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Date
Re: How can I measure the bandwidth of an audio transformer with the HP8903B ?
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
By Attilio · #122923 ·
Re: How can I measure the bandwidth of an audio transformer with the HP8903B ?
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
By Froggie the Gremlin · #122922 ·
Re: HP 1727A CRO: Problem with the vertical output amplifier.
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
By Tom Lee · #122921 ·
Re: HP 1727A CRO: Problem with the vertical output amplifier.
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.
By Alex_03 · #122920 ·
Re: How can I measure the bandwidth of an audio transformer with the HP8903B ?
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
By Attilio · #122919 ·
Re: HP 1727A CRO: Problem with the vertical output amplifier.
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
By Francesco Messineo · #122918 ·
Re: HP 1727A CRO: Problem with the vertical output amplifier.
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
By Alex_03 · #122917 ·
Re: massive attachments
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
By Matt Harris · #122916 ·
File /Above 10000 to 89999/50000 to 59999/54720A/54720A_FW_EPROM_DUMP.rar deleted #file-notice
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:*
By [email protected] Notification <noreply@...> · #122915 ·
Re: hp3478A
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
By Dave McGuire · #122914 ·
Re: How can I measure the bandwidth of an audio transformer with the HP8903B ?
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
By saipan59 (Pete) · #122912 ·
Re: eCal & HP-8753E
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,
By Lothar baier <Lothar@...> · #122911 ·
Re: How can I measure the bandwidth of an audio transformer with the HP8903B ?
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
By Froggie the Gremlin · #122910 ·
Re: Storage Cap Ripple
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
By Jinxie · #122909 ·
Re: How can I measure the bandwidth of an audio transformer with the HP8903B ?
Thank you all, it is understood that then in real operation it will be different from the measurements made only on the transformer, but I will be able to use the measurements for a first comparison
By Attilio · #122908 ·
Re: eCal & HP-8753E
Hi! I'm running FW 7.14 on my 8753D Option 000 CPU upgrade. The FW 7.14 is the latest release for the 8753D. However, it has been mentioned several times that this CPU board can use the 8753E
By LeonP · #122907 ·
4145B Boot Disk, photo of original?
Hi all, Does anyone have an original 4145B boot disk they can take a photo of the label? I want to make my own labels, so wouldn't mind replicating the original disk label if possible. Thanks!
By Jared Cabot · #122906 ·
Re: How can I measure the bandwidth of an audio transformer with the HP8903B ?
You will need to match the source and load impedances to get an accurate result. Ideally you should also pass the same DC current through the core as the quiescent current of the amplifier as a DC
By Gavin Watkins · #122905 ·
Re: How can I measure the bandwidth of an audio transformer with the HP8903B ?
Do you have any specs on the transformer?? Like input and output impedances?? What tubes will it be used with?? Output impedance 4/8/16 ohms?
By Jim Allyn - N7JA · #122904 ·
Re: How can I measure the bandwidth of an audio transformer with the HP8903B ?
To obtain a good measurement of BW in an impedance matching transformer like this, it does indeed need to be tested with correct terminations on both sides. Since the output of your generator is an
By Gary Johnson <gwj@...> · #122903 ·