ to try get some more beef out of the mode. Didn't seem to make any noticeable difference unfortunately. However, I was at home with a baby asleep upstairs so didn't get the chance to get it up to any decent level of volume. Had a gig the next day so put the original back incase something could possibly go bang. Maybe I'll try it again and see if it does help the beef of that mode at reasonable volume, it should do I would think. Anyway, I digress, I too have heard many times of substituting the 12AT7 in various other amps for similar reasons. Can't believe I hadn't thought of this before. Definitely gonna scour eBay for one after next payday and check it out.

Thanks for the inspiration.

Great video by the way. Proper chunky tone you got there.
Her highness the Veenus
(Mark V/V4 & V7 12AT7 Combo)

2 x 12 Vertical Cab
GSP1101

Gibson LP Studio with alnico ii pro
Schecter C1-XXX with emg 81/85 18v
Jackson Dinky XL with Duncan designed???
Sigma DNC-1STE

mace
Mark III
Posts: 276
Joined: Sun Feb 02, 2014 11:51 am

Re: Mesa MarkV / Saturation 'mod'

Post by mace » Sun Apr 09, 2017 9:51 pm

Hi Apeman,

Thanks for the tube advice, it sounds interesting. Do you know if it makes a difference if it is the Jan Philips Grey or Black 12AT7WC tube? I see online that both versions are offered.

Thanks!

Mace
Rankings: #1 Mark V head, #2a TC50 combo, #2b Rectoverb 25 head

APEMAN
Mark III
Posts: 309
Joined: Tue Nov 08, 2011 10:48 am

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Post by APEMAN » Sun Apr 09, 2017 11:28 pm

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Last edited by APEMAN on Fri Feb 28, 2020 10:28 am, edited 1 time in total.

bdubbs
Mark II
Posts: 53
Joined: Tue Jun 25, 2013 1:53 pm

Re: Mesa MarkV / Saturation 'mod'

Post by bdubbs » Mon Apr 10, 2017 1:36 pm

This makes sense. There is definitely a frequency there that is pretty much gone when its disabled. I've been using with the loop off for a while.

bandit2013
Triple Recto
Posts: 3152
Joined: Fri Feb 22, 2013 7:31 am
Location: North Carolina

Re: Mesa MarkV / Saturation 'mod'

Post by bandit2013 » Wed Apr 12, 2017 4:48 am

Good call there....

I have actually done this before. I also loaded V4 and V5 with the Jan/phillips 12AT7 and that changed everything. Gave the amp a more vintage tone which was nice for a change. I will have to give one of the Jan/Phillips 12AT7 another go but in V6 and leave everything else as is. Also have a JAN/GE 5751 to try there as well. I will have to check my inventory, may even have an RFT 12AT7 available as I bought the 12AT7 for replacements in my RA100's.

I have not given up on the Mark V yet.

APEMAN
Mark III
Posts: 309
Joined: Tue Nov 08, 2011 10:48 am

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Post by APEMAN » Wed Apr 12, 2017 11:47 am

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Last edited by APEMAN on Fri Feb 28, 2020 10:27 am, edited 1 time in total.

bandit2013
Triple Recto
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Joined: Fri Feb 22, 2013 7:31 am
Location: North Carolina

Re: Mesa MarkV / Saturation 'mod'

Post by bandit2013 » Thu Apr 13, 2017 6:04 am

I will agree with this and will do the acid test this weekend. I had started my tube rolling with all EH tubes, sounded good for a while but once they had a few hours on them I could not get rid of the low frequency hum on the clean channel. If I got past the noise level and just played the amp I did not notice the idle noise. Same applied to the Tung Sol, Loaded the amp with those and it sounded good for a while. Seems that tubes with coiled heater elements tend to add power supply noises (especially the tube positions that use the AC sourced heaters). Old Mesa 12ax7 tubes from the 90's (Chinese tubes with foil square getter) were the best overall in noise reduction. Gain characteristic was more compression on CH3. Also did the mix and match as well but never found ideal tubes to make the amp sound like I wanted it too. Main reason why I bought the JP-2C which ended my tone quest. After that, I lost my interest in the Mark V, and that carpet weight is beginning to collect dust which I find disturbing to the point if I do not use it, it must go mentality. Still if and when it is operating optimally it is a great amp to play though and make use of. The love/hate thing has to stop sometime....right?

