)
I let myself get locked into this drill. Fluke 732a secondary voltage reference. and then a JRL Kelvin Varley divider plus a Fluke cable compensator to calibrate a Valhalla DC Calibrator then Fluke thermal converters and a 6 1/2 digit dvm to calibrate an Optimation AC Calibrator and a Fluke 8506A enhanced precision AC/DC meter to check the calibration etc. so I could trust the meters so I can know that the level and frequency response of the amp is what its intended to be.
However the reality is that I learned a lot more about the meaning of "uncertainty" and sources of error. Even though most of this stuff is old enough to vote, the state of the art in a standards lab hasn't moved much. Its just a lot easier to use. I played with a galvonometer so that I could say I had but after reading that NIST uses DVM's I retired the galvos to the collection. Chasing parts per million in electronics teaches a lot about noise, grounding, stability and resolution. I also learned a lot from working on and with those instruments. At those levels of accuracy technique and design skill are central to meeting the performance requirements.
However the reality is that I learned a lot more about the meaning of "uncertainty" and sources of error. Even though most of this stuff is old enough to vote, the state of the art in a standards lab hasn't moved much. Its just a lot easier to use. I played with a galvonometer so that I could say I had but after reading that NIST uses DVM's I retired the galvos to the collection. Chasing parts per million in electronics teaches a lot about noise, grounding, stability and resolution. I also learned a lot from working on and with those instruments. At those levels of accuracy technique and design skill are central to meeting the performance requirements.
hello guys....
i saw that the 3d is moving toward the scound card/sw distortion analyzer but....i'm still....could be my preconcept....more inclined to have real instruments.....but a different solution could be as good or even better than that...i know....just by using a very good sound card....but it is challenging.....and the risk to fried your $150 sound card is not appealing to me at all.....therefore i prefer something more solid!!
By speaking of this analyzer here....i would need your suggestion....
On ebay it is possible to find apperantly good deal on HP 334A HP331A and so on....
Once i have read on the forum that a good tool would be the sound technology ad ever since i have searched for it....but it is not easy at all to find one in good working condition and for a relativetly low price.
But it is appealing since it has a low noise signal generator built in..and since i need a sig gen as well...here's the dial.
Right now i ask for some advice....
what used analyzer should i look for at around $150-200 ?
I neeed some soggestion on these...since i have never used a dist analyzer and i would like to buy something that could be a good mate for a long time....not something that once you have learned to use it you throw it 'cause not very precise......but obviously for the range of price indicated i don't expect unbelievable performances as well....
ok that's all folk....hope i was able to exlain sufficiently my self....
thanks a lot for your patience...hope to receive good suggestion.
i saw that the 3d is moving toward the scound card/sw distortion analyzer but....i'm still....could be my preconcept....more inclined to have real instruments.....but a different solution could be as good or even better than that...i know....just by using a very good sound card....but it is challenging.....and the risk to fried your $150 sound card is not appealing to me at all.....therefore i prefer something more solid!!
By speaking of this analyzer here....i would need your suggestion....
On ebay it is possible to find apperantly good deal on HP 334A HP331A and so on....
Once i have read on the forum that a good tool would be the sound technology ad ever since i have searched for it....but it is not easy at all to find one in good working condition and for a relativetly low price.
But it is appealing since it has a low noise signal generator built in..and since i need a sig gen as well...here's the dial.
Right now i ask for some advice....
what used analyzer should i look for at around $150-200 ?
I neeed some soggestion on these...since i have never used a dist analyzer and i would like to buy something that could be a good mate for a long time....not something that once you have learned to use it you throw it 'cause not very precise......but obviously for the range of price indicated i don't expect unbelievable performances as well....
ok that's all folk....hope i was able to exlain sufficiently my self....
thanks a lot for your patience...hope to receive good suggestion.
Hi Stefano,
The HP 33x THD meter is a clear choice. The HP 333 and 334 will auto null. You want that. The HP 334 is the same as the HP 333 except that the HP 334 has an AM detector built in. Most people never use this.
If you can find an HP 339 - go for it! That is if it works okay. They normally go around $400 USD or more. I have seen a couple go for around the $375 area. That's still $400 in my book.
Expect to clean the switches by hand. No spray cleaners!
-Chris
The HP 33x THD meter is a clear choice. The HP 333 and 334 will auto null. You want that. The HP 334 is the same as the HP 333 except that the HP 334 has an AM detector built in. Most people never use this.
If you can find an HP 339 - go for it! That is if it works okay. They normally go around $400 USD or more. I have seen a couple go for around the $375 area. That's still $400 in my book.
Expect to clean the switches by hand. No spray cleaners!
-Chris
Here are some illustrations why low numbers aren't everything and of the value of the spectrum analyzer.
