Jeff, that's exactly how I understood your question. Sorry to be rather terse in response, I'm travelling at the moment and am forced to write quickly.
Philosophically, I do not want any preamp in my system to have a "sound." But that's absolutely a matter of personal choice and philosophy, which is why I discourage the idea of using one like mine when a specific sound is wanted. Unity gain is appropriate for modern signal sources (univerally 2V or higher) and typical power amp sensitivities (generally 1-1.5V). Diyers, of course, can make their power amps with any sensitivity they want.
Philosophically, I do not want any preamp in my system to have a "sound." But that's absolutely a matter of personal choice and philosophy, which is why I discourage the idea of using one like mine when a specific sound is wanted. Unity gain is appropriate for modern signal sources (univerally 2V or higher) and typical power amp sensitivities (generally 1-1.5V). Diyers, of course, can make their power amps with any sensitivity they want.
SY said:
That's great, but in the context of a specific audio system there is either an audible difference between using the preamp and using nothing or there isn't. If it's the former you can't say it sounds like no preamp; if it's the latter there is no sonic reason to use it unless it provides needed gain. It might make you feel better that it has low output impedance or breaks ground loops, but if either of those attributes were solving significant problems in the context of the specific audio system, you would hear it during the comparison.
There is absolutely every reason to use a preamp that adds nothing apart from controls, and only takes away the nasty noise and stuff. I could quite easily go into magazine reviewer style hyperbole, but it would be a disgrace to the amp to do so.
OK, if you want an admission of audible difference, yes there is. Every source I have pugged into it is now very quiet, including torture tests like cable TV boxes, or even CRT TV sets. Worth it in my book for that alone. Because of the decent amount of drive from the line stage, you won't hear much, if any, difference between decent interconnect cables that worse amps will interact with to produce audible effects. Again, something that any audiophile with pretentions to accuracy should be greatful for.
edit: probably best to carry on this discussion elsewhere, we don't want to get too far off topic.
OK, if you want an admission of audible difference, yes there is. Every source I have pugged into it is now very quiet, including torture tests like cable TV boxes, or even CRT TV sets. Worth it in my book for that alone. Because of the decent amount of drive from the line stage, you won't hear much, if any, difference between decent interconnect cables that worse amps will interact with to produce audible effects. Again, something that any audiophile with pretentions to accuracy should be greatful for.
edit: probably best to carry on this discussion elsewhere, we don't want to get too far off topic.
pinkmouse said:
All of the controls and the gound loop breaking input transformer could be added to nearly any power amp circuit without much effort or compromise, with the added benefit of one less interconnect and two less connectors in the signal path.
I fully understand there are good reasons to use a unity gain preamp. It just seemed bizarre to compare it to using no preamp at all.
Re: The truth hurts . . .
As I've been telling you for a long time, the only way to get the kind of control you seek is to plant your nose in the books and build lots of stuff. If you don't want to do this, you don't get the control. In order to get exactly what you want you'll have to stumble upon it by accident. This latter method eventually works for most people (me included), but it takes a lot of time and is not without pain.
rick57 said:
As I've been telling you for a long time, the only way to get the kind of control you seek is to plant your nose in the books and build lots of stuff. If you don't want to do this, you don't get the control. In order to get exactly what you want you'll have to stumble upon it by accident. This latter method eventually works for most people (me included), but it takes a lot of time and is not without pain.
= $sJeff
> I've been telling you for a long time, the only way to get the kind of control you seek is to plant your nose in the books and build lots of stuff
Your imploring may soon bear fruit, though of an unsown variety: I have 90 % decided to build three preamplifiers: the Triplex (www.mapletreeaudio.com/magic5.htm). Then I will have three options in a single wife friendly box.
If only I knew of this fast tracking yonks ago . .
Cheers
> I've been telling you for a long time, the only way to get the kind of control you seek is to plant your nose in the books and build lots of stuff
Your imploring may soon bear fruit, though of an unsown variety: I have 90 % decided to build three preamplifiers: the Triplex (www.mapletreeaudio.com/magic5.htm). Then I will have three options in a single wife friendly box.
If only I knew of this fast tracking yonks ago . .Cheers
jeff mai said:
That's great, but in the context of a specific audio system there is either an audible difference between using the preamp and using nothing or there isn't. If it's the former you can't say it sounds like no preamp; if it's the latter there is no sonic reason to use it unless it provides needed gain. It might make you feel better that it has low output impedance or breaks ground loops, but if either of those attributes were solving significant problems in the context of the specific audio system, you would hear it during the comparison.
Actually, what I did hear was things quiet down. The satellite system always caused a small background buzz in all sources no matter what I did. That's gone.
