Hi Tom,
I recently had the pleasure of listening to a recently completed Parallel 86 at a friends house, and was very impressed.
I wonder whether you would consider doing a further run of the boards, or does anyone have a spare pair ?
I would be very interested in building a pair of mono's to drive my Quad 989 ESL's.
I recently had the pleasure of listening to a recently completed Parallel 86 at a friends house, and was very impressed.
I wonder whether you would consider doing a further run of the boards, or does anyone have a spare pair ?
I would be very interested in building a pair of mono's to drive my Quad 989 ESL's.
That is precisely what I think is going on. Also, when separating the two wires, you change the mutual inductance.
Wait?! Are you suggesting a scientific approach? Nah... That would make too much sense.
The mention of science does almost bring us back on topic, though.Tom
...and now we're back on topic. Thank you.
I had two or three "final, ultimate, no really...." runs over the summer and they all sold. Sadly, TI has decided to discontinue the LM4780 used in the Parallel-86. As far as I know, RS is sitting on all the worldwide stock and have 38 left.
I have seen the Parallel-86 boards pop up in the Swap Meet section, so you may have some luck with a WTB post there. You'll probably want to secure your LM4780s before you buy boards, though.
To take the place of the Parallel-86, I will have the Modulus-286 Rev. 1.1 available by Christmas (this year!). The boards are in the fab and should be on my doorstep by December 20th.
The Modulus-286 has two channels of Modulus-86 on one board. There is a resistor option for putting the two channels in parallel. With the two channels in parallel, the prototype measured performance similar to that of the PAR86 except with slightly lower output power - 50 W (8 Ω); 100 W (4 Ω). That's 0.8 dB lower than the PAR86. Sorry...
Each channel by itself performs as well as the Modulus-86 except with slightly lower noise floor.
The Modulus-286 uses surface mounted components. That's the other main difference. The boards will be $149/each. I forget the total BOM cost, but I seem to recall the total build cost being about the same as 2xMOD86.
Tom
I had two or three "final, ultimate, no really...." runs over the summer and they all sold. Sadly, TI has decided to discontinue the LM4780 used in the Parallel-86. As far as I know, RS is sitting on all the worldwide stock and have 38 left.
I have seen the Parallel-86 boards pop up in the Swap Meet section, so you may have some luck with a WTB post there. You'll probably want to secure your LM4780s before you buy boards, though.
To take the place of the Parallel-86, I will have the Modulus-286 Rev. 1.1 available by Christmas (this year!). The boards are in the fab and should be on my doorstep by December 20th.
The Modulus-286 has two channels of Modulus-86 on one board. There is a resistor option for putting the two channels in parallel. With the two channels in parallel, the prototype measured performance similar to that of the PAR86 except with slightly lower output power - 50 W (8 Ω); 100 W (4 Ω). That's 0.8 dB lower than the PAR86. Sorry...
Each channel by itself performs as well as the Modulus-86 except with slightly lower noise floor.
The Modulus-286 uses surface mounted components. That's the other main difference. The boards will be $149/each. I forget the total BOM cost, but I seem to recall the total build cost being about the same as 2xMOD86.
Tom
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And as usual, you don't seem to appreciate the scientific approach and the critical thinking many who frequent this thread apply. You'd think that after a while of this you'd figure out the pattern...
I'll be happy to help you figure out your test setup issues. Just start a thread in a more appropriate forum, for example one of the loudspeaker forums. I'll be happy to participate on your thread there and help out to the extent my time allows.
Tom
And as usual, you don't seem to appreciate the scientific approach and the critical thinking many who frequent this thread apply. You'd think that after a while of this you'd figure out the pattern...
I'll be happy to help you figure out your test setup issues. Just start a thread in a more appropriate forum, for example one of the loudspeaker forums. I'll be happy to participate on your thread there and help out to the extent my time allows.
Tom
Nah, we all appreciate you sticking to blinkers to win the distortion race.[emoji85]
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Maybe not all.
I have spent most of my life listening to distortion, only in the last few years with lower distortion in my system have I enjoyed music more.
That and removing the cabinets from my loudspeakers.
There's also the overwhelming body of research which shows good measurements correlating well with a positive listening experience. For those interested, I suggest looking at Sean Olive and Floyd E Toole's work.
