-

[Wayno]

Great to see this thread still catching people's eye. Just saw it referenced over on a different forum too. Helps to prove the AT7 works as described for sure!

[Markageddon]

Yep and perhaps another tribute to the V, and the genius behind it: - 10 years this amp has been out, and its still shocking people with new depths of coolness and utterly ripping tone..

[Wayno]

[sherrillsml]

Sorry guys but I am a little confused. I see posts referencing tubes V6 and V7 as 12AT7 candidates. Obviously those indicating V7 have to be my MarkV:90. I have an AT7 in V4 that I am happy with so my first question is there a consensus on using an AT7 in V6 or V7 on the MarkV:90?

Secondly, I purchased my MarkV:90 new in 2010 and at least with mine I get a much less "fizzy" sound by hard bypassing the loop. Do you think I am doing something wrong or was this an issue inherent on the early models? It doesn't matter if I have anything actually in the loop or not.

[Markageddon]

I don't remember V6 on the V being anything that made me want to keep it there. It think it caused less gain, but didn't have the effect that V7 (Phase inverter) did, IIRC V7 or not at all, for me as far as swapping out beyond the V4 slot swap goes.
V7 made everything seem richer and more 3D sounding.
Same as V6 on the V25/V35.

But if you look back, Apeman's first work here was V6 (Page 1) and he had it as a cure all for the 'FX LOOP On/Bypassed' tone difference.
Might be worth a read for you.

[dlpasco]

Secondly, I purchased my MarkV:90 new in 2010 and at least with mine I get a much less "fizzy" sound by hard bypassing the loop. Do you think I am doing something wrong or was this an issue inherent on the early models? It doesn't matter if I have anything actually in the loop or not.

I've definitely found that the Mark V can suffer from tone suck with the fx loop engaged and spent quite awhile using the slave out to drive my effects through some floor monitors.

I haven't noticed it as a problem since I switched to using 12AT7s as described in this thread. I have no idea why it helps, but it does.

[Markageddon]

Thats the thing: Theres zero risk of technical foreknowledge corrupting experience via expectation.
Its an objective thing that works for all (After some dialling relearning for you new fav tones)
Whether or not you can name resistors on sight or if you're the least technical guy on the block: It works the same.
The proof very much being in the pudding.

[JD1965]

Well, I did it Saturday - the Jan Phillips AT7 in V6 & V4.

The results?

A noticeable difference in smoothness to the gain on Channel 3.

Not 'night and day' for me but a more useable channel.

I don't use that channel for searing metal or thrash, don't really play that style of music. Instead, I use #3 as my designated 'lead saturation' channel. I know the Mark I mode in Channel 2 would be ideal to capture the 'Santana tone' but I use channel 2 for my medium gain/grit rock sound.

So I decided to go with #3 to get my 'Carlos' on and the 'mod' was a help!

[Markageddon]

It affects dialling potential with gain and therein lays the night and day part of the act. If you're keeping it bare bones and low key gainwise, its definitely the smoothness you'd notice for real. And the capacity for more bass before flub etc is still handy even at near clean.
Cross genre/style/gain level appeal: Another sign that its just an objectively good mod.

[bandit2013]

Great to see this thread still catching people's eye. Just saw it referenced over on a different forum too. Helps to prove the AT7 works as described for sure!

I have been sharing this thread with others in the Mesa boogie fan club on Facebook. It is good to see this thread is still growing and many already have been sharing this to others as well.

[motown]

Hi everyone, long time viewer and first time post-er.

Did the Sat Mod of V1 tungsol, V2 & V6 Jan Phillips AT7 and I can confirm what most peeps have been saying. My Mark V:35 has gone from a great amp to a weapon! One point that most people posted on here was the way in which you'll need to get a bit wild with your EQ and they were right!

Anyways, just wanted to say thanks to everyone that posted their results and that this has changed my amp for the better!

[Markageddon]

You're welcome..! Yeah it really opens up the possibilities.
Absolutely fire breathing. And the low gain dialling also just sounds so much sweeter and more vintagey. It re-writes the book, or at least its like amazing new chapters in your favourite book. All good, none of the bad. The 1st AT7'd V:25 still is going like a dream after two plus years of heavy usage. Havent yet had to tubeswap/replace anything, nothings failed. My friend's 35 done not long after then is still walking tall too. So you can definitely sit back and enjoy knowing that it was a good and safe move..!

[Wayno]

Fire breathing for sure just wish I had more time to play the thing!

[Markageddon]

Quite a thing to miss/look forward to.
Its one of those rare things in life that rarely disapppoints when you get round to it:
Even accounting for the hype/expectation that your mind builds when of it when you don't get the chance for a bit.

[timothymartin220]

I am actually curious as to what years your amps were manufactured. I recently purchased a used Mark v 90 that had a manufacture date of 2016. I have never noticed the icepick highs (I did used to own a Studio Preamp and that unit DID have icepick highs). I further did the tube rolling thing with the 12at7 in v-4, v-6, and v-7(janphillips 12at7wc), and what I got was in v-4 I lost some gain from channel 2 crunch. I also got channel 3 IIc+ and markIV sound alike except more gain on IV(lost the unique character of Mark iv and it just became another slightly pushed version of the IIC+....however here was the kicker.....I lost extreme mode as a pleasant sounding channel.....so v-4, down to two useable modes on chan3 but they essentially sound the same).....v-6, not much to recommend it to me, lost the beauty of the v-4 mod on channel 3 and now both IIc+ and IV sound the same, but I did get extreme mode back and the gain was back in crunch.) V-7, got the difference back between IIc+ and IV, have the gain back on crunch, and have extreme mode working, but gave the overall amp a brighter character on all channels that was not particularly pleasant and defeated the bright switch on channel 3.....so back to all stock, and have all 3 channels back working properly....with the differences between markiv and IIc+ and extreme... I guess my question is this, as in reading the thread I noticed that Mesa DID an update sometime around 2012.....did Mesa further update the amp after that (and did this further update negate the necessity of the 12at7 switch, cause I am not getting it......I will point out that I have 2 of the janphillips12at7's but did not try replacing more than 1 at a time, maybe if someone with a newer amp could tell me is there a point in going further, I am not really unhappy with the amp, but am always amenable to improvements if warranted)