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Comparing the Sound of Barclay Crocker Dolby B Tapes to Vinyl

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Over the past week or so I have been listening to a fair number of my Barclay-Crocker tapes (I have about 110 of them). I also have the vinyl versions of about half (all of the Argo, L'Oiseau Lyre, some Vanguards and a few others). I have felt in the past that most all of the B-C tapes come quite close to the vinyl versions (provided that the vinyl is in good shape), but there was a little gap. The problem has been in the dolby B decoder - I have been using an Advent Model 100, which was the best I could find. When playing in the bypass mode, it was clear that the electronics add a definite coloration to the music. It is less noticeable with dolby B decoding engaged, since the positive effects of the decoding mask a lot of the electronic coloration. However, this has changed! I have been using a prototype dolby B decoder that was built by one of our members. The sound of the B-C tapes is quite incredible - really comparable to the sound of the vinyl. I have never heard prerecorded 7.5ips tape sound so good. One comment, as you have probably read in my other posts, the TP tapes are a full step better than the vinyl. But other than that, I haven't heard anything like the B-C tapes with this decoder. Characteristics of the sound - depth of soundfield, wonderful hall ambience, clarity of instruments, lack of electronic glaze.

I have been playing the tapes with my Bottlehead Technics 1506 using the quarter track playback heads - through the Bottlehead Repro preamp and then through the decoder. I have been using the balanced outputs of the Repro. The decoder accepts balanced inputs - but also can be modified to accept RCA inputs.

The lack of true audiophile quality dolby B decoders has been a real problem to those who want to hear the best out of their tapes. The creator of this wonderful device may want to comment on what was done. 


Larry-If you are using the Bottlehead repro unit, does that mean you are using IEC playback equalization for 15 ips tapes?

Mark, the Repro has a switch in front for NAB or IEC. For the prerecorded tapes other than TP, I use NAB EQ. For the tapes I have done from my 45 Vinyl collection, I recorded and am playing back on IEC. AFAIK, all the commercial 7.5ips tapes I have are NAB, which I use.  Thanks, Larry

Thanks for the kind words Larry.
Just like when I first decided to get back into reel to reel, I always thought that the Barclay-Crocker tapes had a lot more in them than is generally thought. And like a few other members here, I went through a number of Dolby decoder units and found that they were all either edgy and hard sounding or muffled and veiled sounding. Neither genre had any soundstage to speak of and they robbed the tapes of that rich midrange that I love magnetic tape for.
After unsuccessfully trying to find someone to modify and upgrade one for me I finally decided to do it myself. It involved endless trial and error upgrades (over 2 years on and off) and Larry has the results.

The unit does pretty well with BC tapes but on some other brands, it does a fine job of showing just how important it is to have high duplication standards. The BC's also have the advantage of having a calibration tone included. From my experience, I don't think that it's necessary to have the calibration spot on but it does need to be close ( the spec is +/-  2dB).

I've still got some fiddling around to add a little gain for our tube repro gear but for balanced in and single ended out, it's finally done! Yippie!

Oh shoot! I forgot to say that the working name for this unit (since it spent so much time being experimented on) is " Pavlov's Dolby".

Steve was kind enough to build one of his units for me. It has been sitting on the rack waiting for the ATR deck and the Bottlehead Tube Repro for some months but since they are taking forever to arrive I decided to give it a try. I fixed a set of cables and connected a BH Sex amp as an additional gain stage between the Seduction and the Dolby unit (the Seduction doesn't have enough gain to get the unit to operate correctly). I let it burn in for a few reels and tonight I finally sit to fully test it.

It is very, very good. The BC tapes sound nothing short of spectacular. As opposed to Larry's perception I do detect a very light "electronic glaze". The decoder doesn't deny it's 70's electronics heritage (or is it the BC tapes that show that heritage?). But gone is the coloration and mudiness associated with Dolby processors. There's lots of detail and the timbre of the instruments is right on the spot. The unit is silent and doesn't add noticeable noise.

Ironbut got this one right!

I listened to selections of various tapes but in particular I listened to Mozart Sinfonia Concertante for Violin and Viola (Argo F 679) and to the spectacularly sounding Rimsky-Korsakov's Scherezade (Philips 6500-410). Following the Dolby unit is a Bottlehead Extended Foreplay preamp and six BH 300B Paramounts with Magnequest iron that triamp what used to be a set of Edgarhorns that now utilize RCA 1930's field coil drivers for the mids, a Karlson K18 with a sand amp fills the bass below.


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