Mark IV Tone change after retube?? SUCCESS!!!!!!!

[mdortona]

Hi!

I have a Mark IVA that I just retubed with the tone kit from Doug's Tubes
(including Tung-Sol 12AX7,High Gain JJ ECC83,Penta 12AX7,Shuguang 12AX7 9th gen, & a Sovtek 12AX7 LPS V1-V5) and a matched quad of Mesa 6V6s. Running in tweed, Simulclass as recommended.

I find that the R1 channel sounds great. However, R2 and the Lead channels have taken on a very nasal, mid-trebly quality with a lack of bottom and warmth. They sound very thin. Also, the reverb has gotten extreme - anything past 2 = Grand canyon.

Lowering tweaking the treble on R2 and Lead channel helped slightly but did not correct the problem.

Anybody have any ideas? Thanks in advance for the help! :?

Matt D'Ortona

 

[ANIMATED SUSPENSION]

Sounds like one or more dodgy pre amp tubes if it's not affecting R1. Try swapping the old ones back one at a time.

 

[Esromeron]

I myself use the new tone kit that Doug's Tubes recommends and its only slightly different (and think it sounds great). A Mullard reissue 12AX7 in the V2 instead of the JJ ECC83.

I'd try switching out the Shuguang 12AX7 9th gen in the V4 with the old tube you had in it, as for Mark IV's V4-A is the Second Lead High Gain stage.

Also, did you use 6V6's before the retube? as they are very different from 6L6's.

 

[ibanez4life SZ!]

^The 6V6 vs 6L6 is a very good point!

Also, you might want to consider swapping out the Tung Sol...I always found the tube to be unpleasant and very artificial in the high end. I'd never put on in my Boogies again.

 

[trem]

Hi there people,

Please notice that IV A has a different tube configuration than the B. Most significantly, reverb tube (V4) should be 12AT7. Having a high gain tube in that position will result in an ugly washy sound. V3 has the most effect on the lead channel. Keep experimenting with V1 and V2 to get the most overall balance between channel.

Obviously Doug is not familiar with Mark IVA.

~trem

 

[devilrob1979]

I got the same configuration as Esromeron and so far I'm really digging it. I'm not having anyproblems with the Tung Sol.

 

[mdortona]

Thanks for advice and leads guys! I do a little tube switchero and see what happens. 8)

Matt

 

[MusicManJP6]

Just to put your mind at ease (somewhat) - those GT tubes in it were only about 6 months old (with about 50 hours or so on them) when we traded so they should all serve as viable backups still!

I've thought of retubing my amp with a Doug's set too but i've heard mixed reviews about them on here so i'll hold off for now I guess...

Best of luck nailing that tone in your head! Glad you are still digging the Mark IV... 8)

 

[mdortona]

Hi Adam!

The thought about the the mileage on the tubes never even crossed my mind! If everyone's suggestions don't work, I may just bite the bullet and get a set of Mesa tubes and be done with it. Keep your fingers crossed. :wink:

Matt

 

[mdortona]

Trem & Esromeron nailed it - The Shuguang 12AX7 in V4 was the culprit! Put in a new EH 12AT7 and the amp is back on-line and crankin' with full tone!

I really appreciate the help guys and hope I can return the favor in the future!

Matt

 

[MusicManJP6]

Glad to hear it! Rock on.......

 

[Esromeron]

Awesome man! I'm glad I could contribute something back to this awesome forum.

 

[trem]

Glad I could be of some help. What configuration did you end up with?