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Old 21st April 2003, 02:37 PM   #1101
Join Date: Mar 2003
Location: Lisbon, Portugal
You didn't understand what Peter Daniel meant.
I did.
When you really like the music, and it's well recorded, and, better still, the system makes it justice, you just want to tap your feet and groove on!
But unfortunately some systems are sleep-inducing.
As an example, a friend of mine took his cd player to my home (a Rega Planet 2000), because he didn't believe in the capabilities of my tweaked Audio Alchemy DDE v3.0 Dac (regulated PSU made by myself, OPA627s...).
Of course my dac trashed the humble Rega, the man (an audiophile) didn't believe what he was hearing from my dac.
It was an A-B test with the planet working also as a transport.
I almost slept hearing Ben Harper on the Planet.
Definitely not for me.
It kills good (and well recorded) music.
Doesn't offend, in fact, but doesn't have dynamics and resolution.
I'm puzzled about the rave reviews in the magazines.
Oh, I even opened it!
It has a 22-pin Sanyo op-amp!!?
And very fiddly construction.
Weird animal...
Old 21st April 2003, 02:44 PM   #1102
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Au contraire, I understood exactly what Peter meant. I just disagree.
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
Old 21st April 2003, 02:44 PM   #1103
Join Date: Mar 2003
Location: Lisbon, Portugal
Talking nw, please show up...

... and bring the bottle.
Old 21st April 2003, 02:48 PM   #1104
Join Date: Mar 2003
Location: Lisbon, Portugal
Unhappy Ok, SY...

After reading my post you say simply that...
Oh, well...
Just as I told to nw, it's useless, I feel like praying in the desert!
Old 21st April 2003, 02:50 PM   #1105
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Default Re: Gain Clone Madness ?

Originally posted by mrfeedback

There is muscicality, and then there is precision, and they can be two different beasts, and the two are not mutually excusive.
It has all precision I ever wanted and I don't think it's distortion that make it sound good. I just prefer it with less caps. And I'm not alone in that opinion.
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
Old 21st April 2003, 03:25 PM   #1106
Join Date: Mar 2003
Location: Lisbon, Portugal
Talking Talking about caps...

Hi Peter Daniel,

Talking about caps, on your Gainclones have you tried to bypass with smaller ones?
For instance, after the 1000uf, a 100uf, and another 0.1uf poly.
And another 0.1uf poly between the + and - pins on the chip.
This is good practice with op-amps.
I suppose it would give good results with power op-amps too.
Sorry for talking about GCs in this thread, but National was kind to me again, (thankx for those LM6172s some months ago) and sent me some LM3875s, which arrived today!
I'm going to give it a try, I'm only needing to get a good transformer for this.
Old 21st April 2003, 04:15 PM   #1107
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Default Re: Re: The Two Peter's .......

Originally posted by Peter Daniel

What I'd like to agree on, is that although two amps may seem to sound the same in a blind test to a person, they might not sound the same in subjective environment, the one we are accustomed to in our usual way of listening and this should be treated as "real" reality, more important than just aesthetics. This might not appeal to everybody and of course is not the same to everybody, but in some ways it's real.

If there is some truth to what I just wrote, the blind test is useful for nothing more than just proving that we are indeed not perfect, but I am not sure if that's a limitation or an advantage.
Peter, I 100% agree with your view here. But in this forum we are mixing up two things:

1 Enjoyment of music through equipment of our own making/design whatever. In this context, indeed it doesn't make so much difference if you cannot distinguish between two in DBT;

2 Trying to design/modify better equipment. Here it is absolutely essential to have some scientific, reproducible way to find out if there are or are not any differences. Otherwise, the effort amounts to nothing more than repackaging a similar amp. But I have the feeling that most DIY'ers want to improve it (excluding people like circlotron who's perverted purpose is just to be waaaay different - just joking of course).

I like to try new designs to make things "better" , so I need some objective way to assess performance. Other than that, if it sounds good, it IS good.

Jan Didden
Old 23rd April 2003, 11:47 AM   #1108
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Location: Cambridge, UK
Default Re: Decaying Thread ?


It can be pretty much taken for granted nowadays that modern amplifiers will have full FR, and Low THD figures (0.01%), but to my ear dynamic under load behaviour (load dependance = amplifier/speaker/room decay behaviour) is the key element to long term listening enjoyment.
(and also Hugh's previous comments about instability).

I'll basically agree with that. Just about all amps I've measured are hard to fault on frequency response and distortion; lots of open-loop gain, and therefore negative feedback, fix these up a treat.

However it's exceedingly easy to provoke and measure instability (and full-blown oscillations) in just about anything, and the effects of these are easily audible (ranging from just 'fuzziness' through inexplicably high background noise, to receiving AM radio...).

Lack of phase margin around the overall feedback loop is just one of the reasons for this. In theory, an inductive load and a resistive output impedance from the output transistors doesn't actually give phase shift in the right direction; a capacitive load will.

However, output transistors can oscillate on their own perfectly easily - an inductive load plus various stray capacitances turn them into Colpitts oscillators at the drop of a hat. (This is particularly true when the base is not being strongly driven, at the crossover point - hence you often get little burst of oscillation at crossover).

There are also 101 ways to generally couple the output signal back into the input - poor grounding, poor circuit board/wiring layout etc. (For instance, in one case the capacitance between the cases of the output transistors and the heatsink was coupling the output signal into some dodgy grounding, which was enough to start longwave radio transmissions).

So these days I don't spend much time agonising about 0.1dB in the frequency response. I *do* spend a lot of time connecting the amp up to nasty sources and loads and poking about the output with a scope...

Old 23rd April 2003, 09:09 PM   #1109
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Thumbs up on that salutary note...

folks may find the views of Katsu-san interesting.....
Old 27th April 2003, 04:06 AM   #1110
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Default Cabinet Colourations ?.

Turbosound FAQ's

Q: Why are Turbosound speakers blue?

A: In a blind listening test carried out with several similar speaker cabinets from various manufacturers, a panel of experts were asked to evaluate the sound of each product. The blue cabinets sounded better.
I believe not to believe in any fixed belief system.

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