John Curl's Blowtorch preamplifier part II

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Well Scott, either read the magazines, go to the hi fi shows, like the most recent one at Newport Beach, or whatever it takes, to find that pre-recorded tapes are making a comeback.

I dunno, I haven't seen The Tape Project's catalog expand much in the past five years. Only 24 titles are currently active. Who else is offering pre-recorded reel tapes except The Tape Project and the old 7" 3-3/4 ips tapes found on eBay?

se
 
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However, reel to reel, 7 1/2-15 ips is coming back for collectors, and other serious audiophiles.


I don't consider current performance practice worthy of the highest-end. Wow, Sheffield Labs on tape, played on unobtanium recorders.

As Steve said one would have to work hard to collect a few dozen titles. BTW Steve, I have seen at least one collection of 7 1/2 ips versions of the old RCA LSC series.
 
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I've heard a number of the Tape Project tapes in various cities and shows. Very, very nice stuff, but wouldn't a well mastered 96/24 file played thru and excellent DAC sound just as good?

Yes, i think so. Its getting really good and the HD of masters downloaded are the next best thing to listening to your own recorded master tapes. I have made recordings in the Bay Area using a variety of analog recorders - including a modified Studer/Revox 1/2 track 15ips used with external, discrete (not IC) Dolby et al. Which I still have. Digital is very good now... not perfect and room to improve (esp. A/D) but very, very good. Until recently, analog masters were my best source but now I have heard similar with digital. For most music systems, the preamps and amps are not what keeps music from sounding real. Its the source. Still is. -R.Marsh
 
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For original mastering, 1/2 tr-15ips or full track-30 ips was normally used.
Full track-30ips goes back to WW2 and German development. It was so 'good' at the time, that it confused the Allies as whether it was possible to have a speech or symphony broadcast, from the region that was recently bombed.
Later, tape recording was developed in the USA (copied from the German machines) mostly for its superior editing convenience and quality, for AM broadcasting.
While the first machines were 30 ips and full track (1/4" wide), 3 channel film recorders were developed that used sprockets to guide the tape, like 35 mm film, and had 18ips-full track with for each track. This was often used for some of the very best recordings, especially stereo, in the 1950's. Westrex made a very good machine, for example. Some of the best recordings that we have from the past were put on vacuum tube based tape machines, recorded at 15, 18 (magnetic film), or 30 ips. As tape 'improved' pressures were put on the industry to use 15 ips-1/2 tr for the majority of mastering applications. It was NOT an improvement, but it saved the cost of tape. When I worked at Ampex in the late '60's, 30 ips was virtually forgotten, and solid state replaced vacuum tubes. Multiple channels were then being made, with 16 ch-2''-15 ips being standard studio fare by 1970.
 
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There are a few more:
beron

Thanks, love this stuff... "This all new circuitry removes the syncro circuit, muting circuit, fixed output circuit, these are entire circuits composed of 38 FET’s that inhibit the purity of the signal path."

They go on of course to state that the highest quality BB IC's are now used in the signal path. So all these wonderful reviews are of music through IC's ? You high-end guys just can't agree.
 
Thanks, Robert F for putting up that article from 'PF'. I did not see it previously, and it clearly shows the direction people are going with tape, and WHY.
In my opinion, REMOVAL of parts from the circuit path is important for best fidelity. The early machines were relatively simple in thru-path and they sounded wonderful, much of the time, but later tape recorders, added FEATURES, and each and every one, usually added more junctions to go through. That, with 'noise reduction circuitry' Class C output stages (to save temp rise), too many channels on too little tape, etc. made transition to digital, easier, for many, but NOT everybody.
 
Thanks, love this stuff... "This all new circuitry removes the syncro circuit, muting circuit, fixed output circuit, these are entire circuits composed of 38 FET’s that inhibit the purity of the signal path."

They go on of course to state that the highest quality BB IC's are now used in the signal path. So all these wonderful reviews are of music through IC's ? You high-end guys just can't agree.


Ha, ha, very funny!
I looked it up and found another "gem":

Even the same High Quality gold relay used in the Conrad Johnson Art preamp is used as a switching device between input and playback, this change alone will eliminate 8 FET’s in the signal path!

So a "High Quality" (notice the capitals) gold relay can eliminate 8 FETs ?
:D
I am not worthy ! ;) (I could not make this stuff up if I wanted to.)
 
Well Scott, either read the magazines, go to the hi fi shows, like the most recent one at Newport Beach, or whatever it takes, to find that pre-recorded tapes are making a comeback.

Where there's demand, there will be supply. This 'comeback' happens due to large numbers of high quality tape machines being dumped/sold off for peanuts by broadcasters all over the world. Now these machines are in hands of private individuals, who would have never bought them at their original prices "back then". These days Joe "The Audiophile" Sixpack proudly owns some Studer that he bought for under 1k and he needs some tapes to play to his friends ;)
It's a great new niche market for those who know how to exploit it, however.

Best,
 
Or my furnace?

Actually furnace relays tend to be odd voltages like 22 volts. There are two possible reasons:

One is that the control transformers were standardized long ago for furnaces and when rectified at a low line level that is the voltage that they are sure would be seen.

The other is that the control board has many protection layers to prevent explosions or fires, so they don't want you repairing them. If you have the skills to just change a failed relay you probably don't know how to verify all the protection loops are still working.

Of course I doubt many furnace relays use gold plated or even flashed contacts.

Now a proper audio relay has gold or palladium plated bifurcated crossbar contacts with a mechanically remote magnet structure. They are made. The design started out from the telephone system requirements. Today these relays are mostly used in low level or RF test equipment.
 
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