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Post by blackglass on Jan 20, 2009 10:16:12 GMT
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Jan 20, 2009 17:40:13 GMT
At £99 postage to Spain, I ain't even askin'
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Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
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Post by Will on Jan 20, 2009 21:18:57 GMT
Thats definitely a sub-module from something pre-1970. On the radio side, apart from a few instances, valves stopped being used in the UK Army kit late 60, early 1970.
Vehicle harness would also be telephony bandwidth, so no good for even lo-fi.
It really does look familiar, though.
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Post by PinkFloyd on Jan 21, 2009 12:08:40 GMT
Certainly very interesting looking and @ £19.99 not expensive for what it appears to be...... maybe Rick would like to chip in here......
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Jan 21, 2009 17:36:27 GMT
Looks to be a plug-in module for the monitor section of an old recording console. www.thomas-schick.com/Siemens.htmschmitronicshop.de/images/DSCI0855.JPGUnlike the majority of todays "small boards" old school machines were user coice based so you would start out with a basic "frame" then add plug in modules to perform the actual end functions to suit your own end application,something that also makes servicing a snap since you only have to "pull" the offending module to make repairs leaving the console in a still usable state rather than having to take the whole shooting match off-line which time being money is not an option. As for this module I like the idea of using "submini tubes" and the SE Class-A pentode output : www.tubecollector.org/6021.htmwww.tubecollector.org/cv4029.htmbut would need more specifics before I could say if in my own opinion it is usable as a QUALITY headphone monitor amp. I can say I would NOT use it with Grados unless I was only interested in monitoring "signal" rather than signal quality without a changes which again the circuit being a mystery would have to be reverse engineered to identify the specific parameters needed in the replacement (is there a feedback tap ? What is the primary impedance that loads the output pentode ? what is the final gain factor) If you think about the era and what were considered studio monitor headphones of that time you will come to the conclusion that this "amp" is meant to drive a medium-high impedance load and one that needs a lot of voltage "drive" (high-MU gain tubes used in mic preamps or phono stages for instance) which is the exact opposite of what you want if you are driving the very efficient low-impedance Grado load but Beyers,older AKG and maybe early Senns it would be dead on assuming the noise levels are low enough for modern system headphone usethough the "triple" gain stage is a bit of a worry it being again an "unknown" until the unit is identified (make/model) or reverse engineered,something you need to do anyway if you want to match up the "Bus Plugin" connector to consumer audio use. Either way this is a very high gain stage and would need some tinkering to make it useable with any modern source and headphone drive which makes me question if this knucklhead selling the amp is being dishonest or fooling himself because the combination of the output load and the high gain driven by a CD player is a damn scary scenario (thinking 30dB gain here folks !). My suspician is there is both a low level line input and a high level line input for matching the monitor section input to varios subsections on the main board or maybe even a mini-mixer is involved here with each 6021 being a separate input,each scenario which would again require deciphering the bus to make it usable BTW-looks to be Telefunken/Seimens by layout so maybe the info on it is available here : audio.kubarth.com/rundfunk/index.cgi
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