Sherwood S-5000 #B920J4 output-trans per Sam's Photofax

Posted by Interstage Tranny (A) on April 29, 2016 at 17:35:34

In Reply to: Sherwood S-5000 output-transformers posted by Tubecase on April 29, 2016 at 10:45:31:

Let us see if we can decipher the real answers to your questions; shall we ?

The Sam's Photofact from Folder 9 Set 475 for the original series S-5000 was tested at 117V AC @ 1.05A in; the power trans #B922J3-3 was rated/tested at 720 VCT@100 mA; 60VCT@150 mA; 5V@2A; 6.3VCT@5.2A. Sherwood used a 1.5A Type 3AG Slow-Blow fuse.

Tubes were 5 ECC83/12AX7 + 1 x 7199 + 4 x 7189 + 1 x 5AR4/GZ34.

The 7189 opt tubes were set up/tested at 413V Ep; 410V Escrn; .5V Ek; -20V Eg.

Since the 60V winding was used for the bias and two 12AX7 filaments, the B+ winding's 100 mA B+ tested rating can be interpreted as 20-25 mA at idle for each 7189.

Now, to interpret the percentage of Ultralinear taps, the DCResistance of the opt is a good indicator. Sam's testers measured from Opt CT to each screen 70 Ohms and to each plate 190 Ohms; approx. 380 Ohms DCR overall plate to plate lead. They measured a primary impedance of 7800 Ohms CT with taps at 800 Ohms CT to 4, 8, 16 Ohm secondaries.

Hoping this helps to answer your actual questions, remember that the size of these opt trannies represents a usual wide bandwidth 25-30 Watt, even 40 watt opt tranny. Personally, I would have no objection to using these fine opts up to 100 mA per half primary winding; but preferably at a lower voltage. I also would trust these as fine sounders without using the UL taps; i.e. for PP 245, VT52 or 250 triodes or 6BQ5/EL84 pentodes...

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Follow Ups Full Thread

Topic - Sherwood S-5000 output-transformers - Tubecase 10:45:31 04/29/16 (20)

RE:Please verify that both OPTs have the same model number. - DAK 19:23:22 04/29/16 (6)

RE:Please verify that both OPTs have the same model number. - Tubecase 05:55:16 04/30/16 (2)

RE:Please verify that both OPTs have the same model number. - DAK 09:08:55 04/30/16 (1)

RE:Please verify that both OPTs have the same model number. - Tubecase 09:24:22 04/30/16 (0)

His are the 7189s because he said they have the UL tap - Michael Samra 01:08:27 04/30/16 (1)

RE: His are the 7189s because he said they have the UL tap - Tubecase 05:58:02 04/30/16 (0)

RE:Please verify that both OPTs have the same model number. - Eli Duttman 20:08:54 04/29/16 (0)

Sherwood S-5000 #B920J4 output-trans per Sam's Photofax - Interstage Tranny 17:35:34 04/29/16 (1)

RE: Sherwood S-5000 #B920J4 output-trans per Sam's Photofax - Tubecase 05:50:24 04/30/16 (0)

RE: Sherwood S-5000 output-transformers - Eli Duttman 12:36:08 04/29/16 (10)

RE: Sherwood S-5000 output-transformers - Tubecase 05:20:13 04/30/16 (4)

RE: Sherwood S-5000 output-transformers - Eli Duttman 19:32:39 04/30/16 (1)

RE: Sherwood S-5000 output-transformers - Tubecase 11:52:29 05/01/16 (0)

7189/ 6P14P-ER - geezerrocket 09:02:20 04/30/16 (1)

RE: 7189/ 6P14P-ER - Tubecase 09:31:03 04/30/16 (0)

I like the Tri/pent for those trafos as there are no surprises. - Michael Samra 01:18:45 04/30/16 (4)

RE: I like the Tri/pent for those trafos as there are no surprises. - Tubecase 06:23:30 04/30/16 (3)

RE: I like the Tri/pent for those trafos as there are no surprises. - Eli Duttman 10:44:25 05/01/16 (0)

RE: I like the Tri/pent for those trafos as there are no surprises. - Eli Duttman 19:16:26 04/30/16 (1)

RE: I like the Tri/pent for those trafos as there are no surprises. - Tubecase 12:03:52 05/01/16 (0)

Follow Ups

Sherwood S-5000 #B920J4 output-trans per Sam's Photofax - Interstage Tranny 17:35:34 04/29/16 (1)

RE: Sherwood S-5000 #B920J4 output-trans per Sam's Photofax - Tubecase 05:50:24 04/30/16 (0)

Sherwood S-5000 #B920J4 output-trans per Sam's Photofax

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