Best Valve pre-amp match for ME 550 amp - Page 8 - diyAudio
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Old 10th January 2013, 02:30 AM   #71
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Quote:
Originally Posted by Zaphod Beeblebrox View Post
The secondary windings are connected to the input of the ME550.
So the 550 is not plugged into 240v power, but instead is powered by the secondary windings of the preamp transformer. What about the secondary windings that connect to the preamp as well, are they secondaries then connected to preamp and the input of the 550 (instead of it being plugged in) or am I missing something ??
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Old 10th January 2013, 02:34 AM   #72
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Originally Posted by TigerScent View Post
So the 550 is not plugged into 240v power, but instead is powered by the secondary windings of the preamp transformer.
NO! You are buying a pair of AUDIO COUPLING transformers to add to your preamp, in order to lower the output impedance to a suitable figure. Those transformers (one for left and one for right) are connected between the output of the preamp and the audio input of the power amp.

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Originally Posted by TigerScent View Post
What about the secondary windings that connect to the preamp as well, are they secondaries then connected to preamp and the input of the 550 (instead of it being plugged in) or am I missing something ??
Consider my offer of a loan ME preamp. You will rapidly dispense with your experiment that I suspect you are not qualified to perform.
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Old 10th January 2013, 02:52 AM   #73
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Quote:
Originally Posted by Zaphod Beeblebrox View Post
NO! You are buying a pair of AUDIO COUPLING transformers to add to your preamp, in order to lower the output impedance to a suitable figure. Those transformers (one for left and one for right) are connected between the output of the preamp and the audio input of the power amp.
ahhhh, well now its making more sense...lol (It didnt make much sense to me, but in case there was some esoteric element to the whole thing ie: using the secondary in both the secondary in the preamp and secondary in the power amp at the same time, is what I was actually thinking, but the way you wrote it, made it hard to follow, so just 'asking'. I knew you would correct me

so, can you specify the audio coupling transformers I should use (ie: RS components or element14), based on the pcb and 550?


Quote:
Originally Posted by Zaphod Beeblebrox View Post
Consider my offer of a loan ME preamp. You will rapidly dispense with your experiment that I suspect you are not qualified to perform.
I am a beginner - we all start somewhere. I am learning as I go along --- which is why I ask questions

I might take you up on your loan offer when I put the silver wiring in my 550...

Last edited by TigerScent; 10th January 2013 at 03:05 AM.
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Old 10th January 2013, 02:38 PM   #74
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So would the Audio Coupling transformers have any bearing on the degradation of quality of sound? If not; then high impedance is a moot point - and easily rectified...
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Old 10th January 2013, 07:48 PM   #75
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Originally Posted by TigerScent View Post
So would the Audio Coupling transformers have any bearing on the degradation of quality of sound? If not; then high impedance is a moot point - and easily rectified...
Of course. Transformers introduce phase shift, frequency response errors, distortion, etc. Nothing is without (audible) cost.
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Old 10th January 2013, 09:44 PM   #76
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Of course. Transformers introduce phase shift, frequency response errors, distortion, etc. Nothing is without (audible) cost.
So, there must be a way of rectifying/counterbalancing that then, as they are used in circuits - so surely there is a simple enough way of doing that?
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Old 10th January 2013, 11:30 PM   #77
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Originally Posted by TigerScent View Post
So, there must be a way of rectifying/counterbalancing that then, as they are used in circuits - so surely there is a simple enough way of doing that?
Avoid them. Use the appropriate technology to deal with the problem. Valves are not the appropriate technology to deal with your problem. SS is. That said, high quality transformers (which are expensive) will do pretty much all you require, without serious degradation of performance. Frankly though, I can't see why you would bother. A zero GNFB, low output impedance SS preamp is exactly what you need. Think of it this way:

Take a crappy, 20 year old Hyundai Excel, with bad tyres. Bolt a fifth wheel to it and you may well gain an improvement.

Now take a new Porsche 911, shod with Pirelli P-Zeros. Bolt a fifth wheel to it and you can pretty much guarantee that you will damage it's performance. That is what you are trying to do with your ME550 - cripple it's performance.
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Old 11th January 2013, 12:47 AM   #78
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Quote:
Originally Posted by Zaphod Beeblebrox View Post
Avoid them. Use the appropriate technology to deal with the problem. Valves are not the appropriate technology to deal with your problem. SS is. That said, high quality transformers (which are expensive) will do pretty much all you require, without serious degradation of performance. Frankly though, I can't see why you would bother. A zero GNFB, low output impedance SS preamp is exactly what you need. Think of it this way:

Take a crappy, 20 year old Hyundai Excel, with bad tyres. Bolt a fifth wheel to it and you may well gain an improvement.

Now take a new Porsche 911, shod with Pirelli P-Zeros. Bolt a fifth wheel to it and you can pretty much guarantee that you will damage it's performance. That is what you are trying to do with your ME550 - cripple it's performance.
...so which high quality transformers would you recommend to use - given that there would need to be a selection made ?
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Old 11th January 2013, 02:54 AM   #79
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...so which high quality transformers would you recommend to use - given that there would need to be a selection made ?
I don't know. I would need to spend several hours trawling the web to find them. I'll leave that to you.
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Old 12th January 2013, 01:26 AM   #80
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I don't know. I would need to spend several hours trawling the web to find them. I'll leave that to you.
Yes, Ill have to go through it with a fine tooth comb. I am very optomistic about this however, seems like it has not been tried before, or at least to a significant enough degree --- quite exciting really....
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