I used a Jensen output, 4:1 for the V76. Nice chunk O Ni, sounds great. Input can be your favorite flavor of the month x-former for 72/76. Higher the ratio, more rolloff, except Ollie's V76 in which has 1:30 ratio but no rolloff.
cj
cj
Transformer lists for projects.
- Thread starter Mbira
- Start date
Help Support GroupDIY Audio Forum:
Cainester
Well-known member
What ever happened to that 2622 "hack" that was discussed?
Caine
Caine
You mean this:
Cainester
Well-known member
Thats the one! :thumb:
I'd love to have 4 or 6 of those. Did anyone ever inquire on getting a run produced?
I'd love to have 4 or 6 of those. Did anyone ever inquire on getting a run produced?
Family Hoof
Well-known member
I added the Lynx Audio AT600/600-G under the list of N*eve gapped output transformers.
It's just a normal transformer that has the lams all facing the same direction instead of interwoven. An E-I core is a two piece lam that has one piece shaped like an E, and another piece which is just a rectangle. In a gapped transformer, the rectangle like lams are all stacked together so the form a brick like shape. This brick is layed across the E lams in a gapped transformer. In a non gapped core, one E lam will go one way, then the next E lam will be stacked opposite it's neighboring lam, alternating back and forth across the entire core.
In a gapped transformer, there may or may not be a piece of insulation in between the lams. A typical gap is made out of something known in the x-former bussiness as Kraftpaper, sometimes abbreviated KP. It looks just like the old brown wax paper they used to wrap your lunch in, if you are that old.
So you might see spmething like Gap: .002 KP, which means a piece of Kraftpaper that is .002 inches thick (or thin I should say).
This gap between the lams does two things.
1) It keeps the core material from becoming magnetized by any DC in the primary.
2) It keeps the transformer from saturating.
It does this by interupting the magnetic path of the core.
A transformer saturates when the core is no longer able to handle any more magnetic flux. This flux is the result of an ac signal in the coil which surrounds the core. As you increase the voltage, and thus current in a coil, the magnetic lines of flux also increase. The amount of flux in a given area is called flux density. Transformer designers usually have there favorite constants of flux density for different alloys. They usually express this constant as kilogauss per kilogram. Certain metals are able to handle different amounts of flux density, or kilogauss per kilogram of core material. M6, or grain oriented silicon steel, can handle a lot more flux density than 50/50 (an insiders slang for 49% Nickel core) and Superperm, (80% Nickel). That is why it is used in situations that produce a lot of flux, such as output transformers and power transformers.
A coil without a core, (air core transformer) , will have a very hard time linking the primary signal with the secondary signal, because the magnetic lines of flux tend to radiate into space, where they can do little good as far as inducing a voltage in the adjoining winding in the coil. The transformer core acts to pull these lines of flux inward, back from outer space, where they can be used to link the signals between coils. The more "permeability" a core has, more concentrated the flux becomes for a given signal, or the easier time it will have pulling the flux lines in where they can do work.
The Nickel core transformers will concentrate the flux produced by a coil in a lot more efficient way. A superperm core, for example, will only need to be roughly 1/5 th the size and weight of a M6 core to produce the same flux density. The problem is, since it is so good at concentrating flux, it can become overloaded, or saturated much easier than an M6 core. Think of it as an amplifier. The more gain an amp has, the quicker it will become overloaded. A Marshall stack will crunch out before a Fender will. So, a superperm core will overload quicker than a regular steel core.
In a case where you have a very weak signal that you want to get off the noise floor as soon as possible, (mic pre), you want a core material that will give you a lot of flux density for a minimum of signal. This is why you will find the best mic input transformers made out of 80% Nickel. Since mic signals are relatively weak compared to line level, speaker level and power level signals, you rarely have to worry about overloading the core, unless it is made out of very small lams, in which case, you might actually want the core to become slightly saturated. This is where the term "colored sound" or the phrase "the sound is in the iron" comes from. Some people actually want to impart a little alteration to the original signal in order to get a different tone.
