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Topic: Ultimate Pre-Amp for Dummies

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Posted by Romy the Cat on 05-16-2009
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It is not my quests. I do have my ultimate preamp and I experience absolutely no frustration about it. However, writing today about the new Lamm LL1 I suddenly realized that I never conceptualized for public what in my view the contemporary truly ultimate preamp shall be. I never seen others did but I see many manufactures do produce many versions of something that I would call “stupid preamps”. So, regardless of the price and the implementation topology, what shall be features on ultimate preamp?

This thread is dedicated to look deeper into the subject.

The Cat

Posted by Paul S on 05-16-2009
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I am also content with my "pre-amp", and I think a lot of my satisfaction comes from the fact that all I ask from the pre is sensible switching (including variable attenuation), and no interference.

But what about the more usual situation, where the user demands "something extra" and then "more" from his pre-amp?

When I think of pre-amps that exist to offer "something" to the situation and/or sound, I wonder if anyone today thinks about the electricity, and how this will inevitably effect the pre-amp as an electrical component.  If anyone is really thinking about this, I have not heard these thoughts yet.

Along with the above, I wonder if anyone has yet designed/perfected the electrical pre-amp that takes good electricity for granted, such as use along with a dialed-in power corrector, for those who own and use such a wonder.

Piling on, I think of many assults on the "ultimate pre-amp" as starting with very large, elaborate power supplies that are mostly included to compensate for bad electricity but that also generally extract their own sonic toll.

Paul S

Posted by Romy the Cat on 05-25-2009
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It kind of strange that so many manufactures produce preamps, so many users use preamps but no one talks about them seriously. The dealers sell them, the reviewers write their doodle but the manufactures do each year a new version but what we, the consumers, the preamp users truly need? The inspiration for this article was Lamm release a new LL1 Reference preamp that I mentioned in here:

http://www.goodsoundclub.com/Forums/ShowPost.aspx?postID=10521

The inspiration was not the preamp itself but the $43K price tag. The price is high, in a way ridiculously higher for what is quantivly delivered. The identically double-boxer BAT REX, that has much more functionality, equally offensively targeted and much-much more complex in design is priced twice lower. However, what I very much like in the Lamm new preamp is that it opened for me motivation to think what I actually would like to have in pram if it was made with price and objectives being subject of no limitation. So, I am taking about an hypothetical absolute ultimate preamp and about how far we are from there. 

About my personal evolution with preamplifiers. When I reformated my playback in 1995, in the format that a label-worshiping western audio-person would recognize as high-end, I use a first BAT preamp, it think it was VK3i, then it was VK5i. In 1999 Lamm L1 introduced me a totally another level of what preamps might do. Then in 2000 it was Lamm L2.  I wrote about Lamm’s preamps and I consider them as a very enigmatic figure in audio.

http://www.goodsoundclub.com/Forums/ShowPost.aspx?postID=257

There were many people out there use Lamm L1/L2 but absolutely dominating majority still clueless what they use and what benefits those preamps do in playback. Lamm preamps had own issues and I was not aggressively in 2000-2002 was bringing many other preamps trying how they would do. Let me see… It was a top of line Audio Research, Mark Levinson, Atmosphere, CAT, Spectral, VAC, VTL, Theta and perhaps something else that I do not already remember. They all come and go and then it was 3 different Placettes that pretty much ended my frustration. That is what I went through and here is what I think. This is my requirement for ultimate preamp and if the manufacturers are willing to do another $30K or $70K preamp then they better to learn what we – the users- would like to have. So, here is my “The 15 Commandments of Ultimate Preamplifier”.

1) A preamp shall have right Sound. I would not even comment on it. A preamp shall sound better then any other source a system has.

2) A preamp shall have a remote control. I have expressed a well found view that a Remote Control is an ultimate enemy… but if you sell a preamp for $50K and with no remote control then you did not try very hard. The Remote Control shell be for volume, lines switching and phase inversion.

