What makes amps sound different?

tmd · « **Reply #120 on:** 19 Jan 2003, 05:31 pm »

I have been away for a few days and had to catch up. I have lots of questions and observations but will have to read it again to comment. What I really want to know now is what you all do for a living?
Hugh is the most straightforward as he is selling kits to build what sounds like really excellent and reasonably priced amps.
Dejan, I haven't seen on your site or anywhere else that you build or sell any amps.
MarinRider, (my neighbour) do you build or sell anything at the moment?
Dan also sells amps he has designed I guess.
The reason I ask is that I am now itching to build something and would love to see if I can put the knowledge here to good use. Should I try an existing design and go out and buy all the parts I can or just buy a kit like an AKSA? Would you guys help me if I wanted to play around with the design?
Would you all get together and build a SUPER AMP? That isn't to suggest that you don't already do so but there is always room for improvement and many heads are usually better than one.
I really think this thread is excellent. I get excited when I check and there are new posts to it! I am really an incurable geek I guess:)
Neil.

DVV · « **Reply #121 on:** 19 Jan 2003, 05:44 pm »

Quote from: tmd

I have been away for a few days and had to catch up. I have lots of questions and observations but will have to read it again to comment. What I really want to know now is what you all do for a living?
Hugh is the most straightforward as he is selling kits to build what sounds like really excellent and reasonably priced amps.
Dejan, I haven't seen on your site or anywhere else that you build or sell any amps.

I do not make or sell anything, I'm a free lance journalist.

Quote

MarinRider, (my neighbour) do you build or sell anything at the moment?
Dan also sells amps he has designed I guess.
The reason I ask is that I am now itching to build something and would love to see if I can put the knowledge here to good use. Should I try an existing design and go out and buy all the parts I can or just buy a kit like an AKSA? Would you guys help me if I wanted to play around with the design?

A bit of advice, if I may. If you haven't designed any of your own so far, I would suggest you buy a kit, obviously an AKSA in this instance, and strat your practical electronics life with a tried and proven design. Euro 239 (plus shipping) for a 55W per side amp seems like a very fair price to me. And it is spoken of in excellent terms, making it a still better deal.

Quote

Would you all get together and build a SUPER AMP? That isn't to suggest that you don't already do so but there is always room for improvement and many heads are usually better than one.

Speaking for myself, I don't mind, but in realistic terms, I don't see it happening. You are asking Dan and Hugh to compete with themselves, to give away free what they sell for a living, or simply sell.

In designer terms, that would be a feat indeed. While we are agreed on quite a few things, especially aspects regarding general amp design philosophy, we are nevertheless VERY different in our approaches. Example: Hugh says stay away from cascodes, I say go for cascodes in particular places. Dan says regulate the whole thing, I say regulate the voltage gain stages, Hugh doesn't regulate at all. Dan says go for Motorola power devices, Hugh and I say go for Toshiba. You see what I mean, just different enough to make a coherent team impractical because of each one's individual philosophy.

Quote

I really think this thread is excellent. I get excited when I check and there are new posts to it! I am really an incurable geek I guess:)
Neil.

Welcome to the club.

Cheers,
DVV

tmd · « **Reply #122 on:** 20 Jan 2003, 02:20 pm »

That does make perfect sense. I don't expect that these guys will put themselves out of business. Perhaps the thing to do is have anyone who isn't selling something try it?
I still think the sellers could get involved as they seem to be geographically diverse. If they came up with a product, they could sell in different regions of the world. Let's face it, sellers who do so direct to the public don't usually sell in the thousands anyway so they would hardly encroach on each others territories.
In any case, when I manage to get the cash together (which won't be too soon) I am going to buy one of the AKSA kits and start building. I can then hear for myself what difference the different bits and pieces make.
Neil.

DVV · « **Reply #123 on:** 20 Jan 2003, 05:53 pm »

Quote from: tmd

That does make perfect sense. I don't expect that these guys will put themselves out of business. Perhaps the thing to do is have anyone who isn't selling something try it?

Er, ... that would me all alone.

Quote

I still think the sellers could get involved as they seem to be geographically diverse. If they came up with a product, they could sell in different regions of the world. Let's face it, sellers who do so direct to the public don't usually sell in the thousands anyway so they would hardly encroach on each others territories.
In any case, when I manage to get the cash together (which won't be too soon) I am going to buy one of the AKSA kits and start building. I can then hear for myself what difference the different bits and pieces make.
Neil.