So the bottom line with a gapped transformer is that it will sacrafice some permeability for an increase in it's abillity to handle dc in the primary. It's a tradeoff. You will need a few more tuns of wire in the coil to get the same flux density, but you can hit the transformer with higher levels before the core will cause distortion in the lower frequenciy ranges of the audio signal. If you are still confused, ask somebody who actually knows how to explain this rather hard to understand thing called a transformer.
:razz:
In a gapped transformer, there may or may not be a piece of insulation in between the lams. A typical gap is made out of something known in the x-former bussiness as Kraftpaper, sometimes abbreviated KP. It looks just like the old brown wax paper they used to wrap your lunch in, if you are that old.
So you might see spmething like Gap: .002 KP, which means a piece of Kraftpaper that is .002 inches thick (or thin I should say).
This gap between the lams does two things.
1) It keeps the core material from becoming magnetized by any DC in the primary.
2) It keeps the transformer from saturating.
It does this by interupting the magnetic path of the core.
A transformer saturates when the core is no longer able to handle any more magnetic flux. This flux is the result of an ac signal in the coil which surrounds the core. As you increase the voltage, and thus current in a coil, the magnetic lines of flux also increase. The amount of flux in a given area is called flux density. Transformer designers usually have there favorite constants of flux density for different alloys. They usually express this constant as kilogauss per kilogram. Certain metals are able to handle different amounts of flux density, or kilogauss per kilogram of core material. M6, or grain oriented silicon steel, can handle a lot more flux density than 50/50 (an insiders slang for 49% Nickel core) and Superperm, (80% Nickel). That is why it is used in situations that produce a lot of flux, such as output transformers and power transformers.
A coil without a core, (air core transformer) , will have a very hard time linking the primary signal with the secondary signal, because the magnetic lines of flux tend to radiate into space, where they can do little good as far as inducing a voltage in the adjoining winding in the coil. The transformer core acts to pull these lines of flux inward, back from outer space, where they can be used to link the signals between coils. The more "permeability" a core has, more concentrated the flux becomes for a given signal, or the easier time it will have pulling the flux lines in where they can do work.
The Nickel core transformers will concentrate the flux produced by a coil in a lot more efficient way. A superperm core, for example, will only need to be roughly 1/5 th the size and weight of a M6 core to produce the same flux density. The problem is, since it is so good at concentrating flux, it can become overloaded, or saturated much easier than an M6 core. Think of it as an amplifier. The more gain an amp has, the quicker it will become overloaded. A Marshall stack will crunch out before a Fender will. So, a superperm core will overload quicker than a regular steel core.
In a case where you have a very weak signal that you want to get off the noise floor as soon as possible, (mic pre), you want a core material that will give you a lot of flux density for a minimum of signal. This is why you will find the best mic input transformers made out of 80% Nickel. Since mic signals are relatively weak compared to line level, speaker level and power level signals, you rarely have to worry about overloading the core, unless it is made out of very small lams, in which case, you might actually want the core to become slightly saturated. This is where the term "colored sound" or the phrase "the sound is in the iron" comes from. Some people actually want to impart a little alteration to the original signal in order to get a different tone.
So the bottom line with a gapped transformer is that it will sacrafice some permeability for an increase in it's abillity to handle dc in the primary. It's a tradeoff. You will need a few more tuns of wire in the coil to get the same flux density, but you can hit the transformer with higher levels before the core will cause distortion in the lower frequenciy ranges of the audio signal. If you are still confused, ask somebody who actually knows how to explain this rather hard to understand thing called a transformer.
:razz:
dukasound
Well-known member
Hi Chris
What do you think about UTC HA-108 transformer and where I can put this
transformer?
Duka
What do you think about UTC HA-108 transformer and where I can put this
transformer?
Duka
That would be great in a Pultec EQP or MEQ as an input to the passive filter section. Handles 20 db, great for today's levels.
Or anyplace else that uses a 600:600.
Or, you could try a trick I just heard about from my old timer x-former buddy:
Since you have a 50 ohm tap on the pri, use it as a 50:600 ohm step up. You turn a 1:1 xfmr into about a 1:3.5 step up, which could be used to drive a Neve input from a mic, if the mic did not mind the low impedance. Or maybe even a line in to a Neve if you used it in reverse, or maybe ( I haven't tried this yet) a mic to grid if it has enough turns to provide the inductance needed for the tube grid.
