| Home |
| Search |
| Today's Posts |
|
|
|
#1
January 1st 10, 05:14 PM
posted to rec.radio.amateur.boatanchors
|
|||
|
|||
hammarlund sp-210 xformers
Richard Knoppow wrote:
"frank" wrote in message ... Hello Colin, COLIN LAMB wrote: Hello Frank: The push-pull output transformers should be fairly common and easy to obtain. Antique Electronic Supply, in USA, is a good source. As I recall, the output tubes are 6V6s, so that would use a common transformer as well as driver transformer. actually the output tubes and the driver are all 6F6. Also the output audio impedance of the SP-200 series is 600 ohms, I wouldn't mind too much to have directly an output impedance for driving a 4-8 ohm speaker, but my first option would be restoring the set as much as possible close to the original. I'd be happy to find any information about the transformers, like power, turn ratios and so on. Best 73 es HNY Frank IZ8DWF The 6F6 tubes are connected as triodes and operated nearly at Class-B, the output transformer is 10,000 plate to plate. This is a common impedance. The original transformers have a 500 ohm main output and a loosly coupled 8,000 ohm winding for the headphones. -- Richard Knoppow Los Angeles WB6KBL On old tube manual shows that the 6F6 in push pull triode connection with self bias (730 oh cathode resistor) delivered 14 watts with 350 volts on the plate and a load resistance of 10,000 ohms plate to plate. With fixed bias (-38 volts) it would deliver 18 watts into 6000 ohms plate to plate. For fixed bias the input transformer ratio primary to 1/2 secondary was 1.67. For self bias the ratio was 1.29. The driver tube would also be triode connected, 250 volts plate, -20 volts bias and a plate load of 10,000 ohms. No figures given for operation at 250 volts for the output stage, but the output impedance would be about the same and resting plate current would be adjusted to about 45ma. Power output would probably be about 2/3 the value at 350 volts. BTW, the types 42 and 6F6 are the same except for the base, types 42 and 2A5 are the same except for the heater voltage. (some SP models might have used the other tubes) The tube lineup in the SP210 was 6K7x2(rf), 6L7 mix, 6J7 vfo, 6K7 if#1, 6SK7 x2 IF 2-3, 6H6 detector, 6N7 nl, 6SJ7 bfo, 6SK7 avc, 6H6 avc rect, 6C5 af#1, 6F6 driver, 6F6 x2 output, 5Z3 rectifier, 80 rectifier Must have had two different plate voltages, hence the two different rectifier tubes. The SP400 power supply used the second rectifier as a bias rectifier, maybe that's what was done here? I'm looking at the tube lineup from the book 'communications receivers' by R.S. Moore. |
|
#2
January 5th 10, 03:40 PM
posted to rec.radio.amateur.boatanchors
|
|||
|
|||
|
hammarlund sp-210 xformers
"Kenneth Scharf" wrote in message ... Richard Knoppow wrote: "frank" wrote in message ... Hello Colin, COLIN LAMB wrote: Hello Frank: The push-pull output transformers should be fairly common and easy to obtain. Antique Electronic Supply, in USA, is a good source. As I recall, the output tubes are 6V6s, so that would use a common transformer as well as driver transformer. actually the output tubes and the driver are all 6F6. Also the output audio impedance of the SP-200 series is 600 ohms, I wouldn't mind too much to have directly an output impedance for driving a 4-8 ohm speaker, but my first option would be restoring the set as much as possible close to the original. I'd be happy to find any information about the transformers, like power, turn ratios and so on. Best 73 es HNY Frank IZ8DWF The 6F6 tubes are connected as triodes and operated nearly at Class-B, the output transformer is 10,000 plate to plate. This is a common impedance. The original transformers have a 500 ohm main output and a loosly coupled 8,000 ohm winding for the headphones. -- Richard Knoppow Los Angeles WB6KBL On old tube manual shows that the 6F6 in push pull triode connection with self bias (730 oh cathode resistor) delivered 14 watts with 350 volts on the plate and a load resistance of 10,000 ohms plate to plate. With fixed bias (-38 volts) it would deliver 18 watts into 6000 ohms plate to plate. For fixed bias the input transformer ratio primary to 1/2 secondary was 1.67. For self bias the ratio was 1.29. The driver tube would also be triode connected, 250 volts plate, -20 volts bias and a plate load of 10,000 ohms. No figures given for operation at 250 volts for the output stage, but the output impedance would be about the same and resting plate current would be adjusted to about 45ma. Power output would probably be about 2/3 the value at 350 volts. BTW, the types 42 and 6F6 are the same except for the base, types 42 and 2A5 are the same except for the heater voltage. (some SP models might have used the other tubes) The tube lineup in the SP210 was 6K7x2(rf), 6L7 mix, 6J7 vfo, 6K7 if#1, 6SK7 x2 IF 2-3, 6H6 detector, 6N7 nl, 6SJ7 bfo, 6SK7 avc, 6H6 avc rect, 6C5 af#1, 6F6 driver, 6F6 x2 output, 5Z3 rectifier, 80 rectifier Must have had two different plate voltages, hence the two different rectifier tubes. The SP400 power supply used the second rectifier as a bias rectifier, maybe that's what was done here? I'm looking at the tube lineup from the book 'communications receivers' by R.S. Moore. The 80 tube (5Y3 in later versions of the supply) is a -50 volt bias supply for the AVC and other circuits. The SP-600-JX has a similar arrangement but using a 6AL5 as the bias rectifier. Earlier versions of the Super-Pro did use glass tubes. I think there are a couple of early instruction manuals on line showing this version. The early 1940's version used all metal tubes except for the rectifiers and post war sets including the SP-400 used a 5U4 in place of the 5Z3 and 5Y4 in place of the 80. These two are identical except for the base and envelopes. -- Richard Knoppow Los Angeles WB6KBL |
| Reply |
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Forum | |||
| FA: Hammarlund HQ-215 | Boatanchors | |||
| Query: 400Hz Xformers | Boatanchors | |||
| FS: Hammarlund HQ-160 | Boatanchors | |||
| Wanted:4 or 8 ohm to 500 ohm xformers | Boatanchors | |||
| FS 500VA Motorized Variac Voltage Stabilizer. Step up/down xformers.Lotsa other stuff. | Swap | |||
Hybrid Mode
