New (to me) ST 1510A question

[tapepath]

Hello,
I just received a Sound Technology 1510A tape recorder test instrument and have managed to download and print the owner's manual. My question deals with the "self test" operation. During the test the display cycles from "A" to "T" then quickly goes through "UVWX...". Then the display says, "test complete rev 14", but I don't see the "I'm okay you're okay" that the manual indicates. I can hear the test tones changing as the test proceeds, but wondering if that's all it's supposed to show?
Thanks, Ken

[tapepath]

Well, I went ahead and tried some distortion and frequency response measurements and it seemed to be doing what it should. It is pretty amazing the great information it can produce. Now I have to buy a test tape from MRL to be able to check playback.
Definitely cool..!
Ken

[ironbut]

Cool Ken,
I know that there's a few ST 1510 owners here in the membership but some only visit every blue moon.
Nice piece of kit as they say.

[stellavox]

It's just fine!

Charles

[tapepath]

Beauty, thanks guys!

[Ki Choi]

It's just fine!

Charles

Say no more.... if Charles says fine.  You have a nicely working 1510A...

[C_Campbell]

I too am learning the details of the 1510A as it applies to tape recorder alignment, and in the process have put together some "working notes," including actual sequences of buttons to press for standard tests. This is still very much a work-in-progress, but I'll attach it here in two flavors (PDF, RTF) in case it proves useful to anyone else. If it appears that I've misunderstood something or you notice any corrections to be made, please let me know.

[C_Campbell]

I was curious about the original MSRP of the Sound Technology 1510A, and tried to google the original cost, but found only this web page:

http://www.broadcaststore.com/catalog/by-brands/s/Sound-Technology/Signal-Management-and-Processing/Test-Equipment/Misc-Test-Equipment/_models/1510A/1510A.htm

where it lists the MSRP as $6,450. Given that this model was introduced in about 1981, that seems an improbably high price. Does anyone have an original price list or actual knowledge of the cost of the 1510A when it was still in production?

Thanks.

[steveidosound]

I was curious about the original MSRP of the Sound Technology 1510A, and tried to google the original cost, but found only this web page:

http://www.broadcaststore.com/catalog/by-brands/s/Sound-Technology/Signal-Management-and-Processing/Test-Equipment/Misc-Test-Equipment/_models/1510A/1510A.htm

where it lists the MSRP as $6,450. Given that this model was introduced in about 1981, that seems an improbably high price. Does anyone have an original price list or actual knowledge of the cost of the 1510A when it was still in production?

Thanks.

I have a friend who worked there during the introduction of the 1st one of these. He might know or have literature with original $. The San Jose store I worked for also bought one soon after they came out. They already had ST gear on the tech benches and wanted this for our front room tape recorder and turntable set-up bench. I do remember it was pretty expensive and a rather state of the art piece of equipment for it's day.
OK, a bit more online sleuthing reminded me that it was probably the 1500 not 1510...

[C_Campbell]

Hi Steve,

I did a search of some of the rec.audio groups last night, and found two versions of a post from 1995 offering a 1510A for sale. One lists the original cost as $6500, the other as $2600, which seems more plausible.

http://groups.google.com/group/rec.audio.tech/browse_thread/thread/a98830cba50b9437/e2fa68ef8aa75e7e?lnk=gst&q=1510A#e2fa68ef8aa75e7e

FOR SALE: Sound Technology Analyzer
Steve Kuettel  
May 15 1995, 3:00 am

We have a Sound Technology 1510A analyzer for sale. In great shape, with manuals, etc. Analyzes and plots frequency response, levels, IM and THD distortion on a built-in display as well as external monitor. Was $2600 new, would like offers around $1500. Located in San Francisco, will ship.

