Transformer coupled / Capacitor coupled


Just a question from my curiosity. I remember someone recently mentioned here that capacitor coupled pre-amp sounds better and is more expensive and rare, than transformer coupled ones. Could someone elaborate, as to the difference of those two and how each design works and why either sounds better? Thank you!
khokugo

Showing 6 responses by jcaudio

THE THREAD ACTUALLY STATED THE OPPOSITE! Most manufacturers utilize capacitor coupling. Very few use transformer coupling as it is expensive and time consuming.
The most unusual feature is line output stage, which is configured as a small power amplifier stage with a 5687WB double triode per channel. An output transformer is then coupled to the output signal which serves as an interface to the power amp being used. This allows the pre-amp to utilize not only two sets of single ended RCA outputs but also a 600 Ohm fully balanced output using a Lemo type connector. This unique way of transformer coupling the output stage means that the pre-amp can be used with any power amplifier whether valve or transistor.

Transformer coupled pre-amps are much more expensive but in all the shootouts we have done here are much better. I have attached one of those posts where a passive device (several) were compared to transformer coupled pre's. In addition we have done shootouts with pre-amps that were capacitor coupled costing as much as $15,000. always with the same result.

Why do the Audio Note preamps sound so much better
I took Joe over at JC Audio up on the offer of a shoot out. Actually it was the second time. About nine months ago I went over and had a shoot out between my EVS Nude Attenuators and the Kora triode preamp. I have to give Joe credit he agreed if you could live with the inconvenience and lack of flexibility that the EVS attenuators sounded as good.

But I made a bad mistake today. I went over and did the same shoot out with the Audio Note M5. I should have never done this. The M5 made the attenuators sound dry and lifeless. The M5 sounded prettier with much more top in extension without ever sounding bright. It was more transparent and fuller bodied at the same time. And the layering and the soundstageing was just beautiful. This is disturbing to me for I have been a big proponent of passive, especially the attenuators since you even eliminate a set of interconnects and a power cord. Why does this line stage sound so much better.
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08-02-02



Responses
08-02-02: [email protected]
Dear Bilbondo,

Why??

Quite simple, in the M5 (and all our other transformer coupled pre-amplifiers, the M3, M6 and M8), there are no impedance mismatches, there is more than sufficient gain to maintain the dynamic envelope of the signal intact combined with a natural (meaning not created artificially by feedback or other trickery!) drive impedance so low as to render the load (the power amplifier input) irrelevant.

The disadvantage is cost, you heard for yourself the sonic advantage.

Sincerely,
Peter Qvortrup

You could not do transformer passive. That is impossible by the very nature in how it works. There are many tube pre-amps but most only use capacitor coupling. This makes impedance matching to the amplifier Sorry
Interesting article. Learn something new every day. Unless I'm reading this wrong you still have some impedance issues. Is this correct?
Interesting article. Learn something new every day. Unless I'm reading this wrong you still have some impedance issues. Is this correct?
The issue is more than just impedance. As capacitors drain during dynamic passages you will hear it as strained or harsh sounding. In addition, many manufactureres use cheap capacitors. That being said even the best have a sonic signature. I will include the post here for you.

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Why do the Audio Note preamps sound so much better
I took Joe over at JC Audio up on the offer of a shoot out. Actually it was the second time. About nine months ago I went over and had a shoot out between my EVS Nude Attenuators and the Kora triode preamp. I have to give Joe credit he agreed if you could live with the inconvenience and lack of flexibility that the EVS attenuators sounded as good.

But I made a bad mistake today. I went over and did the same shoot out with the Audio Note M5. I should have never done this. The M5 made the attenuators sound dry and lifeless. The M5 sounded prettier with much more top in extension without ever sounding bright. It was more transparent and fuller bodied at the same time. And the layering and the soundstageing was just beautiful. This is disturbing to me for I have been a big proponent of passive, especially the attenuators since you even eliminate a set of interconnects and a power cord. Why does this line stage sound so much better.
[email protected]

08-02-02



Responses
08-02-02: [email protected]
Dear Bilbondo,

Why??

Quite simple, in the M5 (and all our other transformer coupled pre-amplifiers, the M3, M6 and M8), there are no impedance mismatches, there is more than sufficient gain to maintain the dynamic envelope of the signal intact combined with a natural (meaning not created artificially by feedback or other trickery!) drive impedance so low as to render the load (the power amplifier input) irrelevant.

The disadvantage is cost, you heard for yourself the sonic advantage.

Sincerely,
Peter Qvortrup
[email protected]

08-02-02: Rcprince
Some will call it tube colorations; it's the classic music vs. accuracy debate. FWIW, I have always preferred components which deliver a realistic reproduction of what I think the recorded performance/musical event sounded like rather than what the master tape sounds like; after all, if you listen to performances from Row J in the orchestra section of a concert hall it'll sound quite different than what you'd hear if you sat where most microphones are placed. I think my Jadis preamp falls in that category, and perhaps the Audio Note does as well.
Rcprince (Answers)

08-02-02: Trelja
Rcprince hit the nail on the head. As usual.

I am a huge fan of Audio Note. No, it is not cheap. But, like Jadis, I believe it offers REAL value. That is because it is one of the few marques that can be considered a last purchase. The purchase is made, the component is inserted, and it is simply enjoyed. Hour upon hour, year after year. They are not for audiophiles so much as music lovers. They are not meant to impress in terms of calling attention to themselves. They are components who want music to sound like music; real, natural, organic.

To my love for the components of Audio Note and Jadis, I have also found the same thing true of my Blue Circle preamp. Just as Peter described of the AN, I have found in the BC preamp. I doubt I will ever sell my Jadis or Blue Circle components, they are lifetime companions. And, one day, I will also own an Audio Note pre or power amp.
Trelja (Threads | Answers)

08-03-02: Jcaudio
I would like to thank those members who took the time to take me up on a shootout between passive devices and transformer coupled pre-amps. Thanks again
JC Audio (Threads | Answers)

08-03-02: Jdubusc
I will concede from the outset that I have a bias, forgive the play on words, for I am an AN owner. The point I wish to make is regarding my experience with two passive preamps: the EVS attenuators and the Placette passive preamp. IMHO, I found them both to be anemic, profoundly anemic, as compared to my Audio Note M-5. The differences were not subtle! Good Listening, Jim.
Jdubusc (Answers)





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Clueless,
I believe per the article that the transformer application he is attempting is in a passive device. I think that is why the active transformer coupled pre's don't have that issue. They are 600 ohm instead of the 50k or 100k many actives use. We drive not only a variety of tube amps but the Gamut solid state which has 10k ohm active balanced curcuit with unbelievable authority and resolution. This amp is in stark contrast to the tube amps we drive with input impedance numbers as high as 100-150k. Wide range for a single pre do be able to handle such extremes with no loss of any musical content. His article points out the very reasons passive devices cannot compete in most real world situations. Thanks again for the heads up. I like to stay current on all this cool stuff. Wish you were local. You could attend one of our shootouts:)