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PostPosted: Mon Mar 05, 2018 3:30 pm 
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Teo Audio wrote:
I'm not a flea watt kinda guy, no, not at all. I like to pound reggae, iffin' I get the chance. my personal record of power applied to a pair of Apogee Duetta MKII's is..at 4 ohms....1400 watts per channel. They take it pretty well...

I've been trying to find a solution for this dilemma for a very long time. Decades. Like everyone else. I explained my solution to this problem to a very well known audio designer who's name would be recognized by pretty well every member of this forum. He is well aware of the problem. Like all of them. When I explained the solution in detail, the science, the physics, and reasoning behind it... and showed him the (c)(copyrighted schematic), he said quietly, "that's **** genius..."

Just have to get to the point where we can afford to publish an amplifier. And the given 24 transistor 600 watt 180A per channel 1000 damping factor 60 lb mono amplifier will finally sound like a single transistor pair. For the first time. I'm doing a final build test on the solution for the fourth time, in this case... on a 500/Wpc 80lb power amplifier with 32 15A 250mhz transistors.

I want it all. Just like you, just like everyone else.

Well, until your genius comes up with something our retired electrician can actually buy, can we at least agree that right now, more is better....at least up to a point?

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PostPosted: Mon Mar 05, 2018 3:54 pm 
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Can buy? Thanks for your comment ripblade, not to worry. I have many long times friends still in the biz, new and used. A few years back, via a tip from a pal who deals in used audio, I scored a near mint Krell Ksa 250 for around $1500 CDN. As we speak my knights have their eyes open and will inform me when something nice shows up for a great price.

FYI, the KSA 250 sadly had to go when my ex and I split up. No matter. I am not saying a KSA 250 is the cream of the crop but it drove my Logan revamped Requests very nicely.

We will see what turns up in the kingdom.

-- 05 Mar 2018 23:56 --

Nice to see so much input on this matter. Even if I don't reply to each comment I do read all of them often twice. Some three times are necessary. All are very much appreciated.

Much thanks.


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PostPosted: Mon Mar 05, 2018 4:07 pm 
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retiredelectrician wrote:
Can buy? Thanks for your comment ripblade, not to worry. I have many long times friends still in the biz, new and used. A few years back, via a tip from a pal who deals in used audio, I scored a near mint Krell Ksa 250 for around $1500 CDN. As we speak my knights have their eyes open and will inform me when something nice shows up for a great price.

Lucky you! I have usually wound up paying full fare (more or less) for my assets. BTW, the 'can buy' refers not to your resourcefulness, but rather the unobtainium that Ken is promising to deliver upon us... someday.

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PostPosted: Mon Mar 05, 2018 4:41 pm 
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ripblade wrote:
A better indicator of whether an amp has good control over a woofer is to look at the number of output devices it has. Higher is better, IMO.
Teo Audio wrote:
Except for the dirty sound brought about by too many output transistors....this might have been a good idea.
The best sounding amplifies with the cleanest clearest sound quality, with no additions and no subtractions and no obscuration of the fine detail we are actually listening for..have one to two output devices per channel. That--and no more.
Whether it is $1000 from china or $50,000 from some western country makes no difference.

That many transistors per rail is a problem. A serious problem that is never spoken of but everyone in the business --who actually listens to the amplifiers-...... knows it is there.
My own class A design has 16 mosfets/ch. I wouldn't exchange my amps with any other on the market. Even with more money.
Mr. Pass himself said that he adds outputs as he wants and sleep well at night.

Uunderhill wrote:
When power transistors are connected in parallel, they need to be matched sets.
Otherwise, one will start conducting more current than the others.

The power resistors connected in series with each power transistor
also helps alleviate matching problems.

Feedback is highly useful if its used properly.
The problem occurs when Feedback is used to fix a poor amp design.
Exactly. Tight matching is the key. When all outputs are perfectly matched as close as we can, the outputs will behave as only one. I agree that that's a very difficult task.
Some manufacturers like Spectral use dedicated supply for each transistor (as I do). And I guess their transistors are 'uberly' matched to start with.

ripblade wrote:
...can we at least agree that right now, more is better....at least up to a point?
Totally agree. More outputs will also help to tame the back EMF from the speakers.
EMF can force the amp to distort. That effect will end by affecting also the higher freq. Not only low freq.
I prefer more damping factor than less.

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PostPosted: Mon Mar 05, 2018 4:45 pm 
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ripblade wrote:
Lucky you! I have usually wound up paying full fare (more or less) for my assets. BTW, the 'can buy' refers not to your resourcefulness, but rather the unobtainium that Ken is promising to deliver upon us... someday.