Or, use it in reverse as a step down transformer. The core is big enough for a parafeed output stage in a tube pre, Pultec, or LA2. It even handles 0.5 ma dc, so maybe even get away with a direct coupled 12AX7a output to line, but you would probably run into saturation at higher levels, which may or may not be a nice thing, depending on your recording philosphy.
cj
Or anyplace else that uses a 600:600.
Or, you could try a trick I just heard about from my old timer x-former buddy:
Since you have a 50 ohm tap on the pri, use it as a 50:600 ohm step up. You turn a 1:1 xfmr into about a 1:3.5 step up, which could be used to drive a Neve input from a mic, if the mic did not mind the low impedance. Or maybe even a line in to a Neve if you used it in reverse, or maybe ( I haven't tried this yet) a mic to grid if it has enough turns to provide the inductance needed for the tube grid.
Or, use it in reverse as a step down transformer. The core is big enough for a parafeed output stage in a tube pre, Pultec, or LA2. It even handles 0.5 ma dc, so maybe even get away with a direct coupled 12AX7a output to line, but you would probably run into saturation at higher levels, which may or may not be a nice thing, depending on your recording philosphy.
cj
dukasound
Well-known member
Thanks Chris :thumb:
CJ - Now that is an AMSWER ! Wholly s---t!
I don't understand everything (or anything maybe) but sometimes if I reread and reread sothing I don't understand, eventually one day my brain just seems to get it.
The trouble is now you got me interested in Transformers! Will this curiosity ever end? I just wanted to play music, then I started to record music and got into recording gear and techniques. I wired an entire studio more than once, I didn't want to but because I know my mixing board better than my tech, ended up repairing the 5 out of 7 strips that were not functioning properly and its given me confidence to repair the last 2 which seem to be more dificcult to fix. Now I am gathering parts for a few LA2As.
One of these days I'll have to get back to songwriting and playing! I envy my friends that only play music! I was born with this insatiable appetite for learning things on my own. I love it!
Too many things to learn and do and too little time.
Thanks CJ for taking the time to answer a question with a very precise response.
Jim
I don't understand everything (or anything maybe) but sometimes if I reread and reread sothing I don't understand, eventually one day my brain just seems to get it.
The trouble is now you got me interested in Transformers! Will this curiosity ever end? I just wanted to play music, then I started to record music and got into recording gear and techniques. I wired an entire studio more than once, I didn't want to but because I know my mixing board better than my tech, ended up repairing the 5 out of 7 strips that were not functioning properly and its given me confidence to repair the last 2 which seem to be more dificcult to fix. Now I am gathering parts for a few LA2As.
One of these days I'll have to get back to songwriting and playing! I envy my friends that only play music! I was born with this insatiable appetite for learning things on my own. I love it!
Too many things to learn and do and too little time.
Thanks CJ for taking the time to answer a question with a very precise response.
Jim
Well, I haven't actually tried the things I mentioned for the HA-108, so...
But if there is enough wire on that thing, he might luck out.
I usually rely on PRR to staighten out my posts, but I haven't seen the ol boy around for a while.
If you are putting together a home studio with cool gear, you probaly won't touch a musical instrument for about two or three years.
But the songs will be building up and the instrument will seem fresh again when you get back to it. Right? I hope!
But if there is enough wire on that thing, he might luck out.
I usually rely on PRR to staighten out my posts, but I haven't seen the ol boy around for a while.
If you are putting together a home studio with cool gear, you probaly won't touch a musical instrument for about two or three years.
But the songs will be building up and the instrument will seem fresh again when you get back to it. Right? I hope!
[quote author="CJ"]If you are putting together a home studio with cool gear, you probaly won't touch a musical instrument for about two or three years.
But the songs will be building up and the instrument will seem fresh again when you get back to it. Right? I hope![/quote]
I had a studio built and running a while ago BK BB (....before kids...before business), so much of it was already there. But I had to buy new board, monitors, mikes etc. Main work is wiring and getting the board to work 100% (almost there). I'm a bit anal about things running 100% (or near). Once I start playing and recording I don't want the equipment to get in the way.