I just picked up an HP467A amplifier. It was interesting because it claims 10W to 1 MHz and would be helpful for a project I'm working on. I thought I would measure it since its an old design ('70s I think) but pretty ambitious.
At max output into 8 Ohms before clipping its shows .006% THD, extremely good even by todays standards for an amplifier. However the distortion residual looks pretty bad:
And on the spectrum analyzer of the distortion output we see how bad it really is:
I just picked up an HP467A amplifier. It was interesting because it claims 10W to 1 MHz and would be helpful for a project I'm working on. I thought I would measure it since its an old design ('70s I think) but pretty ambitious.
At max output into 8 Ohms before clipping its shows .006% THD, extremely good even by todays standards for an amplifier. However the distortion residual looks pretty bad:
An externally hosted image should be here but it was not working when we last tested it.
And on the spectrum analyzer of the distortion output we see how bad it really is:
An externally hosted image should be here but it was not working when we last tested it.
Hi Demian,
I'm one guy that needs zero convincing on this. What unit are you using?
I have been considering buying a new 'scope (Agilent 6000 series) that does have some FFT math functions built in. It doesn't have the resolution, but it does give you most of the answers. It seems to be aimed at higher frequency events though.
-Chris
Which is why I've wanted a spectrum analyzer in the worst way for years.
I'm one guy that needs zero convincing on this. What unit are you using?
I have been considering buying a new 'scope (Agilent 6000 series) that does have some FFT math functions built in. It doesn't have the resolution, but it does give you most of the answers. It seems to be aimed at higher frequency events though.
-Chris
The spectrum analyzer is a Wavetek 7530A FFT plugin for a Tek 7000 scope. Its in an old 7403N frame I had (with no readout) and the plugin has its own readout. Its quite neat. Its got a 70 dB range so you must precondition the signal and a mag feature that allows high resolution of any small segment of the range.
This guy: http://cgi.ebay.com/100MS-s-PC-Based-USB-digital-storage-oscilloscope-2090_W0QQitemZ270179246321QQihZ017QQcategoryZ104247QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Looks like a close copy of a Picoscope for $150 or so. It has the FFT functionality. Just hook it to the output of the HP339 or even an HP333 and see what you get. nIt may be enough. But you need a computer to see its output.
Looks like a close copy of a Picoscope for $150 or so. It has the FFT functionality. Just hook it to the output of the HP339 or even an HP333 and see what you get. nIt may be enough. But you need a computer to see its output.
1audio,
My compliment for your equipment and analysis as well....
Can i ask your support?
Sombody told me that the HP 334 or something similar would be a good choice here.
Unfortunatelly i can't catch right now differencies on analyzers since i don't have the necessary experience to say that still....obviously....
i'm really obsessed for this the Sound Technology 1700B.....
Would it be possible for the experienced guys here kto take a look at the specifications and highlight for me the differences, if there are, within the HP334A or similar and the Sound Technology 1700B?
Just Keep in mind that the Sound Technology has a low noise signal generator built in as well...which i need it and that i would eventually have to set money aside since i still don't have it.
Sorry guys to make you do this for me but i have a guy now that i have to give an answer to about the sound technology ad I wouldn't be able bymyself to take a good decision with regard to this subject.
My compliment for your equipment and analysis as well....
Can i ask your support?
Sombody told me that the HP 334 or something similar would be a good choice here.
Unfortunatelly i can't catch right now differencies on analyzers since i don't have the necessary experience to say that still....obviously....
i'm really obsessed for this the Sound Technology 1700B.....
Would it be possible for the experienced guys here kto take a look at the specifications and highlight for me the differences, if there are, within the HP334A or similar and the Sound Technology 1700B?
Just Keep in mind that the Sound Technology has a low noise signal generator built in as well...which i need it and that i would eventually have to set money aside since i still don't have it.
Sorry guys to make you do this for me but i have a guy now that i have to give an answer to about the sound technology ad I wouldn't be able bymyself to take a good decision with regard to this subject.
and sorry....just as a note on the previous post......
i have read on the web that there are also modifications for the ST 1700B......in case.....does anybody here have more detiled informations on this topic?
And last......is it possible to find a service manual for calibration procedure?....i got this possibilty to get ST 1700B but i don't know if it is the right choice and most of all...i suppose that since these are old stuff if they weren't recently serviced, i supposed that they would need calibration...and the flat rate for it is too hig (talking about $1k...crazyyy!)
i have read on the web that there are also modifications for the ST 1700B......in case.....does anybody here have more detiled informations on this topic?
And last......is it possible to find a service manual for calibration procedure?....i got this possibilty to get ST 1700B but i don't know if it is the right choice and most of all...i suppose that since these are old stuff if they weren't recently serviced, i supposed that they would need calibration...and the flat rate for it is too hig (talking about $1k...crazyyy!)