Once he builds it, you may not be able to afford it.

Have you heard TEO Audio's Liquid Preamp?

This reviewer wrote this in his conclusion:

"In summary, this is the only preamp I can say that to my ears did everything right with every piece of music played, and never once stumbled by introducing grunge, either mechanical or electronic. I cannot think of a single instance where I thought, “This doesn’t sound right,” but I can think of many where I thought, “This sounds perfect!” At $4,200 the TEO Audio Liquid Pre is in the realm of possibility for real world enthusiasts, and I’m endorsing it by purchasing it. I have been on the hunt for a top-end preamp for the better part of two years, and the Liquid Pre is the closest to a Cost-No-Object preamp without sonic drawbacks I have laid hands on."

https://www.dagogo.com/teo-audio-liquid-pre-preamplifier-review/

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Last edited by NordicNorm on Mon Mar 05, 2018 7:49 pm, edited 1 time in total.

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PostPosted: Mon Mar 05, 2018 6:08 pm 
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ripblade wrote:
Teo Audio wrote:
I'm not a flea watt kinda guy, no, not at all. I like to pound reggae, iffin' I get the chance. my personal record of power applied to a pair of Apogee Duetta MKII's is..at 4 ohms....1400 watts per channel. They take it pretty well...

I've been trying to find a solution for this dilemma for a very long time. Decades. Like everyone else. I explained my solution to this problem to a very well known audio designer who's name would be recognized by pretty well every member of this forum. He is well aware of the problem. Like all of them. When I explained the solution in detail, the science, the physics, and reasoning behind it... and showed him the (c)(copyrighted schematic), he said quietly, "that's **** genius..."

Just have to get to the point where we can afford to publish an amplifier. And the given 24 transistor 600 watt 180A per channel 1000 damping factor 60 lb mono amplifier will finally sound like a single transistor pair. For the first time. I'm doing a final build test on the solution for the fourth time, in this case... on a 500/Wpc 80lb power amplifier with 32 15A 250mhz transistors.

I want it all. Just like you, just like everyone else.

Well, until your genius comes up with something our retired electrician can actually buy, can we at least agree that right now, more is better....at least up to a point?



Yep, up to a point. I mean, we can hear the progression from the (20+ years ago) 2b to the 3b to the 4b, and the 2b was always the sweetest and cleanest sounding of the bunch. You kinda had to go for the 4b if you wanted power and grunt.

There was an odd thing, though, about how the 4b was internally adjusted. They were set up, run in a bit, then set in bias ..then run in for 100hrs and then the bias was finalized at the 100hr point and running temp.

You could hear this pattern repeat itself, if you ran a 4b for over 100 hrs. right at almost the 100hr point, it would just clear up and lock in. CRT projectors are like that, as well, they follow their adjustment procedure that was done when they were initially tuned up, right to a T.

As for the given amp, maybe, maybe not. I'm a bit lazy, not interested in money, and more philosophically buddhist than anything else. Karma and all that. Casting influence has it's costs.


As for the passive preamp, two reviewers agree, passive or active, tube or solid state, nothing touches it. It is pinnacle. Period. That is the only reason it was made, not to be halfway or competitive --- but the best, at any price. Too high a price for the vast number of enthusiasts, they don't believe it is possible and for those who can afford the best and those who sell the best, the price is too low so they ignore it.

Especially if it invalidates their last $40k preamp purchase and especially-doubled, if it was the given store who would have to fess up they sold something inferior... over a tiny thing...that has no money that can be made, compared to the $40k items the well heeled buyer expects. Those who can afford it, don't believe it exists and those who can afford it 10x over, their salesmen want it to be dead and not exist and will never advise their customers to buy it. Give people what they want and nobody buys it. The world is a very screwy place.

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PostPosted: Mon Mar 05, 2018 6:47 pm 
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The highest DF to be in an audiophile amp, is no more than 120.
In conventional A/B design, that is.
At 150 the global feedback is already pretty high, and at 1000 it is catastrophic, killing all air, texture and delicacy.
Marantz 1300DC = 65
Pioneer SX-1280 = 30
Tube amps = 5 ... 30 ... normally... rarely up to 100


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PostPosted: Mon Mar 05, 2018 7:25 pm 
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Teo Audio wrote:
As for the passive preamp, two reviewers agree, passive or active, tube or solid state, nothing touches it. It is pinnacle. Period. That is the only reason it was made, not to be halfway or competitive --- but the best, at any price. Too high a price for the vast number of enthusiasts, they don't believe it is possible and for those who can afford the best and those who sell the best, the price is too low so they ignore it.

