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Group purchase for Jensen input transformer

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#41
Yeah. Currently there's not much interest in or demand for vintage input transformers. Instead you've got Asians paying nearly $1,000 for vintage microphone transformers to use as MC step-up transformers.
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Vintage buyers are truly nut. They bid 15095A up to the sky and completely ignore the 15335A


Yeah, but I don't think Ed Reichenbach had anything to do with Peerless.
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There are some interesting pictures of Ed at Altec Lansing on the Cork Board. After Ed left Altec Lansing he manufactured audio and power transformers and inductors on his own. Eventually, Ed formed Reichenbach Engineering and developed a line of transformers which became ubiquitous standards in the pro audio industry. Tom worked with Ed until 1979, when he formed CineMag.

http://www.cinemag.biz/corporate_profile.html


Yeah. I was just over on eBay checking out some completed auctions for 15335As and found one auction that sold four of them for $85 (auction ended early with a Buy it Now).

I looked at the name of the buyer and it turns out it was Mike! 🙂
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He overpaid.
 
#46
I may be interested in four

I need to run long interconnects (8 meters) between my bottlehead Foreplay preamp and my Bottlehead Parabee amps. I've read that these transformers are the way to go to balance the line and then unbalance it (is that what they do?) again but I've been not able to understand how to do the actual application in my specific case. If you guys could help me I would definitely be in.

xavier
 
#47
These particular models are for the input end. There are other models more appropriate for the output end. However, using them at the input only gets you most of the advantages. There are several white papers and application notes on the Jensen web site. Have you read them yet? They may answer some of your questions.
 
#48
#49
Re: I may be interested in four

xcortes said:
I need to run long interconnects (8 meters) between my bottlehead Foreplay preamp and my Bottlehead Parabee amps. I've read that these transformers are the way to go to balance the line and then unbalance it (is that what they do?) again but I've been not able to understand how to do the actual application in my specific case. If you guys could help me I would definitely be in.

xavier
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This may help, 'caveat', I'm definitely no expert here.

http://www.jensen-transformers.com/as/as001.pdf

Stan
 
#51
Look at the link in the first post. The resistor RL and the amp to the right are your present amp that you want to put the transformer into. RL on a tube amp is likely to be very large, i.e., much greater than 10k. Therefore, the addition of R1 and C1 are likely a necessity. The jack on the left would be the input jack of your amplifier. An RCA jack can be used for input, also, but should not be grounded to the enclosure.
 
#58
Before finding this thread I had written to Jensen asking about my particular need. Here´s the answer in case someone is interested:

Hello Xavier,

Thanks for writing Jensen. I apologize for taking so long to reply - I was out of town for most of July.

Since both your preamp and power amplifier use unbalanced audio connections, very high immunity to ground loop noise can be provided with a single transformer. Our JT-11P-1 transformer is extremely transparent sonically, while providing about 100 dB reduction of hum due to "ground loop" effects.
This transformer is available as a discrete transformer (with wire leads) or in a ready-to-use box with gold-plated connectors as our ISO-MAX model CI-1RR (single channel) or CI-2RR (dual channel) isolator. See http://www.jensentransformers.com/ci1rr.html and
http://www.jensentransformers.com/ci2rr.html respectively. To maintain good
high-frequency bandwidth, either of the isolators MUST be installed so that the cable between its output and the power amplifier input is no more than 3 feet long (or a length that keeps cable capacitance under 100 pF). The cable from the preamp output to the ISO-MAX input is not length restricted.

It is a myth that a signal line must first be balanced and then unbalanced to attain high noise rejection. Don't hesitate to contact me if you have further questions or want to discuss issues raised here.

Cordially,
Bill Whitlock, president
Jensen Transformers, Inc.
Member Audio Engineering Society
Senior Member Institute of Electrical and Electronic Engineers
(from my home office)
 
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