Indeed, if you're only using a single power amp, you can build the volume control into it. That does mean that you will not be able to conveniently place monoblocks right at the speakers unless you don't mind a lot of running around to change the volume. And without a master level control, multiamping can be a nightmare. But all in all, I would not argue at all with the proposition that no preamp is the best, if you can get away with it; I think we have no disagreement there.
Back on topic, yes, rick, a common cathode with no cathode degeneration would be what I'd go for. And to get the even order stuff a bit higher, use a relatively low load on the CF.
rick57 said:I hope to use less accident, more survey
If you mean by "survey" to listen to a lot of gear (by building it or borrowing it), then I agree that it's a good method.
If you mean by "survey" to base purchasing decisions on someone else's opinion or a consensus of opinion, well, good luck. This type of "survey" purchasing is exactly the reason for the healthy trade in second hand gear.
rick57 said:Thanks SY
Do you know any link on cathode degeneration and load on the CF, or could you expand a tad?
Cheers
No links at hand, but you can't go wrong studying Morgan Jones's treatment in "Valve Amplifiers."
To expand a little (can't do more, I'm in a departure lounge at Heathrow at the moment), if the CF is biased up so that the cathode to ground voltage is only slightly more than the max peak to peak swing of your biggest expected signal, you'll get a fine spectrum of even harmonics. By tuning that voltage and the current through the CF, you can more or less dial in what you're looking for.
Finding personal Nirvana
I agree that listening is several times more effective than reading opinions.
But even in this city approx 3.7 million, of the amps I’d like to hear
Audio Note M7
SY’s Heretical
a Rankin preamp?
Rozenblit’s Grounded grid
transformer coupled 26
Frank's 12BH7A WCF
Aksa GK-1
Magic 5B Triplex
How many are available? Two if I’m lucky
When I used to read chaps like Magnetar (?) buying lots of drivers to find what he likes, selling the discards I thought “way too far gone”.
But now I feel that it is the most effective way.
Yes it’s better for the market in second hand gear than I’d like.
But Jeff, maybe I’m just a more serious audio man than you
I agree that listening is several times more effective than reading opinions.
But even in this city approx 3.7 million, of the amps I’d like to hear
Audio Note M7
SY’s Heretical
a Rankin preamp?
Rozenblit’s Grounded grid
transformer coupled 26
Frank's 12BH7A WCF
Aksa GK-1
Magic 5B Triplex
How many are available? Two if I’m lucky
When I used to read chaps like Magnetar (?) buying lots of drivers to find what he likes, selling the discards I thought “way too far gone”.
But now I feel that it is the most effective way.
Yes it’s better for the market in second hand gear than I’d like.
But Jeff, maybe I’m just a more serious audio man than you
SY
> you can't go wrong studying Morgan Jones
When my house returns from the disorder of room shifts, I will look for my copy of MJ with added zeal . .
> By tuning that voltage and the current through the CF, you can more or less dial in what you're looking for.
Like Nelson likes to do with Class A – didn’t know it was doable with tubes too - Great tip!
Happy flight
> you can't go wrong studying Morgan Jones
When my house returns from the disorder of room shifts, I will look for my copy of MJ with added zeal . .
> By tuning that voltage and the current through the CF, you can more or less dial in what you're looking for.
Like Nelson likes to do with Class A – didn’t know it was doable with tubes too - Great tip!
Happy flight
Re: Finding personal Nirvana
You forgot a word. Insert the word "hundred" between "several" and "times".
Good luck...you're going to need it.
I dunno. You haven't had a system set up for serious listening since I've known you (about three years). Sometimes I wonder about your seriousness.
rick57 said:
You forgot a word. Insert the word "hundred" between "several" and "times".
rick57 said:
Good luck...you're going to need it.
rick57 said:
I dunno. You haven't had a system set up for serious listening since I've known you (about three years). Sometimes I wonder about your seriousness.
Was it Sergeant Hans Schultz http://bostondirtdogs.boston.com/Headline_Archives/2006/01/the_leaks_stop.html who said
“Discussing preamp topologies - who could enjoy that?”
(with no disrespect to any army sergeants in attendance)
“Discussing preamp topologies - who could enjoy that?”
(with no disrespect to any army sergeants in attendance)
rick57 said:
Initial thoughts are where conflict emerges, priority is given to/ not given to:
Lack of harshness 95%
Detail 80%
Transient response 90%
Warmth 60%
845 like meaty richness 75%
Extension 50%
Getting back on topic. I'd really like to know exactly what you mean by the above. What are the percentages in reference to?
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