• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Cheap SE output transformers

Jump to Latest
#2
Re: cheap se output transformers

gja said:
I am looking for the cheapest output transformers and these looked quite good.
Click to expand...

I can't imagine them NOT being good value for $17.52. The only thing I know of that are cheaper are these:
http://triodeelectronics.com/tfchxfwi48oh.html
but they are only 100Hz-20kHz and 5W. At that price you would even have to look hard on eBay to find a cheap vintage transformer pulled out of a console that costs less.
 
#6
The transformers are not good for the proper tube single ended
design...
datas, like usual common rule, are without crutial units of the device,
like
primary inductance
capacitances, leakage inductances
wire diameters
gap lenght...
we have only, like in most cases, impedance ratios
that means nothing
(but most designers do not write those values at schematic diagrams,
why should manufacturers do so ?..)
Anyway the transformer and simillar models can be
with great succes implemented in guitar amplifiers and old tube radios...
 
#7
Zoran said:
The transformers are not good for the proper tube single ended design...
Click to expand...

I agree but disagree in this context. You are right that an SE amp built with these will unlikely be mistaken for something built using Plitrons, Lundahl, etc. 🙂 However, the original post clearly stated this was about building a first tube amp and trying to keep budget down. In that context I believe these transformers are an excellent choice.
 
#8
I can't speak for the Edcor transformers, since I had never heard of them until now. I will order a pair and subject them to my usual torture testing.

I have tested the Triode Electronics units that were mentioned. I was amazed that some decent sound could come out of such a tiny transformer. The Triode unit is specced for 40 mA max, I had no problems running 60 mA with a 300B. The sound was clean and I did not notice any transformer saturation with real music playing through speakers at about 3 watt peaks. It helps that my speakers have an impedance bump at the frequency that saturation should start (70Hz). Many of the listeners could not always tell which had better sound, the Triode unit or a Hammond 125CSE. It was easy to pick out the One Electrons though.

The Edcor units are twice as big for only a few dollars more. I hope they work twice as good.
 
#10
I don't know if the PP transformers can take the voltage of the 845. I don't know where you intend to operate them.

I just ordered a pair of the cheap ones (XSE15-8-5K). The sales girl said their transformers were not stocked, and are built to order. She said that mine would go out next week. I will subject them to listening tests and frequency response tests with a few different tubes when I get them. I will report the results here. If I like them, then I may try some of their other transformers.

They have some line to voice coil, and amplifier to line transformers made for sound distribution with acceptable frequency response that are reasonably priced. I am thinking PSE 6336's or PPPSE 6AS7's ( I don't have any 6C33) driving a 140 volt to 8 ohm transformer.
 
#11
Dang !!! :bigeyes:

If these guys make a decent xfrmr, they will be the diyer's new best friend. I looked around the site and found they offer interstage, SE, PP, ribbon mic, and attenuater Xfrmrs...all VERY resonably priced. And if that isn't enough, they offer a custom service with no setup fee, and no minimum order,

Did I say Dang !!!
 
#12
tubelab.com said:
I don't know if the PP transformers can take the voltage of the 845. I don't know where you intend to operate them.
Click to expand...

...I don't either. :whazzat: I vascillate between the current low voltage "fad" of around 450VDC and a more respectable 750VDC. Anything over that becomes too expensive for components that are reasonably spec'ed for safety.

FWIW, I've tried the Edcor 10k:600 transformers(their cheapest version), and they pale in comparison to similarly priced power toroids...although a number of people have given positive reviews of them.
 
#18
I got my pair of XSE15-8-5K today. Unit construction is great.

On a 3 watt 6EW7 amplifier, we're talking 19Hz >>20KHz (sig gen doesn't go higher) with 5dB NFB and 25Hz >>20KHz with zero NFB.

Nothing wrong with this tranny for SE.
 
You must log in or register to reply here.
Top Bottom