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Old 18th March 2013, 07:58 PM   #31
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The DL103 is a poor choice by modern standards.
It has 40 Ohm Johnson noise and not much output.
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Old 19th March 2013, 01:47 PM   #32
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Quote:
Originally Posted by Joachim Gerhard View Post
The DL103 is a poor choice by modern standards.
It has 40 Ohm Johnson noise and not much output.

The DL103R is 14 Ohms. What's the point anyway? It's easy to get the background noise well below the noise when dropped into an unmodulated grove.
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Old 19th March 2013, 05:51 PM   #33
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I would like to suggest that replacing R4 (825k) with a red LED will drop the noise pretty significantly.

Just happen to have a bunch of THAT340's on hand...
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Old 14th September 2013, 12:42 AM   #34
RNMarsh is offline RNMarsh  United States
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Hello --

I didnt even know this subject existed until doing search on the Web about measuring Rbb and saw this .....

i owned a Denon DL103 so that is what i used. Medium output voltage.

I just had access () to those transistors I used - so i used them. No attempt to make the worlds lowest noise MC step-up but it was very quiet in the home music system. I had a Denon step-up transformer to compare against for noise and distortion and response.

The important point I wanted to find out was -- if a lower than 100 Ohm cart load (the typical MC value used) made the sound have lower distortion as was reported via listening by Peter Moncrief, then could I make the input Z of a MC pre-preamp with a very low z and would it sound even better -- or at least better than what I had been using. What would it sound like to My ears. The passive Rload on the cart had been to make it sound 'cleaner' and lower distortion but, of course the cart output level was reduced as well. So it was just an interesting affect but not practicle.

It was developed to provide a very low input Z, direct coupled as much as possible and a sysmetrical design with the benefit of lower distortion coming off the cartrdige.

--- now that i dont even have a phono/LP any more --- to maximize its potential with better transistors etal. I gave it to Kavi, also. If I had a phono system I would love to hear what improvements you will make to it.

Eventually - try to see how the cartdrige distortion is affected, somehow.

The gain is somewhat self leveling by input Z of cartdrige, it seemed [lower output and lower Z cart... higher gain]. well, that was the idea. i dont remember much more about it anymore. I hope this info helps you in some way.

Enjoy !

Thx-RNMarsh

Last edited by RNMarsh; 14th September 2013 at 01:07 AM.
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Old 15th September 2013, 05:58 PM   #35
RNMarsh is offline RNMarsh  United States
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Linear Audio will be publishing a remake of this MC pre-preamp topology but using fet's instead of bipolars. Should be interesting.

Thx-Richard Marsh
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Old 20th September 2013, 08:45 AM   #36
RNMarsh is offline RNMarsh  United States
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Has anyone put this little circuit to the SIM yet?

might be good - might be bad. Erno's method should be fine I would imagine. I had the JC MC (battery powerd) pre-preamp and a Denon transformer that is made for the Denon 103 cart and could compare but could not measure things like s/n and distortion at MC levels back then. At that time, I had a high efficiency custom made 3-way all JBL system and there was no noise heard (all horn... bass... mid..highs). Triamped with custom variable crossover and seperate amps. It was quiet and sounded the best of the three. I cant remeber any tech details this far beyond it.

Still looking for a follow-up on how much the distortion from the cartridge is reduced at the input to the amp via low Z loading.

THx-RNMarsh

Last edited by RNMarsh; 20th September 2013 at 08:51 AM.
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