Advent 100A Dolby B noise reduction.

[murugan19]

Since this thread has been resurrected, I just want to share my recent experience with the Dolby B tapes. I have some Dolby B tapes from Stereotape, Ampex (DGG recordings) and Barclay-Crocker. Interestingly, most of the squeaky tapes I have encountered are Dolby B encoded (Ampex and Stereotape). The older tapes from the 1960s do not suffer from this problem, so it could be due to a change in the tape formulation during the 1970s. Liquid silicone took care of the problem. I also find that the Dolby tapes are more prone to crosstalk, probably because they were transferred at a higher level. One tape of Pollini Chopin Etudes (DGG) made by Ampex has obvious pumping during the quiet bits, which is frustrating because the louder pieces sound great. I am using the Nakamichi NR-200, and some Barclay Crocker tapes can sound excellent. Overall though, I find it is unnecessary to use Dolby for these 4 track tapes. I have some non-Dolby tapes that sound astoundingly good, with very little noise and excellent dynamics.

Hi adrainywu,
Unfortunately, I have a couple of Barklay Crocker 4 ch tapes, and although they sound astounding (compared to their age), I do need to use Dolby B to eliminate the tape hiss on my Dokorder 8140. Maybe I'm doing something wrong?
I don't have any crosstalk (maybe because I have my headstack aligned) but the hiss is apparent during the "quiet" parts of the symphonies.
Sincerely,
John Graham

 

[tapepath]

Hello,
Unfortunately the HiFi Engine doesn't have the owner's manual for the 100A, only the service manual. Here is a link to Keith Snook's excellent web site with the complete, three part, article in Wireless World explaining the operation (including calibration) of the Dolby B noise reduction system. Dolby Laboratory was fairly controlling in how each licensed manufacturer would develop their commercial units and how they would function. In other words, if you understand how one company's Dolby B was setup then the method for everyone's else's followed the same arrangement. Anyway here is the link:

https://keith-snook.info/wireless-world-articles/Wireless-World-1975/Wireless%20World%20Dolby%20noise%20reducer.pdf

 

[adrianywu]

Hi adrainywu,
Unfortunately, I have a couple of Barklay Crocker 4 ch tapes, and although they sound astounding (compared to their age), I do need to use Dolby B to eliminate the tape hiss on my Dokorder 8140. Maybe I'm doing something wrong?
I don't have any crosstalk (maybe because I have my headstack aligned) but the hiss is apparent during the "quiet" parts of the symphonies.
Sincerely,
John Graham

Dolby NR will only eliminate the hiss coming from the tape being played realtime. It will not eliminate the hiss inherent in the recording. If the source tape has hiss, which is typical of recordings from Mercury, for example, Dolby will not fix it. You would need a single ended noise reduction system such as the Behringer SNR2000, which works very well in these situations.

 

[murugan19]

Dolby NR will only eliminate the hiss coming from the tape being played realtime. It will not eliminate the hiss inherent in the recording. If the source tape has hiss, which is typical of recordings from Mercury, for example, Dolby will not fix it. You would need a single ended noise reduction system such as the Behringer SNR2000, which works very well in these situations.

Hi Hi adrainywu,
Thank you for the reply. I will keep that in mind.
As FYI: My Advent 100A and my Teac AN-300 both do a credible job of "hiss" reduction.
Sincerely,
John Graham.

 

[murugan19]

Hello,
Unfortunately the HiFi Engine doesn't have the owner's manual for the 100A, only the service manual. Here is a link to Keith Snook's excellent web site with the complete, three part, article in Wireless World explaining the operation (including calibration) of the Dolby B noise reduction system. Dolby Laboratory was fairly controlling in how each licensed manufacturer would develop their commercial units and how they would function. In other words, if you understand how one company's Dolby B was setup then the method for everyone's else's followed the same arrangement. Anyway here is the link:

https://keith-snook.info/wireless-world-articles/Wireless-World-1975/Wireless%20World%20Dolby%20noise%20reducer.pdf

Hi tapepath,
Thank you for the link to Wireless World! Brings back memories - my first Williamson amp was built from schematics in a Wireless World (circa 1973 I think).
I managed to track down an Advent 100A Owner's Manual on eBay - Original (but a little waterstained) which I received yesterday. Have managed to scan and OCR it so I have an electronic copy. If anyone wants it, I'd be happy to oblige since HFE does not have one.
Sincerely,
John Graham.

 

[tapepath]

Hello John,
If you can find the Dolby unit made by Integrex it would be worthwhile. This was offered in kit form by Wireless World and also sold by Barclay-Crocker, although not in kit form if memory serves. Here is a link:

Integrex WW Dolby Noise Reducer Noise Reduction | Reel to Reel

Add Integrex WW Dolby Noise Reducer Noise Reduction To Your Tape Recorder And Improve The Signal To Noise Ratio On Your Stereo System. A Directory of

reel-reel.com

If you need any parts for your Advent unit, please contact me, I'd be happy to send whatever you need.
Regards, Ken

 

[murugan19]

Hi All,
Teac AX-300 Mixer:
I searched diligently through this forum 9and other forums) but couldn't find much information on manuals for the Teac AX-300 mixer.

I came across a Teac AX-300 mixer (4 Line in/Mic + 2 Mic In; 4 channels out) which would make a perfect compliment with my Dokorder 8140. (My Teac 40-4/DX-4 has a Teac Tascam Series 3 mixer which is a perfect combo).

More details at https://hifi-wiki.com/index.php/Teac_AX-300

Unfortunately, there is no Owner's manual and/or Service manual to be found (free or for sale) including HFE.
Teac distributors in the US all say "not available".

Hookup/operation shouldn't be difficult (just as painstaking as any Ext. IN and Pre-Out on any amplifier hookup is) except that channels can be re-directed. Unfortunately, the Teac AX-300 has been modified - Ch 1 is dead, Ch 3 Mic XLR's have some resistors soldered in, one Input lead is cut (and not properly terminated). To resurrect it, I would at least need the Service manual/schematics.

Does anyone have the Owner's manual and/or the Service manual?

Would appreciate it if anyone does.

Sincerely,
John Graham