MARK V Dec 2009 build date - any issues?

Picked up a used really clean Dec 2009 build date MARK V.

I had 2013 one earlier. Sold it. Missed Channel 1 cleans, and the Channel 2 Mark I mode.
Needed to get it back.

Anyway- are there any major changes on this first year version from more recent years?
The previous owner did put a JAN Phillips 12AT7 tube in the V6 slot.
Otherwise it looks like all Mesa tubes.

Amp works great. Sounds great.

Thanks for any input.

The only thing I am aware of is the tone stack for CH3. Revision took place in 2010 but when is unclear.

I would personally recommend the 12AT7 in V4 position so you can swap V4 with V6 to try that out if you so desire.

What was the change on the tone stack on Channel 3??

There was a change to the gain and high-end of Channel 3:
http://forum.grailtone.com/viewtopic.php?f=33&t=73457#p498071

IronSean said:

There was a change to the gain and high-end of Channel 3:
http://forum.grailtone.com/viewtopic.php?f=33&t=73457#p498071

Click to expand...

Thanks. Interesting read.
Sometime I might open mine up.
Being it has a 12/14/2009 build date it could be either the original CH 3 design or the revised one.

I have no complaints about any of the channels to be honest.
Since it has a 12AT7 in V6 that might be a factor. Not really getting any ice pick out of the norm or that I find to be an issue.
Glad I have one back and like what I hear.

Well, curiosity got the best of me so I cracked open the hood on mine.
I apparently have the newer array of resistors. I guess since it was made in December 2009 maybe they started using the slightly different resistor parts by then.
I can’t say I heard any difference in sound between this 2009 one and the 2013 model I had before so that makes sense since they were the same in CH 3.

When you say “newer array of resistors” what are you comparing it to? I know there have been some other photos here (bandit for example, when he snipped the C39) but the area on the board in your photo doesn’t seem to match bandit’s C39 area (between V4 and V5).

Could you re-post the photo you are comparing yours to? Thanks!

I assume he's just comparing the resistor values that changed between the old and new schematic.

Also, regarding issues I forgot, there were someone JFETs that failed in the reverb circuits for people so if that hasn't already been done it might become an issue.

mace said:

When you say “newer array of resistors” what are you comparing it to? I know there have been some other photos here (bandit for example, when he snipped the C39) but the area on the board in your photo doesn’t seem to match bandit’s C39 area (between V4 and V5).

Could you re-post the photo you are comparing yours to? Thanks!

Click to expand...

Yes. Bandit 2013 picture of updated resistors.
Same resistors as in his pic.


I actually talked to Mesa support about this and they reviewed the pics and schematics, etc. They asked around the shop and nobody thought any changes were of any big significance there.
They stated that it is not uncommon for minor changes to occur and to source different parts and suppliers, etc, but they chuckled at the idea that a unit from one year sounds significantly different from another year.
They stated they always strive to maintain the same model sound when there are any changes.
In fact, the Mesa staff I talked to had an early 2009 and a 2012 Mark V himself and does not feel there is any difference he could hear FWIW.

That said- there was a change (and he said he was not really even aware of it until I sent him the info) and he acknowledged the info from here looked totally legit. I am not doubting at all those who feel that it was for the better in their view.
I have not heard the versions pre- change so have no comment.


All I know for sure is I like mine. :mrgreen:

-

APEMAN said:

I never saw or heared a markv with the 2009 tone stack... maybe this certain schematic came from the prototype days and never went into production.

(Apart from that, please don't get me wrong, I really love Mesa, but for shure they will always say things like... faithful 2C+ recreation and with the next amp comes a even faithfuller recreation ... or ... this new recto sounds the same then the old ones ... it is a company and they get up in the morning to build and sell amps.)

Click to expand...

