Small HT transformer 250 -0- 250V plus 2 x 6.3V wanted - UK Vintage Radio Repair and Restoration Discussion Forum

Jez1234 · 5th Jun 2023, 11:26 pm

Just bought a "bargain" item of USA origin test gear and found it's been more "got at" than I suspected.... seemingly in the 60's from the age of the parts in the bodge. It's a lovely thing https://www.radiomuseum.org/r/milita...set_anprm.html but would be lovelier still if 100% working and at least as much back to standard as possible. All the plug in coils are present and correct at least (phew!) and it does work as a basic GDO (very accurately!) but unfortunately the 6005 (6AQ5) and 6X4 original rectifier are AWOL as it arrived from ebay so no modulation available as is.

Original mains transformer is 250 -0- 250V 15mA, 6.3V 1A, 6.3V 0.6A

Voltages must be as above (pretty standard really) and currents in the right ballpark for it to be small enough to bodge into the space where the 60's UK bodge TX is fitted. A previous owner has fitted a 240V primary, 250V, 2 x 6.3V secondaries TX and a selenium bridge rectifier after removing the 6X4 (thankfully socket and wiring still present).

Oh and if anyone has a 8uF (a little larger would be OK), 350V or more paper in oil type smoothing cap then that's something I'd like to return to near standard as possible also. See photos in link above but original about 4" x 5" x 1/2" or thereabouts. In UK those pale green TCC and Dubilier ones are probably the closest thing but my own junk box gave up only 4uF 250V and 1uF 350V items.

Thanks in advance.
Jez

Valvepower · 6th Jun 2023, 10:20 am

Jez,

I have a transformer lurking on the transformer shelf that is similar to your specifications, however, it’s only l got one 6.3V winding and it could be on the big size looking at the pictures on the Radio Museum site.

HT 250-0-250V off load. I recon its got to be good for 50mA or so.

Anyway, its sat in the workshop for ages and ages, and has never been used, so I’d let it go to a new home for a radio rally ‘couple of quid’ Cancer Charity donation.

Pictures attached.

Regards
Terry

Jez1234 · 6th Jun 2023, 1:24 pm

Quote:

Originally Posted by Valvepower

Jez,

I have a transformer lurking on the transformer shelf that is similar to your specifications, however, it’s only l got one 6.3V winding and it could be on the big size looking at the pictures on the Radio Museum site.

HT 250-0-250V off load. I recon its got to be good for 50mA or so.

Anyway, its sat in the workshop for ages and ages, and has never been used, so I’d let it go to a new home for a radio rally ‘couple of quid’ Cancer Charity donation.

Pictures attached.

Regards
Terry

Hi Terry, We used to chat a lot on the Leak forum many years ago, hope you are well.
Thanks for the offer but it needs to have twin 6.3V windings and it looks a bit large.

A possible dodge I'm considering is to use a couple of 1N4007 with a 6X4 (have to buy a 6X4 and the 6005 yet) to make a bridge... I have to check out why the 6005 as well as the 6X4 is missing and whether it has any reflection on the condition or rating of the second 6.3V winding which supplies just these two valves. The 6005 is used as a meaty cathode follower which acts as AM modulator when so selected, and it seems as series pass valve when CW selected, so both it and the 6X4 need elevated heater supply. As it arrived from ebay there is a distinctly non standard Erie 22K resistor across the 6005 socket to give "somewhere near" the right HT to the 955 in the tuner unit...

I'll probably get excommunicated or something for even thinking this but after spending hours searching my multifarious junk boxes and thinking about "what have I got that I don't use that could donate a TX", the Leak Troughline MkI that's been sitting in a cupboard for 20+ years should be getting very worried about now! Yep 250 0 250V and twin 6.3V windings and I'm guesstimating that it should be just about small enough.

I'll get my coat

Cruisin Marine · 6th Jun 2023, 10:39 pm

I'll probably get excommunicated or something for even thinking this but after spending hours searching my multifarious junk boxes and thinking about "what have I got that I don't use that could donate a TX", the Leak Troughline MkI that's been sitting in a cupboard for 20+ years should be getting very worried about now! Yep 250 0 250V and twin 6.3V windings and I'm guesstimating that it should be just about small enough.

You just made me laugh out very loud- thanks

Valvepower · 7th Jun 2023, 9:02 am

Hi Jez,

All’s OK here.

I figured it would be tad too meaty plus it has only one 6.3V winding. I’ll hang on to it as it might make a suitable transformer for small amp project in the future using an EL84 with a lower Va.

