Partridge audio output transformer value

bentoronto · 25th September 2008, 07:30 PM

Long ago, I built nifty power amps with glass-enclosed vacuum amplifying elements, esp, with motional feedback bridge circuits. So I collected a bunch of output transformers.

Sitting in my parts box for 40 yrs or so is a Partridge output transformer, a magnificent ultra-linear potted unit with all the windings brought out to pins. Seems to be CFB/0/1.7, 60 watts, about 10 lbs (might be Type P4170/1, not certain). I have a bunch of spec sheets and docs from that period and letter from Partidge, 1967. Bought from Harvey Radio in NYC. Incredible square waves pictured in the spec sheet. Needs a good home.

Can anybody tell me if this (once) magnificent unit has much value? Originally sold for $50 which would scale up to thousands today (only kidding).

BTW, I'm glad to scan and eMail the spec sheet pages to anybody interested.

Thanks for any help.

SHiFTY · 26th September 2008, 01:45 AM

well according to ebay completed listings, a similar output transformer (not potted) went for 286 pounds in the UK, about $US500. The description was

Partridge Type W WFB
Sought after Partridge Type W WFB/0/1.7ohm. unused judging by the soldered pegs. Top Row AN HT+ HT+ 10-12 kilohms AN
then eight sections -connect in parallel for 1.7ohms. Untested , 14cm high , 12cm wide , 13.5cm deep.

If that's any help...

bentoronto · 26th September 2008, 01:32 PM

Wow. Thanks for checking.

Well, they are truly beautiful units and my guess is that there hasn't been as much advance in the state of the transformer art, at least compared to say, capacitors. Likewise, minimal deterioration over time. Or perhaps that's just wishful thinking.

It would be nice to sell among "friends," like here at diyaudio, but hard to beat the opportunities that eBay provides.

i also have a Wharfdale 2-way crossover in a painted wood box, potted in wax, at least as old. Looks like an antique to me. Maybe that is worth big bucks on eBay too!

Are there any hi-fi museums?

bentoronto · 26th September 2008, 04:31 PM

Dunno what I was dreaming about, this is not an ultralinear transformer. But it is one of their higher-class units with grain-oriented steel. Those folks sure made fancy units back then. Of course, a British transformer had to be potted against all kinds of tropical weather and insects so it could be used across the empire... back then.

It is made for a 10,000 ohm anode-to-anode load but the primary is brought out to solderable pins as two independent windings for center-tapping

With eight secondary windings coming out to solderable pins independently, you can take one of the windings and make a feedback loop from it - the way Stromberg-Carlson and McIntosh did it. Nice approach.

I put the various spec sheets at:

http://tinyurl.com/othertech

Tom Bavis · 26th September 2008, 05:16 PM

Page 2 appears to be incomplete. Do you mind if I post the pages on my web page? http://www.audiophool.cjb.net/Techno.html

bentoronto · 26th September 2008, 05:32 PM

Quote:

Originally posted by Tom Bavis
Page 2 appears to be incomplete. Do you mind if I post the pages on my web page? http://www.audiophool.cjb.net/Techno.html

Sorry for that bug - the full page is now at the site. Thanks for mentioning it.

Yes, I'm sure Partridge would be glad to see their stuff memoriallized. I'll send more Partridge stuff directly to your valuable website by and by.

bolly · 15th February 2009, 04:36 PM

Thank you for posting those scans bentoronto!!

My amps use the WWFB 0.95's

25th September 2008, 07:30 PM	#1
bentoronto diyAudio Member Join Date: Jan 2008 Location: Toronto and Delray Beach, FL	Partridge audio output transformer value Long ago, I built nifty power amps with glass-enclosed vacuum amplifying elements, esp, with motional feedback bridge circuits. So I collected a bunch of output transformers. Sitting in my parts box for 40 yrs or so is a Partridge output transformer, a magnificent ultra-linear potted unit with all the windings brought out to pins. Seems to be CFB/0/1.7, 60 watts, about 10 lbs (might be Type P4170/1, not certain). I have a bunch of spec sheets and docs from that period and letter from Partidge, 1967. Bought from Harvey Radio in NYC. Incredible square waves pictured in the spec sheet. Needs a good home. Can anybody tell me if this (once) magnificent unit has much value? Originally sold for $50 which would scale up to thousands today (only kidding). BTW, I'm glad to scan and eMail the spec sheet pages to anybody interested. Thanks for any help. __________________ Dennesen ESL tweets, Dayton-Wright ESL (110-3200Hz), Klipschorn mixed-bass woofer w/param. EQ plus 1954 AR-1W or giant OB HiFi construction since 1956

26th September 2008, 01:32 PM	#3
bentoronto diyAudio Member Join Date: Jan 2008 Location: Toronto and Delray Beach, FL	Wow. Thanks for checking. Well, they are truly beautiful units and my guess is that there hasn't been as much advance in the state of the transformer art, at least compared to say, capacitors. Likewise, minimal deterioration over time. Or perhaps that's just wishful thinking. It would be nice to sell among "friends," like here at diyaudio, but hard to beat the opportunities that eBay provides. i also have a Wharfdale 2-way crossover in a painted wood box, potted in wax, at least as old. Looks like an antique to me. Maybe that is worth big bucks on eBay too! Are there any hi-fi museums? __________________ Dennesen ESL tweets, Dayton-Wright ESL (110-3200Hz), Klipschorn mixed-bass woofer w/param. EQ plus 1954 AR-1W or giant OB HiFi construction since 1956

26th September 2008, 04:31 PM	#4
bentoronto diyAudio Member Join Date: Jan 2008 Location: Toronto and Delray Beach, FL	Dunno what I was dreaming about, this is not an ultralinear transformer. But it is one of their higher-class units with grain-oriented steel. Those folks sure made fancy units back then. Of course, a British transformer had to be potted against all kinds of tropical weather and insects so it could be used across the empire... back then. It is made for a 10,000 ohm anode-to-anode load but the primary is brought out to solderable pins as two independent windings for center-tapping With eight secondary windings coming out to solderable pins independently, you can take one of the windings and make a feedback loop from it - the way Stromberg-Carlson and McIntosh did it. Nice approach. I put the various spec sheets at: http://tinyurl.com/othertech __________________ Dennesen ESL tweets, Dayton-Wright ESL (110-3200Hz), Klipschorn mixed-bass woofer w/param. EQ plus 1954 AR-1W or giant OB HiFi construction since 1956

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26th September 2008, 01:45 AM	#2
SHiFTY diyAudio Member Join Date: Jul 2002 Location: New Zealand	well according to ebay completed listings, a similar output transformer (not potted) went for 286 pounds in the UK, about $US500. The description was Partridge Type W WFB Sought after Partridge Type W WFB/0/1.7ohm. unused judging by the soldered pegs. Top Row AN HT+ HT+ 10-12 kilohms AN then eight sections -connect in parallel for 1.7ohms. Untested , 14cm high , 12cm wide , 13.5cm deep. If that's any help...

26th September 2008, 05:16 PM	#5
Tom Bavis diyAudio Member Join Date: Jun 2002 Location: Macedon NY	Page 2 appears to be incomplete. Do you mind if I post the pages on my web page? http://www.audiophool.cjb.net/Techno.html

15th February 2009, 04:36 PM	#7
bolly diyAudio Member Join Date: Nov 2006	Thank you for posting those scans bentoronto!! My amps use the WWFB 0.95's

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