Hiraga Le Monstre

[sq225917]

It's a perfect example that preference barely correlates with measured performance. Lets be honest once you get past -80db unless the noise or distortion is a real zinger in one tight frequency most people probably can't spot it.

Beyond a certain point its a numbers game only.

 

[russel]

I couldn't give a flying ****. I AM a rude condescending know it all... and after spending a lifetime at this and becoming one of the best amp designers around..

Designing a great sounding amplifier is easy, there are plenty on diyaudio and here that can do that, the tricky part is getting the cost down which is largely irrelevant for diy.

 

[anubisgrau]

I've built at least 2 of his preamps and an Aleph 5 (which Nelson says is like a 3 with a bit more grunt). IMO they are all at the unsatisfactory end of the subjective scale.
Many of his articles are just him reinventing the wheel, or a wheel-like object that does the same job as a wheel.

Then again, I'm in the minority in not liking coffee.

You dislike Pass stuff? Welcome to the club.

 

[Dan K]

Have a look here:
https://www.transcendentsound.com/pinnacle.html

Sounds stunning (with the right speakers) and something like 0.5%THD at 6W

Note that the harmonic distortion has been presented at 500Hz and not the industry std of 1kHz. I wonder why?

Obviously has tons of feedback. Local, global etc and is PP. That's the price you have to pay, along with negligible output for deleating the output transformers.

 

[Dan K]

Resistors arrived to replace the DC offset pot and intention was to also replace the 2x 1K resistors with variable pots, allowing adjustable bias. I was expecting to be able to adjust the offset via these pots, this is not the case. I should have read the following more carefully:

https://sound-au.com/tcaas/monster27.htm

I only need to adjust one of the 1K pots (up or down) to set the bias for that board. I could simply set one of them at 560R and adjust the other by itself.

Is there any advantage to keeping the +/- resistances equal, given that the whole thing balances out anyway? This has no effect on DC offset.

Every day's a school day

 

[iansr]

I might be wrong, but I don't think it's quite so straightforward. THD is an RSS value obtained from the 1st to 6th order harmonics based on a 1kHz input signal. Even order harmonics occur in nature and are perceived as echoes. Valve amps can often have a very large (dominant) 2nd order harmonic which may result in a high THD, but the other harmonics might be low. I have a pair of Transcendent Pinnacles that sound absolutely gorgeous and supposidly have a measured THD of '<0.5%'

Another issue I have with THD is that it's usually only measured at 1kHz when music isn't a single tone. I do suspect there are plenty of amps out there that measure amazingly at 1kHz, but terribly at say 3, 6, 10k etc. I'm not a fan of ASR with regard to this.

There are many serial amp builders and designers on DIYA who are of the view that THD is not a predictor of how good an amp will sound (assuming its below a reasonable figure) but that its the profile of the harmonics that counts; specifically that the 2nd harmonic should be dominant and that the higher order harmonics should taper away. I’ve read that Hiraga was also of this view based on his own informal research. And yeah, there’s not much science going on at ASR . . .