garnet interstage

[Andy Le Blanc]

I've been digging.....

stancor universals are 1:3, any one fluffing out their catalog like hammond
would replicate or make equivilents to pick up where the last manufacture left off.

Later stancor catalog have what the late comers (the late 50's early 60's)
youth culture boomers would want, amp transformers.
Transistors and efforts towards miniaturization where already in the marketplace
replacing the wider applications for transformers.

stancors were for a 7k or 15k plate load and were 1:3 ratio, 45k sec. at most.
The older UTC catalog mentions interstage's with sec. up to 135K.
The 15K primary is interesting because its in more than one catalog.
So with a primary designed to make a 15k plate load, your looking at impedance
ratios as high as 1:9, there was a whole range of split or tapped secondary
transformers with much higher ratios. I have old microphone matching
150r ct to a 150K tube grid. T-51645-H. From a Mil. projection set 1953.

Thats what up with your gibson

Now you have to ask what the grids of a pair of 6CA7 , parallel, like to see?

47k? 100k?

[Phil_S]

Yes, you are digging in all the same places I did. BTW, the UTC and similar quality brand i/s trannies bring good prices for sellers on eBait. Sometimes in the hundreds, particularly for a pair.

The one in the Gibson is a physically small unit. I'm posting a picture. The turns are ~1:2.4. There IS some sort of mojo in this one. No, you can't have it!!!!!

Can't comment about a pair of 6CA7. The Gibson takes input from 1/2 12AU7 to PP 6BQ5's I have no clue as to the impedance rating. DCR is 719 on the primary and 3.4K on the secondary outer legs. Wish I had an LC meter, but I don't.

I don't know that much about transformers, but I'm thinking vertical output transformers can be of substantial physical size and are now truly worthless. I realized that I've got one and am thinking it can be disassembled and made into an output transformer. No CT on it, but several windings.

[Andy Le Blanc]

the stancor universal has a DCR of around pri. 380r sec. 1.4k, the
thordarson mic trannies measure to 4K, but have no ct.

Triode electronics markets an interstage but the secondaries
are quad split. They describe it as a 1:1 or 1:2 20k pri. 80K sec. with each
quarter being half the 80K or 4X 40K, but they don't qualify the product with
any statements of balance or for any other applications for the product. $30

store.triodestore.com/unintrui.html

Signal generator? how did you figure a turn ratio? 1v on primary

[Phil_S]

Yes, I ran some low voltage through it to determine the turns. I don't remember exactly what, but made a note of the turns. I would have used two meters, one on the primary and one on the secondary; no guessing.