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Messages - stellavox

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226
Want to offer to do the above mentioned services.  Have done repair / mods / upgrades for 30 years now on many brands of decks including Ampex; Studer and Technics.  Specialize in Stellavox.

By "integration" I mean adapting one type of playback or record/playback electronics to work with a different transport - which is what stimulated Doc's interest in this tape project in the first place.

Pictures of a Stellavox SR-8 undergoing a "switchectomy" and my latest personal playback/dubbing setup using modified MCI JH-110's are attached.

Charles King
[email protected] 

227
Reel to Reel Tape Machines / Re: MRL tape
« on: January 25, 2007, 06:49:03 AM »
AZ_Gary,

According to my info for a Reference Fluxitivity of 250 nWb/m, then it is the 15ips IEC tape #21J203.  Cost is up around $100 now.

They do have 3 other tapes depending on the ref flux. - from 200 to 355.  Doc/Paul - what tape will you be using?

If you're not going to be recording withthe deck, then the actual ref. flux. is not that critical - the azimuth and frequency response tones are what you really need.

Charles


228
Suggestion Box / Re: Test tones on ALL tape releases??
« on: January 21, 2007, 07:21:37 AM »
Paul,

Star Wars experiences PLEASE - as you feel the urge.  Otherwise, thanks for the fascinating background!

Charles 

229
Reel to Reel Tape Machines / Re: Technics RS1500 head rewiring
« on: January 20, 2007, 07:48:19 AM »
Xavier,

I'd suggest wiring the cables from the outboard tape preamp to the center contacts on the headblock switch.  This retains the ability to select either 2 track or 4 track playback head - so you can play both tape types if you have them.  As I mentioned in my mod post - the switch is of very good quality, with gold wiping surfaces.  I do suggest taking it apart carefully and cleaning / lubricating, it as the few I worked on were pretty dirty.

A word of caution - don't lay the machine down on its face without some way to prop it up slightly or you risk breaking the switch lever on the headblock, along with the possibility of bending the reel table posts.

I used the Cardas cable which Doc likes - its available from Welborne Labs.  It has two center conductors so I suppose you could get by with only one cable - but run the risk of crosstalk - anyone tried this?

Another 1500 series "foible" I stumbled across was a noticeable reduction in tape tension when the machine was on its back versus standing upright.  Anyone else noticed this? Solution?

Charles

230
Suggestion Box / Re: Test tones on ALL tape releases??
« on: January 18, 2007, 06:44:09 AM »
Paul,

I believe that a separate MRL tape is an unnecessary expense - Plus there are unnecessary tones on the tape.  If the playback deck is of any kind of good quality, knowing/being able to adjust the machine at 100hz, 1Khz and 10 khz are within say +- 1dB is all you need to be able to do - the "flatness" over the rest of the band is up to the head/electronics.   3 tones of 20 seconds each - plus the 1khz allows you to set channel balance is all you need - total of 1 minute.  Splice them at the beginning of the first tape and put 6 ft. of leader between so that a user can "fast forward" past them if he/she doesn't want to bother. 

Here's a question - do your masters you plan on using have these test tones?  A number of the masters I have do.  If your's don't, how do you know if the machine they were recorded on was in fact in calibration that day?  Once the tones are on the tape with the original material they are ALWAYS there "thru thick and thin" - even if the subsequent playback/recording (dubbing) chain is in fact slightly?? out of EQ.   

I do agree that once a quality machine is set up correctly, it will stay there - for a LONG time - if not bounced around.  This is where tape has it ALL OVER the finicky LP. 

Charles

231
Prerecorded Tapes / Re: Barclay-Crocker tape catalog?
« on: January 17, 2007, 02:57:20 PM »
I have a catalog and a catalog for Direct to Tape recordings (from New Jersey as I recall) - someone want to copy it?

Charles

232
Suggestion Box / Test tones on ALL tape releases??
« on: January 17, 2007, 10:40:07 AM »
Doc,

I may have missed this topic and you may already have it covered - if so I apologize.  I feel it is imperative for you to put (mono, 1Khz?) channel balance and say 3 test tones (100hz, 1K and 10K) at the beginning of EVERY tape, so the customer can check the channel balance and (rough) EQ of their machine.  On second thought, put it at the end of the tape.

Charles

233
Reel to Reel Tape Machines / Technics 1500 series suggestions
« on: January 17, 2007, 10:30:43 AM »
Not to denigrate Doc B's tubed Seduction NAB tape preamp efforts in any way; but I did a 1500 mod for a customer that worked out REALLY well.

Added a new set of high quality RCA's on the back next to one pair of the existing (cheap) paralled line output jacks. Wired a shielded cable from it directly to the output of the tape preamp section in parallel with R197 just before the monitor select switch. When this switch is in the "source" position, the tape preamp output is "unloaded" i.e. disconnected from the rest of the circuitry. Also changed C151 to a high quality mylar and C's 159 and 193 to Elna Cerafine's. Tape preamp is a decent simple design.

Sounds REALLY nice, although the gain is down about 15 dB from the main output jacks - about the same as from a Seduction. Don't have a way to compare them but bet it would be close. So you do need to feed the signal into a preamp with 15dB or more of gain and an input impedance of at least 10K ohms.

"Tweaked" 15ips response is within 2dB from 35 hz to 20kHz (upper limit of my Sound Technology 1500A). 7 1/2 response within 3dB from 35hz to around 18 Khz. NOT shabby! Record sounds VERY good also - with better line input jacks and better caps. Record/playback response tweaked to same as above. Power supply voltages to the electronics are regulated.

Regarding IEC equalization - in the playback amp, this appears to be switched in via transistor TR128. and it appears that the components to add this equalization are built it to all the 1500 series "Main Amplifier" PC boards - but this function is only enabled on the "higher order" models (1520). I don't have enough of the schematics to fully analyze this however, so I can't suggest if/how it can be turned on or off.

Keep your heads clean and your tails out!

Charles King


234
Prerecorded Tapes / Two-track Stereo Tape "tapeography"
« on: January 16, 2007, 06:47:51 AM »
I've been working on and updating a two-track stereo tape list for 15 years or so.  These tapes were all produced between (roughly) 1955 and 1960 when they were superceeded by 4 tracks.

Can see the latest list here:

http://launch.groups.yahoo.com/group/Reel_Tapes/files/

It includes all the Capitol listings I could find.
 

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