New 12AX7's in Mark V....problem??

[RocknRory]

Ugh, so many posts from me! Anyway.

I've replaced 6/7 preamp tubes with Dougs tube cocktail.

- V1 Tungsol 12AX7
- V2 High Gain JJECC83
- V3 Penta 12AX7
- V4 Penta 12AX7
- V5 Mesa 12AX7 (Didnt change it)
- V6 Shuguang 12AX7 9th gen
- V7 Sovtek LP/LPS

Ive been switching 4 5 and 6 around to see what the problem is and here it is.

Channel 1 and 2 work fine, but channel 3 is low output and no gain, very faint signal.
In other setups messing with V4 V5 V6 i found out that with certain setups, all channels wouldnt work. Maybe a bad preamp tube? I'm trying to isolate it so Ill put the standard mesa tubes back in and leave one of the new ones out.

Which tube do you think it is if Channel 1 and 2 work, but not 3? Wonder what the problem is.

 

[eudaimonia02912]

Does the reverb also not work? Then it's probably V4 or V5.
Does the effects loop not work? Then it's probably V6.

Since you didn't change V5, I'm guessing it's V4 or V6.

 

[RocknRory]

ok so i tested it with V4 V5 V6 mesa and it all works, then i put the Penta labs in V6 and everything works fine, reverb etc. I think its the Ruby 12AX7 (the V4 one)

 

[Marcus71]

Is the idea to have the smoothest tube in V1?

Can someone give me the link to the post this cocktail is discussed?

I have a bunch of old tubes like Telefunken and RCAs, but nothing really high gain like an old Ei. Telefunken tubes are great for clean channels but not so much for high gain. RCA is the same.

I have never used JJ 12AX7. Are they any good? What about Chinese tubes?

 

[eudaimonia02912]

Hi Marcus,

The ideal V1 tube for a Mark V would have ultra-low microphonics, ultra-low noise, and great clarity. It would also have lots of gain (if you play metal) or less gain (if you don't). Finally, it would have tonal characteristics based on what the user wants from the amp. So, for instance, I found the amp a bit harsh at high volumes, so for me, a smooth V1 tube is best.

I have an NOS EI that I love, but those are not generally good tubes for V1 in a high gain amp. Though they have a low noise floor and a great sound, even the best of them are prone to microphonics. I use my EI on V2, which is the second gain stage of channel 2. It adds some sizzle, gain, and flavor there. An EI might also be good for V3.

Many people here prefer the Tung Sol reissue for V1. That seems to be the forum favorite. I didn't like it, at least not with the stock Mesa 6L6 power tubes. However, I just switched over to using EL34 power tubes instead of 6L6s, and I might find that the Tung Sols work better with the EL34s for my ears.

The JJs can be a bit dull or dark. Whether that's good or bad depends on what you need from the amp. Peavey amps, for example, tend to be very bright, so JJs are good for them.

The Chinese tubes are okay, I guess. I tried a bunch of Rubies and Pentas, but nothing impressed me. In fact, right now, I've got all Mesa tubes (either 12AX7s or the SPAX7s) in the Mark V, except for V2, which has the EI. I'm in the minority here in that I don't like Tung Sols. (However, I just switched to SED EL34s for power tubes, and so I might like the Tung Sols with that combination.)

 

[sean106alcon]

Doug lives near me and his cocktail worked wonders. I really like the results. I had some bad preamps brand new out of the box!

So I changed em all and also really dig the EL34s. I even was able to get the Mark I setting to sound awesome thanks to you guys in the settings thread.

 

[Heritage Softail]

Is the idea to have the smoothest tube in V1?

Can someone give me the link to the post this cocktail is discussed?

I have a bunch of old tubes like Telefunken and RCAs, but nothing really high gain like an old Ei. Telefunken tubes are great for clean channels but not so much for high gain. RCA is the same.

I have never used JJ 12AX7. Are they any good? What about Chinese tubes?

Tube Depot is a good one to call. Maverick 2x12, Timbre Wolf, and a few others are very experenced with mesas and tube swaps. I have found the JJ's are good for EL34's but like Tung Sol reissues for 12ax7's. Sounds like you already have some excellent tubes, just need to dig thru some of the old tube threads to see where others put them with good results.

 

[Anonymous]

Is the idea to have the smoothest tube in V1?

Can someone give me the link to the post this cocktail is discussed?

I have a bunch of old tubes like Telefunken and RCAs, but nothing really high gain like an old Ei. Telefunken tubes are great for clean channels but not so much for high gain. RCA is the same.

I have never used JJ 12AX7. Are they any good? What about Chinese tubes?

For V1 try a mullar RI 12AX7, you'll loose some gain so if that is an issue, you can order a Mullard RI for high gain..... it is a nice smooth overall tube!!!!!!!!

FYI the mark V stock preamp tubes are relabelled JJ's (this is been confirmed in this forum many times before :wink: )

good luck

 

[RocknRory]

problem fixed! found th bad preamp tube (the ruby 12AX7) and im gonna send it back to doug today and get a replacement, nice!