My mission is to ensure that the amplifier is as transparent as possible. I do that by pushing the performance envelope as hard as physics and commonly available parts will allow me. I use measurements to quantify how close to the boundary set by physics I've come and rest assured that if the numbers are sufficiently close to that boundary, the people who build my circuits will be happy. I use industry leading calibrated measurement gear and validate my setups before I post the data.
Others are free to have a different design philosophy or philosophy in general. Above is my philosophy.
Tom
My mission is to ensure that the amplifier is as transparent as possible. I do that by pushing the performance envelope as hard as physics and commonly available parts will allow me. I use measurements to quantify how close to the boundary set by physics I've come and rest assured that if the numbers are sufficiently close to that boundary, the people who build my circuits will be happy. I use industry leading calibrated measurement gear and validate my setups before I post the data.
Others are free to have a different design philosophy or philosophy in general. Above is my philosophy.
Tom
I understand the desire for ultra-low distortion in sources and amplification, but ultimately the transducers which allow us to actually experience the music have distortions in the range of 1% or more for speakers and 0.1% or more for headphones, so why strive for distortions several orders of magnitude lower in the electronics?
If you use an analogue front end that say produces 1% distortion feeding a phono amp and then single ended cables into a pre amp (say another 1% distortion in total) this then goes into your amplifier with say 1% THD.
You could say I only have 1% distortion in my system, or are you up to 3% ?
Because amplifiers boost the signal/apply gain, are they not multiplying the distortion they are being fed, by the distortion factor of the design.
So how much distortion are we feeding our loudspeakers before they add further losses ?
This is why I firmly believe in fully balanced systems including cables and designs with the lowest possible THD.
So Tom has my full blessing to stick with his philosophy of design.
You could say I only have 1% distortion in my system, or are you up to 3% ?
Because amplifiers boost the signal/apply gain, are they not multiplying the distortion they are being fed, by the distortion factor of the design.
So how much distortion are we feeding our loudspeakers before they add further losses ?
This is why I firmly believe in fully balanced systems including cables and designs with the lowest possible THD.
So Tom has my full blessing to stick with his philosophy of design.
the typical THD for speakers is generally around -40dB to -60dB, but at high output SPL of around 90dB to 96dB.
At our normal listening levels the THD is much lower.
But it is more difficult to measure and show on plots.
Considering how easy it is to get sources and line level stages with vanishingly low distortion, I'm not quite sure the additive line of reasoning is really worth pushing to the extreme up to the amp, at least audibility wise.
Imho, once you get at the level of performance offered by an ucd180 (as an example), law of diminishing returns hits hard.
Still, the engineering feat is mighty impressive and I can see why someone would rather go for that extra bit of performance (and peace of mind ), instead of the extra power, for about the same price.
Imho, once you get at the level of performance offered by an ucd180 (as an example), law of diminishing returns hits hard.
Still, the engineering feat is mighty impressive and I can see why someone would rather go for that extra bit of performance (and peace of mind
), instead of the extra power, for about the same price.Considering how easy it is to get sources and line level stages with vanishingly low distortion, I'm not quite sure the additive line of reasoning is really worth pushing to the extreme up to the amp, at least audibility wise.
Imho, once you get at the level of performance offered by an ucd180 (as an example), law of diminishing returns hits hard.
Still, the engineering feat is mighty impressive and I can see why someone would rather go for that extra bit of performance (and peace of mind
Have you tried comparing a UCD with an Ncore? The latter is in a different league. I buy into Tom's philosophy because for the most part it reconciles with my experience. (Objectivism meets subjectivism !). And that's with both amplifiers and speakers - I use the JBL M2s, which Toole and Olive would probably say are at the leading edge of speaker design. However I am at a loss explain why vinyl sounds better than CD to me and why the best SET amps also do something rather special. Some distortion is euphonic is the usual explanation, but I don't think anyone has satisfactorily demonstrated that in any scientific way. So I just accept the dichotomy and enjoy the music.
+1
My own experience is that I rather enjoy playing vinyl through my Mod 86 and conversely I tend to like CDs through my tube gear (push pull, not SET). Not what one would predict. I think to my ears the valve gear "softens" the CDs and Mod "sharpens" LPs, it's all good.