I have a 1700b and used it for years. Its a much better instrument thatn an HP334 and more useful, with a built in oscillator. It has auto-null and can consitantly get down to .oo2% or less in the midband. It can be tweaked to have lower distortion with improved op-amps, but its hard since it uses op-amps in cans. There are adapters available.
They can be a pain mechanically with switch interlocks etc. And the oscillator settling circuit is touchy. You can service them yourself but you will need to get suitable optocouplers and jfets for the AGC circuits and be very patient with the switch array.
Here is an example of the highest level of the 1700 series for a reasonable price: http://cgi.ebay.com/Sound-Technology-Distortion-Analyzer-1710A-Opt-3-4_W0QQitemZ330177438639QQihZ014QQcategoryZ25423QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
It has the higher balanced output and the precision attenuator and the IM analyzer. He's asking $285.
They can be a pain mechanically with switch interlocks etc. And the oscillator settling circuit is touchy. You can service them yourself but you will need to get suitable optocouplers and jfets for the AGC circuits and be very patient with the switch array.
Here is an example of the highest level of the 1700 series for a reasonable price: http://cgi.ebay.com/Sound-Technology-Distortion-Analyzer-1710A-Opt-3-4_W0QQitemZ330177438639QQihZ014QQcategoryZ25423QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
It has the higher balanced output and the precision attenuator and the IM analyzer. He's asking $285.
Yeah...i saw it already...but thanks for the highlight.
Unfortunatelly that item doesn't work on European standards with the 220-240V 50Hz.
Your post was very usefull...since now, i'm very appealed toward this sound Analyzer 1700B.
I already saw the service manual on line for $14...dangiet they take advantage of everything...tomorrow we will wake up knowing that we have to pay our daily breathing air dose ..... but through PayPal....so we don't have to worry.......hihihi....
So you tell me that with the right tool and with the service manual and with a lot of patience the item can be finely serviced even from who has never calibrated instruments?
Niceee!!!
I' sorry i have never used the tools you mentioned before....what is an optocouplers and what type of jfets do i need for the AGC circuits?
Thhhankkkkssss a lott!!!!
The guy that is selling the 1700B analyzer doesn't know how to run self-tests to guarantee me the funtionalities of the ST....but it took pictures for me showing me some of the tests he was able to run.
He showed me the meter going up.......but obviously i don't know if that is enough to tell me that it's workinng or not.
What should i ask him to do with the analyzer to make sure, at least , that it works?
For the calibration i don't care i will take the time later to do it on my own.
I appreciate your help very much.
Unfortunatelly that item doesn't work on European standards with the 220-240V 50Hz.
Your post was very usefull...since now, i'm very appealed toward this sound Analyzer 1700B.
I already saw the service manual on line for $14...dangiet they take advantage of everything...tomorrow we will wake up knowing that we have to pay our daily breathing air dose ..... but through PayPal....so we don't have to worry.......hihihi....
So you tell me that with the right tool and with the service manual and with a lot of patience the item can be finely serviced even from who has never calibrated instruments?
Niceee!!!
I' sorry i have never used the tools you mentioned before....what is an optocouplers and what type of jfets do i need for the AGC circuits?
Thhhankkkkssss a lott!!!!
The guy that is selling the 1700B analyzer doesn't know how to run self-tests to guarantee me the funtionalities of the ST....but it took pictures for me showing me some of the tests he was able to run.
He showed me the meter going up.......but obviously i don't know if that is enough to tell me that it's workinng or not.
What should i ask him to do with the analyzer to make sure, at least , that it works?
For the calibration i don't care i will take the time later to do it on my own.
I appreciate your help very much.
Anyone tried the EMU 0202, seems to be a bit noisy at HF:
http://www.libinst.com/EMU 0202 USB.htm
Seems it would work well with a distortion magnifier when needed.
Pete B.
http://www.libinst.com/EMU 0202 USB.htm
Seems it would work well with a distortion magnifier when needed.
Pete B.
yes, i would think so, since the seller confirmed me that the 1700B model has a switch on the back for the 220V.
I set the price for the 1700B at $150 which is an half of what the seller of the 1710 is aking for.
I' m sure that the 1710 is a better and more performant unit but i wouldn't like to spend right away $300 for a distortion analyzer since i have never used one...and i would like to learn first and......and if... i 'll became an "expert"... and feel the need for something better....then buy a better analyzer like yours (boonton).
In the meantime, would it be possible for you give me some good hints on how and what to ask to the seller to make sure that the analyzer is working?
hope i'm not bothering you with all this questions.
Thanks in advance.
