Hi all,
i have a transformer that is 110 volts to 50 v ac of course and i would to try and use it as a output transformer on a compressor circuit. From what i have read materials and the way they are made and different winding ratios are what give output transformers there particular sound. What i would like to know is is it possible to use power transformers as this providing you work out the turns ratio and impedance and try and match it up. If anyone has done this or knows anything about it could you please let me know as obviously it could be a cheaper alternative. I have been trying to work out how to modify other transformers i have. I got to admit iam not overly keen on the whole wind yourself method. Of what i can see you need some sort of jig roller with a counter to hold the tention and count the turns to do a good job. but trying to work out best method. Anyone can go and buy the correct part and install. But having not huge funds to play with i try and find alternative methods to make things a bit cheaper. Who doesn't love a bargain. So sometimes its worth the effort. I think in output transformers this may be one possible one. I would love to hear from anyone who has done some output transformers with standard power transformers thanks
i have a transformer that is 110 volts to 50 v ac of course and i would to try and use it as a output transformer on a compressor circuit. From what i have read materials and the way they are made and different winding ratios are what give output transformers there particular sound. What i would like to know is is it possible to use power transformers as this providing you work out the turns ratio and impedance and try and match it up. If anyone has done this or knows anything about it could you please let me know as obviously it could be a cheaper alternative. I have been trying to work out how to modify other transformers i have. I got to admit iam not overly keen on the whole wind yourself method. Of what i can see you need some sort of jig roller with a counter to hold the tention and count the turns to do a good job. but trying to work out best method. Anyone can go and buy the correct part and install. But having not huge funds to play with i try and find alternative methods to make things a bit cheaper. Who doesn't love a bargain. So sometimes its worth the effort. I think in output transformers this may be one possible one. I would love to hear from anyone who has done some output transformers with standard power transformers thanks
You'd have to derate the transformer and make sure there's no DC on it.
You might (for example) be able to use a 100VA mains transformer with split primaries, ie. 120 + 120V, as a pushpull output transformer at maybe 20 Watts, but for guitar use only, it'll be hopeless for HiFi. You could try a quad of EL86's with (really guessing here) a 150V supply?
I'll probably get shot down in flames for the heresy....
You might (for example) be able to use a 100VA mains transformer with split primaries, ie. 120 + 120V, as a pushpull output transformer at maybe 20 Watts, but for guitar use only, it'll be hopeless for HiFi. You could try a quad of EL86's with (really guessing here) a 150V supply?
I'll probably get shot down in flames for the heresy....
Yes, no DC as there will be no air gap. You might not have to derate, as higher frequencies will help. However, I assume we are talking about instruments rather than hi-fi. It was common in the past for radio amateurs to use power transformers as AM modulation transformers, although only a limited frequency range (up to about 3kHz) was needed.
High quality audio transformers use thinner laminations in the core. Thinner metal reduces eddy current losses in the iron at higher frequencies. Disadvantage is that it costs more and is somewhat more difficult to make when using thinner laminations (thinner means more of them, and assembly time is increased as a result). This will become evident as higher losses and a degrading linearity at higher frequencies.
paul
paul
I tried it out before and didn't go well
That's right , You would have to ensure there's no DC , and it would be good enough for guitar use , maybe a practice amp .
And you need to make sure there's 4ohms or 8 ohms or so if you desire coming out of the secondaries .
How much power do you need ?
Ok, so general consensus is it'll work, but probably not the spare transformer you already have as it probably has a single primary (implying single ended and therefore DC use) and the 50V secondary will be far too high impedance for speakers (you'll probably want something in the 6/9/12 Volt range).
I also tried it out some time ago with a 6080 driving a 120/120 primary toroid with low voltage secondary and it too wasn't too promising.
Anybody else fancy a go and reporting back?
Regards
Henry
I also tried it out some time ago with a 6080 driving a 120/120 primary toroid with low voltage secondary and it too wasn't too promising.