Jim
But the songs will be building up and the instrument will seem fresh again when you get back to it. Right? I hope![/quote]
I had a studio built and running a while ago BK BB (....before kids...before business), so much of it was already there. But I had to buy new board, monitors, mikes etc. Main work is wiring and getting the board to work 100% (almost there). I'm a bit anal about things running 100% (or near). Once I start playing and recording I don't want the equipment to get in the way.
Jim
well, I hope you pop in every now and again once you get all your stuff straight.
I will probably disappear for a while so I can try out all my new toys together.
Speaking of disappear, where has that Bluebird character gone?
World tour or something?
I will probably disappear for a while so I can try out all my new toys together.
Speaking of disappear, where has that Bluebird character gone?
World tour or something?
Nah! I'm here for a long time. If the LA2As is a positive experience (no reason other than fear of the unknown not to be) I want to build more!
1176, SSL comp and then maybe some preamps. More LA2As? I really love tube gear, as a long time ago thats what I built and find it easier in many ways to Solid State circuits (not always). Mostly because of the point to point. I have yet to solder anything on a copper clad board!
Hey I just bought a Weller soldering station! I bought a crappo clone of it on Friday and blew it de-soldering my A-24 transformers (need to get them cleaned up). The Weller is almost double the price! Hope it lasts as long as my friend's Weller WTCPT (that I have been borrowing for the last 5 years!). I have a Radio Shack multimeter but no oscilloscope yet.
Sorry for getting so off topic here.
CJ, do you really wind your own transformers?
Jim
1176, SSL comp and then maybe some preamps. More LA2As? I really love tube gear, as a long time ago thats what I built and find it easier in many ways to Solid State circuits (not always). Mostly because of the point to point. I have yet to solder anything on a copper clad board!
Hey I just bought a Weller soldering station! I bought a crappo clone of it on Friday and blew it de-soldering my A-24 transformers (need to get them cleaned up). The Weller is almost double the price! Hope it lasts as long as my friend's Weller WTCPT (that I have been borrowing for the last 5 years!). I have a Radio Shack multimeter but no oscilloscope yet.
Sorry for getting so off topic here.
CJ, do you really wind your own transformers?
Jim
I have wound a few on some crude equipmemt. I want to get a real winding machine so I can go to town and wind a few of the xfmr's I have dissected.
Next up will be a Peerless S-217-D, if I can just get Mike at Magnequest to answer his emails. I send a message, and he answers it. Then nothing for a month. Then another messager, he answers it. Then another month!
He still has the 12L lams for me, but won't tell me total price and mailing address for payment.
Winding xfmr's is rewarding, but probably as expensive as buying one, as the factories have all their debt paid (competive profit margin) , and are all set up for processing and mechanical, which is really the biggest pain as far as transformes are concerned (vacuum chambers, dry out ovens, varnish and wax, core brackets, terminal strips, mu cans, etc).
But it would be nice to have a set up where you could say: "OK, I think I want to build an API preamp. Don't have any iron, money, or time for evilbay hassles,so I guess I'll just wind my own."
:thumb:
Be careful with those UTC terminals. The wires from inside the transformer are actually stuffed into those terminals, sometimes you can see the breakout leads wrapped around the outside. So if you de-solder them, the wire might work it's way loose, but usually it is well setteled as it has not been disturbed for years. Get your self a solder sucker and some copper braid (solder wick) for cleaning up those terminals. It's always a good idea to resolder vintage transformer terminals as they can become pretty groody from all those years, plus, the solder was pretty nasty back than as far as flux and rosin is concerned.
Next up will be a Peerless S-217-D, if I can just get Mike at Magnequest to answer his emails. I send a message, and he answers it. Then nothing for a month. Then another messager, he answers it. Then another month!
He still has the 12L lams for me, but won't tell me total price and mailing address for payment.