I set the price for the 1700B at $150 which is an half of what the seller of the 1710 is aking for.
I' m sure that the 1710 is a better and more performant unit but i wouldn't like to spend right away $300 for a distortion analyzer since i have never used one...and i would like to learn first and......and if... i 'll became an "expert"... and feel the need for something better....then buy a better analyzer like yours (boonton).
In the meantime, would it be possible for you give me some good hints on how and what to ask to the seller to make sure that the analyzer is working?
hope i'm not bothering you with all this questions.
Thanks in advance.
Hi Stefano,
If you want a better oscillator and THD meter, then the HP 339A is my preferred instrument. I have used the 1700. It is a giant and the HP unit will do what you need in a much smaller package. The noise floor is stated at 0.0018% THD - that's it's internal oscillator looped into the distortion section. I have confirmed this.
The ST 1700 is noted for switch contact problems. That was earlier in time. The fact that it is large enough to block you view out of a window is a consideration. I used to want one until I used the 339A.
With regard to the 333A/334A, they have very high frequency response. That is their value. Higher than the ST or 339A. For that reason I have one. One thing I can say is that all of these outperform the Japanese THD meters by a long shot. Leader LDM-171 for example. I have one of those as well. I may try to rework it (it's smaller and pretty - sort of).
In my view, the HP 339A is a better instrument than the ST 1700. This is reflected in the higher cost on places like Ebay. They normally sell for $400 and they need work. Freshened up, they sell for more.
For what it's worth. Demian and I may possibly disagree on this point.
Demian, I can't remember if you said that you have used an HP 339A before or not. I think it was an 8903 (a or b) that you used. I have never seen one in action.
-Chris
If you want a better oscillator and THD meter, then the HP 339A is my preferred instrument. I have used the 1700. It is a giant and the HP unit will do what you need in a much smaller package. The noise floor is stated at 0.0018% THD - that's it's internal oscillator looped into the distortion section. I have confirmed this.
The ST 1700 is noted for switch contact problems. That was earlier in time. The fact that it is large enough to block you view out of a window is a consideration. I used to want one until I used the 339A.
With regard to the 333A/334A, they have very high frequency response. That is their value. Higher than the ST or 339A. For that reason I have one. One thing I can say is that all of these outperform the Japanese THD meters by a long shot. Leader LDM-171 for example. I have one of those as well. I may try to rework it (it's smaller and pretty - sort of).
In my view, the HP 339A is a better instrument than the ST 1700. This is reflected in the higher cost on places like Ebay. They normally sell for $400 and they need work. Freshened up, they sell for more.
For what it's worth. Demian and I may possibly disagree on this point.
Demian, I can't remember if you said that you have used an HP 339A before or not. I think it was an 8903 (a or b) that you used. I have never seen one in action.
-Chris
I have played with an HP339A but never really used one. The ST700 often has the IM module which really works well. Its big, and the ST1710 is bigger. For some this may not be an issue. The only switch that ever saw much use on mine was the range switch. I left it set at 2X so 20, 200, 2K and 20K were all one push apart. You can do that with the HP339A as well. John Curl uses an ST1700B still, although his has been tweaked with better opamps.
If you look at the photos above you will see that my primary stack of instruments is very tall. I'll post pictures of the lab soon. I need a function generator, a monitor scope and a main scope as well as the distortion analyzer and a DVM and a counter usually. But most may not need so much stuff.
At $400 I would get a Boonton if I could find one. The microprocessor control just makes it easier and faster. Or the Amber looks good. The HP3904 is just a little klutzy to use (poor UI) and its performance isn't much different from an HP339A. All of these have GPIB allowing automation of the measurements. The HP339A commands a higher price partly from familiarity with the name. I used to have a manual for an HP3900, I think, that was a Japanese built analyzer.
The Shibasoku is possibly the lowest distortion instrument made so don't write off the Japanese instruments too fast. But the cheaper ones for assembly lines are pretty modest in performance.
If you look at the photos above you will see that my primary stack of instruments is very tall. I'll post pictures of the lab soon. I need a function generator, a monitor scope and a main scope as well as the distortion analyzer and a DVM and a counter usually. But most may not need so much stuff.
At $400 I would get a Boonton if I could find one. The microprocessor control just makes it easier and faster. Or the Amber looks good. The HP3904 is just a little klutzy to use (poor UI) and its performance isn't much different from an HP339A. All of these have GPIB allowing automation of the measurements. The HP339A commands a higher price partly from familiarity with the name. I used to have a manual for an HP3900, I think, that was a Japanese built analyzer.
The Shibasoku is possibly the lowest distortion instrument made so don't write off the Japanese instruments too fast. But the cheaper ones for assembly lines are pretty modest in performance.
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