Especially if it invalidates their last $40k preamp purchase and especially-doubled, if it was the given store who would have to fess up they sold something inferior... over a tiny thing...that has no money that can be made, compared to the $40k items the well heeled buyer expects. Those who can afford it, don't believe it exists and those who can afford it 10x over, their salesmen want it to be dead and not exist and will never advise their customers to buy it. Give people what they want and nobody buys it. The world is a very screwy place.
Hi Ken,
I believe you than your preamp can actually sound good. Even very very good.
But there is no best preamp. All is in the match with what it is linked. To me, preamp and amp are part of a one thing; amplification.
Then I see a preamp as a stage. It must then be very well matched to the rest of the amplification stages. It's why some good pre can sound good
with an amp and not as good with another amp. Your preamp could be indeed the very best, but there's no real way to be sure of that.

My own monoblocks sound extremely pleasant to my ears. To know better their quality, I did make a comparison in my home, with my system, with all the
same component with others high quality amps. Halcro DM58, Pass Lab 30.5, ML 20.6, Spectral DMA-100s, Plinius SA-103, Primare 928, Krell KSA-50 and Nak PA-7AII.

All of the amps had their own strong point. As example the noise floor of the Halcro is low. Ultra low, dead background. Ultra wide soundstage. But they sound dull.
The Spectral seemed to be the most neutral. My own amps the most transparent. But at the end, the Plinius (in class A mode) was the most musical.
It has a something that I just can't get my fingers on. I can't recall all their damping factor, but I remember that some were very different of some others.
The only time I found my own amps better that all others was when paired with ML CLSII. But I will never claim that my amps are the absolute best.
Though not heard on my system, the ASR Emitter II is another amp (integrated) which I think sounds better than mine.

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PostPosted: Mon Mar 05, 2018 7:47 pm 
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Interesting commentary and insight. While the concept of DF is simple, the relationship regards to resistance at the output device vs at the voice coil if direct driven without a passive crossover is new to me. So I now learn DF means squat with speakers biwired from a single dual mono amp thru a typical passive crossover using inductor coils. Better to leave that to the subwoofer people. I prefer a single engineered full range enclosure over the not necessarily engineered variable of a free standing bass unit. Will ignore or take in advisement big DF numbers on future hardware.

Really enjoyed the circuit and physics chat. It's nice to listen to intelligent conversation.

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PostPosted: Mon Mar 05, 2018 8:03 pm 
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ripblade, thanks for the clarification. I was pretty sure that's what you meant which is why I posed my reply that way.
As in the "not to worry" part.


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PostPosted: Tue Mar 06, 2018 3:14 am 
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NordicNorm wrote:
ripblade wrote:
Lucky you! I have usually wound up paying full fare (more or less) for my assets. BTW, the 'can buy' refers not to your resourcefulness, but rather the unobtainium that Ken is promising to deliver upon us... someday.


Once he builds it, you may not be able to afford it.

Have you heard TEO Audio's Liquid Preamp?

This reviewer wrote this in his conclusion:

"In summary, this is the only preamp I can say that to my ears did everything right with every piece of music played, and never once stumbled by introducing grunge, either mechanical or electronic. I cannot think of a single instance where I thought, “This doesn’t sound right,” but I can think of many where I thought, “This sounds perfect!” At $4,200 the TEO Audio Liquid Pre is in the realm of possibility for real world enthusiasts, and I’m endorsing it by purchasing it. I have been on the hunt for a top-end preamp for the better part of two years, and the Liquid Pre is the closest to a Cost-No-Object preamp without sonic drawbacks I have laid hands on."

https://www.dagogo.com/teo-audio-liquid-pre-preamplifier-review/



I heard one and was not overly impressed. Sounded like a typical passive to me. Which is all it is. There were three of us at the listening session and two of us preferred a tricked out Bottlehead to the TEO. The third individual said he preferred the lows and mids of the Bottlehead but the highs of the TEO. Definitely not the grand slam it's purported to be, but that's Audio for you… :roll:

-- 06 Mar 2018 07:28 --

racecars wrote:
Interesting commentary and insight. While the concept of DF is simple, the relationship regards to resistance at the output device vs at the voice coil if direct driven without a passive crossover is new to me. So I now learn DF means squat with speakers biwired from a single dual mono amp thru a typical passive crossover using inductor coils. Better to leave that to the subwoofer people. I prefer a single engineered full range enclosure over the not necessarily engineered variable of a free standing bass unit. Will ignore or take in advisement big DF numbers on future hardware.

Really enjoyed the circuit and physics chat. It's nice to listen to intelligent conversation.


