[Ferbose]

Quote:

Originally Posted by adhoc AFAIK actually both tubes work a little more than half cycle apiece, and then their results are 'superimposed' on each other. in other words, the 'push' overlaps the 'pull' to some extent and vice versa.

I see.
So for small signals it is class A push-pull.
Is class A push-pull possible without output transformers?
I have never heard of class A push-pull solid state.

 

[adhoc]

Quote:

Originally Posted by Ferbose I see. So for small signals it is class A push-pull. Is class A push-pull possible without output transformers? I have never heard of class A push-pull solid state.

i am still quite new to electronics, and as we all know, it is not knowledge that is dangerous - it is a little knowledge. i'll try my best anyhow. all AFAIK.

yes - it is possible with OTL topologies.

but why would you want to do that? valves rarely can drive low impedance loads by themselves, and the attempts to rectify this imply the consequential use of (exotic) valves that were never designed for audio use is usually neccesary.

 

[SV_huMMer]

Quote:

Originally Posted by Ferbose As a follow up, I recently got JAN GE 5670 and Russian 6N3P-EV (military spec, low noise). 6N3P-EV has the lowest noise of all the 2C51 I've tried. It is very accurate sounding, a great tube for hi-fi. JAN GE 5670 has the a similar noise level as Chinese 6N3, but is significantly warmer. It does not have the accuracy of 6N3P-EV, but I prefer its warmth with K1000. In fact, the GE tube will probably be too warm and too euphonic in other systems but I prefer it for now.

Could only second that! My Laconic amp uses military gtrade 6N3P-EV, and it's really noiseless. No wonder, if you think about the primary use these tubes were intended for!

 

[Ferbose]

Quote:

Originally Posted by SV_huMMer Could only second that! My Laconic amp uses military gtrade 6N3P-EV, and it's really noiseless. No wonder, if you think about the primary use these tubes were intended for!

Now I am using Electro Harmonix EL84, and I am surprised that they extract out significantly ambience information compared to JJ. I plug my K1000 directly into DAC1 and don't hear that much ambience, and using EH EL84 seems to extract out a good amount of ambience from nowhere. This is quite puzzling but very pleasant to the ears. With the EH EL84, I now prefer 6N3P-EV over GE JAN 5670, due to clarity. Tuberolling is a lot of fun and in my limited experience the key seems to be cahracter and synergy rather than hunting down expensive, exotic tubes. It is also good ear-training to differentiate the differences between tubes

 

[creeky]

Sorry to revive a dead thread but I have a question!

I recently took a chance and brought a similar amp to the one you have brought (Yarland FVCIII)

The amplifier sounds great but I have one worry though the chassi gets very warm almost on the verge of being hot. As you have a very similar amp I just wanted to know if your amp also gets quite warm. My main concern is the power transformer being a different spec as the voltage for china is 220V 60Hz compared to the 230v 50Hz we have in the UK (Both the voltage increase and lower frequency can cause problems)

Thanks

Kris

 

[Ferbose]

Quote:

Originally Posted by creeky As you have a very similar amp I just wanted to know if your amp also gets quite warm. My main concern is the power transformer being a different spec as the voltage for china is 220V 60Hz compared to the 230v 50Hz we have in the UK (Both the voltage increase and lower frequency can cause problems)

My amp runs very warm. I think the power transformer heats up in addition to the tubes.

 

[creeky]

Quote:

Originally Posted by Ferbose My amp runs very warm. I think the power transformer heats up in addition to the tubes.

Ah ok thanks very much for your help

Cheers

Kris

 

[mojorisin676]

So if I was to use my Grado SR 225's on this amp (which I already purchased), would it even be better than my LDII because according to the review that low-impedance headphones will produce an altered frequency and a hum? Have I made a bad buy? I always thought that Grado's needed a lot of power to be driven perfectly...

 

[Ferbose]

Quote:

Originally Posted by mojorisin676 So if I was to use my Grado SR 225's on this amp (which I already purchased), would it even be better than my LDII because according to the review that low-impedance headphones will produce an altered frequency and a hum? Have I made a bad buy? I always thought that Grado's needed a lot of power to be driven perfectly...

Based on my experience it would not work too well with Grado.
But there may be unit-to-unit variations as well.
Grados need little power to drive, since all of them allow for portable use.
As for "perfect," I have little experience in this area.
If there is a headpnone that requires this much power, it is K1000.

 

[mojorisin676]

Quote:

Originally Posted by Ferbose Based on my experience it would not work too well with Grado. But there may be unit-to-unit variations as well. Grados need little power to drive, since all of them allow for portable use. As for "perfect," I have little experience in this area. If there is a headpnone that requires this much power, it is K1000.

You are probably correct, I just heard somewhere on head-fi that they needed to be driven with enough power to pack a real "punch"...O well...I hope that when it arrives I am not completely dissapointed

 

[haziz]

As I am typing this Johnny Hartman and John Coltrane are doing a private gig in my living room, courtesy of the Sophia Electric Baby driving Merlin VSM Millennium speakers ($6000-8000 new, fortunately purchased used). I actually prefer it significantly more compared to a $4000 dual 300B SET amp (18W/channel) I also own. The Merlin VSM speakers are usually driven by a Manley Stingray integrated amp (EL84x4 per channel), unfortunately the Stingray broke down last week and needs repair. The sound from the Stingray is very similar in character though it can go louder, as it should since it puts out 40-50W per channel. I would probably push the Sophia Electric to it's limits if I put on a Tchaikovsky Symphony with the VSMs (88 dB/W/m, 8 Ohms) and expect concert hall volumes, though I have used it for symphonic music and pop at reasonable volumes. The Sophia Electric is usually used to drive my AKG K1000s otherwise. The Sophia amp has a lively, occasionally slightly brash, but not bright presentation that I find very appealing. The midrange is sweet and slightly warm, but not excessively “tubey” or tubby.

The original poster/reviewer sounded slightly envious of the Sophia Electric Baby. Interestingly I have a reverse envy eyeing an amp that uses the much more ubiquitous EL84 tubes, moreover owning the Stingray, I have EL84s from 3 manufacturers at home that I can use for tube rolling. The Sophia Electric Baby appears to restrict you to Russian military 6P1T tubes, which seem to have only one (possibly two, there may be a Chinese manufacturer) source/manufacturer. I did some research and as best as I can tell the 6P1T internally is very similar electrically to an EL90 but uses a very different 9 pin (as opposed to 7 pin) base. They may be the same as the 6P1P/6P1P-EV tube. I have not compared the Sophia Electric Baby to the Yarland EL84 based version or for that matter the Yarland/Aria/Whatever labeled version using the 6P1T tubes, which I assume is the same amp as the Sophia Electric. For all I know the 6P1T may be superior!? Somebody should try to do a head to head comparison if he or she can get their hands on both versions.

Pricing of the Sophia Electric Baby appears to be all over the map. I bought it ostensibly used (thru Audiogon) but on arrival it appeared to be in new condition. I suspect there is a good degree of markup in the importation but it should be possible to get it at a significant discount. This is entirely unsubstantiated since I have not done any shopping for a new unit through a dealer.

Regardless, this is one mighty fine amp. Anybody looking for a tube amp for efficient speakers or difficult headphones needing a "speaker level" output should not hesitate because of the price.

Sincerely,

Hany.