Scott Transformers

wrenchone · 18th February 2010, 10:12 PM

I recently got the power and output iron from an old Scott Amp or receiver. The power transformer (TR15), appears to have been used with ~30W/channel units with 7591A output tubes. The output transformers are TRA-8-5-2, and I haven't been able to find any info about them on the web so far. If they really belong with the TR-15 power transformer, I would suspect them of being 30-35W capability, but I'm not sure. They certainly look hefty enough. Can anyone out there offer any clues?

Tom Bavis · 19th February 2010, 12:26 AM

Possibly 340 receiver.

See H.H.Scott Amp Specs

wrenchone · 12:50 AM

I saw that page, too, but the output transformer numbers I have don't match what's listed there, though the power transformer number does agree. I had one of the output transformers on the bench, and it checks out at 6k plate-plate primary impedance, with primary inductance almost too high to measure under large signal excitation (~300H). Sure looks like a 7591A transformer to me...

Eli Duttman · 19th February 2010, 12:55 AM

Quote:

Originally Posted by wrenchone

I saw that page, too, but the output transformer numbers I have don't match what's listed there, though the power transformer number does agree. I had one of the output transformers on the bench, and it checks out at 6k plate-plate primary impedance, with primary inductance almost too high to measure under large signal excitation (~300H). Sure looks like a 7591A transformer to me...

If it works with 7591s, it works with 6L6s.

Scott "iron" lacks UL taps. How about AB2 triode wired 6L6GCs?

wrenchone · 19th February 2010, 01:44 AM

Hard to say at this point - I may do something fiendish with sweep tubes. I'm getting in quite a windfall of classic iron. How did the Scott output transformers compare to similar Fisher units? So far, I have output transformers for Fisher 500B, 500C, 400, and now these Scott things.

Eli Duttman · 19th February 2010, 01:49 AM

I don't know about specifics, sorry. Neither Fisher nor Scott used junk and their stuff was priced accordingly.

wrenchone · 19th February 2010, 05:32 AM

Well, the way my "Kingfisher" amp sounds indicates that the old Fisher iron was good stuff, and that amp used transformers from a 500B. The 500C transformers are supposed to be even better. I'll have to think a bit to come up with an appropriate use.

planet10 · 19th February 2010, 06:12 AM

Our EL84 Class A triode El Cheapo variant uses a Scott LK48 as a donor, and it is a stunningly little amp. Nice iron.

dave

wrenchone · 19th February 2010, 05:29 PM

The only EL84-ish iron i have around at the moment came from organs, along with a pair of Sony SE transformers from (I think) a R-R tape deck. I haven't measured the characteristics of those transformers yet. As far as 6L6-type iron is concerned, all the organ transformers I've gotten in so far have inferior characteristics as compared to the Scott and Fisher iron (at least as far as primary inductance is concerned). This is to be expected, as the Scott and Fisher units have lam stacks that are about 3X thicker than the organ transformers. Having said that. I'll be trying to use a pair of 6K Wurlitzer transformers in a new creation. More information (and a new thread) when it gets going.

wrenchone · 19th February 2010, 07:27 PM

Possible home for a pair of the Fisher 500C transformers - P-P amp using 300B or 6S4S in A2 mode. Since the price of even 4 Chinese 300Bs is a bit heart-stopping, I may go with the 6S4S instead.

18th February 2010, 10:12 PM	#1
wrenchone diyAudio Member Join Date: Feb 2004 Location: Silicon Valley	Scott Transformers I recently got the power and output iron from an old Scott Amp or receiver. The power transformer (TR15), appears to have been used with ~30W/channel units with 7591A output tubes. The output transformers are TRA-8-5-2, and I haven't been able to find any info about them on the web so far. If they really belong with the TR-15 power transformer, I would suspect them of being 30-35W capability, but I'm not sure. They certainly look hefty enough. Can anyone out there offer any clues?

19th February 2010, 12:49 AM	#3
wrenchone diyAudio Member Join Date: Feb 2004 Location: Silicon Valley	I saw that page, too, but the output transformer numbers I have don't match what's listed there, though the power transformer number does agree. I had one of the output transformers on the bench, and it checks out at 6k plate-plate primary impedance, with primary inductance almost too high to measure under large signal excitation (~300H). Sure looks like a 7591A transformer to me... Last edited by wrenchone; 19th February 2010 at 12:50 AM. Reason: sp

19th February 2010, 01:49 AM	#6
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	I don't know about specifics, sorry. Neither Fisher nor Scott used junk and their stuff was priced accordingly. __________________ Eli D.

19th February 2010, 06:12 AM	#8
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	Our EL84 Class A triode El Cheapo variant uses a Scott LK48 as a donor, and it is a stunningly little amp. Nice iron. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

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19th February 2010, 12:26 AM	#2
Tom Bavis diyAudio Member Join Date: Jun 2002 Location: Macedon NY	Possibly 340 receiver. See H.H.Scott Amp Specs

19th February 2010, 01:44 AM	#5
wrenchone diyAudio Member Join Date: Feb 2004 Location: Silicon Valley	Hard to say at this point - I may do something fiendish with sweep tubes. I'm getting in quite a windfall of classic iron. How did the Scott output transformers compare to similar Fisher units? So far, I have output transformers for Fisher 500B, 500C, 400, and now these Scott things.

19th February 2010, 05:32 AM	#7
wrenchone diyAudio Member Join Date: Feb 2004 Location: Silicon Valley	Well, the way my "Kingfisher" amp sounds indicates that the old Fisher iron was good stuff, and that amp used transformers from a 500B. The 500C transformers are supposed to be even better. I'll have to think a bit to come up with an appropriate use.

19th February 2010, 05:29 PM	#9
wrenchone diyAudio Member Join Date: Feb 2004 Location: Silicon Valley	The only EL84-ish iron i have around at the moment came from organs, along with a pair of Sony SE transformers from (I think) a R-R tape deck. I haven't measured the characteristics of those transformers yet. As far as 6L6-type iron is concerned, all the organ transformers I've gotten in so far have inferior characteristics as compared to the Scott and Fisher iron (at least as far as primary inductance is concerned). This is to be expected, as the Scott and Fisher units have lam stacks that are about 3X thicker than the organ transformers. Having said that. I'll be trying to use a pair of 6K Wurlitzer transformers in a new creation. More information (and a new thread) when it gets going.

19th February 2010, 07:27 PM	#10
wrenchone diyAudio Member Join Date: Feb 2004 Location: Silicon Valley	Possible home for a pair of the Fisher 500C transformers - P-P amp using 300B or 6S4S in A2 mode. Since the price of even 4 Chinese 300Bs is a bit heart-stopping, I may go with the 6S4S instead.

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