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I have just recently started collecting old Hewlett Packard test equipment, though I have been actively collecting and restoring Tektronix equipment for over a year. I started my HP collection with

Hello, I did not ask this question earlier to be argumentative but only for my own curiosity.? When I was in high school (It was a very dark cave!), during the golden age of tube hi fi amplifiers, we

Answer...u,clear the intended frequency range, so type in l8ad.is in question. 1/ no need to vary the load resistance as hi-fi amplifiers are rated driving a 4 or 8 ohm resistance load, not a voice

I haven't done the math or measurement, but I question that (for example) a 20 ohm, 20 watt rheostat has enough inductance to be important at audio frequencies. It's an air-core coil, wound on

That's probably all the information you need to make approximate measurements of the transformer frequency response.? As others have said, if you want precision, you pretty much have to build the

Why would the inductance of either the rheostat or a wire wound load resistor be of significance when it is basically substituting for a voice coil (a coil of wire)? Jack

Thanks Jon, the rheostat would serve to match the reflected impedance to the amplifier tubes to test different transformers. Alternatively I could think of a switch to select different anti-inductive

Atillo, 1/ use a non inductif 8 ohm power resistance NOT rehostat for load. Too inductif! Carborundum made "globar" tubular loads for dummy loads for TX. 2/ Use classic RCA valve app notes 1950s on

Hi Alex, I wouldn't describe that output stage as a push-pull topology. The pulling up is just passive; there's only active pulldown. The output stage is a slightly modified, but otherwise

That is certainly what it looks like, but looking at the schematic the vertical output amp is not like any push-pull driver I am used to seeing.

Thanks Jon, you are right, but the measurement can be used to make comparisons and to have a first indication of the transformer. Pete, great idea, I had thought about it, but I had not thought about

Just my 2 cents here, but to me it looks like crossover distortion, so you might want to check around the base polarization of a final push-pull amplifier or a push-pull driver. Of course could be a

The input signal for the captures was not the calibrator, it was an external function generator. I chose triangle because it makes it easiest to see the distortion on the screen, sine shows it too and

Reminds me of a saying... It is better to don sandals than carpet the world. What's next?? Demanding people wear certain things (that has nothing to do with covering indecent exposure) in public or

The following files and folders have been deleted from the Files area of the [email protected] group. * /Above 10000 to 89999/50000 to 59999/54720A/54720A_FW_EPROM_DUMP.rar *By:*

Greetings Roberto. The Panasonic BR-2/3AE5SPN is an exact replacement and is readily available from the standard electronics suppliers. I usually purchase them from either Mouser or DigiKey in the

From the advice, it would seem that the best approach would be to build a tube driver and output stage (or modify an existing one) in such a way that it is very easy to swap the transformer with

The FW change does not affect the calibration constants nor options however you might end up with a black screen, the main issue here is that the 8753E and higher used a LCD rather than a CRT display,

Bonjour how Attillo Very fine question Audio output Transformers with a steel core are nonlinear, the induction, and parameters vary with frequency and voltage excitation. Thurs a network or impedance

Okay, well I can't find anything amiss with C7 on A20. It measures 10uF @ 0.5 Ohms in circuit (a *very* low ESR for a 10uF 63V cap!) so I don't see how replacing it would help at all, I'm sorry to