3) A preamp shall have multiple configurable Inputs that all sound the same. Come on! A person who runs just a CD player would not buy the “Ultimate Preamplifier” for $30K or $70K. It is obviously that the  Ultimate Preamp will be incorporated into more or less evolved installation that most likely will have multiple objectives. So, I feel 5-6 Inputs is absolutely mandatory for an Ultimate Preamp. I would like to have option to configure how many inputs I would have. My current Preamp has 11, I think it is too much for general use but 5-6 Inputs with extendibility to 7-9 I think does make since. An ability to set a drop for a few DB for a few inputs is also would be useful.

4) A preamp shall not have digital volume control – digital can’t filter or attenuate

5) A preamp shall not have a lot of gain. I presume that a person who would go for $30K or $70K Ultimate Preamplifier would not be a fool and all moments of matching gain with sensitivity of speakers will be resolved on amplifiers level. So, most of the time the Ultimate Preamplifier will be attenuating of working near a unity gain.

6) A preamplifier shall be active. Restive of inactive preamps are fine for $500 preamplifier and for $2000 worth loudspeakers.

7) A preamplifier shall have a headphone output. I do not ask about a great one but it shall be one and it costs nothing to implement.

8) A preamplifier shall have output impedance of sub 100R and shall be able to put out a lot of current.

9) A preamplifier shall have at 2 least RIAA inputs. There is no reason do not integrate a 50-80dB gain phonostage into a preamp as it allow to optimize sages and make the whole phono operation very comfortable

10) A preamplifier shall have 0.1K, 1K and 10K generator aboard.

11) A preamplifier shall have a hard-wired bypass switch.

12) A preamplifier shall have multiple configurable options for grounding layout and shall have a shared across all inputs and outputs, very massive cooper bass terminal.

13) A preamplifier shall have multiple outputs, 2-3 is OK.

14) A preamplifier shall not use vacuum tubes as output devises. Come on, get real! No one yet built an absolutely transparent tubes buffer. The output stages of an Ultimate preamplifier shall be DC-coupled SS devise.

15) A preamplifier shall have an absolute phase inversion option.

That is all for now.
The Cat

Posted by Lbjefferies7 on 05-26-2009
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Let it be known that I am nearly clueless when it comes to electronics.  Building speakers, racks, pianos, or just about anything mechanical is no problem for me to build myself and, unlike Romy, it is usually pleasant for me for various reasons.  Where my enthusiasm in creation dies is in electronics.  It is a problem that, it appears, will have to be remedied as my system's performance is far behind my own "performance."  The idealist side of me makes be feel that a person should not have to have any more "circuit consciousness" than I, especially when the Ultimate Preamp or any other component will sell for a substantial price.  I write this just so that we are all clear on the context of my comments.

A possible #16 may be an elegant way of current-loading cables.  Perhaps this should include an attenuator to achieve the proper current for a given cable?

Having said that, the 15 Commandments above look like a fine solution-based pre-amp...and the title reminds me of Mel Brooks as Moses. Smile  http://www.youtube.com/watch?v=8YX-gqRdK_8

LBJ (a dummy...but perhaps not a moron)


Posted by Romy the Cat on 05-26-2009
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 Lbjefferies7 wrote:
Having said that, the 15 Commandments above look like a fine solution-based pre-amp...and the title reminds me of Mel Brooks as Moses.
  
Yes, it was exactly my point of reference.  
 Lbjefferies7 wrote:
A possible #16 may be an elegant way of current-loading cables.  Perhaps this should include an attenuator to achieve the proper current for a given cable?
 
The Commandments #8 implies it. The current-loading cables is not the functionality of preamps but the properly of the cable load. So, the preamp shall have very low output impedance and the output stage shall run very deep in class A1 with very hot bias, with a lot of heat sinks. The SS devices, most of them run feedback, allow to have ultra low output impedance – a few Ohms - and if the output stage do not oscillates in this operation ten it is very good. The oscillation would the property of the cable capacitance as well, so the few dozen Ohms output anti- oscillation resistor would not be a bad thing…
 
I am sure the right people who do Ultimate Preamps would do this research in SS devises and I am sure would fund the right solution. I personally would like to see the Ultimate Preamp measurements and to observe of it transparency at 50MHz. Yes you did not misread me – at 50MHz - at videos single. I would like to see a preamp made with all rules of HF transmission like with unlimited bandwidth and unlimited power (unlimited for liner level).
 