APEMAN
Mark III
Posts: 309
Joined: Tue Nov 08, 2011 10:48 am

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Post by APEMAN » Thu Apr 13, 2017 8:11 am

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Last edited by APEMAN on Fri Feb 28, 2020 10:27 am, edited 1 time in total.

bandit2013
Triple Recto
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Location: North Carolina

Re: Mesa MarkV / Saturation 'mod'

Post by bandit2013 » Thu Apr 13, 2017 7:29 pm

I use Mesa SPAX7 in V1 as I found this seems too roll of the top end, at least in this amp of mine. Ran though two 12AT7 tubes (RFT and JAN/GE, selected the ones with the least amount of tarnish, not sure if the black is due to silver content or nickel). Was not a fix for me.... These tubes work great in my RA100 since the design uses them on the FXloop send and return. I could have tried the current Mesa 12AT7 as I have a few of those as well but opted out. The Stock 12AX7 tube seems to work great so what I had installed I will stick with at the moment. Mullard long plate RI 12AX7 also do a great job from V4 though V6. Those will roll off the top end. I found that tubes I install into V3 will be the culprit for the hum if they have the coiled heaters (heater wire is actually coiled like a light bulb filament) which are supposed to reduce noise but not introduce it. Typically a non-coiled heater element works better in that position and does not seem to contribute to the hum. Preamp tube positions that use the 6V AC heater circuit: V3, V4, V6, and V7. The tubes that use a 12VDC heater circuit are V1, V2 and V5.

I was looking at the schematic again....
CH3 signal path is: V1A -->CH3 tone stack--> V1B -->CH3 Gain control -->V5A-->V4b-->V3A-->(send return reverb CH3) -->V6A --> EQ Sliders--> FXLoop send/return -->V6B (master/solo). Of course if you opt to bypass the FX loop the signal would just go to the PI circuit (V7).

Since V5 is more critical in the gain chain than V6 I found the 12AT7 to be more effective there but at the time I was experimenting I did not have the schematic. The effect was Darker tone and less gain. V5 may be a better position for a tube with better top end roll off to eliminate the higher harmonics in the distortion (will provide softer clipping on the signal waveform). Would have to borrow the scope and frequency generator for a stable waveform to verify. More rounded corners and perhaps a dip in the center of the square wave would reveal high frequency roll off effects. A signal analyzer would also help to determine the harmonic content based on a single test frequency. This brings back memories some 24 years ago when I had access to such equipment in college. I used my Mark III as a test subject to determine frequency content and gain characteristics during my Senior year project.

APEMAN
Mark III
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Joined: Tue Nov 08, 2011 10:48 am

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Post by APEMAN » Tue Apr 18, 2017 2:20 am

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Last edited by APEMAN on Fri Feb 28, 2020 10:27 am, edited 1 time in total.

Wayno
Mark III
Posts: 357
Joined: Sun Sep 27, 2015 2:50 pm
Location: Good ole England

Re: Mesa MarkV / Saturation 'mod'

Post by Wayno » Fri Apr 28, 2017 3:42 pm

Holy sh!t balls batman. Apeman is spot on.

Only had half hour and had to be quiet not to disturb baby but still...

Just received a couple JAN GE 12at7 from eBay today, popped one in V6 and wow, everything Apeman said is right. The top end is warmer, even at low volume. Much closer to how the amp sounds with loop bypassed. Can now dial in more gain without getting screech. Chuffed as punch as I find the solo feature extremely useful with the band and now it sounds as good as without as far as I can tell at low volume. Can't wait to get the chance to crank her up and really get her purring.

Also after reading through some of the other threads on tube rolling from bandit and Co I've hopefully got a couple 5751's winding their way over. Gonna have a swap around with them to see what I end up with.

Current V1 - V7:

V1 - Tungsol
V2 - JJ stock mesa
V3 - Sylvania 12AX7 long grey plate
V4 - Sylvania 12AX7 long grey plate
V5 - JJ stock mesa
V6 - JAN GE 12AT7
V7 - Sovtek LPS

V8 - 10 JJ EL34ii

Still have the stock 6L6's so will have to try them again too.

