Mullard GZ-34 identification?

[Mark]

I have a Mullard GZ-34, on the tube it says made in Holland, the base is black plastic, with five pins, the print says Mullard 9F, the writing on the glass says 131 and X8L underneath that.

The base/key way has small hole in the centre, there aren't any notches on the plates it is the dark grey smooth plate variety.

Does anyone know much about this particular GZ-34?

I'm wondering if this is the tough variety that can handle the 80uF filter cap?

Look forward to your reply, and thanks for your assistance.

[Firestorm]

Philips codes are confusing. It's not Blackburn (and it says Holland). I'll to find my references, but whether it's especially robust...? I would say 60uF is safe for any Philips GZ34. More, if you never hot switch them.

[Firestorm]

Yeah. All I got. The X in the third line is Sittard (Holland). There's some date and batch code I can't decipher. Go 80uF but never hot switch it.

[Mark]

Thanks for checking that out for me. I assume it isn't a sort after part but good to have all the same.

As far as the Rocket goes I have a sacrificial Chinese 5AR4. It appears to be copy of my Mullard tube, the build quality is rough as guts but I've had it for a long time and it keeps on plugging away.

As far as tonal differences between rectifier tubes, I've yet to hear a difference in tone between them. I've used NOS on my 18 watter and this rectifier and they all sound much as muchness.

I live to be enlightened of course.

[Firestorm]

Mullards make a huge difference in some amps, not so much in others. I think Martin modeled some tube recs and concluded the hot switching is what takes them over the edge. GZ34 comes up slow, so the first filter isn't such a big deal if you don't switch hot.

[Mark]

What are the amps where the rectifier makes a lot of difference?

I haven't experienced any amps where the rectifier made a difference.

The 18 watter uses an EZ-80 I think, I went from using a Sovtek to a NOS tube and I can't say it made any difference at a all.

I used the Mullard on 15 watt Rocket amp I was fiddling with and again the Mullard didn't effect one.

[Firestorm]

Super Reverb, Deluxe Reverb, Bluesbreaker. Big difference.