Telefunken M15 vs Studer A80RC

DasguteOhr

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Sep 26, 2013
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seems to have survived the two years in the box well, all functions work. hear a little tomorrow:p
funktionstest.jpg
 

adrianywu

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Nov 15, 2021
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I build head preamps by modifying our VK-P10/12 phono stages, the modification is not complicated, I have done four so far, one is working with A80.
Hi Victor, are you doing the mod for customers ? Any chance of accommodating more than one Eq ?
 

Foxbat

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Jun 11, 2020
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No, all these just for my personal use. As far as different EQ's - yes. All the ones I built have on their front panel two toggle switches and four trimpots with digital dials. This allows you to set any two EQ curves. For instance, one unit is set to have 15ips NAB/IEC, and the three others have the 15(IEC)-30ips selection. For each unit there is a card with the digital dials settings, so it can quickly be switched, should I want a different pair of settings.
 
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adrianywu

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No, all these just for my personal use. As far as different EQ's - yes. All the ones I built have on their front panel two toggle switches and four trimpots with digital dials. This allows you to set any two EQ curves. For instance, one unit is set to have 15ips NAB/IEC, and the three others have the 15(IEC)-30ips selection. For each unit there is a card with the digital dials settings, so it can quickly be switched, should I want a different pair of settings.
That's great. You should offer this to commercial customers, since there is a demand for a good tube based tape head preamp. I built a fully differential tube preamp from my late friend Allen Wright's RTP-3C design almost 20 years ago, and put it in storage after I bought a factory unit. I took it out about 5 years ago and modified it with a similar approach to yours. I changed the RIAA section to accommodate CCIR and Nagramaster (which I use for my live recordings). The result was better than I had imagined. I connected the repro head from the Nagra T with just plain twisted pure silver solid wire in PTFE insulation to the preamp, and played around with the input capacitative and resistive loading to get a response more or less similar to what you showed with your preamp above. It was only down 1.2dB at 20K. The sound is much more natural, with much better tonality, greater depth than the native repro electronics. I always found the Nagra T sounding a bit electronic in the past, although the sound is very dynamic. My recording partner, who owns a Nagra T and a Telefunken M20, is very interested in a tube tape head preamp, and I think your preamp will suit him to a T !
 

andromedaaudio

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Here is mine, calibrated and measured by myself. :) I can't quite read the scale on yours. I usually set the upper frequencies at about +.5dB.

I can be as anal as anyone else, however, flat FR has almost nothing to do with sound quality.
The scale he used with my M 15 A is marked with a black X .
The upper thick black line is + 2 db and the lower line is -2 db .
The thin lines separate 0,4 db
My machine stays within + - 0,4 db over the 60 hz - 20 khz range .
At 30 hz its 2 db down

In my experience it has everything to do with sound quality .
Its a prerequisite for good accurate sound but off course doesnt tell the whole story
Tonallity / dynamic swings need to spring/ emerge from a neutral line ,
if not dynamics swings are perceived as much less vivid / accurate.
The speakers i design measure flat as well and i am being used to this for 5 - 6 years now (regarding this particular speakerdesign)
Non linear/ accurate reproduction becomes immediately annoying at a show / dealer

1637051425366.jpeg
 
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andromedaaudio

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My XPE design measures 400 hz - 10 khz +- 2,5 db .
1/6 octave smoothfactor.

And with 1/2 octave smooth factor its 700 hz -20 khz +- 1 db
 
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andromedaaudio

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Recording - Reproduction is a chain .
CD players measure flat ( 0, something range , amps measure more or less flat and for a reason i suppose
Speakers have more problems but lets say +-3db is acceptable
 

andromedaaudio

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My 2 studer B62 s measure less accurate , they have the same cards as an A 80
1,5 db down at 100 hz , same scale
Between the thick black lines is 2 db difference ( i hope you can see it now ) 1637055759805.jpeg
 
