Hello-
I have been involved in Ham radio since mid 1960's and have built quite a few tube projects. Over the years I have parted tube military and commercial gear. Of interest here are the interstage transformers from AM transmitter modulators. I have interest in using some interstage transformers in guitar amplifiers as experiments. I wanted to mention some of these interstages here as possibly some of you'll have ran across or used them. Of particular interest is the interstage transformer from a mid 1950's CAA (FAA) VHF 50 watt AM transmitter model TV-3 by Kaar. I have the technical manual for it. The I/S is circuit component Kaar #T-104, Kaar part #1022, General Transformer #2A213, a nice hermetically sealed one weighing around 2.5 pounds. It is a single ended primary (10K, 20 mA DC) with two separate 18.75K secondaries. The transformer was used with secondary windings in series (75K) driving the grids of a pair of 6146 tubes in push pull class AB1 with a negative fixed bias of about -45 vdc on center tap of secondary. The primary of transformer had a 6C4 triode, class A cathode bias, with around 150 vdc on transformer primary, and a 1.8K cathode resistor bypassed with a 0.1 ufd capacitor. I measured DC resistances of pri as 735 ohms and each secondary in vicininty of 2.5K.
Just curious if anyone else has used I/S transformers from older AM modulators. I have some smaller, about 1 lb, Berkely Transformer, hermetically sealed interstages from the 1958 TV-15 modulator in nearly identical service, a 10K 20 ma primary (1/2 12AU7) and 75K CT secondary (driving grids of P-P 6146's).
My interest is to use a fairly decent I/S transformer driving grids of P-P 6L6GC/5881 or KT-88 in a clean guitar amp. I have studied some of the Gibson designs and the fairly small I/S (TF-1001D) they used. I believe Mercury builds a larger, better version of it. If anyone has a suggestion for me am all ears here.
Thanks,
Byron W5FH
I have been involved in Ham radio since mid 1960's and have built quite a few tube projects. Over the years I have parted tube military and commercial gear. Of interest here are the interstage transformers from AM transmitter modulators. I have interest in using some interstage transformers in guitar amplifiers as experiments. I wanted to mention some of these interstages here as possibly some of you'll have ran across or used them. Of particular interest is the interstage transformer from a mid 1950's CAA (FAA) VHF 50 watt AM transmitter model TV-3 by Kaar. I have the technical manual for it. The I/S is circuit component Kaar #T-104, Kaar part #1022, General Transformer #2A213, a nice hermetically sealed one weighing around 2.5 pounds. It is a single ended primary (10K, 20 mA DC) with two separate 18.75K secondaries. The transformer was used with secondary windings in series (75K) driving the grids of a pair of 6146 tubes in push pull class AB1 with a negative fixed bias of about -45 vdc on center tap of secondary. The primary of transformer had a 6C4 triode, class A cathode bias, with around 150 vdc on transformer primary, and a 1.8K cathode resistor bypassed with a 0.1 ufd capacitor. I measured DC resistances of pri as 735 ohms and each secondary in vicininty of 2.5K.
Just curious if anyone else has used I/S transformers from older AM modulators. I have some smaller, about 1 lb, Berkely Transformer, hermetically sealed interstages from the 1958 TV-15 modulator in nearly identical service, a 10K 20 ma primary (1/2 12AU7) and 75K CT secondary (driving grids of P-P 6146's).
My interest is to use a fairly decent I/S transformer driving grids of P-P 6L6GC/5881 or KT-88 in a clean guitar amp. I have studied some of the Gibson designs and the fairly small I/S (TF-1001D) they used. I believe Mercury builds a larger, better version of it. If anyone has a suggestion for me am all ears here.
Thanks,
Byron W5FH