Search found 396 matches

by jvk
Thu Nov 14, 2019 4:50 pm
Forum: Mark Series
Topic: Mark IIC (not IIC+) draft schematic
Replies: 26
Views: 13400

Re: Mark IIC (not IIC+) draft schematic

Hi, that schematic contains the same error in the switching circuit that was present in the original Mesa schems. Here's the actual circuit: (I've traced more than one 2C, a 2C+ and also MKIVB) https://lh5.googleusercontent.com/iRIK9weqLC2OPEAIrD8mdKJ8BXh0-HdG6sWln6Y2f1iKkRq9LaO1qOba-cnF2cJzh7V2XKm...
by jvk
Thu Nov 14, 2019 3:58 pm
Forum: Mark Series
Topic: Mark IIC (not IIC+) draft schematic
Replies: 26
Views: 13400

Re: Mark IIC (not IIC+) draft schematic

Hi, that schematic contains the same error in the switching circuit that was present in the original Mesa schems. Here's the actual circuit: (I've traced more than one 2C, a 2C+ and also MKIVB)

https://drive.google.com/file/d/1yHC65i ... sp=sharing

Cheers
by jvk
Thu Jun 11, 2015 11:22 am
Forum: Modern Era Amps (1991-Present)
Topic: So ARE there any known F-50 Mods?
Replies: 48
Views: 15687

Re: So ARE there any known F-50 Mods?

@jvk, do you think the Mesa's real frequencies are really too distant from the labels?? 6600 to 4823 is waaaay far!!! Have you found some more info about this??? Hey. Just reading my old posts and replying to years old PMs and posts :D What happened to your pedal? I build one and modded the circuit...
by jvk
Wed Mar 10, 2010 11:37 am
Forum: Vintage Amps (Before 1991)
Topic: OT Comparison - 562003 vs. 562004 vs. 100W
Replies: 20
Views: 7068

Re: OT Comparison - 562003 vs. 562004 vs. 100W

jvk I believe for the last one in the list you accidentally cited the 60/100 OT#. Pretty sure you meant "SC-152019B" vs T100-152019 Hi George, Long time no speak :) hope you're doing well. The thread was titled "OT Comparison - 562003 vs. 562004 vs. 100W " so I guess that's why I included the 100w ...
by jvk
Wed Jul 29, 2009 11:53 pm
Forum: Mark V
Topic: Mark V gutshots
Replies: 20
Views: 7763

Re: Mark V gutshots

phyrexia wrote:Those are my pictures. I posted them initially here:

http://forum.grailtone.com/viewtopic.php?f=33&t=37070

I think it's funny somebody sent them to you. :D
It's a small internet world :) thanks for posting them.
by jvk
Wed Jul 29, 2009 11:33 am
Forum: Mark V
Topic: Mark V gutshots
Replies: 20
Views: 7763

Re: Mark V gutshots

Jmango wrote:...I would go so far as to say that if you were to run your fingers across the guts with your eyes closed, it would feel the same too...
Drugs... are bad for you :roll:

And if you ran your fingers accross the guts, you'll no doubt get a very large electric shock from the filter caps :lol:
by jvk
Tue Jul 28, 2009 11:56 pm
Forum: Mark V
Topic: Mark V gutshots
Replies: 20
Views: 7763

Re: Let's see your Mark V gutshots

Well mostly yeah :lol: just enjoy my gutshots then :D
by jvk
Tue Jul 28, 2009 10:32 pm
Forum: Mark V
Topic: Mark V gutshots
Replies: 20
Views: 7763

Mark V gutshots

...anyone had a peek inside their Mark V and wanna share? Someone sent me these. Let's see more of the chassis if you have any. They've fitted ALOT in a small space :shock: http://lh5.ggpht.com/_o912b1uGg_c/Sm-wZ5did8I/AAAAAAAAACU/UxhRwT_hA5Q/s800/markvgut1.jpg http://lh6.ggpht.com/_o912b1uGg_c/Sm-v...
by jvk
Tue Jul 28, 2009 9:07 pm
Forum: Mark V
Topic: How would you improve the Mark V
Replies: 72
Views: 5928

Re: How would you improve the Mark V

dmcguitar wrote:has anyone called mesa to see if they will mod the amp in any way? is it possible to get that IIc+ cap value changed to the EQ model value?
That would be easiest mod ever, hell you could even make it switched. All I need is a few weeks with a Mark V to work out it's schematic.
by jvk
Mon Jul 27, 2009 11:12 am
Forum: Mark V
Topic: How would you improve the Mark V
Replies: 72
Views: 5928

Re: How would you improve the Mark V

Personally I want complete elimination of all pops and switching noise. This applies to ALL Mesa amps. Popping is difficult to avoid when switching between different output levels (ie different wattage levels), but a $3000 amp should not pop when switching between channels or modes. Other Mfgrs have...
by jvk
Mon Jul 27, 2009 10:30 am
Forum: Mark Series
Topic: Mark IIC (not IIC+) draft schematic
Replies: 26
Views: 13400

Re: Mark IIC (not IIC+) draft schematic

The link should be fixed now.
by jvk
Mon Jul 27, 2009 12:24 am
Forum: Mark V
Topic: How would you improve the Mark V
Replies: 72
Views: 5928

How would you improve the Mark V

I've been reading posts on this forum by many users with interesting opinions & complaints on their new Mark V amps. Question: If you had your way with re-designing the Mark V, what would you change, improve, add or remove from it's features, in order to improve it and make it your perfect amp? Don'...
by jvk
Mon Jul 27, 2009 12:06 am
Forum: Mark Series
Topic: Mark IIC (not IIC+) draft schematic
Replies: 26
Views: 13400

Re: Mark IIC (not IIC+) draft schematic

Hello gentlemen. Here you go: IIC+ pcb bottom http://lh6.ggpht.com/_o912b1uGg_c/Sm0y8oTmN7I/AAAAAAAAABA/r2By-2Y06Q4/s144/DSC02855.JPG Word of caution... the level of butchery that I've performed here should only be practiced if you don't mind sacrificing the amp (partly at least), because you would ...
by jvk
Sat Jul 25, 2009 8:48 pm
Forum: Mark Series
Topic: MarkIIC+ FX loop trouble - HELP
Replies: 2
Views: 467

Re: MarkIIC+ FX loop trouble - HELP

Hi Gerald, You've stumbled upon a design flaw concerning tube powered serial loops, where about 5% of the dry signal can be heard and you can't get rid of it. Cause: there are in fact two tubes inside the case of a 12ax7 tube. Each side's called a triode, and each can be used as a separate amplifier...
by jvk
Sun Jul 19, 2009 6:34 pm
Forum: Mark Series
Topic: Mark IV intermittent Failure
Replies: 4
Views: 647

Re: Mark IV intermittent Failure

The way you describe it, it sounds like the power cuts *completely*, right? First thing I'd do is try a different power lead from another appliance, the lead could have developed a breakage inside it from years of use & abuse. Also try and see if you can reproduce the fault by moving the power cable...