I only find it weird because the text in the manual says the VOLUME control is set internally to 7.75, and that original schematic works out to about that setting. But the revised schematic inside the actual amps has it set to 7 exactly (and because it's a logarithmic pot, that's actually a noticeable change that high on the dial).

So the text for the manual as well was certainly written for the first schematic, whether or not it ever shipped.

IronSean said:

APEMAN said:

I never saw or heared a markv with the 2009 tone stack... maybe this certain schematic came from the prototype days and never went into production.

(Apart from that, please don't get me wrong, I really love Mesa, but for shure they will always say things like... faithful 2C+ recreation and with the next amp comes a even faithfuller recreation ... or ... this new recto sounds the same then the old ones ... it is a company and they get up in the morning to build and sell amps.)

Click to expand...

I only find it weird because the text in the manual says the VOLUME control is set internally to 7.75, and that original schematic works out to about that setting. But the revised schematic inside the actual amps has it set to 7 exactly (and because it's a logarithmic pot, that's actually a noticeable change that high on the dial).

So the text for the manual as well was certainly written for the first schematic, whether or not it ever shipped.

Click to expand...

Interesting. The Mesa Tech that I chatted with was not aware of any significant design changes, and asked around with some other veteran staff there and they were not really either.
He did think the schematic info from here looked legit.
I wonder how many, or if anyone has seen an actual production unit with the early design from that schematic. Maybe that was a prototype or early run.
The Mesa tech was really nice- not skeptical or anything, Curious more than anything and he had been around there for awhile.

Lkdog said:

IronSean said:

APEMAN said:

I never saw or heared a markv with the 2009 tone stack... maybe this certain schematic came from the prototype days and never went into production.

(Apart from that, please don't get me wrong, I really love Mesa, but for shure they will always say things like... faithful 2C+ recreation and with the next amp comes a even faithfuller recreation ... or ... this new recto sounds the same then the old ones ... it is a company and they get up in the morning to build and sell amps.)

Click to expand...

I only find it weird because the text in the manual says the VOLUME control is set internally to 7.75, and that original schematic works out to about that setting. But the revised schematic inside the actual amps has it set to 7 exactly (and because it's a logarithmic pot, that's actually a noticeable change that high on the dial).

So the text for the manual as well was certainly written for the first schematic, whether or not it ever shipped.

Click to expand...

Interesting. The Mesa Tech that I chatted with was not aware of any significant design changes, and asked around with some other veteran staff there and they were not really either.
He did think the schematic info from here looked legit.
I wonder how many, or if anyone has seen an actual production unit with the early design from that schematic. Maybe that was a prototype or early run.
The Mesa tech was really nice- not skeptical or anything, Curious more than anything and he had been around there for awhile.

Click to expand...

Mine is serial number 0008xx so would guess it's defo before the revision. Interesting point of note too, mine doesn't have a date and final check initials written on it anywhere. Will have to find out the certificate to see if it's on there anywhere. Sure I had posted a picture if my CH3 tone stack on that thread so will have a looksie for it.

The image posted was for the tone stack.... sorry I am late on this as I was out of town for a while. C39 is another topic which is associated with the V4B gain stage.

It is not just the resistors that make a difference (ok, perhaps the voltage divider ratio may be slightly different and that will effect things). It is connections of C18 is the important factor as this is a brightness cap that bypasses some of the voltage divider resistors on the tone stack. Original circuit, it runs parallel to R22 and R23 and also bypasses the treble pot wiper connection. I believe in the update, C18 is only parallel to R22 and R23 with a series resistance of 82.5k and is connected on the wiper connection vs acting as a full bypass to the treble pot. It appears to be the same as the layout in the image provided and is identical to the one I have taken of that area (of course it is not the same picture since the resistors are not installed in the same orientation : look at the 82.5k resistor next to C18, note that resistors are not polarized so it one is inverted vs the other it makes no difference) If the 82.5k resistor (color code for 1% : white, red, green, red, brown) is next to C18, chances are you have the 2010 update board.