Hello from California -silicon valley

[paul n]

I was introduced to high end audio by a fellow mountain biker who builds and customizes high end speakers, amps and cd players. By day I work at a semiconductor company that makes low noise jfets and transitors used in audio and other markets. Over the years I have used his input to assist in directing our marketing and product design efforts to address the needs of audio consumers.

I became aware of this website while doing some online research for an upcoming product release. Of what I have seen in some of the different forums, there quite a diverse audience. It presents me with a good opportunity to see first hand at the user level, the specific consumer needs as well identify areas in which consumers are seeking a better solution.

My purpose in joining was to expand my understanding of the diy market as well any cross over with the professional audio manufacturing markets. I will look forward to the opportunity to interface with your members to answer my questions and develop a better insite into some of the issues which my company might be able solve. Along the way I hope to meet some interesting people as well.

Sincerely,

Paul Norton

[Geek]

Hello and welcome!

Nice to see people @ related companies taking an interest in end-user DIY.

.......... and develop a better insite into some of the issues which my company might be able solve.

Can you guys make a $15, 300B vacuum tube?

Hope you enjoy your stay!

[paul n]

Sorry, we only make jfets(low noise, high gain etc). We have worked with individuals seeking to make a semiconductor based tube replacements, but it looks like they still have a bit further to go before releasing a product.

Sincerely,

Paul

[hifiZen]

Hey, welcome aboard! It's always nice to see more locals on here...

I rather doubt anyone will be able to successfully imitate a tube in solid state, but there are definitely lots of transistor types which have their own desirable traits. Japanese FETs and BJTs from Toshiba and Hitachi are probably the most sought after for audio work... since they were generally designed with audio in mind. But, these types are often very difficult to get in N America and Europe, and the knock-offs often don't measure up because they're usually some other generic transistor type that's got similar characteristics and has just been packaged and marked as an equivalent.

Parts like 2SK389 / 2SJ109, 2SK170 / 2SJ74 are the most coveted audio FETs. 2SA970 / 2SC2240 are favoured BJTs... High linearity (large Early Voltage), tightly matched pairs packaged on the same die (like the '389), and good complementary N and P types are the most useful. It helps to have a high ft and low input capacitance too... search around for Erno Borbely's designs - he's pretty much on the cutting edge of audio design with JFETs, and I bet he'd be willing to talk with you and your colleagues about what makes a good audio FET. The folks at Pass Labs might also have some valuable input - Nelson Pass is famous for his MOSFET power amplifier designs.

See you around...
Chad.

[planet10]

Welcome to the forum... it's always nice to have a diversity of talents

dave

[paul n]

Brad- Thanks for your input. I have heard alot about the popularity as well the supply problems associated with some of the japanese audio jfets. At the company I work at, they have been working with some audio microphone and amplifier designers to create some new audio jfets which they expect to release in first qtr 2005. There will be a single and monolithic (2 jfets on same die)dual N-channel versions. The noise to capacitance ratio is expected to be very low, as well the actual voltage/current noise. They will be offering the dual in different grades of tight matching(delta vgs). Thank you for pointing out Mr. Borberly, I have seen his stuff in audio express. I was not sure if it was the same Mr. Pass associated with a company called Threshold we used to deal with in the 1990's. Their inputs would be very valuable.

Sincerely,

Paul

[planet10]

Originally posted by paul n
I was not sure if it was the same Mr. Pass associated with a company called Threshold we used to deal with in the 1990's. Their inputs would be very valuable.

One & the same... he hangs out here a bit....

dave

[PoweRex]

Originally Posted by paul n

Sorry, we only make jfets(low noise, high gain etc). We have worked with individuals seeking to make a semiconductor based tube replacements, but it looks like they still have a bit further to go before releasing a product.

Sincerely,

Paul

Hi Paul,
Will Linear Systems launch the LSJ74 equivalent for the Toshiba's 2SJ74 ?
Same question for the 2SJ109 dual J-Fets.
Thanks,
Fred.