Anybody else fancy a go and reporting back?
Regards
Henry
Hi, If you want to diy output trans then I would suggest reading up
the theory and winding techniques.I have not tried it myself but after
reading all the theory it is a formidable task and you need the hardware as well.Of course you can sort of wing it.Like if you want to account for the
DC saturation then you would have to strip the transformer E and Is
and stack them separately and use a suitable isolator of a certain thickness
of paper to get the desired DC current provided the core dimensions are
comensurate with the current or power output.
You can as an emergency use power transformer of equivalent
turns ratio as a stop gap measure but the disadvantages apply.
It's not a matter of the secondary voltages but the turn ratio that
matches the original output transformer.The important thing to know
is ... turn ratio equals voltage ratio.So...for instance the output
requires 3000 ohm/ 8 ohm speaker.Then the ratio is... just for illustration
1500 primary turns divide by 100 turns secondary =15 :1
Say you have a shorted left channel. Just pump a little AC voltage into the good one and measure how much is at the secondary and do the math.
You need to take it out of the circuit or amp.
So you would select a power transformer with 120V primary divide by
8V secondary or somewhere close = 15:1
In this case use a much larger capacity transformer maybe 2 or 3 times
to account for the DC but don't get excited about the frequency response.
The above description is for single ended use.For pushpull you need a center tap
so calculate accordingly or maybe use two tranformers in series.Remember this is
for temporary use only.Don't forget the winding direction for series connection
because if wired in opposite or opposing direction it will cancel out the other transformer
and your meter will measure zero volts.
the theory and winding techniques.I have not tried it myself but after
reading all the theory it is a formidable task and you need the hardware as well.Of course you can sort of wing it.Like if you want to account for the
DC saturation then you would have to strip the transformer E and Is
and stack them separately and use a suitable isolator of a certain thickness
of paper to get the desired DC current provided the core dimensions are
comensurate with the current or power output.
You can as an emergency use power transformer of equivalent
turns ratio as a stop gap measure but the disadvantages apply.
It's not a matter of the secondary voltages but the turn ratio that
matches the original output transformer.The important thing to know
is ... turn ratio equals voltage ratio.So...for instance the output
requires 3000 ohm/ 8 ohm speaker.Then the ratio is... just for illustration
1500 primary turns divide by 100 turns secondary =15 :1
Say you have a shorted left channel. Just pump a little AC voltage into the good one and measure how much is at the secondary and do the math.
You need to take it out of the circuit or amp.
So you would select a power transformer with 120V primary divide by
8V secondary or somewhere close = 15:1
In this case use a much larger capacity transformer maybe 2 or 3 times
to account for the DC but don't get excited about the frequency response.
The above description is for single ended use.For pushpull you need a center tap
so calculate accordingly or maybe use two tranformers in series.Remember this is
for temporary use only.Don't forget the winding direction for series connection
because if wired in opposite or opposing direction it will cancel out the other transformer
and your meter will measure zero volts.
Last edited:
Hi check this out...
Building The DIY Gyraf 1176 Clone
Audio | element14 Australia
If you want to experiment with mains transformers use small one some 2-5W for this line out application. And be careful because if you pick one with 220v primary and 6v secondary and reverse it you will get very high voltage at output. High enough to burn the unit which follows.....on the other hand if you connect it normal than the output voltage will be to low. So you need transformer with low ,,gear,, something like 220v to 110v...and you will get 2:1 ratio. But because of high number of turns and separate pri-sec.....high parasitic inductance and capacity......don't expect batter results than cc35Hz to some 5Khz of response....which means no highs,,,,
Regards
Building The DIY Gyraf 1176 Clone
Audio | element14 Australia
If you want to experiment with mains transformers use small one some 2-5W for this line out application. And be careful because if you pick one with 220v primary and 6v secondary and reverse it you will get very high voltage at output. High enough to burn the unit which follows.....on the other hand if you connect it normal than the output voltage will be to low. So you need transformer with low ,,gear,, something like 220v to 110v...and you will get 2:1 ratio. But because of high number of turns and separate pri-sec.....high parasitic inductance and capacity......don't expect batter results than cc35Hz to some 5Khz of response....which means no highs,,,,
Regards
seedseed said
Strickly speaking or in theory ,winding ratios are for matching output
tubes resistance with the speaker load so to achieve maximum power
transfer.It has nothing to do with how it sounds.
