What audio system do you have, or plan on getting?

[AnotherSpin]

Agreed Sergei! We are of one mind.

Thank you, but if I may, a small clarification: two minds sharing the one knowing and understanding of life...

[Harry]

Thank you, but if I may, a small clarification: two minds sharing the one knowing and understanding of life...

Absolutely correct!

[drogulus]

GE 6ca7 tube has arrived, and it sounds very good with my amp. It's marvelous this week.

    I have a sentimental fondness for the 7591/a.

[Fëanor]

...
Some might say: "But it's the Pass X250! That's an excellent amplifier!" And it is — just not the right one for this speaker.
...

Proper matching - I would venture to add one more element, perhaps the most vital of all: a listener poised for discovery, never content to rest on past accomplishments. The point of convergence where all things meet. A marvel, both astonishing and boundless in its potential.

Yeah well I thought my Pass Labs amp was great 'till I got a Purifi 'EIGENTAKT'-based amplifier.

The latter delivered greater detail & transparency, most instruments sound more like the real thing, also deeper, more articulate bass.  (I won't mention that the Purifi device was <1/5 the price of the Pass.)

I have discovered in recent decades that component matching is no trick if you stick to ultra-low distortion devices up & down the chain.

How do you know if a device is "ultra-low distortion"?  Yep, you guessed it.

[Daverz]

Proper matching - I would venture to add one more element, perhaps the most vital of all: a listener poised for discovery, never content to rest on past accomplishments. The point of convergence where all things meet. A marvel, both astonishing and boundless in its potential.


Yeah well I thought my Pass Labs amp was great 'till I got a Purifi 'EIGENTAKT'-based amplifier.

The latter delivered greater detail & transparency, most instruments sound more like the real thing, also deeper, more articulate bass.  (I won't mention that the Purifi device was <1/5 the price of the Pass.)

I have discovered in recent decades that component matching is no trick if you stick to ultra-low distortion devices up & down the chain.

How do you know if a device is "ultra-low distortion"?  Yep, you guessed it.

How much power did the Pass have?

I was never tempted by the Pass Labs stuff.  Too heavy, too hot, much too expensive per watt.  Even if I could afford it, I don't like the aesthetics.  Also, the whole "class A with no feedback is superior" line is just part of an audiophile orthodoxy which seemed to ossify in the 1970s and which has no data to back it up.

[Fëanor]

How much power did the Pass have?

I was never tempted by the Pass Labs stuff.  Too heavy, too hot, much too expensive per watt.  Even if I could afford it, I don't like the aesthetics.  Also, the whole "class A with no feedback is superior" line is just part of an audiophile orthodoxy which seemed to ossify in the 1970s and which has no data to back it up.

The Pass Labs amp I had was the relatively humble X150.5 whose info you can check out HERE.  The X150.5 was class AB, not class A, though it would do 10 watts or so in class A.  It delivered 150 watts  to 8 ohms or 300 to 4 ohms which was what my speakers were at the time.

Nelson Pass believes in low feed back. He insists (still I think) that low feedback produces less high-order, (>3rd order), harmonics which sounds bad.  (There is research that supports high-order sounding bad.)  Pass Labs amps tend to produce not particularly low distortion but it is mostly 2nd or 3rd order harmonics which are benign, even pleasant sounding.

My X150.5 was pleasant sounding, come to that.

However Bruno Putzeys, Purifi designer, argues that while some feedback produces high-order HD, more feedback reduces all sorts of distortion including high-order harmonics.  Effectively if some feedback is a problem, more feedback is the answer.

The Purifi and few other class D and class AB amps prove that Putzeys is correct about lots of feedback, IMO.

[Harry]

Slowly but surely, the system is waking from its collective slumber. Like a cathedral warmed by the first sunrays after winter, the Bricasti components stretch their limbs. The M20, despite its age, benefits from years of demo use — its circuits are already seasoned, though its long storage left it understandably shy at first. The M1 Series 2 DAC is the youngest of the trio in practical terms: just two years old, but with too few hours behind it to be fully expressive. It's improving by the day, especially with chamber works — where timbral nuance, harmonic interplay and inner detail are now emerging with sweetness and poise. The surprise: solo organ music, particularly Bach, sounds unusually right — weighty, reverberant, even majestic at times.

