Richard,
I would like to make mine that good. ; )
What are the .1uf caps that you are using?
Did they come in the analyzer?
If you had another pic at the opposite angle
points down so I could see what is on the other
side of the 5K trimmer.
You still have C48 in there, but it shouldn't do anything.
What did you use for your Quad opamp?
And what you used for the quad op amp.
Maybe the circuitrim 2K is the pot to use
for the osc level.
I would like to make mine that good. ; )
What are the .1uf caps that you are using?
Did they come in the analyzer?
If you had another pic at the opposite angle
points down so I could see what is on the other
side of the 5K trimmer.
You still have C48 in there, but it shouldn't do anything.
What did you use for your Quad opamp?
And what you used for the quad op amp.
Maybe the circuitrim 2K is the pot to use
for the osc level.
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That is an averagew not RMS reading, if you are asking about the Panasonic's display. The RMS will be about as shown on the ShibaSoku 725D.
RichEEM, yes I was.
So, on the 725D, that is -110dB (switch), plus an additional -10dB (from the meter), is -120 dB. Then there is the analyzer gain switch with +10dB.
Do we also need to account for the ShibaSoku Ag16b which shows an additional
20.40dB down? I don't know how the cables are routed...I assume though this.
Then, that leaves us with -120db + (-20.4db) so combined -140.4dB?
OR
Maybe they are for comparison HP339a with Panasonic vs.
ShibaSokus.
So, on the 725D, that is -110dB (switch), plus an additional -10dB (from the meter), is -120 dB. Then there is the analyzer gain switch with +10dB.
Do we also need to account for the ShibaSoku Ag16b which shows an additional
20.40dB down? I don't know how the cables are routed...I assume though this.
Then, that leaves us with -120db + (-20.4db) so combined -140.4dB?
OR
Maybe they are for comparison HP339a with Panasonic vs.
ShibaSokus.
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Not sure how to combine all the info -- my own 339A oscillator has harmonicss that are in the -130dB range, so the THD+N could be at around -120. I do need to circle back around to the 339 and see if I can get a little better performance out of it. I've been reluctant to go back there because it is so dang hard to work on -- at least the 8903 has boards you can pull out, even if there isn't anything much you can do after that...
Thanks David. You have one for sale cheap?
I like that little AG16b too, that's a nice looking
and easy to use generator.
RichEEM, that works for 6903. Pull the boards
tweak them, that is about it?
Me thinks you were right on the money when you
said they were a PITA. I would even go so far to
put the letter F in between the T and the A for the
old (emphasis added).
I like that little AG16b too, that's a nice looking
and easy to use generator.
RichEEM, that works for 6903. Pull the boards
tweak them, that is about it?
Me thinks you were right on the money when you
said they were a PITA. I would even go so far to
put the letter F in between the T and the A for the
old (emphasis added).
Not me but there is one on ebay for 975US.
I'll bet you could talk the guy down a bit. I got mine 900US.
Worth ever penny and more.
This is down from -90dBV. Meaning 0dBV on the plot is -90dBV on the monitor port.
Attachments
It aint a ShibaSoku but it can source and measure directly for THD+N to just under .001% with minimal upgrades.
= THD+N
= THD
The 2H and 3H dominate the THD at -120dB....20dB better than the 339A can measure. The osc 4H and 5H + are at -130dB and -140dB from the 339A source.
This is quit good for many tests. When a notch filter and FFT are used to look at residuals, it can do quite well to see extremely low levels.
THx-RNMarsh
= THD+N = THD The 2H and 3H dominate the THD at -120dB....20dB better than the 339A can measure. The osc 4H and 5H + are at -130dB and -140dB from the 339A source.
This is quit good for many tests. When a notch filter and FFT are used to look at residuals, it can do quite well to see extremely low levels.
THx-RNMarsh
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Okay,
I guess the Panasonic is still
"just slightly ahead of our time."
Will have some updates soon.
Richard, Thanks for the pics.
Any one know how easily, difficult, expensive
we can repurpose
some of the old NTSC/PAL/SECAM gear
for general audio high end audio?
There is a lot of out out there not that
digital is supplanting the old standards.
I bet you still get the this does that and
this for that, and this one over here almost does that.
Still better wiht the 725D then tweaked TV gear.
It never ends unless you find that one thing....
That just works when you need it, does what ou want
simply, provides for accurate reading etc....hopefully
its still in buddget or mmakd the budget for it and figure oiut
how to meet the budget.
I appreciate your support gentlemen. I couldn't be doing
this stuff without y'all.
I guess the Panasonic is still
"just slightly ahead of our time."
Will have some updates soon.
Richard, Thanks for the pics.
Any one know how easily, difficult, expensive
we can repurpose
some of the old NTSC/PAL/SECAM gear
for general audio high end audio?
There is a lot of out out there not that
digital is supplanting the old standards.
