FS: vintage transformers for tube circuits and more!
Jul 19, 2016 13:42:25 GMT -6
chromies, c0rtland, and 1 more like this
Post by EmRR on Jul 19, 2016 13:42:25 GMT -6
OK, time to let some things go so they can be put back into use. Input, interstage, output, repeat coils, and power. Some singles, some pairs.
In this issue:
Kenyon T-26 pair 600:600
RCA BA-3 program amp input and output transformer set
(2) RCA MI-38482 nine pin plug-in transformers (McMartin MT-4) tube inputs
Gates console panel with 3 transformers
Presto PPP 6L6/807 tube record lathe power amp output transformer and choke
Tube output transformer for four 6L6
Pair of IOaudio input transformers for Pultec
RCA potted power transformers 70VCT 800mA
ADC HUM-1 video humbuckers
Kenyon T-26 pair 600:600
One NOS/NIB. +24db, hum bucking construction, typical multiple tap coil, see UTC A-20 impedance diagram as example.
$120 plus shipping/insurance on 3 lbs.
RCA BA-3 program amp input and UTC output transformer set
Indeed. Both test well. The UTC output is NOS, very difficult to find a high level single ended output like this with good low frequency response. The input is in great shape.
Input is 150/600 to grid.
Output is for single ended 6V6 or 6L6 (RCA did both with this) to 600/150/15/7.5/5 at +30dBm with less than 1% THD 30-15K as used in a BA-3. Lots of BA-3’s in use for vintage audio speaker listening, especially with efficient horn systems.
$600 plus shipping/insurance on 9 lbs.
(2) RCA MI-38482 nine pin plug-in transformers
Accessory transformer for the 1970’s SA-115 transistor general use amplifier, which appears to be a rebadged McMartin unit. A good guess would be these are rebadged McMartin MT-4’s.
groupdiy.com/index.php?topic=73580.msg935848;topicseen#msg935848
pins 1-3 7.5Ω DC = 125-150 pr
pins 1-4 16Ω DC - 600 pri
pins 5-6 139Ω DC = 10K bridging input
pins 8-9 91Ω DC = 10K sec
pins 2-9 349Ω DC = 60K sec
9 pin sockets frequently available NOS on ebay.
$100 plus shipping/insurance
Gates console transformer panel
All three measure 8R : 0.7DCR roughly, would appear to be 150:speaker Z. Possibly identical, with center piece having shielding to prevent crosstalk. Maybe perfect for Paul’s bass trick, speaker as microphone.
$30 plus shipping/insurance on 3 lbs.
Presto tube record lathe power amp output transformer and choke
From a model 88-A power amp, using (4) 6L6/807 type power tubes. Has plate cap attachment for use with 807 tubes, can be removed for standard wiring to 6L6’s. Also the transformers on the later 92-A/B models, which spec within 1dB 20-17K. output impedances of 500/250/15/6 ohms at 50W output. Choke is 10H. The last picture shows how it was used on the 92-A amp, with plate cap attachment.
www.hifido.co.jp/KW/G0105/E/0-50/C05-23362-51346-00/
www.steveespinola.com/lathetrolls/resources/Presto_92A_Manual_Schematic_gif.pdf
$200 plus shipping/insurance on some lbs; heavy.
Tube output transformer for four 6L6
Apparently from a Baldwin organ with several references suggesting 40W power, tests fine for DCR, leads in good condition. Nice hefty chunk of iron for a power amp build. Part #512-14633D. Organs have to pass some low lows, so inductance should be better than average.
$40 plus shipping/insurance on 5 lbs
Pair of IOaudio input transformers for Pultec
As provided with his MEQ500 mid range Pultec project back in 2008 or so. They didn’t work for me as I was trying to use them with true 600 ohm source impedances, and they are somewhat rolled off on the bottom in that case. Feed them with a 50 ohm source such as many converters provide today, and they are full range on the bottom, with IOaudio measuring a -3dB point of 14Hz in that case.
$20 plus shipping/insurance on 1 lb.
RCA potted power transformers 70VCT 800mA
Multiple pieces of very nice potted/shielded power transformers for SS projects. Two are US voltage only, seven more that cover international voltage ranges.
$25/ea plus shipping/insurance on 5 lbs.
ADC HUM-1 video humbuckers
Off the audio path, into video. I have a number of these to sell. New in original shipping boxes. BNC connectors. Pass audio too, an interesting euphonic sound, probably from the low 75Ω loading.
Here's a typical ad for one at $160:
www.markertek.com/product/hum-1/adc-by-te-connectivity-hum-1-humbucking-coil
$30 + shipping and insurance. Slightly under 4 lbs / 1.8 kg shipping weight per piece.