BTW, having a system configuration like mine – with multiple line level filters is very educational as the output impedance of preamp is the very essential design factor of my playback. Whatever people do they shall not be limited by preamp’s output impedance.

The Cat

Posted by Amir on 09-20-2018
 Romy the Cat wrote:

1) A preamp shall have right Sound. I would not even comment on it. A preamp shall sound better then any other source a system has.

2) A preamp shall have a remote control. I have expressed a well found view that a Remote Control is an ultimate enemy… but if you sell a preamp for $50K and with no remote control then you did not try very hard. The Remote Control shell be for volume, lines switching and phase inversion.

3) A preamp shall have multiple configurable Inputs that all sound the same. Come on! A person who runs just a CD player would not buy the “Ultimate Preamplifier” for $30K or $70K. It is obviously that the  Ultimate Preamp will be incorporated into more or less evolved installation that most likely will have multiple objectives. So, I feel 5-6 Inputs is absolutely mandatory for an Ultimate Preamp. I would like to have option to configure how many inputs I would have. My current Preamp has 11, I think it is too much for general use but 5-6 Inputs with extendibility to 7-9 I think does make since. An ability to set a drop for a few DB for a few inputs is also would be useful.

4) A preamp shall not have digital volume control – digital can’t filter or attenuate

5) A preamp shall not have a lot of gain. I presume that a person who would go for $30K or $70K Ultimate Preamplifier would not be a fool and all moments of matching gain with sensitivity of speakers will be resolved on amplifiers level. So, most of the time the Ultimate Preamplifier will be attenuating of working near a unity gain.

6) A preamplifier shall be active. Restive of inactive preamps are fine for $500 preamplifier and for $2000 worth loudspeakers.

7) A preamplifier shall have a headphone output. I do not ask about a great one but it shall be one and it costs nothing to implement.

8) A preamplifier shall have output impedance of sub 100R and shall be able to put out a lot of current.

9) A preamplifier shall have at 2 least RIAA inputs. There is no reason do not integrate a 50-80dB gain phonostage into a preamp as it allow to optimize sages and make the whole phono operation very comfortable

10) A preamplifier shall have 0.1K, 1K and 10K generator aboard.

11) A preamplifier shall have a hard-wired bypass switch.

12) A preamplifier shall have multiple configurable options for grounding layout and shall have a shared across all inputs and outputs, very massive cooper bass terminal.

13) A preamplifier shall have multiple outputs, 2-3 is OK.

14) A preamplifier shall not use vacuum tubes as output devises. Come on, get real! No one yet built an absolutely transparent tubes buffer. The output stages of an Ultimate preamplifier shall be DC-coupled SS devise.

15) A preamplifier shall have an absolute phase inversion option.

That is all for now.
The Cat

16) A preamplifier shall have balance control for balancing gain of L/R channels (good speaker position change the gain)

Posted by rowuk on 03-03-2020
Besides Romys short list of features:
1) A preamplifier shall be modular - the ability to insert n quantity (maybe 20?) of input cards on a backplane (for phono MC/phono MM/line level/Balanced/Single ended/TOSLink) as well as be configured for multiple outputs. Why send a preamp back to the manufacturer to get a couple more inputs?
2) All preamplifier input channels shall be individually adjustable in gain and polarity.
3) A preamplifier shall be immune to bad electricity. (a very loaded requirement)
4) At least one preamplifier output module shall have the possibility for X-factor/Sonic Holography/other phase adjustments.
5) A preamplifier shall have a front panel output for an oscilloscope/Spectrum Analyzer. Why should we crawl behind a rack to troubleshoot?
6) A preamplifier shall have at least 1 set of inputs on the front plate. Why should we crawl behind the rack to test a new piece of equipment?
7) A preamplifier shall not be microphonic.
8) I would add 50Hz to the required test tones to be able to check phase with a real LF channel.
9) A preamplifier should have a sort of phantom power switchable to the output to load cables.

