Hey Bonzo - would please supply some more info on the GM 70 amp. If its good I don't care about resale value - I do care about the quality of the parts that make up the amp - thank you...
SET amp owners thread
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Hey Bonzo - would please supply some more info on the GM 70 amp. If its good I don't care about resale value - I do care about the quality of the parts that make up the amp - thank you...
From past experience with high sensitivity horns, the low powered SETs sound more pure and immediate. It even matters the number of gain stages the SET amplifier has. If the speaker is sensitive enough, this can clearly be heard.
Push pull amps, even low powered ones, do not sound anywhere near the purity of SET. They may provide more headroom (again, depending on sensitivity and ease of drive), but they sound veiled and congested compared to good SET designs.
I also tried in the past low powered solid state amps (e.g. First Watt), they do not have the purity of tube SETs and still sound solid state, even though many “reviews” state otherwise.
All is in my experience.
This is from a decade+ ago when I owned high efficiency speakers.
Push pull amps, even low powered ones, do not sound anywhere near the purity of SET. They may provide more headroom (again, depending on sensitivity and ease of drive), but they sound veiled and congested compared to good SET designs.
I also tried in the past low powered solid state amps (e.g. First Watt), they do not have the purity of tube SETs and still sound solid state, even though many “reviews” state otherwise.
All is in my experience.
This is from a decade+ ago when I owned high efficiency speakers.
Nothing has significantly changed. Lately, I have come down strongly in favor of interstage coupled amps…when there is more than one stage that is
. My previous AC amps, this small 2A3 amp I got from Silvercore and now a Russian 520b amp from NEM. All sound better than the amps I have had that were cap or direct coupled between stages. I recently was at a friend’s who bought a demo model Diana Integrated amp from AC. It sounded glorious on his Odeon 32s.Hi
We use the E130L, a tube with extremely low internal resistance (several times lower than say a 300B and magnitudes lower than a 845 for example) and great linearity. Of course the trick is the NOIES which takes this into next level. One tube per channel, and one for the NOIES stage. -80db distortion at 1W and -60db until clipping without NFB of course. Single stage, single ended.
Not for everybody(low watt) and low input impedance/low gain. Needs a good preamp to kick it.
Cheers
I've been running high efficiency speakers about about 28 years. My experience is the opposite of yours in that a low powered PP amp is easily more transparent, more resolving and overall more musical than SETs made of the same power tubes or SETs of the same power.
But so much depends on design and execution variables! If you've not heard all that's out there, if your list of amps for comparison is relatively short then its very easy to have committed a logical fallacy of small sample size. Obviously that argument can be turned around; that I might not have heard the right SET yet. In that regard we've had about 20-25 SETs come through the shop for various reasons. Some are pretty good and some are downright bad but so far that magical amp hasn't shown up.
The data sheet suggests this tube is meant for television sweep service, but can be used as an audio output tube too. I assume you have it wired in triode?
Yes- they are 16 Ohms.
Any output transformer that has a 16 Ohm tap is more efficient driving that than any other tap. When you go to lower impedance taps, especially 4 Ohms, you can lose up to an octave of bandwidth off the bottom end. That is something no tube amp can afford to lose.
IOW if you want the most out of your tube amplifier investment 16 Ohms is the way to go. It was a lot more common when I first started in audio back in the early 70s. Even 8 Ohm speakers are harder to find these days.
My 18 W SET amplifiers drive 105 dB 16 ohm speakers. I figure I may use about 10% of the rated output when I turn the volume way up.
That is the way to do it. The next thing to could be to to find out what you experience if you prevent bass getting into the amp. You'll need a subwoofer to do that properly so the there's no lack of bass trying this. All you need to keep bass out of the amp is a small enough capacitor at its input of the right value. If you look at the thread on Ron's system you'll see this is something he's working on.
Our shop speakers are 16 Ohms and also 8 Ohms. Some of the SETs did and some did not.
Thank you Ralph, but I do not want to hook up my other pair of ML2s to drive subs in this room. I do not know what I might experience, but I have no curiosity really as I am very satisfied with the performance as is.
Yes, of course. Vladimir Lamm told my dealer David Karmeli that the ideal speaker for his ML2 amps is the early version late 1950s Vitavox CN-191. The speakers were not easy to find. I bought both the amps and the speakers after hearing the combination.
Did you have the capacitors in the crossovers replaced? Its hard to imagine they would still be good after nearly 60 years.
That’s a question for David Karmeli. He gave them a thorough inspection before shipping them to me.
Why so coy, Peter? It's a bit difficult to believe that you don't know the answer to Ralph's question.
David posted:
I'm not endorsing anything Francisco and personally wouldn't modify vintage speakers or buy one that is modified. It's not because that there isn't room for improvement but because there aren't many people out there competent enough to holistically improve the overall sound without butchering it. I don't have that knowledge either but if I could get Vladimir Lamm staying with me for a few months I'd consider modifying Bionor's crossovers!
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I think David either is skeptical about replacing capacitors in vintage loudspeakers, or has a policy of not replacing capacitors in vintage loudspeakers.
Are you remotely serious here ? As a previous Vitavox CN-191 owner myself I do not know whether to laugh or … laugh harder at this utter BS fable , I actually feel quite sorry for you Peter that your entire musical fidelity world seems to revolve around this construct that you were sold by Karmeli .
He later changed this as he modified Tang’s Eurodyn. That was the first speaker he modified. I am for modifying all vintage speakers
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