--------recently sold--------
RCA OP-6 input transformers
In this issue:
Kenyon T-26 pair 600:600
RCA BA-3 program amp input and output transformer set
(2) RCA MI-38482 nine pin plug-in transformers (McMartin MT-4) tube inputs
Gates console panel with 3 transformers
Presto PPP 6L6/807 tube record lathe power amp output transformer and choke
Tube output transformer for four 6L6
Pair of IOaudio input transformers for Pultec
RCA potted power transformers 70VCT 800mA
ADC HUM-1 video humbuckers
Kenyon T-26 pair 600:600
One NOS/NIB. +24db, hum bucking construction, typical multiple tap coil, see UTC A-20 impedance diagram as example.
$120 plus shipping/insurance on 3 lbs.
RCA BA-3 program amp input and UTC output transformer set
Indeed. Both test well. The UTC output is NOS, very difficult to find a high level single ended output like this with good low frequency response. The input is in great shape.
Input is 150/600 to grid.
Output is for single ended 6V6 or 6L6 (RCA did both with this) to 600/150/15/7.5/5 at +30dBm with less than 1% THD 30-15K as used in a BA-3. Lots of BA-3’s in use for vintage audio speaker listening, especially with efficient horn systems.
$600 plus shipping/insurance on 9 lbs.
(2) RCA MI-38482 nine pin plug-in transformers
Accessory transformer for the 1970’s SA-115 transistor general use amplifier, which appears to be a rebadged McMartin unit. A good guess would be these are rebadged McMartin MT-4’s.
groupdiy.com/index.php?topic=73580.msg935848;topicseen#msg935848
pins 1-3 7.5Ω DC = 125-150 pr
pins 1-4 16Ω DC - 600 pri
pins 5-6 139Ω DC = 10K bridging input
pins 8-9 91Ω DC = 10K sec
pins 2-9 349Ω DC = 60K sec
9 pin sockets frequently available NOS on ebay.
$100 plus shipping/insurance
Gates console transformer panel
All three measure 8R : 0.7DCR roughly, would appear to be 150:speaker Z. Possibly identical, with center piece having shielding to prevent crosstalk. Maybe perfect for Paul’s bass trick, speaker as microphone.
$30 plus shipping/insurance on 3 lbs.
Presto tube record lathe power amp output transformer and choke
From a model 88-A power amp, using (4) 6L6/807 type power tubes. Has plate cap attachment for use with 807 tubes, can be removed for standard wiring to 6L6’s. Also the transformers on the later 92-A/B models, which spec within 1dB 20-17K. output impedances of 500/250/15/6 ohms at 50W output. Choke is 10H. The last picture shows how it was used on the 92-A amp, with plate cap attachment.
www.hifido.co.jp/KW/G0105/E/0-50/C05-23362-51346-00/
www.steveespinola.com/lathetrolls/resources/Presto_92A_Manual_Schematic_gif.pdf
$200 plus shipping/insurance on some lbs; heavy.
Tube output transformer for four 6L6
Apparently from a Baldwin organ with several references suggesting 40W power, tests fine for DCR, leads in good condition. Nice hefty chunk of iron for a power amp build. Part #512-14633D. Organs have to pass some low lows, so inductance should be better than average.
$40 plus shipping/insurance on 5 lbs
Pair of IOaudio input transformers for Pultec
As provided with his MEQ500 mid range Pultec project back in 2008 or so. They didn’t work for me as I was trying to use them with true 600 ohm source impedances, and they are somewhat rolled off on the bottom in that case. Feed them with a 50 ohm source such as many converters provide today, and they are full range on the bottom, with IOaudio measuring a -3dB point of 14Hz in that case.
$20 plus shipping/insurance on 1 lb.
RCA potted power transformers 70VCT 800mA
Multiple pieces of very nice potted/shielded power transformers for SS projects. Two are US voltage only, seven more that cover international voltage ranges.
$25/ea plus shipping/insurance on 5 lbs.
ADC HUM-1 video humbuckers
Off the audio path, into video. I have a number of these to sell. New in original shipping boxes. BNC connectors. Pass audio too, an interesting euphonic sound, probably from the low 75Ω loading.
Here's a typical ad for one at $160:
www.markertek.com/product/hum-1/adc-by-te-connectivity-hum-1-humbucking-coil
$30 + shipping and insurance. Slightly under 4 lbs / 1.8 kg shipping weight per piece.
--------recently sold--------
RCA OP-6 input transformers