I think it's a mistake to dismiss separate peace modules. Huge improvements to be had there. In part because often the best location for your bass speakers is not the best location for your full range. Also I find lower power amplifiers to sound better than their higher power counterparts. If you buy amp with a separate peace and closure you can use an amplifier of your choice for the full range and use a high damping factor connected directly to your sub for the bass


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PostPosted: Tue Mar 06, 2018 4:12 am 
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I have never heard the Teo pre amp, so none of the following has anything to do with Mr. Ken Hotte or his products, but, since a bit of this thread took a wee turn about pre amps, and it is passive, it raises another point.

The following statement is not science based, it is based only on my personal common (hopefully) sense.

"No pre amp is better than no pre amp" or "A millions dollars won't buy a pre amp that sounds better than not having a pre amp"

I mean, let's assume someone "only" listens to music via a Macbook (CD's downloads etc). And let's assume the Macbook has enough voltage out to drive a given power amp.
Why use a pre amp? Why plop something, anything, no matter how good or expensive it is into the signal path if you don't need it?

Macbook directly to power amp as it were.

Right now on another buy and sell site there is a Robert Koda Takumi R15 REFERENCE Pre amp for sale, suggested retail $50,000.
So. In this set up, the only source a Macbook, what will sound better, Macbook to power amp? Or Macbook, routed through the Takumi R15 REFERENCE, to power amp?

Side note: I know a U of T student, (huge classic jazz lover for his age I might add) who likes to have good sound but has no real interest in "stereo" (and openly states he knows and cares nothing about stereo as we do), who has a Revox B226 CD player which has variable volume out (and direct out) connected right to an old Bedini 25/25, connected to a set of Energy Reference's, the older rosewood ones where the stand/base is part of the speaker.
When I first saw his stereo I said, "interesting, no pre amp", his reply was, why do a need a pre amp?

Anyone have any thoughts?

-- 06 Mar 2018 12:25 --

If this whole issue comes down to expensive pre amps having a high quality high cost volume control, potentiometer, in the scenario of the Revox B226, if the issue is the volume control in the Revox not being a good one, then how about use the "direct" RCA out and buy the most expensive potentiometer you can, place it in a nice little hammond box, and go Macbook to potentiometer to power amp,,,just a thought is all.


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PostPosted: Tue Mar 06, 2018 4:58 am 
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ripblade wrote:
A better indicator of whether an amp has good control over a woofer is to look at the number of output devices it has. Higher is better, IMO.


Most MOSFET's used in audio power amps, are actually
designed for switching purposes.
Both Bi polar transistors and switching MOSFET's have a positive temperature co efficient.
So as they heat up, they conduct more - so they can run into issues of thermal run away.
Hence the need for matching them and the typical 0.33 ohm power resistor connected in series with
each of them.

Where as lateral MOSFET's are actually designed for audio use.
They have a negative temperature co efficent.
So as they heat up, they conduct less - so paralleled sets of them
become self matching as they heat up.

The problem with lateral MOSFET's is that the major manufacturer - Toshiba
keeps on discontinuing and changing the making of these.
Its kind of a basic design rule that components should not
be designed in a product if there is a "single source."
In other words, only design a product where you can get the components
from numerous manufacturers.

Also, true class A power amps, use a follower output stage.
This has the lowest output impedance of any configuration.
This is why true 30 watt solid state Class A amps grip a speaker so well.
However, I think 30 Watts in a class A amp is way too much
- its going to sit there, idling and dissipating power and create heat.
I think 10 w or 15 W is plenty for a class A amp - the problem is
who would even consider trying to market a 10 W or 15 Watt amp ?


Last edited by Uunderhill on Tue Mar 06, 2018 5:10 am, edited 1 time in total.

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PostPosted: Tue Mar 06, 2018 5:04 am 
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retiredelectrician wrote:
When I first saw his stereo I said, "interesting, no pre amp", his reply was, why do a need a pre amp?

Anyone have any thoughts?

A pre-amp serves to act as a:
1. source selector
If your only have one component, you may not require a pre-amp.
2. volume control
If either your power amp or your source have volume control, you may not require a pre-amp.
3. line level matching (for the various source input signals)
If your source outputs a line level signal, you may not require a pre-amp

If you have all three, then you don't require a pre-amp (as you discovered in the case of your friend).

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PostPosted: Tue Mar 06, 2018 5:28 am 
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I don’t think it’s a clear case of no preamp = the best performance, even if one is not required for obvious source selecting etc. There have been many who have gone from no pre or a passive one to active and felt there was an improvement.


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