But orchestral material reveals its limitations in current state. Dense tuttis can trigger stress — upper midrange glare, and treble sharpness that veers into discomfort. The DAC still hesitates when parsing complex passages — not for lack of capability, but from lack of experience, so to speak. And here the M15 amplifier, while beautifully refined, may be reaching its natural ceiling. Its intimacy and low-level resolution are admirable, but when the music demands scale, slam, or dynamic propulsion — particularly in large orchestral scores — it strains to deliver. The M25, with its dual mono architecture and greater current reserves, may well be the answer. But only once the front end has fully come into bloom. Until then, I listen, wait, and mark the progress — step by careful step — toward the sound I know is there, just waiting for time and warmth to coax it into being.

[drogulus]

[Kalevala]

Slowly but surely, the system is waking from its collective slumber. Like a cathedral warmed by the first sunrays after winter, the Bricasti components stretch their limbs. The M20, despite its age, benefits from years of demo use — its circuits are already seasoned, though its long storage left it understandably shy at first. The M1 Series 2 DAC is the youngest of the trio in practical terms: just two years old, but with too few hours behind it to be fully expressive. It's improving by the day, especially with chamber works — where timbral nuance, harmonic interplay and inner detail are now emerging with sweetness and poise. The surprise: solo organ music, particularly Bach, sounds unusually right — weighty, reverberant, even majestic at times.

But orchestral material reveals its limitations in current state. Dense tuttis can trigger stress — upper midrange glare, and treble sharpness that veers into discomfort. The DAC still hesitates when parsing complex passages — not for lack of capability, but from lack of experience, so to speak. And here the M15 amplifier, while beautifully refined, may be reaching its natural ceiling. Its intimacy and low-level resolution are admirable, but when the music demands scale, slam, or dynamic propulsion — particularly in large orchestral scores — it strains to deliver. The M25, with its dual mono architecture and greater current reserves, may well be the answer. But only once the front end has fully come into bloom. Until then, I listen, wait, and mark the progress — step by careful step — toward the sound I know is there, just waiting for time and warmth to coax it into being.

Whatever works for you and makes you happy. 

All the best,

K

[Irons]

GE 6ca7 tube has arrived, and it sounds very good with my amp. It's marvelous this week.

Nice. A NOS tube? More commonly known as EL34 in UK, a tube/valve that packs a punch unlike many other flea-powered tubes.

[Dry Brett Kavanaugh]

Nice. A NOS tube? More commonly known as EL34 in UK, a tube/valve that packs a punch unlike many other flea-powered tubes.

The tube was used by approximately 40 percent. Someday I want to have Mullard and Phillips EL34s.

[Irons]

The tube was used by approximately 40 percent. Someday I want to have Mullard and Phillips EL34s.

I had a a peek where I purchase my tubes. EL34s are not cheap!

https://www.ebay.co.uk/sch/i.html?_nkw=el34+valve&_sacat=0&_from=R40&_trksid=p2334524.m570.l1311

[drogulus]

Nice. A NOS tube? More commonly known as EL34 in UK, a tube/valve that packs a punch unlike many other flea-powered tubes.

    It was a common replacement for the EL34 though it's a tetrode while the EL34 is a pentode. The 6CA7 is more closely related to the 6L6GC and sounds like one in a guitar amp.

[Dry Brett Kavanaugh]

I don't know for sure but heard that Americans started to make 6CA7 because EL34 had a patent protecting it.

[Irons]

It was a common replacement for the EL34 though it's a tetrode while the EL34 is a pentode. The 6CA7 is more closely related to the 6L6GC and sounds like one in a guitar amp.

Thanks. I understood that 6CA7 and EL34 were interchangeable. Tubes are big business, if not bigger, for guitar amps.

[drogulus]

I don't know for sure but heard that Americans started to make 6CA7 because EL34 had a patent protecting it.

    The quality of EL34s declined in the '70s and has never really recovered. My brother worked at Unicord in Westbury, NY in the early '70s and at some point they started subbing 6550s for EL34s in Marshalls because of all the failures. Unicord was the US distributor for Marshall back then.
 
    We brought home a Superlead that was supposed to go to Hendrix and put KT88s in it. It put out 140 RMS watts!

    The 6CA7 is a better sub than a 6550. There were lots of complaints about the 6550 back in the day.