Neve Output transformer a Power Transformer?
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edanderson
Well-known member
sure. "basically"
the neve output transformers are in fact made of pretty much exactly the same materials as a common linear power transformer. so are api output transformers, the output transformer in the 1176 compressor, nearly every tube guitar amp transformer, tube hifi stereos, etc. its just electrical steel, a nylon bobbin, some copper magnet wire and insulating tape.
and it is also true that the way that the parts are put together in a neve output (or any of the other examples above) is not much more complicated than a linear power transformer.
really, if you had a day or two to work on it, you could take apart and unwind a similar size power transformer, and (with nearly infinite patience because it would take several hours to do each step by hand) put those same parts back together as something resembling a neve output. all the info you need is here on the forum if you search for it.
but there are some "little" differences in the way the neve output is constructed. the most important one is the way that the core is put together. if you look at a typical linear power transformer, you'll see that the core is made of thin sheets in the shape of E and I. on 99.9% of all transformers made today, each layer of E and I will alternate direction, because that's what works best for a power transformer and most audio transformers. the single ended neve circuit is an exception where that will not work. if you use a transformer built like that, the bass will sound flabby and distorted, really not good at all. the way that single ended circuits work is that they get their DC operating current through the primary winding of the output transformer. in order for that DC current not to ruin the transformer's performance, the core needs to be constructed so that all the Es and Is are facing the same way, creating a very small gap that runs all the way through the core. the gap prevents the DC current from ruining the audio performance of the transformer. the gap also affects other aspects of the transformer performance as well, which leads to other design changes, and so on...
long story short, power transformers cores generally do not have the gap that is needed to work in a single ended circuit, so they will not work in a neve 1290/1272/1084/1073 type circuit.
a power transformer that size is ~$15 vs the proper 1166 type output transformer at ~$30 from audio maintenance or hairball audio. you are paying "double" for similar parts put together a different way, but it will actually work and that should be worth something to you...
EDIT: i should add that i am "biased" (subtle humor) by the fact that i make the 1166 types for sale in the hairball audio shop.
ed
the neve output transformers are in fact made of pretty much exactly the same materials as a common linear power transformer. so are api output transformers, the output transformer in the 1176 compressor, nearly every tube guitar amp transformer, tube hifi stereos, etc. its just electrical steel, a nylon bobbin, some copper magnet wire and insulating tape.
and it is also true that the way that the parts are put together in a neve output (or any of the other examples above) is not much more complicated than a linear power transformer.
really, if you had a day or two to work on it, you could take apart and unwind a similar size power transformer, and (with nearly infinite patience because it would take several hours to do each step by hand) put those same parts back together as something resembling a neve output. all the info you need is here on the forum if you search for it.
but there are some "little" differences in the way the neve output is constructed. the most important one is the way that the core is put together. if you look at a typical linear power transformer, you'll see that the core is made of thin sheets in the shape of E and I. on 99.9% of all transformers made today, each layer of E and I will alternate direction, because that's what works best for a power transformer and most audio transformers. the single ended neve circuit is an exception where that will not work. if you use a transformer built like that, the bass will sound flabby and distorted, really not good at all. the way that single ended circuits work is that they get their DC operating current through the primary winding of the output transformer. in order for that DC current not to ruin the transformer's performance, the core needs to be constructed so that all the Es and Is are facing the same way, creating a very small gap that runs all the way through the core. the gap prevents the DC current from ruining the audio performance of the transformer. the gap also affects other aspects of the transformer performance as well, which leads to other design changes, and so on...
long story short, power transformers cores generally do not have the gap that is needed to work in a single ended circuit, so they will not work in a neve 1290/1272/1084/1073 type circuit.
a power transformer that size is ~$15 vs the proper 1166 type output transformer at ~$30 from audio maintenance or hairball audio. you are paying "double" for similar parts put together a different way, but it will actually work and that should be worth something to you...
EDIT: i should add that i am "biased" (subtle humor) by the fact that i make the 1166 types for sale in the hairball audio shop.
ed
gemini86
Well-known member
basically stack the E's up together, then the I's and use a few layers of tape to gap them apart a bit, then slip the windings back on and either lacquer or tape it all together again. That's how I recycle walwart trafos from Goodwill(3 bucks) to make small SE ouputs.
edanderson
Well-known member
like rodney says, once you take one apart, you'll see how it can go back together again. you'll probably need to soak the transformer in solvent to get it apart... a heat gun can also help here, but you'll need the lams to be clean-ish to put it back together.
that's one big step. the next part is re-winding the coil. you're not going to get great audio performance from a power transformer coil, where they heavily isolate the primary from the secondary for safety reasons. for more info about coil winding, just search for some of the nice dissections by chris jenrick (username: cj) here on the forum, and maybe try to read a book or webpage about the subject. wolpert or the RDH4 would be a start, and are available for download. rod elliot's pages on transformers are clearly written:
http://sound.westhost.com/xfmr.htm
ed
that's one big step. the next part is re-winding the coil. you're not going to get great audio performance from a power transformer coil, where they heavily isolate the primary from the secondary for safety reasons. for more info about coil winding, just search for some of the nice dissections by chris jenrick (username: cj) here on the forum, and maybe try to read a book or webpage about the subject. wolpert or the RDH4 would be a start, and are available for download. rod elliot's pages on transformers are clearly written:
http://sound.westhost.com/xfmr.htm
ed
Thanks Ed and Rodney. I like your Goodwill idea Rodney
You think like me.
I think CJ is the one who I was reading on transformers to begin with and where the idea in title of the thead came from (if I recall).
Thanks for the information. I've seen that website a while back.
Is there a good source for the more practical information... such as how to identify what steel was used for the Lams, jigs to stack and glue them, lacquer, glues, etc? A few years ago I was talking to one of the old guys at Triad from back when Fender was using their transformers (Tweed Era) and he was telling me he could just see a transformer and by site tell what the laminations were made of. He also said a lot of them were old WWII Jeep bodies!! He was probably in his 70's. Very nice guy. My original goal was to have a batch of the original Triads remade by them but it never ended up happening. None the less he was interesting to talk with. He'd named a few boutique amp companies he'd dealt with recently but I shouldn't share that info publicly of course.
You think like me.I think CJ is the one who I was reading on transformers to begin with and where the idea in title of the thead came from (if I recall).
Thanks for the information. I've seen that website a while back.
Is there a good source for the more practical information... such as how to identify what steel was used for the Lams, jigs to stack and glue them, lacquer, glues, etc? A few years ago I was talking to one of the old guys at Triad from back when Fender was using their transformers (Tweed Era) and he was telling me he could just see a transformer and by site tell what the laminations were made of. He also said a lot of them were old WWII Jeep bodies!! He was probably in his 70's. Very nice guy. My original goal was to have a batch of the original Triads remade by them but it never ended up happening. None the less he was interesting to talk with. He'd named a few boutique amp companies he'd dealt with recently but I shouldn't share that info publicly of course.
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