That's a good way of finding out how it works.

Cheers,
DVV

tmd · « **Reply #124 on:** 20 Jan 2003, 08:50 pm »

Well then Dejan, I guess I will have to become an expert amp designer so that we can collaborate. How old are you? I'll need about 30 years or so to do that and will be at retirement age by then

DVV · « **Reply #125 on:** 20 Jan 2003, 10:02 pm »

Quote from: tmd

Well then Dejan, I guess I will have to become an expert amp designer so that we can collaborate. How old are you? I'll need about 30 years or so to do that and will be at retirement age by then

Still in my teens, just 49.

Cheers,
DVV

tmd · « **Reply #126 on:** 20 Jan 2003, 10:33 pm »

Well then, you will be 79 and I will be 65 when we design the ultimate amplifier!!!!!

MarinRider · « **Reply #127 on:** 21 Jan 2003, 09:00 am »

Collaboration:

I would much prefer to share ideas on these forums - as we are doing. I have also sent a few ideas to Hugh to try to improve the ASKA, however the fact that I use a standard 100W AKSA (with Nirvana) says a lot!
BTW I have tried series and shunt regulated supplies on the low current stages of the AKSA and was not impressed with the resultant sound quality. In comparison a good series reg on the Hood 80W mosfet amps makes a remarkable difference - one of the few cases I have found where the measurements (transient response and o/p impedance of the psu) actually tie up with sound quality.

Commercial interest:
Zero - although I do work in the electronics industry.
I used to design switch mode power supplies, however many years ago I realised I was a follower and not an innovator (unlike Mr Bongiourno and Pass etc) so I moved out of design. I am also realistic (pessimistic?) enough to know how tough it is to make money out of audio, unless you are a marketing superstar.

Super Amp:
I'm not convinced a universal super amp exists. For example I took the AKSA to a dealer recently to audition speakers - we tried a pair of Neat Elites (ribbon tweeter too bright for me) and when I asked the dealer what he thought to the amp he just kept muttering "interesting, interesting, interesting" with a surprised look on his face. We then tried a pair of PMC transmission lines (even though I have never heard a good sounding pair of tr lines) and the sound was really muddy, the dealer assured me they sound great driven from a monster Harmon Kardon amp. Maybe they do, but the point is THERE ARE NO RULES IN HIFI.

Happy building.

Dave

Dan Banquer · « **Reply #128 on:** 21 Jan 2003, 01:22 pm »

There are no rules in High End Audio. Only marketing. That's why it's such a mess. I agree with Bongiorno in his interview at Zero Distortion when he talks about synergy.
A business associate of mine on the west coast measured a PMC loudspeaker hooked up to a very powerful Bryston Amp in a recording studio. It measured very poorly. A transmission line when executed well is really quite good and far superior to the standard box designs out there. If you get a chance, see if you can find anyone with a Fried Loudspeaker and give it a listen. I have a set of rebuilt Fried G3A's. I am not parting with them.

DVV · « **Reply #129 on:** 21 Jan 2003, 01:36 pm »

Quote from: MarinRider

... Maybe they do, but the point is THERE ARE NO RULES IN HIFI.

The rules are what you make them - unfortunately, so those with most money set the ground rules. And for quite some time now, those rules have NOTHING to do with good sound, just dollars and cents.

Cheers,
DVV

AKSA · « **Reply #130 on:** 22 Jan 2003, 04:49 am »

Oh Dear,

You are all such cynics.

The tragedy is that I too agree with most that has been said......

Windows 95. $US500M spent on marketing. Runaway success.

I rest my case.

Cheers,

Hugh

DVV · « **Reply #131 on:** 22 Jan 2003, 07:31 am »

Quote from: AKSA

Oh Dear,

You are all such cynics.

The tragedy is that I too agree with most that has been said......

Windows 95. $US500M spent on marketing. Runaway success.

I rest my case.

Cheers,

Hugh

Cynics are optimists with experience.

Cheers,
DVV

AKSA · « **Reply #132 on:** 22 Jan 2003, 07:50 am »

Dejan,

Cynicism is the last recourse of the true romantic......

Hugh

DVV · « **Reply #133 on:** 22 Jan 2003, 10:10 pm »

Quote from: AKSA

Dejan,

Cynicism is the last recourse of the true romantic......

