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Best Valve pre-amp match for ME 550 amp
Best Valve pre-amp match for ME 550 amp
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Old 6th December 2017, 07:04 PM   #201
Zaphod Beeblebrox is offline Zaphod Beeblebrox  Australia
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Quote:
Originally Posted by Bandersnatch View Post
Your interpretation of the heat generated in the Class A operation ignores the thermal inertia of the silicon itself. Taken over a long period, its average power dissipation is relatively constant, but as its output goes up it gets cooler, and as it goes down, it gets warmer...and thus the rot sets in. Correct this with NFB and you get more rot.
And yet, THD and IMD remain below audible levels at all times. Methinks you are searching for a problem that does not exist.

Quote:
Originally Posted by Bandersnatch View Post

Their low impedance requirement for 'acceptable' performance is just evidence of poor engineering. What a surprise they noticed and dealt with it as you mention.
The designer of the ME550 has constantly challenged the conventional paradigms of amplifier design. Many people, like you, have laughed off his design ideas as dumb. Nonetheless, not only have his radical ideas been copied by many, much larger companies (and smaller ones), but some of his ideas have yet to be duplicated. The low input impedance idea has been proven, via blind testing, to be a good one.

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Originally Posted by Bandersnatch View Post

I have no inability to source valve types I wish to use. So they eventually wear out? They still work better at EOL...LOL
I note you have carefully avoided responding to my other comments about the weak points attributable to valve preamps. Why is that?

Quote:
Originally Posted by Bandersnatch View Post

In any case, do us all a considerable favour, and go argue these points as widely as you can with a solid dedication, it will have a beneficial effect on any tube-based endeavor I choose to pursue. The folks who believe you deserve all they get and a dollar more besides...
cheers,
Douglas
You need to get out more. Valve preamps have a considerable number of very serious deficiencies. Few of which you have cared to acknowledge. Valves offer no tangible advantages over a well designed and implemented solid state preamp. Unless, of course, you regard the various distortions generated by valve preamps (microphonic issues, phase shift and distortion problems, etc) as good things. For my part, I prefer accuracy over such distortions.
 
Old 6th December 2017, 09:14 PM   #202
Bandersnatch is offline Bandersnatch  United States
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IN order:
you can think what ever you want.

As far as addressing things, you are waaaay to far behind to go attempting to request somebody pay attention to something you consider important to your argument.

Valve pre-amps have no weakness-es like you mention. Well, at least what comes of my bench does not.

You know, I was thinking just exactly the same thing about you, only less politely. Like I said, do please go and believe, and as follows such belief, spread The Word as far as you can.
cheers,
Douglas
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Old 6th December 2017, 09:55 PM   #203
Zaphod Beeblebrox is offline Zaphod Beeblebrox  Australia
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Quote:
Originally Posted by Bandersnatch View Post
IN order:
you can think what ever you want.

As far as addressing things, you are waaaay to far behind to go attempting to request somebody pay attention to something you consider important to your argument.
Unfortunately, part of high fidelity listening involves the elimination of any sonic effects from the reproduction equipment. Microphonics, noise and distortion are all audible flaws that are attributable to many valve preamps. For many listeners, these faults are unacceptable. Mid-fi and uncritical listeners may not find a problem with these faults. That's OK.

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Originally Posted by Bandersnatch View Post

Valve pre-amps have no weakness-es like you mention. Well, at least what comes of my bench does not.
Oh yes, they do. The faults mentioned are audible and measurable in many cases.

Quote:
Originally Posted by Bandersnatch View Post

You know, I was thinking just exactly the same thing about you, only less politely. Like I said, do please go and believe, and as follows such belief, spread The Word as far as you can.
cheers,
Douglas
I should mention, at this point, that I have built, owned, listened to and measured a very large number of valve preamps over the past 40-odd years. Some are better than others. NONE are superior to the best solid state designs. Even those where enormous attention has been paid to microphonic problems (compliant PCB mounting, etc), noise problems (highly regulated power supplies, etc) and the other things. Transistors just do the job better and have done so for many years. And, make no mistake: There are some horrible solid state preamps out there too.
 