Posted by Romy the Cat on 03-03-2020
 rowuk wrote:
A preamplifier shall be modular - the ability to insert n quantity (maybe 20?) of input cards on a backplane (for phono MC/phono MM/line level/Balanced/Single ended/TOSLink) as well as be configured for multiple outputs. Why send a preamp back to the manufacturer to get a couple more inputs?
Conceptually yes, but in practicality it never worked this way. Theta had a Casablanca preamp that was truly great, fully plug and play, with multiple configuration options. It sounded fine, well,  …at the Theta level. The idea of cause is wonderful but as in anything ease we need to look at the balance between comfort and quality. My wife use to ask me why at $500 turntable you start rotation with push of a baton but at $150K turntable you need to make the first few rotation of the platter with your hands… Her rational does make sense but hardly anybody who practice high-end audio would agree….
 rowuk wrote:
All preamplifier input channels shall be individually adjustable in gain and polarity.
The same as above but why the polarity? The front ends typically do not reverse polarity and if they do then the sores are typically very unstable from absolute polarity perspective.
 rowuk wrote:
A preamplifier shall have a front panel output for an oscilloscope/Spectrum Analyzer.
I would actually disagree with it. I never cared about the linearity of my preamp, why would I need TRA in there? And the scope? What is the point, what do you want to measure in there. If you care too much about the pre standard equalization curve for records then it is not preamp duty but the phono stage… and BTW the measurements would not show anything.
 rowuk wrote:
A preamplifier shall have at least 1 set of inputs on the front plate. Why should we crawl behind the rack to test a new piece of equipment?
Very enthusiastic support! Gods, how did I did not think about it what I made my own preamp?!!!

Posted by rowuk on 03-03-2020
 Romy the Cat wrote:
 rowuk wrote:
A preamplifier shall be modular - the ability to insert n quantity (maybe 20?) of input cards on a backplane (for phono MC/phono MM/line level/Balanced/Single ended/TOSLink) as well as be configured for multiple outputs. Why send a preamp back to the manufacturer to get a couple more inputs?
Conceptually yes, but in practicality it never worked this way. Theta had a Casablanca preamp that was truly great, fully plug and play, with multiple configuration options. It sounded fine, well,  …at the Theta level. The idea of cause is wonderful but as in anything ease we need to look at the balance between comfort and quality. My wife use to ask me why at $500 turntable you start rotation with push of a baton but at $150K turntable you need to make the first few rotation of the platter with your hands… Her rational does make sense but hardly anybody who practice high-end audio would agree….The technology is there (every professional ethernet switch uses this technology for in and output), dependable and you buy what you need - when you need it, upgrade when available. Just imagine NOT having to have sent your Placette to Guy, rather just having him send you the new module (more gain, additional inputs, lower output impedance). I agree with your wife. Why get the edge of the platter greasy - start management on a 150K turntable makes sense! Dream Turntable in 2020 would be another thread.
 
 rowuk wrote:
All preamplifier input channels shall be individually adjustable in gain and polarity.
The same as above but why the polarity? The front ends typically do not reverse polarity and if they do then the sores are typically very unstable from absolute polarity perspective.I have had CD players that invert.
 
 rowuk wrote:
A preamplifier shall have a front panel output for an oscilloscope/Spectrum Analyzer.
I would actually disagree with it. I never cared about the linearity of my preamp, why would I need TRA in there? And the scope? What is the point, what do you want to measure in there. If you care too much about the pre standard equalization curve for records then it is not preamp duty but the phono stage… and BTW the measurements would not show anything.If I have a "funny sounding" recording (more often pop music than classical), I connect the oscilloscope now. Once I "see" the problem, I do not tear down the playback to try and find "other" problems.
 
 rowuk wrote:
A preamplifier shall have at least 1 set of inputs on the front plate. Why should we crawl behind the rack to test a new piece of equipment?
Very enthusiastic support! Gods, how did I did not think about it what I made my own preamp?!!!

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