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hi, i just bought and OT for cheap, it says its only for 15w power, i wanted to get a 20w but for 18USD its really cheap, its used, i found it on a chinise electronics shop, and its not hammond or mercury but seems quite good for a small project i want to build..

also the have a small transformer, maybe will fit for a 15w build but its quite HV, its 600V @ 65ma on the audio side, and got two taps, one its 5.0V@3.2A, and the other its 6.3V@2.5A, but 600V... will be good for a standard 12AX7 tube preamp, and a power tube??, mabe a pair of EL34 tubes??, or voltage its too high??

is that power tranny 600volt on each side?
or is it 300 0 300, if this is the case you can build a fender champ type amp or maybe even a 5e3-(a little low)
I used a 300 0 300 on a lightning build (el84's) a bit on the hotside, but i used a few zeners to keep the B+ to a
manageable level......lots of voltage so be careful

joeboo88 wrote:is that power tranny 600volt on each side?
or is it 300 0 300, if this is the case you can build a fender champ type amp or maybe even a 5e3-(a little low)
I used a 300 0 300 on a lightning build (el84's) a bit on the hotside, but i used a few zeners to keep the B+ to a
manageable level......lots of voltage so be careful

nop its 600-0-600, i think a champ will be overkill, maybe a bigger amp like a tiny terror will fit that, i have check power ratings and it will be fine, but,,, at 600v on plate... im not so sure though

12AX7 is only rated for 300V. People run them way higher but I don't know about 600V and running the plate voltage above spec does cut down their life, doesn't it? I think power tubes are usually run at 350-450V too. Burning your preamp tubes faster than usual is one thing, but I wouldn't want to go through power tubes any faster than necessary.

Could you put them in series rather than parallel, though? If you have two 12AX7 tubes, put the plates in series, and then run that parallel to a pair of power tubes whose plates are in series? Or does that not work? AA5 style radios put the heaters in series and used power tubes with 50V heaters to soak up the wall voltage.

astrobass wrote:12AX7 is only rated for 300V. People run them way higher but I don't know about 600V and running the plate voltage above spec does cut down their life, doesn't it? I think power tubes are usually run at 350-450V too. Burning your preamp tubes faster than usual is one thing, but I wouldn't want to go through power tubes any faster than necessary.

Could you put them in series rather than parallel, though? If you have two 12AX7 tubes, put the plates in series, and then run that parallel to a pair of power tubes whose plates are in series? Or does that not work? AA5 style radios put the heaters in series and used power tubes with 50V heaters to soak up the wall voltage.

there was another trafo a 330-0-330, but power specs was better, so was probably for a bigger amp, it has 6.3v @3.5A and 330-0-330 @250 ma, probably i can still go for the tiny terror, but can upgrade to the dark terror, which its the same but has a fx loop tube, and maybe im just saying nonsense but it coul use a reverb tube also for that power specs, and only have 15w output wich its the power of the OT. probably tomorrow will post a photo of the OT, and maybe the power transformer

You need to get your head around psu numbers.

This Picture helped me out heaps when I was learning the basics.
Note the current transfer as well as voltage it can catch you out.
Cheers, Phil

phatt wrote:You need to get your head around psu numbers.

This Picture helped me out heaps when I was learning the basics.
Note the current transfer as well as voltage it can catch you out.
Cheers, Phil

this its really useful... i think that the 600V its a choke transformer, but i did not see inductance on the label... but has the aspect as a choke...

copachino wrote:

phatt wrote:You need to get your head around psu numbers.

This Picture helped me out heaps when I was learning the basics.
Note the current transfer as well as voltage it can catch you out.
Cheers, Phil

this its really useful... i think that the 600V its a choke transformer, but i did not see inductance on the label... but has the aspect as a choke...

i have check the OT and ins a hautington transformer, also i think its the same company as TRIAD magnetics... its about 7-50000HZ and has a 8000ohm and a 2000ohm primary, and the mormal 16/8/4 ohms outs.... i have check resistance, and pon primary its about 470ohm at 8kohn input and 235ohm at 2kohm input, outputs are about 1ohm and 1.6 ohms... its normal???, i thought it will be more resistance in the primary.. but...