Old 31st December 2017, 06:07 PM   #204
TigerScent is offline TigerScent  Australia
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Quote:
Originally Posted by audiowize View Post
This is super easy. I'd parallel a pair of 7788s per channel and use a 2.5K gapped transformer for a 2A3. This would give maybe 6dB of gain and give an output impedance under 10 Ohms. More gain just requires another valve and lower step-down ratio.
Hi Bandersnatch & Audiowize ...

What would you suggest in terms of a schematic with details of components - to add-onto the schematic attached? With gain and no loss of audio quality <10ohms??
...maybe a simple circuit that can be attached as a add-on to output of the JP200 pre??

Cheers
Attached Files
File Type: pdf JP200 Preamplifier Schematic.pdf (15.7 KB, 52 views)
 
Old 31st December 2017, 06:53 PM   #205
Zaphod Beeblebrox is offline Zaphod Beeblebrox  Australia
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Quote:
Originally Posted by TigerScent View Post
Hi Bandersnatch & Audiowize ...

What would you suggest in terms of a schematic with details of components - to add-onto the schematic attached? With gain and no loss of audio quality <10ohms??
...maybe a simple circuit that can be attached as a add-on to output of the JP200 pre??

Cheers
Or, you could just use an ME preamp. You know, the preamp that your power amp was designed to be used with.

Just a thought.
 
Old 1st January 2018, 12:27 AM   #206
TigerScent is offline TigerScent  Australia
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Question hinting ??

Quote:
Originally Posted by Zaphod Beeblebrox View Post
Or, you could just use an ME preamp. You know, the preamp that your power amp was designed to be used with.

Just a thought.
... surely you are not implying that I forego my valve preamp project??
I cannot help but feel you may be hinting at this
 
Old 1st January 2018, 01:37 AM   #207
VaNarn is offline VaNarn  Australia
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Best Valve pre-amp match for ME 550 amp
It is difficult to assist TigerScent if he persists in ignoring much of the advice that has been offered to his oft repeated queries. I am at a loss to understand if he is in possession of just the JP 200 board kit or if he has the full pre-amplifier with the case ,power supply, input selector and all the other bells and whistles to suit his source requirements. As such ,whilst it would not be my choice to run this pre-amp with a solid state amplifier, let alone the more specialist M.E. one, his solution is still the same as I previously suggested; namely 'The Champ' audio amplifier* ( x2 ) available from Jaycar or Altronics. This is the easiest and cheapest solution.

* Silicon Chip Magazine, Feb., 1994
 
Old 1st January 2018, 04:40 AM   #208
Zaphod Beeblebrox is offline Zaphod Beeblebrox  Australia
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Quote:
Originally Posted by TigerScent View Post
... surely you are not implying that I forego my valve preamp project??
I cannot help but feel you may be hinting at this
The real question is this:

WHY do you think a valve preamp is appropriate, or even superior to an ME, or another low output impedance design?

Precisely what technical details do you think the ME preamps lack, that a valve (any valve preamp, apparently) possess?

Valves are noisy, inconvenient, change their characteristics, from the moment they are switched on, require coupling components that shift phase, add distortion and generally bugger up sound quality. Which is not to say that some of these problems can be minimised (but not eliminated), but at huge cost.
 
Old 2nd January 2018, 02:53 AM   #209
anatech is offline anatech  Canada
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Best Valve pre-amp match for ME 550 amp
Hi Zaphod Beeblebrox,
No, the real question is why you are taking someone to task over a curiosity they are exploring. They don't have to answer to your line of questioning, and I couldn't help but notice that you didn't offer any information or helpful ideas in your posts.

If you disagree with this technology, you should ask yourself why you are even in this forum to begin with. I don't believe it is so you can be helpful, so therefore you are looking for something else.

I'm going to ask you nicely to leave this area and go post on subjects you can offer help or positive ideas on.

-Chris
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Old 2nd January 2018, 03:56 AM   #210
TigerScent is offline TigerScent  Australia
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Quote:
Originally Posted by VaNarn View Post
It is difficult to assist TigerScent if he persists in ignoring much of the advice that has been offered to his oft repeated queries. <snip>
I was looking for a solution that would not rely on any IC componentry in the preamp valve section...

...interestingly Peter Stein who designed and manufactured the ME, knew what I was doing and gave me information I asked him about...he did not have an issue with me doing what I am trying to do, so I don't know why anyone else would...
 

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