phase splitter question

[stoo]

My guitar amp has a phase splitter that uses a triode with equal cathode and anode resisters so the outputs are taken from the anode and cathode.
How does the other variety work????? Where there are two triodes. the signal from the preamp is fed into one grid. I don't know where the other triode gets it's signal. Each phase is taken from each plate. ( I think Marshall uses this config.)
thanx
stew

 

[andyjevans]

the phase splitter you describe in your amp is the concertina or split load. the other one you refer to is the differential pair, where the signal goes to the first grid, which usually has a 1 meg resistor to the second grid and a small cap from there down to ground (.1uF or a bit more). The second half is driven from the joined cathodes, which have a single resistor to earth (or CCS). As you say, each half has its own anode resistor, and the outputs are from the anodes. If you do a search on concertina and differential pair (diff. pair, long tailed pair) you should pull up some info. Or look at Morgan Jones book "Valve AMplifiers" - a jolly good buy for boning up on theory. Andy

 

[ray_moth]

You can find a couple of technical articles on the long-tail pair splitter at Aitken Amps

 

[aletheian]

There were a couple good conversations on here about the LTP (long tail pair)/differential splitter and the concertina/cathodyne/split-load that you can find if you do a search. You can check over at ax84.com on the BBS to get some great info too.