Post by dcarver on Nov 2, 2018 22:07:01 GMT -7
For the last couple years I've tried various tubes in my Maz 8. Pretty much just randomly trying various brands of 12AX7 in V1 & V2,
and 12AU7 in V3.
Today I decided to take a little more systematic approach.
Step 1 was to go back to the stock JJ 12AX7's in V1 & V2, and EH 12AU7 in V3, to get a base line tone.
Then I tried several different tubes in V1 & V2 one at a time and played through the amp after every tube change.
All testing was done with a G&L ASAT with single coils, amp in Pentode mode, on high output channel, with all 3 tone controls and
the Cut control at 12:00. Reverb at 9:00.
Tubes used in V1 : ANOS 1960's Mullard 12AX7 , new Mullard 12AX7 , new Mullard CV4004 , TAD 12AX7 , TAD 5751 , new Tung-Sol 12AX7.
In V2, I tried both new Mullards, both TAD's, the Tung-Sol 12AX7 and a JJ 5751.
I didn't try ALL the combinations of tubes listed above, but got most of them. Basically if I liked a tube in V1, I'd try it with 3 or 4 of the
tubes in the V2 list.
What I was trying to achieve was a nice smooth, not harsh or spikey pre-amp overdrive, when the Volume was at 3 o'clock or higher.
At the end of the day, (and yes, I did spend pretty much all day on this) what sounded the best to my ear was the TAD 5751 in V1 and
the Tung-Sol 12AX7 in V2.
There were other tubes that sounded good in V2 with the TAD 5751 in V1. Seems like V2 doesn't have nearly the effect on tone that V1 has.
But the Tung-Sol sounded just a little better to me. The differences here are small though.
As if this wasn't enough, I also tried 3 different 6p14p's in V6. These are the Russian tubes Doc puts in at the factory, from forum member
Perry R. , again trying for nice rich creamy output tube overdrive with Master Volume above about 2:00 or 3:00.
Perry's tubes are rated for breakup by a Transconductance number.
What I found was, for my Maz 8, a Tc# of 25 yielded no breakup even with the Master V dimed. A Tc# of 20 gave very little power tube breakup
at high Master V levels. The best overdrive tone came from the power tube with a Tc# of 15.
In conclusion: (finally.... sorry for the monster post)
1) If you want to maximize the clean headroom in your Maz 8, get a power tube with a Tc# of 25 or higher.
If you want nice output tube overdrive, get a 6p14p with a Tc# of 15.
2) The TAD 5751 sounds really good in V1 of a Maz 8.
3) I stayed with the Tung-Sol 12AU7 in V3 (reverb driver). I've had it in there for about a year. I think it's slightly better at high
reverb levels (say above 2:00) than the stock EH 12AU7, although the difference is very small.
and 12AU7 in V3.
Today I decided to take a little more systematic approach.
Step 1 was to go back to the stock JJ 12AX7's in V1 & V2, and EH 12AU7 in V3, to get a base line tone.
Then I tried several different tubes in V1 & V2 one at a time and played through the amp after every tube change.
All testing was done with a G&L ASAT with single coils, amp in Pentode mode, on high output channel, with all 3 tone controls and
the Cut control at 12:00. Reverb at 9:00.
Tubes used in V1 : ANOS 1960's Mullard 12AX7 , new Mullard 12AX7 , new Mullard CV4004 , TAD 12AX7 , TAD 5751 , new Tung-Sol 12AX7.
In V2, I tried both new Mullards, both TAD's, the Tung-Sol 12AX7 and a JJ 5751.
I didn't try ALL the combinations of tubes listed above, but got most of them. Basically if I liked a tube in V1, I'd try it with 3 or 4 of the
tubes in the V2 list.
What I was trying to achieve was a nice smooth, not harsh or spikey pre-amp overdrive, when the Volume was at 3 o'clock or higher.
At the end of the day, (and yes, I did spend pretty much all day on this) what sounded the best to my ear was the TAD 5751 in V1 and
the Tung-Sol 12AX7 in V2.
There were other tubes that sounded good in V2 with the TAD 5751 in V1. Seems like V2 doesn't have nearly the effect on tone that V1 has.
But the Tung-Sol sounded just a little better to me. The differences here are small though.
As if this wasn't enough, I also tried 3 different 6p14p's in V6. These are the Russian tubes Doc puts in at the factory, from forum member
Perry R. , again trying for nice rich creamy output tube overdrive with Master Volume above about 2:00 or 3:00.
Perry's tubes are rated for breakup by a Transconductance number.
What I found was, for my Maz 8, a Tc# of 25 yielded no breakup even with the Master V dimed. A Tc# of 20 gave very little power tube breakup
at high Master V levels. The best overdrive tone came from the power tube with a Tc# of 15.
In conclusion: (finally.... sorry for the monster post)
1) If you want to maximize the clean headroom in your Maz 8, get a power tube with a Tc# of 25 or higher.
If you want nice output tube overdrive, get a 6p14p with a Tc# of 15.
2) The TAD 5751 sounds really good in V1 of a Maz 8.
3) I stayed with the Tung-Sol 12AU7 in V3 (reverb driver). I've had it in there for about a year. I think it's slightly better at high
reverb levels (say above 2:00) than the stock EH 12AU7, although the difference is very small.