question regarding PT

[iknowjohnny]

Say you have 2 PTs, both with the same specs but for one.....one of them is 250Ma and the other 150Ma. At low to medium volumes what would you expect to hear/feel thats different if anything with the lower current PT in a 2XEL34, 3X12AX7 SS rectified amp?

[Stevem]

Well two 34rs with less than 120 ma to run on will be a very soft and spongy sounding amp with no peak power to speak of!
Two 34rs need some 120 ma each just to make 20 watts dependant on the voltage output of the PT in question, IE, the greater the voltage the less current for a given level of power.
Also make note of the heater demands if this PT was geared more towards 6V6s or 6L6GC tubes.

[rp]

Supposedly the JTM45 ran a 150mA. Seems weird to me, here's one version but I've seen others with the same spec:

http://www.tube-town.net/ttstore/Transf ... :5991.html

Use the 250mA, it should run cooler and sound better, punchier more modern sounding in a good way that you want. If the 150 is a Hammond it'll likely perform like a 200. Use the 150mA for a 5E3 type the extra solidity sounds great.

[jhaas]

Yeah, it depends on the plate voltage the PT will give you. The Marshall 50W replacement PTs that Magnetic Components sells are rated at 150mA with 345-0-345 secondaries.
http://www.classictone.net/40-18023.pdf
But I always feel better putting something rated 200mA+ in amps of that sort.

[jhaas]

[double post]

[iknowjohnny]

Thats what the 150 is....a mag comp/classictone. The other is a hammond. I've used them both but haven't used the classictone for a long while and i was wondering is there was a difference i never really noted when i was using it. I thought maybe the 150Ma would make it less bright and hard as i turn up the master.