Of course the method of winding affects the frequency response because
the capacitance between each turn will affect high frequency and the
inductance of the winding will affect the low frequency.So if you want good
low frequency response or bass then a bigger core is necessary and for
high frequencies ,reducing the interwinding capacitance is important.If you can do this then most probably you will have a good sounding output transformer.
Strickly speaking or in theory ,winding ratios are for matching output
tubes resistance with the speaker load so to achieve maximum power
transfer.It has nothing to do with how it sounds.
Of course the method of winding affects the frequency response because
the capacitance between each turn will affect high frequency and the
inductance of the winding will affect the low frequency.So if you want good
low frequency response or bass then a bigger core is necessary and for
high frequencies ,reducing the interwinding capacitance is important.If you can do this then most probably you will have a good sounding output transformer.
wow great response
Wow great response. Thanks guys for all responding. I learn't a lot from that. I love this forum. I guess i have collected transformers here there and everywhere overtime. and you sit back and look at them in your junkbox and think to yourself surely there is a way i can utilise these things so obviously i try and work out different ways to do it. I was figuring that as taj said a 2:1 ratio would be the go but hard essentially to find in general most transformers drop down to a lower level such as 12 v or 15 or whatever. but obviously if you want a 2:1 ratio you need more winding on the secondary. I was not aware that you lose the high frequencies so much but as i play bass guitar this is not such an issue it actually might sound ok. Just a matter of finding a actual 2:1 ratio transformer only one way to find out.
Wow great response. Thanks guys for all responding. I learn't a lot from that. I love this forum. I guess i have collected transformers here there and everywhere overtime. and you sit back and look at them in your junkbox and think to yourself surely there is a way i can utilise these things so obviously i try and work out different ways to do it. I was figuring that as taj said a 2:1 ratio would be the go but hard essentially to find in general most transformers drop down to a lower level such as 12 v or 15 or whatever. but obviously if you want a 2:1 ratio you need more winding on the secondary. I was not aware that you lose the high frequencies so much but as i play bass guitar this is not such an issue it actually might sound ok. Just a matter of finding a actual 2:1 ratio transformer only one way to find out.
I have experimented a bit with using power xformers as OPT's. The short version is: it'll work for low-power push-pull, but it's never going to be hi-fi. Some observations:
- Typically, about a 20:1 turns ratio gives decent impedance matching for a pair of smallish output tubes to an 8R speaker. Since sound quality isn't really a strict requirement (otherwise you'd use proper OPT's), exact impedance matching is not really a requirement. You'll loose some power, but it'll work. I've had fairly good results with 2x115V-9V transformers. I'm not sure where the 2:1 ratio Tajzmaj talks about comes from; that would reflect 4x8=32Ohms to the primary side with an 8R speaker connected; I think you're probably shooting at something like 5k-10k on the primary side, which means you need about a 1000:1 impedance ratio (8K:8R), so a voltage ratio of something between 20:1 and 40:1. Assuming you're looking at transformers with a 230V center-tapped primary, anything with a secondary of 6V to 12V should be usable.
- Core saturation tends to become a significant problem below 50Hz. This is visible on a scope and tends to look pretty bad, but may not be audible. Don't expect much output power below 35Hz.
- I've never gotten a power transformer to keep up with frequencies above about 5KHz - 8KHz. I'm currently using a stereo amp with a pair of 6AQ5's in triode mode in each channel, and its frequency response is maybe -3dB @ 8KHz and keeps dropping rapidly above that. On the low end, the -3dB point is somewhere around 55Hz if memory serves.