[tapepath]

Hi Chris,
Thanks for posting your working notes, do you have the owner's manual? The differences in prices could be related to the various options that were offered. I imagine if you added the "007" 1/3 octave spectral analysis and "009" GPIB computer interface the selling price would get up there.
The problem I'm having is knowing if I've set the input reference correctly when testing the A77. Since the A77 doesn't have VU meter operation on playback I'm not sure what I'm reading. I'm using a combination of Jack Clark's service manual and the ST1510 manual to try and understand what's going on. The first step is to place the ST in the output reference level mode. With the A77 in record mode adjust the record levels for "0" VU reading. The next part is to adjust the A77 so that signal from the ST is recorded and played back it will feed the same level of signal to the ST. The ST manual says to adjust the recorder's playback levels until "0" VU is reached. On the A77 I imagine the best way to do that is to note the voltage level, on the ST, during the output calibration procedure and adjust the playback levels of the A77 to this same level while in the ST input reference level mode.
Does this make sense?
Thanks for any insights, Ken

[C_Campbell]

Hi Ken, There is a fairly standard alignment sequence for analog tape recorders, and Richard Hess summarized it as follows:

I. Repro

1. VU meter calibration
2. Repro: level (all Repro operations use MRL tape)
3. Repro: azimuth
4. Repro: high freq EQ
5. Repro: low freq EQ
6. Repro: level

II. Record

7. Record: level
8. Bias: overbias
9. Record: high freq EQ
10. Repro: low freq EQ
11. Input: level

On many machines, you calibrate the VU meter and input level first. I'm not sure about the workarounds necessary for an A77, but essentially you are setting an input level using the 1510A outputs, then setting the output/repro level with an MRL tape (and reading that repro signal level from the Revox with the 1510A inputs), then setting your record level. You can't set the output level without an MRL tape because that is the necessary source for the output level circuits. Jack Clark is a highly competent and helpful fellow, so I suggest that you check with him for A77 details. Hope this helps.

[tapepath]

Thanks, Chris, I appreciate the helpful suggestions. I do have an MRL 1510 tape and Jack indicates, in his A77 service manual, that playing a 250nW/m reference should produce 1.6v with the A77 playback level all the way clockwise. If the tape is played on the A77 and then the ST would be set with this as the input reference level. Then set the ST output levels to 1.6v and adjust the A77 record levels for "0" VU. This is assuming that if the A77 had VU operation during playback the test tape would produce "0" VU.
In fact I had an interesting thing happen with the alignment tape. I was testing the azimuth with the ST on an A77 that I had done a very thorough overhaul, all the way back to the supporting frame, cleaning everything possible. I kept getting "0" for all four of the azimuth test frequencies, no vertical bars. I thought the ST was bad, maybe the tape wasn't made correctly (very low probability of that) or (most likely) I wasn't doing the test correctly. I then setup an older A77 that is stock and found 4% phase error at the first testing frequency, smaller errors for the remaining frequencies. Put my rebuilt back on the ST and perfect response, no phase errors between the two channels.
Thanks for suggesting Jack Clark, he's been helping me for a long time with A77 and PR99 parts and tips.
Cheers, Ken

[C_Campbell]

Hi Ken,

Your procedure for working the the A77 and 1510A sounds reasonable; strange that the VU meters aren't more flexible. I'm now using a Sony APR-5003V as my primary tape reproducer, but I have both Revox C270 and C274 recorders and have called on Jack Clark more than once in restoring and servicing them. Good luck!

[tapepath]

Hello,
I've been able to make some progress with using the 1510A with the A77, thanks to Jack Clark's tutelage. When doing the initial setup of input/output levels I was getting a +1dB level on the output. As it turns out this is just an idiosyncratic characteristic of the way A77 VU meters work. When you go from the input to "NAB" monitor there's a 1dB increase in the meter reading. With this in mind I've been able to setup the bias and EQ with great results and show a distortion level less than 2% (both 2nd and 3rd order) up to +9dB with ATR tape.
One problem I did encounter was in doing the channel separation phase of the test, I was getting 0dB. I did a test "outside" of the 1510A by feeding a signal into the left channel and measuring the level present in the right channel and got around -43dB (factory specification has it at -44dB). Reading over the operation manual the 1510 shorts out one of the inputs while measuring for opposite channel's inputs. I imagine there's a relay that's not doing this on one of the circuit boards. I disconnected the opposite channel's input from the 1510 and now got the same reading as the "outside" test.
I have to say this analyzer is amazing in showing how a deck is functioning.
Cheers, Ken