Fair enough, but please put that in the context of an audio amp. Does that make this amp unique, or is it just a fancy smoke screen to talk over the heads of non-EE audiophiles? I'd suspect the latter.
From what I can tell, reactive current does not contribute to any power, so it seems it is pure waste. How can a 4 ohm speaker "require" reactive current? I don't get it. Seems like a non-feature if true , and complete word salad if not.
As the output level goes +ve the speaker inductance takes reactive current as well as resistive current.
As it goes back -ve to zero it has to take back in the reactive current it sent out as the voltage across the inductor reverses.
As it goes back -ve to zero it has to take back in the reactive current it sent out as the voltage across the inductor reverses.
Reactive currents relate to the power stage capability. Especially if the speaker features a passive xover network with significant millihenries and microfarads, it requires the power stage to provide current that isn't necessarily in phase with the voltage. This means some challenge wrt the devices' SOAR.
Best regards!
Best regards!
I have successfully built a kitset amp previously and spent lots of time installing better quality components and listening for improvements. I also spend a fair amount of time repairing failed amps that I own - see my other threads; DIYAUDIO has been awesome for suport! - but a scratch-build amp feels way beyond my capability and resources.
(Sadly, I don't even have access to a drill press...)
Hence the reason I was looking for a kitset power amp like the TRANSCENDENT SOUND BRUISER.
I also think power tube replacement cost is a big consideration, so two KT88/KT120 per channel is acceptable, IMHO.
(I don't even consider 300B or 211/805 designs for cost reasons...)
I agree that the BRUISER is a plain-jane kitset that needs some aesthetic titivating - OPT covers, etc. - but those things are manageable from my end.
For $US1300 - $US2500 I don't know of too many other kitset power amp options out there that will deliver (around) 35W into our 4R speakers.
Has anyone got any better suggestions?
I haven't read the whole thread but just noticed that the first page 500Hz FFT shows about 4% distortion, not 'just under 1%' as it says. Not sure how important it is, just thought I'd mentioned it.
Jan
Jan
Some speakers can be very non-resistive around the resonances, so that they look capacitive or inductive - the amp has to handle this. Check out speaker impedance plots to learn more.
What speakers? Their impedance curve speaks directly to whether this amp is suitable or not.
And we need to know to be able to suggest a suitable amplifier.
dave
I’d probably look at the smaller amp, and use 6CA7s. But again, we need to know what speaker?
dave
The fact is that we have a bunch of favourite older speakers that fall into the (approx.) 19L / 4R (min dip) 90dB camp. Sorry, no measurements available.
If we were to buy a new speaker, something like the ATC SCM11 or the bigger ATC SCM19 would be on the cards - depending upon the room size at that time.
Given that (I understand) the ATC SCM19 is the more difficult of the two speakers to drive, I have provided measurements below.
So the question now becomes: How would the TRANSCENDENT SOUND BRUISER fare, driving the ATC SCM19 (V2) loudspeaker?
Listening Habits Note: We do a lot of late night listening. We are not interested in rocking the neighbourhood, but occasionally like to let our hair down. Music ranges from CLASSICAL to ELECTRONICA and everything in-between.
I hope this information helps to answer the questions I have about the new kitset TRANSCENDENT SOUND BRUISER amp - and big ups to AVMENTOR.NET for their very thorough measurements of the ATC SCM19... ATC SCM19 | Review Lab Evaluation - AVMENTOR.net
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With the Bruiser you will likely not have the electrical damping you need with that large a resonant peak. The rest of the spectrum is fairly flat but there will be a bump up at just above 1kHz. It might just counter the trough in the measured FR.
You might well have to push your boxes toward aperiodic to kill that resonant peak.
dave
Jeff, I'm not too obsessed about running KT120s - but BRUCE ROZENBLIT has stated how very impressed he is with this new build tube (Bruce is a hard guy to impress...) so I figured his TRANSCENDENT SOUND KT120 BRUISER amp was a good place to start. Hence the title of this thread.
Frankly, I'm just keen to get the right amp for the job - with tubes that don't cost a fortune to replace.
