1984 IIC+ HRG tube selection

[nwolfe88]

What are your recommendations for preamp and power amp on these? Of the vintage/NOS variety? It's an HRG with the 105 transformer.

Some thoughts for the pre:
Tungrams, c8's (6n4), Phillips 12ax7 WA

Power:
Svetlana winged c
Str415

Any suggestions would be great!

 

[Fiveband]

If you dont already have a stash of those power tubes, get out the wallet!

 

[gts]

Mesa STR 415’s were/ are relabeled Sylvania 6L6’s.
Yes expensive but if you can find them (either the 415’s or those labeled Sylvania) it’s worth it.

The Winged C’s =C= are a very good choice too. Should be less expensive than 415’s and/ or Sylvania labeled 6L6’s

 

[gts]

Lots of choices on 12AX7’s .
Including those you suggest add Tung Sol, Jan-Phillips, to the list.

You could also try using a 5751 pre amp tube which is technically a 12AY7 - a lower gain preamp tube. You could also try a 12AT7 (also low gain and typically found in old Fender amps driving the reverb).

Fwiw what you use in V1 will affect the overall amount of gain. Imho there’s no reason to not try something in V1 that will give lower gain. It all depends on your taste. Experiment, see what works and what doesn’t work.

Mesa suggested their SPAX7 in V1. This due to whatever was in V1 could cause problems like microphonics, hiss, squeal, etc. and anything but their SP might cause those problems. They also suggest whatever is in V1 gets hit hard and could wear out sooner than the SPAX7. It was more robust and could handle a beating better than any other 12AX7.

Tubes labeled 7025 and 6681 are also 12AX7’s

 

[LockStock]

This is what I do, but mine are 60w. I wanted them to sound different so tubed them different.
The July one is has more of a high mids, extended high freq character because of the Miniwatt and Sylvania tubes in the lead gain stages, vs the Mullards in the June one - more low mids focused, and thicker.

1984 June Mesa Mark IIC+ SRG Combo Tubes
V1 1985 Tungsram Tall Bottle 12ax7: (A) Pre-TMB Input Amplifier / (B) Tone Control Amplifier
V2 1960s Telefunken Smooth Long Plate ECC83: (A) Mixer Amplifier (B) Effects Return Amplifier
V3 1970 Mullard Blacburn B0F3 I63 12AX7 Bent Post/Silver: (A) 1st Gain Stage Lead (B) Reverb Return
V4 1973 Mullard Blackburn I63 12AX7 Bent Post/Silver: (A) 2nd Gain Stage Lead B) Reverb Driver
V5 1985 Tungsram Tall Bottle 12ax7: Phase Inverter
V6 Early 80s Mesa STR-415 6L6
V7 Early 80s Mesa STR-415 6L6

1984 July Mesa Mark IIC+ SRX Head Tubes
V1 1975 Mullard Blackburn I63 100/104+ 12ax7 Branded Amperex Globe: (A) Pre-TMB Input Amplifier / (B) Tone Control Amplifier
V2 1971 Amperex Globe Herleen/Holland Dimple Getter ECC83: (A) Mixer Amplifier (B) Effects Return Amplifier
V3 1950s Sylvania Long Black Plate 12AX7 101/104+r: (A) 1st Gain Stage Lead (B) Reverb Return
V4 1960 (January) Philips Miniwatt Herleen/Holland ECC83 90/95: (A) 2nd Gain Stage Lead B) Reverb Driver
V5 1975 Mullard Blackburn I63 100/104+ ECC83 Branded Amperex Globe: Phase Inverter
V6 Early 70s Tall Bottle Sylvania Single Getter 6L6GC
V7 Early 70s Tall Bottle Sylvania Single Getter 6L6GC