Hello all,
Just out of curiosity I'm buying a phono step-up transformer...not just the individual SUTs themselves but the whole box with 2 transformers, RCA ins and outs, a couple of switches, already all wired up, etc.
The thing is that there's basically no information about it and so far based on pictures (I don't have it in my possession yet) there does not appear to be identifying info about the actual SUTs which are tall metal cylinders (or maybe encased in tall metal cylinders.) In the pics they look to be about 1.5"-2" tall without including the pins.
If I can't find any info on the body of the parts, how can I test the SUT to figure out the specs of the thing such as the ratio?
In the pics I've seen, each transformer has seven pins (guessing pins are about 1/2"-3/4" long and there are wires connected to four of the seven.
Any help much appreciated!
Just out of curiosity I'm buying a phono step-up transformer...not just the individual SUTs themselves but the whole box with 2 transformers, RCA ins and outs, a couple of switches, already all wired up, etc.
The thing is that there's basically no information about it and so far based on pictures (I don't have it in my possession yet) there does not appear to be identifying info about the actual SUTs which are tall metal cylinders (or maybe encased in tall metal cylinders.) In the pics they look to be about 1.5"-2" tall without including the pins.
If I can't find any info on the body of the parts, how can I test the SUT to figure out the specs of the thing such as the ratio?
In the pics I've seen, each transformer has seven pins (guessing pins are about 1/2"-3/4" long and there are wires connected to four of the seven.
Any help much appreciated!
As a reasonable approximation I used a Signal genny with 620 ohm and 1.5 ohm resistors as a voltage divider and to decrease source resistance. Set the output to say 100uV across the 1.5 ohm resistor, about 40mV or so from the genny.
Output is a scope with paralleled 47kOhm or whatever input resistance your stage has.
You can make a decent guess of the step up ratio from this. You may need to add source resistance etc depending on your cartridge choice.
Interesting to check the HF response whilst this is set up. A lot of SUTs have significant resonances with certain loads, these can be more or less eliminated with a modest RC filter before the phono stage input.
Output is a scope with paralleled 47kOhm or whatever input resistance your stage has.
You can make a decent guess of the step up ratio from this. You may need to add source resistance etc depending on your cartridge choice.
Interesting to check the HF response whilst this is set up. A lot of SUTs have significant resonances with certain loads, these can be more or less eliminated with a modest RC filter before the phono stage input.
OK, I should clarify my question...
Is there any way to try to figure out the specs of the SUTs with only a multimeter? I don't have an oscilloscope or signal generator. It's not beyond me to buy a used o-scope though frankly I have no idea how to use one in any way that's useful.
Is there any way to try to figure out the specs of the SUTs with only a multimeter? I don't have an oscilloscope or signal generator. It's not beyond me to buy a used o-scope though frankly I have no idea how to use one in any way that's useful.
Maybe some decent info here? how to measure unknown step up transformer?- Vinyl Engine
how to test a step up transformer
how to test a step up transformer
Any info about the manufacturer? If this is a DIY product, can you ask the seller or the person who made it? What are the switches used for? Please attach pictures from its outside front/rear and its internals once you got it.
Pics of the step-up transformer assembly
I hope this works...let's see if the pics show up!
I hope this works...let's see if the pics show up!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Well I wouldn't use a multimeter on it to measure resistances. Received wisdom is that DC on the coils can magnetise the core and degrade the performance. If you have computer audio you can probably get an adequate sine wave signal from a sig genny app on that. You'll need a multimeter with a specified frequency range for RMS volts. Then choose an appropriate frequency - 100Hz should be acceptable for most multimeters and well within any halfway decent transformers FR. Using the resistive divider mentioned above set an appropriate low input signal level - I'd start at no more than 100uV, and measure the output voltage with volume control at full signal.
To my mind that circuit has more of a look of a line buffer than a phono level SUT, after all who'd put a volume pot on a SUT for a phono application? Whether it's 1:1 or some other ratio of course remains to be tested.
To my mind that circuit has more of a look of a line buffer than a phono level SUT, after all who'd put a volume pot on a SUT for a phono application? Whether it's 1:1 or some other ratio of course remains to be tested.
Last edited:
