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I recently heard an "Amity-like" amplifier,and I must say that personally I believe this is pretty much as good as its possible to make an amp.
Offcourse I believe there are "better" amps,but I feel maybe the main rules of DHT with no feedback and transformer-coupling
might be one of the best ways to preserve as much as possible of the original signal.
I belive these are very transparent constructions and therefore I believe parts-quality would be easier to hear.
So since I'm planning to build something with DHT and transformers I'm trying to find out what transformers I should use.
Whats your opinion on transformer quality,are the differences in "music-making" qualities big? ( I don't like using the word sound quality
since its for me all about the music in the end :-) ) Or do the good qualities of such an amp lie more in the use of transformers than the quality of them?
The amp I heard is this one ; http://www.veiset.net/842/index.html ,and he used Sowther transformers.
I have tried to read up on transformers on the net,but I found few sites that go into any real depth about what makes a transformer good.
Audio Note seem to have some unique ideas and have made research to develop the best transformers possible.Do you know of any other? Links?
I have some Audio Note kit gear and I love it all,it sounds so right and natural,while most other hifigear I've heard in comparsion
sound artificial.
As for now I'm thinking of either going with Lundahl or Audio Note,but the Audio Note sure are expensive when one move up the line of double C-core.....So do you have any good tip about who and what make good transformers? Maybe you've made real comparsion of good transformers in
your own project?Cheers,
Rune
Follow Ups:
Keep on posting if you feel like it.
It seems complex and I know that probably everything is important in amps like these,and not better than the weakest link.
And we have the funny thing that its pretty rare that 2 people makes the exact same conclusion regarding "sound".So I guess I just have to start trying myself and get some experience on my own,trying to find what I like. :-)Cheers,
Rune
Mike makes great transformers and he has the Peerless formulations. He knows what makes a good OPT IMO.
Hi.Instead of guessing, costly trial & error, or hearsay, here are some hints, assuming you mean O/P transformers (since you did not mention specificifically).
This boils down to the transformer basics - inductance.
In simple language, for audio O/P irons, larger the better the primary inductance (for better low frequency response) & less the better leakage inductance (for better high frequency response).
A guideline is: leakage inductance should be 1/1,000 of its primary winding inductance.
Primary inductance is normally provided in the specs of the iron, but leakage inductance is normally not. You got to ask the transformer builders or DIY inductance calculation on some basic measurement.
I'll advise you how to measure a transformer's primary inductance & its leakage inductance despite what the transformer specified tomorrow as I am rushing out now for a business meeting.
c-J
Then I likes it lots.When I need more knowin' then I pics me up an ole' standard audio
buildin' textbook for some facts learnin'. That rascal Menno van
der Veen rote-up a heckuva book in: 'Modern High-End Valve Amplifiers'
and i'd sure be fit to recommend it to ya for transformer thinkin'.
Itsa goodn' fer sher.-T.M.
Rune,All output transformers are good. Everyone of them. The original one's that come from the commercial marketplace during the 40's and 50's were designed for a specific set of tubes with a specific set of components in a specific circuit by some truly smart and knowledgeable designers of transformers. These narrowly defined transformers can work amazingly well, if you use them as originally intended. So, if a particular transformer does not sound "good" it is likely due to not being used in the circumstances it was designed for and even the multi use transformers have a "best" set of operating parameters.
Some manufacturers did and others still do provide multi tap wider usage products for the DIY market and some of those even sound quite good. The current range of manufacturers also supply some of this need with Lundahl probably being fore most. Sowter makes very very good products also.
However, what you need to do, to get the best performance from anyone's offerings is to adapt your circuit, components and tube manufacturer choice to the available off the shelf products, or go in search of someone willing and able to flex their designs to suit your needs.
Means you really are going to have to spend some time in driver circuit performance modification, feeding am output power circuit you know and trust. Then you need to move on to power tubes and outputs and explore that ground, in one topology at a time.
Just asking for who is good is not going to get you anything but frustrated, primarily because there are no words you can use to describe what you are personally looking for, to a transformer designer. You need to be able to specify the parameters in the terms of usage that allow any competent designer to characterize your needs in electrical terms and functions.
danlaudionut is quite correct when he says use what you are familiar with, but you need to use it with the intention of exploring the circuit designs and components that surround and modify what the known set up provides. Lot's of very interesting work if you are up for it.
Bud
Ma, come quick! I'm gonna grab me a big ole' chunka pig iron an'
wrap it all up with some bailin' wire --cause it jus aint'
possble to makes a "Bad" transformer! --I heard they're all
good'ns! Eureka!-T.M.
n fur shur at ole pig iurn z gud nuf tu lykle don neyd no baylin ware needer jez de pig whudl fid tru da hoal nda fenz dere
I personally know a guy who has used door bell transformers and out-performed other amps with really "good" outputs in them. Bud is generally correct here, the circuits are all worse than the output iron is what I like to say.Jeff Medwin
Hi Jeff,Mmmmmmm well maybe not quite that biased, from my point of view. As an example, you can take an amorphous core Lundahl SE ouput and put it in an amp with the finest passive components, hand wired , with really expensive 300 B, or your choice of Golden Lions, all point to point connected, with an instrumentation ground scheme and have that amp sound thin on sudden transients, sharp and murky on midrange tones and loose and thick on Bass, because you used a solid core thin plastic wire for the grounds. It isn't the circuit nor is it the wickedly fast OPT that is causing the poor sonics. It's the lousy ratio of copper wire surface area to dielectric mass in the ground wire. When you go back to Greg's lift those extra ground wires and give a listen. Then go find some true Litz wire, with insulated strands and all, slip it into some shrink tubing that fits closely and replace all of the ground wires in his amp. You will be edumacated bout dielectrics, electrostatic moments of coupling to dielectrics and likely how much surface area to dielectric mass is too much.
Just a thought experiment here, but I do exactly this when an OPT or IT that should be just fine is not. And also when I am faced with modern single sided PCB's, with no poured grounds and poor or zero dielectric on what grounds they have, cd players of all persuasions come to mind.
Bud
Yes!, Greg is gonna rebuild the 245 amp with PROPER wiring, of course, after hearing and understanding the wire-consequences on grounds in a SEer !!Jeff
Ha !!You are really barking up the wrong tree.
Start to read up on Power Supply Iron, and read all my posts specifically on Low DCR, Low C, and Low HY .......... 'cause without it, you are OTL.
Jeff Medwin
it helps makes my box go BANG BOOM! --and I likes that lots.
You likes low 'HY' in your OPT? I'm kinda head scratchin' here...-T.M.
Hi Thomas,To clarify, I was talking about power supply iron, not final output stage iron.
Jeff Medwin
.
When your only solution is a hammer, every problem looks like a nail ;)
But uncalled for.Without the hammer and nail, nothing holds together optimally on music playback. You should TRY it like I just did, rather than post up here without a clue.
The triode amp STARTS with the best possible power supply, err, hammer and nail !!
Respectfully and not ill-intentioned,
Jeff Medwin
Because on July 24, 2006, you wrote *I am really only low DCR experienced.* and per Low C, Low Hy, you wrote: *I think it is not yet time for early adaptors to move, based on forum writings, may take a year or more to sort it out, if ever.*
Hi Ron,That was my truth and my perception seven months ago, but its not accurate now.
I have, since then, accumulated parts to do Low HY, Low C and Low DCR supplies so that I could obtain direct experience. The problem was, I've been busy with work and didn't have a SE amp to experiment with.............'till this past weekend.
Now, I HAVE the direct experimental and listening experience, at last!!
I have a good audio friend in KC, MO area that I amp-mentor named Greg. He has had this 245 SE amp that I help him design, powering his lovely RCA MI-1443 Field Coil high frequency drivers mounted on large RCA 90 by 40 horns, all sitting atop Altec 515 Bs in very large bass reflex boxes.
The system uses my 5687 LINE level passive-biamp at 600 ohms Z, with a Peerless output trannie and Daven bridged T pots and an absolute phase reversal switch mechanism installed. The biamp line-passive crossover point is at 400 HZ. Greg's DIY H.F. amp has two separate supplies, and is a two-stager for transparency sake...a symmetrical Type 76, trannie coupled into a 245 ( globe ).
Our experimenting ONLY encompassed his 245 output stage B+ supply Ron !!
He had been using a multi-tapped Signal Transformer DU1/2 power trannie ( a 500 VA stable monster ) with only about 3 ohms DCR, into four TV damper diodes as a full wave tube bridge. Choke input, L1 was 1/2 of a 8 HY Lundahl choke ( 4 HY @ 18 ohms ). C1 was a 100 uF round oil cap, L2 was a 8 HY Lundahl choke, wired as a CMC choke ( two 4 HY 18 ohm windings as CMC ). C2 was another round 100 uF oil cap, into a Plitron 2.5K or so output trannie.
I performed systematic changes and listened to each change to assess its worth. Everything I did was as a result of my understanding of Low C, Low HY, Low DCR supplies, as I have presented it from others up here in the Forum last year.
