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Topics - john

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1
Tape Tech / Head Azimuth Alignment
« on: January 16, 2012, 10:28:35 AM »
Just doing an alignment on my Revox C270 and I am having trouble getting a stable pattern on the oscilloscope at 10Khz and 15Khz. I get a stable reading at 1Khz this I understand is par for the course but just what causes the lissajous pattern to open and close  at 10 and 15Khz is it mechanical, electrical or both !

2
Reel to Reel Tape Machines / Revox C270, playback mods
« on: July 07, 2010, 08:10:34 AM »
I'm interested in making modifications to the playback performance of my C270 and wondered if anybody else here has attempted to do the same either solid state or with Valves/Tubes.

3
General Discussion / Luxman Amp Bias
« on: January 31, 2010, 02:55:40 PM »
Hi everyone, I bought recently  a Luxman integrated amp ( SQ-38 Signature ) whilst checking it I noticed one output tube running a lot cooler than the rest. I checked the bias setting on that particular tube, there isn't any !! absolutely nothing. The other three bias fine
 ( 40mv )  there is continuity from pin three to the circuit board, swapping tubes around makes no difference, any ideas? tube compliment is four EL34, two BH7A and four 12AU7. Unfortunately I don't have a schematic but found this on the web.

 http://audio-database.com/LUXMANALPINE-LUXMAN/amp/sq-38signature-e.html

4
Reel to Reel Tape Machines / Open reel video
« on: October 05, 2009, 03:50:55 AM »
I noticed this Sony reel to reel video recorder for sale on Ebay and thought some of you here might be interested. I seem to remember this type of machine or one like it, being a topic of discussion some time ago.

  http://cgi.ebay.co.uk/SONY-AV-8650-COLOR-Reel-to-Reel-Video-Recorder-Vintage_W0QQitemZ120476336343QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item1c0cf300d7&_trksid=p3286.c0.m14
                                                                                           John.

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Reel to Reel Tape Machines / Butterfly heads.
« on: January 29, 2009, 12:23:54 PM »
I recently came across an advert for a pair of butterfly heads for a Revox C270 is there an advantage in using them over the standard heads. They are very expensive 560GB pounds so i assume that there is.

6
Tape Tech / Oscilloscope for RTR Alignment.
« on: January 25, 2009, 03:26:49 AM »
I'm considering the purchase of an oscilloscope, what are the minimum requirements for tape machine use/alignment. Analogue or digital, frequency etc. below is the spec of one that I'm considering.

Scope Description

2 independent  floating channels

Max sensitivity vertical 5V per div

Min sensitivity 5mV per div 17.5nS rise time

25MHz with 100MS/S sample rate

Trigger Edge,Normal, Single, Auto, TV

Auto measurement of frequency, peak to peak voltage, true RMS voltage, average period.

Math add, subtract, multiply, divide, one channel by the other

Would this be suitable?

7
Raw Tape / Sticky shed symptoms
« on: January 14, 2009, 01:01:01 PM »
So there i was happly rewinding (at play speed) on my Teac X2000R,  tapes I had purchased on Ebay. A collection of classical and opera, just to makes sure they were not wound too tight on the reels. This takes some time of course so I left to make myself a drink. I was greeted on my return by the sight of a small amount of off white powder lying on the desk below the pinch wheels and a white coating the tension arm wheels and heads. I cleaned it off with tape head cleaner, out of twelve 10 1/2 tapes eight were ok ( maxell LD ) and the remainder a mixture of Scotch 207 and 3M were not!! So my question is, is this classic sticky shed or for want of a better description are the Scotch and 3M tapes diseased!!!!
To be safe I have already thrown the tape away and kept the reels, at first I thought it might have been mold but now I'm not so sure.

8
Raw Tape / Ampex GM3600 Grand Master
« on: August 05, 2008, 10:40:52 AM »
Does anybody have experience or knowledge of this tape? I have seen some nos for sale, just curious.

9
Raw Tape / Tape types
« on: August 01, 2008, 11:00:14 AM »
Can anyone explain to me the differences in the various formulations, i am new to r2r but have used cassette tapes for years. One of the reasons cassette was able to close the gap with r2r was better tape stock eg, metal tape or chrome. My question is are any of the various r2r tapes available metal/chrome? and if not why not!! what do the numbers, 468,478,499, 900,911 and GP9 mean?

                                                                         Thanks, John.

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