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they are 400v and have a 6.3v/6.5a filament winding. They also have a 28v center tapped for the bias..I got he pair for 49 dollars including shipping.
They will fit a Dyna ST70 type application if you don't use a 5v rect winding. I know they are ,made in Mexico but,they are an American company so for that kind of money,they are great for projects,like building amps or maybe a tube matcher?
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Follow Ups:
Mikey,
That 0-400 rectifier winding rates to be quite satisfactory working into a hybrid bridge rectifier that uses either a 5R4 or 5Y3, depending on winding's current capability, on the vacuum side. The big forward drop in the types mentioned should put the B+ rail voltage at a nice value, working into a CLC filter.
A Hammond 166-MS should comfortably energize a 2 A. filament. Given the 115 V. primary, you might have to put 2X small resistances in series with the filament. Take the "raw" B+ from the CT, for lowest residual hum.
Eli D.
No center tap on the 400V. Big voltage with a FWB.
I noticed that..You can build some power with that transformer even with a half wave rectifier..They also have 120 watt opt trafos real cheap that are 1.5k however,I think they are more for guitar but at 90 watts,you can no doubt make 20hz to 20hhz with no sweat.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
"I think they are more for guitar but at 90 watts,you can no doubt make 20hz to 20hhz with no sweat"
It's true that reducing power can extend transformer response. However, transformers designed for musical instrument use - especially guitar - are unlikely to have sufficient inductance to produce hi-fi quality lows. They're designed to reproduce the lowest note of a six-string, which is 82 Hz. That's two octaves above 20Hz, much too far to expect hi-fi performance at any power level. You can try it, but I think you'll be very disappointed.
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Buy Chinese. Bury freedom.
I have done it with a fender output at 25 watts that was rated for 40 watts and I was able to do down to flat to 21cps but my high end response just went to 19khz.When I would tweak feedback,you could extend the highs but the low end would roll off at 25hz.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
I have no idea what that transformer was for, but you lucked out. Maybe it was for bass guitar? I've tested a number of guitar-type transformers, and what you're describing is not typical.
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Buy Chinese. Bury freedom.
I was mistaken,it was a Peavey and it was a 40 watt trafo and I was running a pair of KT66s and it at about 25 watts and it made some good numbers but you had to play with FB.I know what you are saying tho because guitar transformers typically don't have any bandwidth to speak of.
Now,there are some nice audio amps that Peavey makes that does have some nice iron and they sound absolutely incredible once you upgrade and mod them a bit.The 120/120 classic,is one that is very impressive.There are others that have heard this amp and will agree.I've rebuilt and upgraded three of these and they make 105wpc at full bandwidth.You can make 120 if you run KT88s and the power trafos handle them just fine.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Michael, that's quite a coincidence. I really love the old Peavey iron for building guitar amps. In fact, I have an amp project on the back burner right now using the OPT from a Peavey Classic 30. It was a six-month search to find the transformer because I wanted to use a pair of EL34s at this power level. The Peavey used four 6BQ5s in PPP, so it's a good match at 3.8K ohms plate-to-plate. This isn't hi-fi response, but the prototype amp does 40W over the range of a six-string. That's a testament to the how well the Peavey iron was built back in the day. Below are some of my notes from the power amp prototype. I'll add preamp and tone control circuitry when I restart the project, hopefully later this year.
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Buy Chinese. Bury freedom.
Now we are on the same page..The classic 120 and the classic are very acceptable hifi quality and with the circuit you drew and implemented for the 120,that amp becomes a real marvel..I used 6CG7s and a 12AY7 on the input and that worked well.
While you will not get the bandwidth of a Citation,Mac,or Peerless trafo,it's one I could live with on a daily basis if I didn't have the others.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Have you tried any of the Hammond organ transformers? I don't mean the little wimpy things from 6V6 models. I have a set right now that were used with a pair of 7591s running at +450V. I haven't built anything with them yet, not even a prototype, but I suspect they'll do 20Hz at reasonable power levels. They came out of a full-size organ, so the lowest pedal note was 32Hz. Also, they only have a single output winding, but it's 8 ohms, so they're compatible with 99.9% of modern speaker systems. I'm looking forward to trying them, but haven't heard much from other people who have used this type of iron.
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Buy Chinese. Bury freedom.
Jack
The only Hammond Trafo I used and it sounds quite good,is a PA-1650R.
I have them in an MFA75 amp and they are decent.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Hammond organs aren't related to the Hammond transformer company in Canada. I don't know who made the organ transformers, probably one of the US manufacturers like Chicago, Triad, etc.
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Buy Chinese. Bury freedom.
called the Mesa Baron?
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Edits: 07/17/16
Being a guitar player I remember seeing these when they were out. For some reason I also remember being told that they didn't sound great but that could have been someone's taste at play.
Danny
The person that may have said it didn't sound great,was probably some guy that calls himself an audiophile,you know the kind that reads the hifi magazines and goes out and buys audio gear on his credit card,soley based on what some reviewer writes? There is no way possible this amp can sound good because it made by a company that makes guitar amps..I will tell,some of the logic I have heard thru the years from those people give us enough lines to write a five hour sitcom.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
...and wasn't suited to most speakers in use at he time. One major logical flaw was to design the output stage such that the output impedance was equal to the load impedance...not the more typical simulation of a low impedance voltage source that many speaker mfgrs assume. Another problem was too much "choice"....32 combinations of feedback level and output stage configuration.See link for the bipolar Stereophile review and try and read the whole thing (if you dare).
Edits: 07/18/16
Steve
I actually heard the amp on a pair of Magnepan 20.1s and it was quite good at the time..We were using the 8db setting but being the Maggies are an easy resistive load to drive,maybe it wasn't the most accurate test. The amp did have potential because the iron was quite good. If I heard it on ESLs,maybe it wouldn't like that impedance swing.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Edits: 07/18/16
!
The Mind has No Firewall~ U.S. Army War College.
Aren't they tho Kenny? Those horrible 6L6s and they are still making those rotten things..Then they have the nerve to make other disgusting offspring such as the KT66,EL37,7581,5881,and 7027s. Shame on them..LOL
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
It will be nice if they know the current ratings. It's pretty much useless when the voltage starts sagging under heavy load. I think may be you can run 100-150W out of them?
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.Thou shall not stand where I type for I carry a bottle of Certified Audiophile Air and a Pure Silver Whip.
You can get 120cps out of them but you will no doubt be saturating the core at 30cps at that power rating.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
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