The output stage B+ supply I ended up with for friend Greg's amp, was this : ( L1/C1/L2/C2/L3/C3 )
Same Signal 500 VA PT and a 5U4GB hybred Graetz full-wave bridge rectifier, L1 is Triad C-56U, 35 mHY @ .75 ohms DCR @ 2A., C1 is a 10 uF round oil, as used by my first amp mentor, Mr. Fulton of Fulton Musical Industries, L2 was a Triad C-40X, .32 HY @ 10 ohms DCR @ 600 mA., C2 was a 40 uF ASC oil from Michael Percy, L3 is another Triad C-40X, and C3 is another Percy 40 uF ASC. ( I didn't get a chance to apply Mills MRA-12 bleeders after C2, to ground, but its on my to-try-next list ).
Also, since the importance of GROUND wiring in SE amps was fully explained in prior posts, I decided Greg's existing ground wiring was woefully inadequate, so I added TWO sets of paralleled clip leads to EACH run in the triple pi filters, and we both listened to that.
What did it sound like??
Fabulous Ron, one of the best amplifier and system transformations I have ever experienced in 40 years of audio experimenting. The amp played better in EVERY parameter, particulary better in its ability to play dynamics with real freedom that we both loved, and it could untangle difficult simulaneous multi-event musical information in a way that thrilled and almost at times even scared me. It WAS playing like a good audio friend of mine says: " a gated 200 watt amp ", with real gusto, verve, and yet with unbelievably great nuance. I never have had such an easy success in all my years of doing audio. IMHO Ron, this experiment and listening experience has way foreshadowed any "DCR-only" stuff I have done or can recall. This B+ output stage supply....... just had it all.
Net result is Greg and I are very enthused and Greg is going to rebuild his 245 SE amps, from a two chassis stereo 245 SEer with separate power supply chassis and umbillicals, to a pair of mono SEers, with ALL the wiring proper and parts placement intimate and well thought out, as per prior Forum suggestions. Ron, no longer will I use umbillicals in my gear.
Oh, one other BIG BIG BIG improvement came when we significantly dropped the OP-POINT on the 245s so that they more closely reflected a Golden Ratio percentage ( 62% ) of the Manufacturer's suggestions. It went from VERY STRAINED sounding at Manufacturer's suggested op-point, to TOTALLY RELAXED and LUCIOUS sounding, just lovely to hear.
Amazing thing to me was ALL of this we covered on-Forum, last year and maybe early this year. Even though I listened to different changes, the amp really was the sum of ALL that we did and it was certainly synergistic. BTW, on his Altec 515's, we found that the ripple was NOT audible, even though it measured very very high at 1.09 VAC on a Fluke 8060A, so I now think output stage ripple is NOT much a factor at all, ESPECIALLY when compared to the overall sonic benefits we both heard from Low HY, Low C and Low DCR. Really, there was "no contest" as to how good this performed. Pretty cool audio news, eh Ron !!
So, Really, YES !! Thats my report.
Jeff Medwin
Greg and I have since the above report, converted the front end B+ supply of the two Type 76s to a similar Low HY, Low C, Low DCR supply, with excellent overall amplifier results.We have decided to eliminate the small L1 and C1 used in my above post ( 35 uHY and 10 uF oil ), and we settled on simply what remains, as the best-sounding configuration for both supplies. i.e.: L1 is .32 HY at 10 ohms, C1 is 40 uF ASC oil, and it is just the same parts, repeated as L2 / C2.
Not stressed sufficiently in the above report is that we found out, from our listening comparisons with this type of supply, that the wire gauge was critical. We did this experimental configuration with clip leads, and I recalled Dennis saying how important it was for the grounds in a SE amp to be substantial. So, I added, in parallel, a second set of clip leads at every point in the filter system, and it was quite a bit better.We eventually settled upon three clip leads in parallel, until Greg rebuilds it all, losing his umbillicals, into two mono chassis with short heavy wire paths.
Heavy wire from the tube rectifiers forward, through L1/C1/L2/C2, is an absolute necessity to properly hear the benefits of this type of supply!! Its great !! We love it. I owe Dennis a debt of gratitude for sharing this with me, and for allowing me to post it up here publically on the Forum mid-2006.
Jeff Medwin
RuneSimple ...
You like the Audio Note sound then stick with it
Each manufacturer has their priorities in design
And each has their own "sound" if you will
But when you get into this level of quality
the difference is really minimalized
Each has their own flavor
You like Audio Note and can afford them - then use themDanL
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