I bet you still get the this does that and
this for that, and this one over here almost does that.
Still better wiht the 725D then tweaked TV gear.
It never ends unless you find that one thing....
That just works when you need it, does what ou want
simply, provides for accurate reading etc....hopefully
its still in buddget or mmakd the budget for it and figure oiut
how to meet the budget.
I appreciate your support gentlemen. I couldn't be doing
this stuff without y'all.
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The Video stuff really has no use unless you are looking for high frequency linearity. I'm about to consign some to the recycle bin.
Shibasoku made tons of that stuff and if we can get it for cheap even just salvaging the transformer would cover the cost. It would be a cash of really high quality parts.
I don't know that any of the functions would be useful for audio but who knows.
Those isolation shielded transformers would be a bonus for sure. Shame to have them thrown away in a land-fill. Maybe some video isolation xfrmers too. Edge connectors. Many good stuff if cheap enough to salvage for parts.
-RNM
-RNM
It must be Christmas time for me..... I just looked around on the floor and wondered what this other analyzer was.... it's another VP-7722A !! I have a backup or parts unit if one fails. 😱 One needs a slight tune up but works fine. [must have been on sale]. When I need a quick check on something, these units are fast and accurate... and gives me individual harmonics. And, they are made (designed?) by same company that makes the ShibaSoku analyzers. They just have 2 notch filters instead of 3 and dont go to the ultimate lowest levels. The advantage of the 339a is low cost and you can add notch filter and FFT. With a few pieces and software you can do what these do all built in. When you are adjusting a pot on a D.U.T. for lowest distortion, an analog meter is best... both the 339 and ShibaSoku 725 have this type ..... you can visually get to the null point quickly. With the all digital display, you have to wait for software and/or digital update times which make tuning more difficult to find the null and slower.
THx-RNMarsh
THx-RNMarsh
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@ RNMarsh,
Can you show the photo around the A1U3?
Have you removed C14~C17, R78 arround U3?
RNMarsh,
Do you know how the VP-7722A measures the 2nd, 3rd, and so on harmonics when the appropriate button is pressed? I'm assuming some filtering to get to the frequency of interest?
Do you know how the VP-7722A measures the 2nd, 3rd, and so on harmonics when the appropriate button is pressed? I'm assuming some filtering to get to the frequency of interest?
HP339a UPDATE
Updates for HP339a:
1kHZ, 3V, Frequency Venier CAL, Level fully CW
per HP Manual.
Generally it is working however the 2H is running pretty high
at about -80 -90 dB at 1kHz with the noise floor 130 db.
Problem 1. Switch filters, 400Hz doesn't work and
no signal passes...not sure yet where the problem lies
at the switch or .033 caps or problem on the board.
HP339a starts to get screwy along the way to the JFET
and the A1 board. This is in the AGC circuitry.
The output of the oscillator U1 measured at
TP1 - 9.45V ac.
TP3 and TP4 are where it should be
according to the schematic.
Problem 2:
TP5 - 23mV - 30mV ac
TP6 - 23mV -26mVac
TP8 - 54mV ac.
Can anyone check their HP339a and see what they
measure on these test points? I'll post some pics
of scope shots after the nightly news. 🙂
Problem 3:
Generally it is working however the 2H is running pretty high
at about 80 - 90 dB. The noise floor is lower than 120 db.
Could this be attributed to the JFET Q2?
Still working on these.
Updates for HP339a:
1kHZ, 3V, Frequency Venier CAL, Level fully CW
per HP Manual.
Generally it is working however the 2H is running pretty high
at about -80 -90 dB at 1kHz with the noise floor 130 db.
Problem 1. Switch filters, 400Hz doesn't work and
no signal passes...not sure yet where the problem lies
at the switch or .033 caps or problem on the board.
HP339a starts to get screwy along the way to the JFET
and the A1 board. This is in the AGC circuitry.
The output of the oscillator U1 measured at
TP1 - 9.45V ac.
TP3 and TP4 are where it should be
according to the schematic.
Problem 2:
TP5 - 23mV - 30mV ac
TP6 - 23mV -26mVac
TP8 - 54mV ac.
Can anyone check their HP339a and see what they
measure on these test points? I'll post some pics
of scope shots after the nightly news. 🙂
Problem 3:
Generally it is working however the 2H is running pretty high
at about 80 - 90 dB. The noise floor is lower than 120 db.
Could this be attributed to the JFET Q2?
Still working on these.
Measurements taken @ 1kHz off a working oscillator.
TP1 9.59Vp This correct. The nominal is 10Vp
TP3 ~ 9Vdc, 24Vpp
TP4 58mVpp, 0Vdc
TP5 ~ 8Vdc
TP6 ~ 3Vpp, 0Vdc
TP8 ~ -2.16Vdc, 100mVpp