Hugh

Aye, quite so.

BTW Hugh, which capacitors do you use in your power supply?

Cheers,
DVV

DVV · « **Reply #134 on:** 26 Jan 2003, 11:14 pm »

Let me enlrage the question - any views of preferred capacitor type and sizes for power amplifiers?

Just to remind you, most amps use these as sources of stored energy and filters, so it's not an insignificant question.

Cheers,
DVV

Ferdi · « **Reply #135 on:** 26 Jan 2003, 11:48 pm »

HI fellow night-owls (US and OZ don't count),

One thing that I find interesting is how you would build the amount of capacitance/PS memory you need. 1 large cap or a bank of smaller ones? Maybe varying sizes?

Maybe I haven't understood my question?

tmd · « **Reply #136 on:** 27 Jan 2003, 11:35 am »

Thank you Ferdi, I was going to ask that question when I next remembered to do so. It seems that the suggestion was to use large ones rather than multiple small ones but I wasn't sure.
Smaller ones would be easier to fit as they can make more use of the space inside the enclosure but would be a pain to solder in and would probably be more expensive.
Neil.

DVV · « **Reply #137 on:** 27 Jan 2003, 07:34 pm »

Quote from: Ferdi

HI fellow night-owls (US and OZ don't count),

One thing that I find interesting is how you would build the amount of capacitance/PS memory you need. 1 large cap or a bank of smaller ones? Maybe varying sizes?

Maybe I haven't understood my question?

By and large, large caps filter better, but are slower. Smaller ones don't filter so well, but are faster.

Paralleling caps reduces their output impedance and of course, increases their capacitance and energy storage capabilities.

Hence, I tend to parallel a say 10,000uF cap with a say 4,700uF cap, or two 10,000 with one 4,700 uF. I find this delivers better on filtering and speed.

However, this does NOT free one from using quality products, for good performance one still needs quality caps.

Cheers,
DVV

Dan Banquer · « **Reply #138 on:** 27 Jan 2003, 09:52 pm »

The usual practice for bypassing large electolytic capacitors is to parrallel some smaller film or cramic caps. This done because large electrolytic capacitors have a fair amount of series inductance. The smaller value cap typically bypasses the series inductance and helps with higher frequency filtering.
For power amps I will typically parallel all electrolytic caps with at least a 0.1uf film cap. Feel free to experiment here. At line level, for every amplifier I am using I will place a 22uf cap parralled with a 0.1uf film cap as close as I can get to the power entry pins of an op amp or as close as I can get to power entry of a discreet amp. Many times when I am using a three terminal regulator I will put a 1uf ceramic at the unregulated voltage input pin of the regulator. That usually does a good job of killing any HF pick up into the regulator. Exotic film caps don't seem to matter here.

DVV · « **Reply #139 on:** 27 Jan 2003, 10:27 pm »

Quote from: Dan Banquer

The usual practice for bypassing large electolytic capacitors is to parrallel some smaller film or cramic caps. This done because large electrolytic capacitors have a fair amount of series inductance. The smaller value cap typically bypasses the series inductance and helps with higher frequency filtering.
For power amps I will typically parallel all electrolytic caps with at least a 0.1uf film cap. Feel free to experiment here. At line level, for every amplifier I am using I will place a 22uf cap parralled with a 0.1uf film cap as close as I can get to the power entry pins of an op amp or as close as I can get to power entry of a discreet amp. Many times when I am using a three terminal regulator I will put a 1uf ceramic at the unregulated voltage input pin of the regulator. That usually does a good job of killing any HF pick up into the regulator. Exotic film caps don't seem to matter here.

All very true, Dan, and my fault for not mentioning that. After so many years, I don't bother mentioning bypasses, I take them as a given.

After the say 10,000 in parallel with 4,700 uF, I would also include a 100uF capacitor, then a 0.1uF cap, and lastly, a series connected resistor with a small cap to the ground. The resistor is 1 ohm, the small cap takes experimenting to find out the required value for that particular setup. It is usuallu 0.68 ... 0.33 uF. Thar RC connection is intended to get rid of any leftover stray inductance of the larger caps.

If you try installing it, you may find your amp reacts somewhat faster, is snappier, with cleared up mid and treble range. Well worth tinkering with, but that 1 ohm resistor should be a metal film type, no less than 7W rating.

Cheers,
DVV