NOS ANOS GZ34 Crazy Prices

[martin manning]

Didn't we already have this conversation and everyone agreed that using tube rectifiers is a hapless expense?


(lmao)

Probably. Hapless? No... Fruitless? Wasteful? Anachronistic? Foolish? I've been curious about the effect of the non-linear resistance, so there it is.

[pdf64]

Didn't we already have this conversation and everyone agreed that using tube rectifiers is a hapless expense

Probably, it keeps cropping up, and I would have agreed prior to my unfortunate experience with the blown speaker.

Martin, could you run the simulation using a max squarewave scenario?
That's where the GZ34 seems to produce a 'supercharger' boost over the sag resistor, both on the bench, and into my poor speaker.
Pete

[martin manning]

Pete, I'm assuming that you mean drive it hard enough to square-off the waveform in the power stage? That's hard to do, but I did get a significant flattening of the peaks on the output waveform (and a lot of crossover distortion). There is no big increase in output power level with the vacuum rectifier vs. The silicon + sag resistor. I can't think of any reason why there would be, though. If the waveform is clipped then the current draw is being limited by the valves.

[Cygnus X1]

Turtles!



Actually, this dummy here ordered a Shunguang 5AR4/GZ34 for the 67 Deluxe Reverb.
I hope it doesn't blow anything up.

You can put a couple of diodes on the tube socket for safety in the chance that your tube shorts. That may save your PT from potential damage.

I know that.
The REAL question is, are the Sino GZ34's safe to run?

[Diablo1]

Last night I pulled a bunch of free tubes from an organ, and low and behold one was a Mullard GZ34. Stuck it in my Capitol guitar amp (four 7591, cathode biased) to replace the Weber WZ34 I had been using, and I couldn't tell the difference....sonically. Sounded just as loud either way, and the tone was the same. I didn't do any measurements.

The organ also had two more GE 7591, three Mullard 12AX7, two Amperex 6267, three Mullard 7247, two Mullard 12AU7, and two Mullard ECL86. All in all, a good treasure hunt.

[Blackburn]

Last night I pulled a bunch of free tubes from an organ, and low and behold one was a Mullard GZ34. Stuck it in my Capitol guitar amp (four 7591, cathode biased) to replace the Weber WZ34 I had been using, and I couldn't tell the difference....sonically. Sounded just as loud either way, and the tone was the same. I didn't do any measurements.

The organ also had two more GE 7591, three Mullard 12AX7, two Amperex 6267, three Mullard 7247, two Mullard 12AU7, and two Mullard ECL86. All in all, a good treasure hunt.

Want to sell me them Amperex and Mullards?

[pdf64]

Mullard GZ34. Stuck it in my Capitol guitar amp (four 7591, cathode biased) to replace the Weber WZ34 I had been using, and I couldn't tell the difference....sonically. Sounded just as loud either way

My experience of (cranked) 70 watts cf 50 watts is only 1.5dB, not something that could realistically be identified except by immediate A/B comparison.
The tone was a bit more edgy with the GZ34 but that was likely the speaker's swansong.
Pete

[Diablo1]

Want to sell me them Amperex and Mullards?

Nah, a man can never have enough tubes or amps.

[Blackburn]

Want to sell me them Amperex and Mullards?

Nah, a man can never have enough tubes or amps.

Totally understand. They're extra special when they're pulls.