Tapeheads Forums


Go Back   Tapeheads Forums > General Audio Discussions > Specialties by Manufacturer > Teac/TASCAM

Universal Capstan Motor
Reply
 
Thread Tools Display Modes
  #1  
Old 09-17-2011, 10:25 PM
vinyldavid's Avatar
vinyldavid vinyldavid is offline
Proud Jaguar Owner
 
Join Date: May 2008
Location: Ballwin, MO
Posts: 2,798
Teac A-3340S abnormally high output level?

Here's an odd issue-

I have been giving my A-3340S some exercise and decided to see what the signal looked like on the inputs of my Technics RS-1500 and Tascam 34B. All decks are routed through a DBX 200, a fully passive device.

Output controls on the A-3340S were setup at the 3 o'clock position (9)-where there is a boldface line on the markings which I always thought denoted "happy output" level. The meters on the A-3340S were reading normally-average level around -5db, but I noticed that my volume control was very low, which prompted this investigation.

So I switched the RS-1500 and 34B into input monitor mode and immediately the meters pegged. The Tascam 34B's input level controls are at the detented calibration point. I rolled the Tascam's output level controls back to 1 o'clock (6) and the meters on the 34B read normally but the meters on the A3340S are peaking at-10db.

Is this a meter calibration issue? I haven't run signal through the deck and back out in a long time, I'll do that tomorrow and see what happens, but this is an odd issue.
__________________

Technics SL-1200mk2, Ortofon OM20, Hyper-modded Audio Research SP3, Poseidon'd Dynaco MkIII's (or a Yamaha PC-5002M), Klipsch Chorus II's
The Deck Collection: Ampex AG-440B (x2), Ampex AG-351, MCI JH-110C, Teac A-3340S, Tascam 34B, 48, 122B, DA-38, 3M 1/2" 4tk M64, Technics RS-1500, Tandberg 62x, Teac 3300S, Otari MX-5050, and more!
Reply With Quote
  #2  
Old 09-17-2011, 11:05 PM
Skywavebe's Avatar
Skywavebe Skywavebe is online now
Skywave Tape Deck Repair
 
Join Date: Jul 2008
Location: Bensenville, IL
Posts: 7,081
Hello Vinyl,
This is a classic condition of too many people getting their hands on the unit and trying to do what they want with it rather than a calibration according to service manual specifications.
It is also an example that people can go on for a long time thinking everything is good when in fact the deck can be far out in left field.

OK, the specified output level can be at the 2 o'clock in some machines and then the other at 3'oclock. Depends on the vintage of the machine you have- there were three different classes of machine one with slide switch transport, next was the full solenoid with black lower electronics and the newest one was the gray or green like electronics which is the newest one made.
Now, the problem you have to find is at what level was the deck calibrated to- this means the playback output level. For instance, the regular level was the Ampex standard of 185 nWb/M at 0 Vu. Then there is the next step up which can be the MRL alignment tape at 200 nWb/M flux density. Then another tape may have been the MRL tape for 250 nWb/M flux density. Then it is possible with some characters that the flux density could have been adjusted for 320 or 355 nWb/M flux density only because the deck has 15 IPS.
The calibration procedure which is the only way to determine why this is the way it is, is to play the reference tone of an alignment tape if only to see where it lands and at the same time measure for the correct output level at the output jacks to confirm the right level is output and then to see what they have the meters set to. The output can be one thing and the meters are not fixed they can be adjusted to all kinds of values. If a person is tinkering as a lot of school AV department do, they will have the unit all screwed up until it get back to a factory service or ME.
What should happen is that with the specified output selected the meters should indicate around 0 Vu and the output should be either at 0 dBu or -8dBu depending on the model you have. The -8 dBu level should be compatible with all Tascam equipment inputs that are RCA type jacks, the 0 dBu might be a bit hot.
Listening to music on a deck does not allow one to find out how badly set up it is. Meter on a deck can show correctly while actual output can be all over the place. So you need an alignment tape, AC millivolt meter and Service manual for the deck you are working with to really determine where you are
__________________
Best regards,

