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Hi Jon, I have no "real data", but I find it VERY hard to believe that a 10 ohm, 10 W resistor could possibly have 55 or 505 *millihenrys" of inductance. I strongly suspect that your numbers units

Wondering if anyone in the group has a set of what I believe are 5U handles for the 8753E. If I am not mistaking the handles were generic, and likely fit other instruments in the same form factor

It should also be understood that no speaker, or speakers w/crossover, will be pure resistive either. I recall seeing reviews of speaker systems where the impedance as a function of frequency was

Hello everybody, I got the HP82357B interface and I can finally use Pete Millett's programs. I entered address 7 for the interface and 28 for the HP8903B. It works well, I just wanted to understand if

Thank you all for the advice and considerations on the measurements of the output transformers. Reading the various posts it seems to me that the best solution is to create a final amplifier, with for

Rebonjour a tous, The long posts raised my curiosity: WWhat about an accurate LCR bridge measurement ofd loads and speakers? My Wayne Kerr 3245 precision inductance meter was just reworked and in cal,

hello part C765 , C766 .0022UF 250VAC I found them on rscomponet https://it.rs-online.com/web/p/condensatori-a-film/0210572 the other two 1000uf 250vac are electrolytic shouldn't be hard to find --

hello Dave thanks i measured the battery yesterday and 3.45v ok for digikey but its better for me if i find it locally i saw it on ebay in germany they sell around 11 dollars new for replacement i saw

First of HP used to build instruments sometimes for decades, the 8660 for example was built for almost 20 years starting with the A and ending with the D model , the changes mostly were applied to the

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