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RobertS61 11th April 2010 12:00 PM

Swapping Threshold S & SA frontboards.
Dear all,

I pressume I can swap my NON-opticalbias Threshold SA/1 frontboard for any other Opticalbias frontboard out of a S/200, S/300, S/500, SA/3, SA/2 without any alterations only then tuning a new biassetting?
Is it true that the mainboards and aluminum sides have already been prefitted with holes where the opticalbias blue thermistor can be shoved in?
Just checking ;)

Nelson Pass 26th April 2010 05:25 PM

I don't think so.


RobertS61 27th April 2010 10:12 AM


I know that the Series II could be retrofitted with Optical biasboard but it is apparently not a simple operation of desoldering connections take the old board out and resoldering the new one and find a new biassetting.
Thanks for the answer.

Nelson Pass 27th April 2010 05:41 PM

I don't think it would be difficult. I simply said that I didn't
think thermistor holes were provided.


RobertS61 27th April 2010 07:30 PM

Near the hole for the 75 degrees Celcius thermal cutout there's a similar second hole poking into the channelbar. I thought the thermistor could be fitted right there.
I see your point that the optical bias was implemented in 1986/1987 and the Series II in 1983/1984 it would be highly unlikely that you preluded on the use of optical bias and made a provision for it before it was first implemented.
Or maybe the second hole was already there for another reason and came in "handy" to put the thermistor for optical bias in the pre-existing hole.

Do you remember any other enhancements then a independent stable biaslevel when using the optical biasboard instead of the Series II board?

Nelson Pass 29th April 2010 01:38 AM

My memory is not that good, but the versions have been posted.

The last board I did in '91 was the best, but I don't recall that
it made it into production. By that time, management was
pinning its hopes on M. Bladelius.


RobertS61 29th April 2010 06:50 AM

Thanks for the info.
I'll examine it further when I can get a chance to review an optical bias version.
Threshold was not distritibuted very well in the Netherlands in the eighties so there aren't many around in this country. Most people bought Levinson and Krell because they had very active distributors over here.
Threshold was pushed actively by WBS in Germany though, so that's where I bought all my Threshold products.

Nelson Pass 29th April 2010 07:52 PM

Those were companies run by sales people. How are they
doing these days?


RobertS61 29th April 2010 09:58 PM

WBS is still run by Werner Barden:
Dipl.Ing. Werner Barden -Geschäftsführer-
WBS Akustik Systeme Vertriebs GmbH
Veilchenweg 21, 65366 Geisenheim, Rheingau, Germany
Still the same place where we once collected a Acoustat model Six in the eighties.
His brands are now: Wadia, XLO and ProAc.
They are still servicing Threshold and PassLabs
Former technician Roland Fischer configured my S/1000 Series II to a SA/1.
I should ask the two driverboards back he took out of the S/1000's ;-).

In the Netherlands Threshold was distributed by Ad van Meedenvoort before he developed his own line of electronics in the beginning of the eighties.
After that only Krell, Levinson and JRDG (small numbers only for Jeff) were sold substantial in this country (in absolute terms still peanuts probably compared to for instance the US and Asia)
Nowadays PassLabs is hot in the Netherlands because of rave reviews in the US and German Audiopress and the positive vibe your bringing along by sharing knowledge to the DIY community.
Levinson is regarded as a display for Harman Int. very business like.
The more expensive old products from MLAS (the ML series, ML-6,7,2 and 3 and the LNP-2) are really in demand and are sold over the initial US retailprice.
Jeff Rowlands Icepower products are getting a lot of scepsis. I think people want products like the model 7 and Coherence from him.
Krell is still doing alright but if Dan can't fight his way back in to his company it's going to be tough for them just like Threshold after you left.
I think apart from the technical merits of the Class A concept that you stress so now and then in articles is very appealing for potential buyers because it's pretty easy to understand and you get the needed substantial hardware for your money. The Blue meters are a nice touch also of course that's why people also cherish your former designs like the Stasis 1, S/1000 an SA/1 because they were graced by meters and were less black boxes only.
In general it's really hard for a lot of retailers to make a sell. The crisis and the Internetsales are carving in in there turnovers.

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