If I understand your comments below correctly, you are suggesting that the BOB LATINO TUBE4HIFI amp that runs 6CA7 (EL34) tubes, might be a better bet for us - dependant upon the choice of loudspeaker.
Anyways, I'm giving it a look... I confess that the exposed electronics on the front of the TUBES4HIFI amps won't win favour with my wife...
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You have to choose, your wife or the amplifier.
Seriously, you could put a cage over it....
I find with my kt120 amp the most difference was with output transformers. Nothing can explain how better the sound is now.
I always liked tube amps, they do have a better texture and smoothness. It comes with a so so transparency vs the high power transistor amps which have more boldness, more inner detail and a dead brutal sound to resume fast.
With new transformers, the sound just stayed the same tube sound, it didn't gained a see through detail quality like the solid state have...
what it did was to bring all the texture and organic quality to intelligible resolution. It means that each texture could be associated to a specific instrument, singer voice, background etc.
I always thought the amp to be like 20% or less of the sound, until this happened which challenged everything I thought possible.
A good tube amp is giving you a superb sound stage, lot of things to see in 3d, a superb realism etc. A good tube amp with an exceptional output transformer will give you God ears.
Seriously, you could put a cage over it....
I find with my kt120 amp the most difference was with output transformers. Nothing can explain how better the sound is now.
I always liked tube amps, they do have a better texture and smoothness. It comes with a so so transparency vs the high power transistor amps which have more boldness, more inner detail and a dead brutal sound to resume fast.
With new transformers, the sound just stayed the same tube sound, it didn't gained a see through detail quality like the solid state have...
what it did was to bring all the texture and organic quality to intelligible resolution. It means that each texture could be associated to a specific instrument, singer voice, background etc.
I always thought the amp to be like 20% or less of the sound, until this happened which challenged everything I thought possible.
A good tube amp is giving you a superb sound stage, lot of things to see in 3d, a superb realism etc. A good tube amp with an exceptional output transformer will give you God ears.
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OK, I get that. But we have to take the designer's word for the fact the typology used in the Bruiser is somehow unique and superior to any other tube amp. Hard pill to swallow without a schematic, which he is not providing on the sales page. All in all, seems the sales page is not intended for the knowledgeable type of customer. In fact, the entire site is full of lofty promises and audiofool phrased:
Hand me a bucket...
This rings very true to me. It was true when I was in search of the right SUT for my analog rig, so why would an amp OPT be any less impacting on the final sound?
Good point, well made.
(BTW, I ended up with a very nice AUDITORIUM23 SUT, but that's a whole other story... 😀 )
Agreed. Bruce Rozenblit is no marketing man. The TRANSCENDENT SOUND website leaves a lot to be desired.
That said, what is not so obvious on a casual visit to the TRANSCENDENT SOUND website - until you spend some time in the site's support forum - is: -
* The number of hugely knowledgeable EE-types that regularly contribute
* The very high level of admiration and respect that those same customers have for the TRANSCENDENT SOUND designs and the products they have built.
Back in 2006, one of the TRANSCENDENT SOUND early OTL designs actually got professionally reviewed in STEREOPHILE - by Jonathan Scull, no less - who was clearly "enchanted" by the amp he sampled.
Read more at Transcendent T8 OTL monoblock power amplifier | Stereophile.com
Transcendent T8 OTL monoblock power amplifier | Stereophile.com
As a past TRANSCENDENT SOUND customer myself - GROUNDED GRID and (Original) SE-OTL - I am loath to dismiss any of Bruce's designs, despite the cringeworthy marketing hype on his site.
All food for thought.
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Thank you!
Transcendent doesn't tell much about the amp design... other than it has 5db feedback, designed for working in triode so you lose a lot of what the kt120 has to offer, has some good driver tube in LTP probably, low noise from the toroid power.
It could be interesting to see the schematic, nonetheless, at the price it is a steal.
The effect of the highR can be looked at as bump up in the Qt so the box Q will move up. Or that as the impedance rises so does the output power creating a peak. Same thing. Boomy bass.
Adding aperiodic ducting on the back and appropriate damping can lower the resonance peak.
dave