35Z5GT Rectifier Tubes

[Triple Rectifier]

Does anyone know if you can use 35Z5GT rectifier tubes in a mesa rectifier? I found some NOS 35Z5GT real cheap.

 

[94Tremoverb]

No, absolutely not. Even though they are rectifiers, they're a completely different type with different pin configuration and voltage specs from any guitar amp. They would definitely not work and depending on which pins are connected to what inside the amp (especially with a Mesa Dual/Triple Rec, where all 8 pins of the sockets are wired across), could even cause damage.

While it's not always true, there is usually a reason a type of NOS tube is really cheap... it's because they have no application for guitar amps or tube hi-fi, which are about the only two markets of any significant size outside of vintage radio and TV restoration.

 

[stokes]

Although they wont work in this application,they are used in older "cheapo" guitar amps that had no PT.The heater voltage on this tube is 35 vac,it was usually used with a 50L6 power tube,a 50 vac heater and then some variant of a preamp tube that would make the heater string equal close to 110 vac.The wall voltage would be rectified and filtered for the plates,thereby needing no PT.

 

[94Tremoverb]

... and requiring the chassis ground to be directly connected to the supply neutral. OK (ish) when it's like that, but *completely freaking dangerous* if the plug gets reversed, so now the chassis is fully live at the supply voltage! Here in the UK it's even worse, the supply voltage is 240VAC, and I have seen one British guitar amp (made in 1948) that used this principle. The *inputs* were isolated instead, using audio-grade isolating transformers (like mic transformers), so the guitar itself was safe, but it still meant that the panel, switches etc could potentially become live with a supply reversal. I've never seen any amp made later than that date like that, although there were radios sold well into the 1960s that were. There were some small backwater towns in the UK that didn't convert from the pre-WWI DC mains supply until after WWII, and of course you can't run a transformer-equipped unit on that, so the direct-rectified ones were marketed as being AC/DC... hence the band .

 

[stokes]

We had them here in the States till well into the '60's,mostly imported from Japan.There are still quite a few around,still working and havent killed anyone I've ever heard of.

 

[94Tremoverb]

240VAC is a very different prospect from 110 though - much more likely to be fatal if you get a good contact, and there were quite a lot of deaths from things like that. That's why the UK has had grounding regulations and non-reversible plugs going back as far as the 1950s.