Sam Palermo, BSEE, past Broadcast Engineer
Skywave Tape Deck Repair- Chicago area
(630)616-0932 Office/ 708-334-2260 Cell, E mail:skywavebe@sbcglobal.net
Past Teac/Tascam Lead Service Technician at Chicago Factory Service still doing repairs.
http://www.thumbtack.com/il/bensenvi...tascam-repairs
Need Tape? http://www.splicit.com/index.html, The BEST SM are from Stereomanuals.com!
Reply With Quote
  #3  
Old 09-18-2011, 12:41 AM
vinyldavid's Avatar
vinyldavid vinyldavid is offline
Proud Jaguar Owner
 
Join Date: May 2008
Location: Ballwin, MO
Posts: 2,798
I got this one from a local high school 5ish years ago, and according to the seller, it had been barely used and never really messed with. However, there is an Antech Labs sticker on the thing so obviously they had their hands on it at one point. I'm not sure if this school had an in-house tape tech, it was reportedly taken from an installation where it had been placed when new and hardly used or moved.

The last time I seriously used this deck I had no calibration reference-now I have the 34B which was very close to 0db=316mV at input calibration. I've been inside the thing only once, to check the belts and lube the counter last year. I've never messed with any of the internal settings.

I do have a voltmeter and a service manual for the unit, and tomorrow I'll dig out my tone generator and see what makes it read 0db from input.

I'd love to have you service, calibrate, and align all my decks at some point, but I doubt I'll ever have the sort of cash it would take to make that happen.

Thanks for the starting point! I'll report back tomorrow.
__________________

Technics SL-1200mk2, Ortofon OM20, Hyper-modded Audio Research SP3, Poseidon'd Dynaco MkIII's (or a Yamaha PC-5002M), Klipsch Chorus II's
The Deck Collection: Ampex AG-440B (x2), Ampex AG-351, MCI JH-110C, Teac A-3340S, Tascam 34B, 48, 122B, DA-38, 3M 1/2" 4tk M64, Technics RS-1500, Tandberg 62x, Teac 3300S, Otari MX-5050, and more!
Reply With Quote
  #4  
Old 09-18-2011, 01:08 AM
goldear goldear is offline
Serious Tapehead
 
Join Date: Jun 2011
Posts: 709
David,

A regular volt-meter will not cut it for tape deck calibration. You need an AC milivolt meter. This is a very task specific device. Even a very high quality multimeter will barely register at these levels.

Also, the meters needs to have a dB scale and to have a flat and extended FR characteristics.
__________________
R2Rs: Sony TC-880-2, TC-766-2, TC-765, Tascam 44OB, 52, Otari 5050 BII & BQII, Tandberg TD-20A & SE, 64X, Revox A/B77, A700, G36, MCI...
Cassettes: Tandberg 3014A, 440A, Nak CR7A, CR4A, BX300, 700, Revox B215s, B&O 9000, Kyocera D810, Pioneer CT-F900, BIC T-3...
Reply With Quote
  #5  
Old 09-18-2011, 01:28 AM
vinyldavid's Avatar
vinyldavid vinyldavid is offline
Proud Jaguar Owner
 
Join Date: May 2008
Location: Ballwin, MO
Posts: 2,798
Right now I'm going for reading 0.316v at 1kHz. I know that a regular multimeter won't cut it, bit I don't intend on making any changes to anything but raw level controls, as the rest of the deck sounds good and had good response.
__________________

Technics SL-1200mk2, Ortofon OM20, Hyper-modded Audio Research SP3, Poseidon'd Dynaco MkIII's (or a Yamaha PC-5002M), Klipsch Chorus II's
The Deck Collection: Ampex AG-440B (x2), Ampex AG-351, MCI JH-110C, Teac A-3340S, Tascam 34B, 48, 122B, DA-38, 3M 1/2" 4tk M64, Technics RS-1500, Tandberg 62x, Teac 3300S, Otari MX-5050, and more!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Teac 3340S Help Please !!! javelin Reel To Reel 4 09-16-2011 11:40 AM
Denon DR-M24HX Output Level Pots ?? CottonSwab Cassette 5 07-23-2011 02:58 PM
Cartridge Output Level Variations braxus Turntables and Vinyl 4 01-28-2011 11:00 AM
A whole nutha level of high priced tape! perry Blank Cassette Tape 34 12-04-2010 01:42 PM
Strange reference level output jazzgene Nakamichi 11 10-06-2010 09:58 AM



For more Tapeheads affiliates and links, see the Links and Resources page.
Would you like to see your company or site here?  CONTACT US


All times are GMT -7. The time now is 09:41 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 2013, Tapeheads.Net. All rights reserved, no use of any element incorporated into this site without express written permission.