First thing will be to try a 5751in V1 and move the Tungsol to V2 and see how channels 2 and 3 respond. More on that soon hopefully if anyone's interested.

Apeman thank you again, still can't believe I hadn't considered the 12AT7 before. Sorry if I've hijacked your thread.

This amp always had balls, now it has cojones :P
Her highness the Veenus
(Mark V/V4 & V7 12AT7 Combo)

2 x 12 Vertical Cab
GSP1101

Gibson LP Studio with alnico ii pro
Schecter C1-XXX with emg 81/85 18v
Jackson Dinky XL with Duncan designed???
Sigma DNC-1STE

APEMAN
Mark III
Posts: 309
Joined: Tue Nov 08, 2011 10:48 am

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Post by APEMAN » Tue May 02, 2017 2:13 am

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Last edited by APEMAN on Fri Feb 28, 2020 10:27 am, edited 1 time in total.

Wayno
Mark III
Posts: 357
Joined: Sun Sep 27, 2015 2:50 pm
Location: Good ole England

Re: Mesa MarkV / Saturation 'mod'

Post by Wayno » Tue May 02, 2017 3:10 am

Hi apeman,

Yeah worked great thanks.

Had another spare hour over the weekend and tried my second 12at7 in there as well.

Revised;
Current V1 - V7:

V1 - Tungsol
V2 - JJ stock mesa
V3 - Sylvania 12AX7 long grey plate
V4 - Sylvania 12AX7 long grey plate
V5 - JAN GE 12AT7
V6 - JAN GE 12AT7
V7 - Sovtek LPS

V8 - 10 JJ EL34ii

Sounds better still, like bandit stated before, has a more vintage feel to it. Really digging it :-) and no noticeable gain drop.

Can't stretch to new 6L6's at the moment as have littluns first birthday coming up but hopefully will get the chance to get the amp out in the garage soon so I can can crank her up a bit and try the stock 6L6's. Preferred the EL34ii's with the original 12AX7'S but got a feeling they might feel better now the highs are tamed a bit.

Got to admit I have been twitching after the JP2C for a while as much as I love the Mark V but this has put that itch well and truly to bed.

I am one happy chappy!
Her highness the Veenus
(Mark V/V4 & V7 12AT7 Combo)

2 x 12 Vertical Cab
GSP1101

Gibson LP Studio with alnico ii pro
Schecter C1-XXX with emg 81/85 18v
Jackson Dinky XL with Duncan designed???
Sigma DNC-1STE

mace
Mark III
Posts: 276
Joined: Sun Feb 02, 2014 11:51 am

Re: Mesa MarkV / Saturation 'mod'

Post by mace » Wed May 03, 2017 6:50 am

Hi,

I also tried the AT7 in V6 to see if it could reduce a bit of ice pick at higher volumes/gain. I was running the Mark V through a Thiele with EVM 1x12 (the older 300W Thiele cabinet). I must say, it seemed my listening position made more of a difference in the tone (on axis or off axis). On axis listening was more harsh on the ears than off axis. This seemed to have a larger effect than the tube V6 tube swap. This was at about 100 dB sound volume.

I'll do a bit more testing with the rectifier 2x12 (stock V30s).

I guess my main point is for those suffering from ice pickiness, listening position and/or cab placement can make a huge difference. Also, just how loud in dB are you experiencing this?

Is it like 90, 100, 110 dB? The human ear can only take so much volume before it also "clips". The perceived frequency response of the human ear is dependent on sound volume. The louder it gets, the more the mids fill in. So, a deep scoped tone at low volume sounds good, but doesn't to me at higher volumes (too much treble and bass). I have some CD's which sound flat and muffled at lower volumes, like 70-80 dB, but when cranked up to 95-100 dB listening level they just come alived, no muffled or soft tones (my tube amp stereo has no tone controls). Guitar tone as similar well. Mesa's are critized for being "muffled" and "under a blanket" or "too thick" and that may be true at home or at low volumes (to some degree). But, when gigging, and turning it up in a big room, the tone balances to the human hearing EQ very, very nicely.

sorry for the ramble...

Mace
Rankings: #1 Mark V head, #2a TC50 combo, #2b Rectoverb 25 head

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