Yeah, often think back to the Leak group… I occasionally see a couple of the Leak forum folk at Tonbridge, and I have kept in contact with Andy Miller. Sadly, a couple of the members have go to lab in the sky. Haven’t communicated with Steve Spicer in ages. Meeting a couple of the engineers who worked at Leak along Harold Leaks Family gave me an understanding of the ethos and world of Leak up until its sale in the late 60s.

Heading of topic here….

Regards
Terry.

5th Jun 2023, 11:26 pm	#1
Jez1234 Heptode Join Date: Mar 2021 Location: Morpeth, Northumberland, UK. Posts: 770	Small HT transformer 250 -0- 250V plus 2 x 6.3V wanted Just bought a "bargain" item of USA origin test gear and found it's been more "got at" than I suspected.... seemingly in the 60's from the age of the parts in the bodge. It's a lovely thing https://www.radiomuseum.org/r/milita...set_anprm.html but would be lovelier still if 100% working and at least as much back to standard as possible. All the plug in coils are present and correct at least (phew!) and it does work as a basic GDO (very accurately!) but unfortunately the 6005 (6AQ5) and 6X4 original rectifier are AWOL as it arrived from ebay so no modulation available as is. *Original* mains transformer is 250 -0- 250V 15mA, 6.3V 1A, 6.3V 0.6A Voltages must be as above (pretty standard really) and currents in the right ballpark for it to be small enough to bodge into the space where the 60's UK bodge TX is fitted. A previous owner has fitted a 240V primary, 250V, 2 x 6.3V secondaries TX and a selenium bridge rectifier after removing the 6X4 (thankfully socket and wiring still present). Oh and if anyone has a 8uF (a little larger would be OK), 350V or more paper in oil type smoothing cap then that's something I'd like to return to near standard as possible also. See photos in link above but original about 4" x 5" x 1/2" or thereabouts. In UK those pale green TCC and Dubilier ones are probably the closest thing but my own junk box gave up only 4uF 250V and 1uF 350V items. Thanks in advance. Jez

6th Jun 2023, 10:20 am	#2
Valvepower Octode Join Date: Aug 2008 Location: Rayleigh near Southend-On-Sea, Essex, UK. Posts: 1,558	Re: Small HT transformer 250 -0- 250V plus 2 x 6.3V wanted Jez, I have a transformer lurking on the transformer shelf that is similar to your specifications, however, it’s only l got one 6.3V winding and it could be on the big size looking at the pictures on the Radio Museum site. HT 250-0-250V off load. I recon its got to be good for 50mA or so. Anyway, its sat in the workshop for ages and ages, and has never been used, so I’d let it go to a new home for a radio rally ‘couple of quid’ Cancer Charity donation. Pictures attached. Regards Terry Attached Thumbnails Last edited by Valvepower; 6th Jun 2023 at 10:27 am.

6th Jun 2023, 10:39 pm	#4
Cruisin Marine Heptode Join Date: Jul 2018 Location: Worthing, West Sussex, UK. Posts: 867	Re: Small HT transformer 250 -0- 250V plus 2 x 6.3V wanted I'll probably get excommunicated or something for even thinking this but after spending hours searching my multifarious junk boxes and thinking about "what have I got that I don't use that could donate a TX", the Leak Troughline MkI that's been sitting in a cupboard for 20+ years should be getting very worried about now! Yep 250 0 250V and twin 6.3V windings and I'm guesstimating that it should be just about small enough. You just made me laugh out very loud- thanks __________________ "Behind every crowd, there's a silver Moonshine"

7th Jun 2023, 9:02 am	#5
Valvepower Octode Join Date: Aug 2008 Location: Rayleigh near Southend-On-Sea, Essex, UK. Posts: 1,558	Re: Small HT transformer 250 -0- 250V plus 2 x 6.3V wanted Hi Jez, All’s OK here. I figured it would be tad too meaty plus it has only one 6.3V winding. I’ll hang on to it as it might make a suitable transformer for small amp project in the future using an EL84 with a lower Va. Yeah, often think back to the Leak group… I occasionally see a couple of the Leak forum folk at Tonbridge, and I have kept in contact with Andy Miller. Sadly, a couple of the members have go to lab in the sky. Haven’t communicated with Steve Spicer in ages. Meeting a couple of the engineers who worked at Leak along Harold Leaks Family gave me an understanding of the ethos and world of Leak up until its sale in the late 60s. Heading of topic here…. Regards Terry.