- Anything smaller than about 20VA is probably going to give an even worse frequency response.
I think you could build a low-powered guitar amp using a power transformer. Maybe bass as well, but you might have to be a bit more picky regarding the transformer. For hi-fi it's a no go, but the drawbacks can be completely acceptable for an instrument amp that is not intended for completely accurate reproduction but rather for having an own, unique sound.
/Edit: Sorry, I thought this was posted in the Valves section, that's how I ended up with the turns ratios mentioned above. I was thinking of tube OPT's.
- Typically, about a 20:1 turns ratio gives decent impedance matching for a pair of smallish output tubes to an 8R speaker. Since sound quality isn't really a strict requirement (otherwise you'd use proper OPT's), exact impedance matching is not really a requirement. You'll loose some power, but it'll work. I've had fairly good results with 2x115V-9V transformers. I'm not sure where the 2:1 ratio Tajzmaj talks about comes from; that would reflect 4x8=32Ohms to the primary side with an 8R speaker connected; I think you're probably shooting at something like 5k-10k on the primary side, which means you need about a 1000:1 impedance ratio (8K:8R), so a voltage ratio of something between 20:1 and 40:1. Assuming you're looking at transformers with a 230V center-tapped primary, anything with a secondary of 6V to 12V should be usable.
- Core saturation tends to become a significant problem below 50Hz. This is visible on a scope and tends to look pretty bad, but may not be audible. Don't expect much output power below 35Hz.
- I've never gotten a power transformer to keep up with frequencies above about 5KHz - 8KHz. I'm currently using a stereo amp with a pair of 6AQ5's in triode mode in each channel, and its frequency response is maybe -3dB @ 8KHz and keeps dropping rapidly above that. On the low end, the -3dB point is somewhere around 55Hz if memory serves.
- Anything smaller than about 20VA is probably going to give an even worse frequency response.
I think you could build a low-powered guitar amp using a power transformer. Maybe bass as well, but you might have to be a bit more picky regarding the transformer. For hi-fi it's a no go, but the drawbacks can be completely acceptable for an instrument amp that is not intended for completely accurate reproduction but rather for having an own, unique sound.
/Edit: Sorry, I thought this was posted in the Valves section, that's how I ended up with the turns ratios mentioned above. I was thinking of tube OPT's.
Hi Mastodon
This 2:1 ratio comes because Seedseed need transformer for comperssor with solid state output......Because I read that thread I know what he was asking........so here comes this misunderstanding. He don't need tube amp output transformer like here was proposed ....... Uh 2:1 with tubes? Maybe with few of 6c33 in parallel......
Regards
Taj
This 2:1 ratio comes because Seedseed need transformer for comperssor with solid state output......Because I read that thread I know what he was asking........so here comes this misunderstanding. He don't need tube amp output transformer like here was proposed .......
Uh 2:1 with tubes? Maybe with few of 6c33 in parallel......Regards
Taj
http://www.diyaudio.com/forums/anal...ompressor-output-transformer-alternative.html
Maybe I was wrong. I noticed this 1176 thread from seedseed.....
Best regards
Maybe I was wrong. I noticed this 1176 thread from seedseed.....
Best regards
Hey guys
I think if you get the right transformer, it could work.
I have made a mono amp with a PCL805 and a handmade 220 to 12 3A and it sounds awesome. It has some really nice sound to it and it gives about 25W at 3Ohms at 170V on the anode.
I can't increase the anode voltage or it'll red-plate.
Anyway, it can work flawlessly if you're lucky enough and get the right transformer.
I think if you get the right transformer, it could work.
I have made a mono amp with a PCL805 and a handmade 220 to 12 3A and it sounds awesome. It has some really nice sound to it and it gives about 25W at 3Ohms at 170V on the anode.
I can't increase the anode voltage or it'll red-plate.
Anyway, it can work flawlessly if you're lucky enough and get the right transformer.
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