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Foxbat

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Jun 11, 2020
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That's great. You should offer this to commercial customers, since there is a demand for a good tube based tape head preamp. I built a fully differential tube preamp from my late friend Allen Wright's RTP-3C design almost 20 years ago, and put it in storage after I bought a factory unit. I took it out about 5 years ago and modified it with a similar approach to yours. I changed the RIAA section to accommodate CCIR and Nagramaster (which I use for my live recordings). The result was better than I had imagined. I connected the repro head from the Nagra T with just plain twisted pure silver solid wire in PTFE insulation to the preamp, and played around with the input capacitative and resistive loading to get a response more or less similar to what you showed with your preamp above. It was only down 1.2dB at 20K. The sound is much more natural, with much better tonality, greater depth than the native repro electronics. I always found the Nagra T sounding a bit electronic in the past, although the sound is very dynamic. My recording partner, who owns a Nagra T and a Telefunken M20, is very interested in a tube tape head preamp, and I think your preamp will suit him to a T !
Problem is - to do it right would take some thinking, planning and careful execution, meaning time, which is not easily obtainable, as I am already working on several projects. What I do for my own use has rather crude interface, which is fine for me. Most importantly, as I mentioned, the market for such product would likely be 1/100 of that for phono stages. As we know, the LP's market share has been growing steadily, and today they outsell the CD's in dollars, soon will overtake them in volumes. The sales of pre-recorded tapes are miniscule by comparison. So the bottom line is - perhaps in the future... I am still thinking... :)
 
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adrianywu

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Problem is - to do it right would take some thinking, planning and careful execution, meaning time, which is not easily obtainable, as I am already working on several projects. What I do for my own use has rather crude interface, which is fine for me. Most importantly, as I mentioned, the market for such product would likely be 1/100 of that for phono stages. As we know, the LP's market share has been growing steadily, and today they outsell the CD's in dollars, soon will overtake them in volumes. The sales of pre-recorded tapes are miniscule by comparison. So the bottom line is - perhaps in the future... I am still thinking... :)
Perhaps offer the instructions for customers to do their own modifications ?
 

Foxbat

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I have never been opposed to that, and have already provided such help to some customers.
 
Jan 18, 2012
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play the end of Midnight Sugar on M15 now and the A80RC MTSL nukes it out of the water!
....less precise and soundstage narrowed in by a couple meters......sounds are charming but flopping around tbh
my wife commented on it too........less precise and untidy

1640105434924.png
 
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Audiophile Bill

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Mar 23, 2015
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play the end of Midnight Sugar on M15 now and the A80RC MTSL nukes it out of the water!
....less precise and soundstage narrowed in by a couple meters......sounds are charming but flopping around tbh
my wife commented on it too........less precise and untidy

View attachment 86725
Sounds like the M15 might have more w&f than the A80RC MTSL.
 

Ron Resnick

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Jan 24, 2015
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I would love to get an excellent condition M15, but I have been, as yet, unable to find an M15 technician in Southern California.

(I bought A820s primarily because the tape machine restorer/technician in Southern California I found specializes in A820s. In other words, I found a technician first, and then bought whichever machine he happened to specialize in.)
 
Jan 18, 2012
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I would love to get an excellent condition M15, but I have been, as yet, unable to find an M15 technician in Southern California.

(I bought A820s primarily because the tape machine restorer/technician in Southern California I found specializes in A820s. In other words, I found a technician first, and then bought whichever machine he happened to specialize in.)
probably a wise move
I buy what I locate if interesting
then I get the manual and start the learning to be close to self supporting
if crises, I´ll always find someone with necessary knowledge (and patience) :D
but I don´t like to be dependant on the fire brigade to solve things, if I haven´t even tried myself
 
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andromedaaudio

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These are solid machines .
Simple straightforward functional german tech.
I have owned it now for 6 years or so , it never missed a beat .
Plus its not that big /heavy like a A 80 ; easy to transport / ship .
I would recommend the Eternal arts tape stage to go with it
 
Jan 18, 2012
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These are solid machines .
Simple straightforward functional german tech.
I have owned it now for 6 years or so , it never missed a beat .
Plus its not that big /heavy like a A 80 ; easy to transport / ship .
I would recommend the Eternal arts tape stage to go with it
A80RC is in a selfsupporting frame and even smaller than a M15 with onboard audio cards
A80R however is "anchored" to the trolley, which makes it a major pain to disassemble for transport
 

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