Winding xfmr's is rewarding, but probably as expensive as buying one, as the factories have all their debt paid (competive profit margin) , and are all set up for processing and mechanical, which is really the biggest pain as far as transformes are concerned (vacuum chambers, dry out ovens, varnish and wax, core brackets, terminal strips, mu cans, etc).
But it would be nice to have a set up where you could say: "OK, I think I want to build an API preamp. Don't have any iron, money, or time for evilbay hassles,so I guess I'll just wind my own."
:thumb:
Be careful with those UTC terminals. The wires from inside the transformer are actually stuffed into those terminals, sometimes you can see the breakout leads wrapped around the outside. So if you de-solder them, the wire might work it's way loose, but usually it is well setteled as it has not been disturbed for years. Get your self a solder sucker and some copper braid (solder wick) for cleaning up those terminals. It's always a good idea to resolder vintage transformer terminals as they can become pretty groody from all those years, plus, the solder was pretty nasty back than as far as flux and rosin is concerned.
CJ - What does a winding machine look like. There are some on eBay but I have a feeling they are limited.
Is it something that is huge or small in size. Could it be built? The friend that I am building an LA2A for has a huge machine shop and I have open access. He is amazing at drawing and inventiing/designing mechanical apparatus. (plural? appariti?) Maybe I can help.
Jim
Is it something that is huge or small in size. Could it be built? The friend that I am building an LA2A for has a huge machine shop and I have open access. He is amazing at drawing and inventiing/designing mechanical apparatus. (plural? appariti?) Maybe I can help.
Jim
See the V72 DIY thread. All I did was put a hand drill in a vise. A mandrel ( the thing that holds the coil bobbin or paper former to which the wire is wound upon) was made from a 1/4 inch bolt and some masking tape. A wire tensioner can be made with a clothes pin and some type of foam, maybe that black stuff that IC's are stuck to would work, or just plain cloth of some type. The biggest problem is materials. Unless you work for a company that does electronic oriented stuff, getting lamination samples from Mag Metals might be tough. Then there's the magnet wire. Very expensive unless you can find rolls at a surplus store.
Winding machines come in all sorts of price ranges, from Chinese made hand cranked jobbies that you see on ebay for 20 bucks, all the way up to 10,000 dollar computerized multiple machines ( they might wind ten coils at a time in a high output shop), or even a 100,000 dollar machine that will do everything but re-fill your coffee cup while you supervise it. Were talkin a machine that will pick up a bobbin, mount it on the mandrel, spin the wire on, tape the leads, and spit it out the other end, all in a matter of seconds.
A friend of mine built his own computerized machine which uses a 1 hp dc General Electric surplus motor. It has a very accurate stepper motor to control the pitch, (the spacing between turns). Sometimes you want a little space between turns in order to control leakage inductance and capacitance. So a DIY machine of sophisicated quality can be done if you have the resources.
cj
Winding machines come in all sorts of price ranges, from Chinese made hand cranked jobbies that you see on ebay for 20 bucks, all the way up to 10,000 dollar computerized multiple machines ( they might wind ten coils at a time in a high output shop), or even a 100,000 dollar machine that will do everything but re-fill your coffee cup while you supervise it. Were talkin a machine that will pick up a bobbin, mount it on the mandrel, spin the wire on, tape the leads, and spit it out the other end, all in a matter of seconds.
A friend of mine built his own computerized machine which uses a 1 hp dc General Electric surplus motor. It has a very accurate stepper motor to control the pitch, (the spacing between turns). Sometimes you want a little space between turns in order to control leakage inductance and capacitance. So a DIY machine of sophisicated quality can be done if you have the resources.
cj
andre tchmil
Well-known member
I have a UTC A-21 . 500ohm to 500ohm. 30-30kc , 500v.hipot.
Max level +15dbm.
Anyone knows what this means , and where I can use this one for ?
Also I have tons of Lundhal LL1524 ?????
Max level +15dbm.
Anyone knows what this means , and where I can use this one for ?
Also I have tons of Lundhal LL1524 ?????
Hmmm, I only see about 28 ohms pri DCR, compared to the A-20, which has about 60. So your inductances might not be up to snuff for something like I mentioned in the answer to Dukasound.
Do you have an inductance meter?
Do you have an inductance meter?
