need opinion on 2nd hand AF analyzers prices

[bembel]

Hi all,
Someone in my area have two analyzers to sell,
I'm not familiar enough with ebay prices or other sellers to have a right opinion on the prices and it seems to me a bit expensive but I'm not sure.
Any comparison is welcome.
Here the stuff:

- HP302A for 300€ (I've found the doc, I clearly see what it is, but if you have some experiences aubout, it's welcome)

- a test bench from Bruel & Kjaer for 450€ (have not yet all details, but I let me told it's the Rohde & schwartz of AF) consisting of:
* an oscillator (with beat generator !?!)
* a printer / tracer
* a selective voltmeter 1/3 octave
* an amplifier (don't know what level, but I think it's for mic input)
- some informations : 3 units rackmount 1.5 meters high. tube era (with common ones) the vendor told me about model 2035 for one of the elements but was not sure, the amp is deffective with 30% mismatch (tubes haven't been tested yet).

thanks

 

[HollowState]

You should be cautious if you buy either of these units. The HP 302A is at least 30+ years old. And while it's solid state, it is germanium technology and looong out of support. But reasonably easy to repair if you have a manual. Assuming euros are still close to dollars, it's on the high side of what's fair. Frequency sweeps are done manually, but there was an outboard motor drive available that mounted on the front panel over the frequency shaft. (knob removed)

Before buying an old 302A I'd look for an HP 3581A as these do the same thing and are much newer. They can be bought on eBay for about the same money as is being asked for the old 302A. The 3581C is similar with some differences like balanced inputs and WECO connectors. And stay away from option 001. That's internal nicad batteries. They're always bad and needed to run the unit.

The Bruel & Kjaer is another matter. Yes, B & K is considered top shelf equipment by many, myself included. But I think this package is also very old based on the size. And I would doubt if a 2035 is the right number or if it's included. A 2035 is a newer style unit that's microprocessor controlled and requires software to run. Repairing it could be a bear, to say the least. And forget about buying parts from B & K.

If, by chance, it really is available, then I would definitely look into it. Depending on how it's configured and if it works correctly it could be a deal. It's down side is that it's limited to 25KHz. The link below will provide a one page 600KB pdf of a 2035.

http://www.pearl-hifi.com/07_Facility_Tour/B_K_2035.pdf

Victor

 

[bembel]

Thx HollowState for your advice.

You confirm what I thought for the HP302A (I don't think the optional 297A motor is attached), better look for a HP3580-3581... on the down side of what's fair ;-)
thx also for the NiCd advice.

The Bruel & Kjaer is another matter. Yes, B & K is considered top shelf equipment by many, myself included. But I think this package is also very old based on the size. And I would doubt if a 2035 is the right number or if it's included. A 2035 is a newer style unit that's microprocessor controlled and requires software to run. Repairing it could be a bear, to say the least. And forget about buying parts from B & K.

If, by chance, it really is available, then I would definitely look into it. Depending on how it's configured and if it works correctly it could be a deal. It's down side is that it's limited to 25KHz. The link below will provide a one page 600KB pdf of a 2035.
Victor

Definitely, I doubt that it is a 2035 (of course there is a tube but he told me of far more vintage gear (did I said Boatanchor ?)
For fixing, apparently tubes should be common ones (He told about EL84, so blindly I date the rig as 1950-1960)
It's very difficult for me to get information on Bruel&Kjaer vintage instruments, any link is welcome.
Is the paper for the tracer expensive, still available ?
Is there in addition to the tracer a sweep gen for a scope X input ?
I forgot to say that there is no microphone coming with it.
finally, can you comfirm me that B&K and Bruel&Kjaer are two different brands ?

thx again for your help

 

[ralphs99]

Hi Bembel,

A decent soundcard is all the hardware you need for measurements. Cheaper, more accurate and much more versatile.

Cheers, Ralph

 

[bembel]

Ralph,

Thx for your advice, but .... I don't like so much the idea of moving my noisy big computer to my " lab / lunchroom" ) for measurements, but I'm waiting to find one day some cheap microboard w/o fans. Also I like the bugproof, stand-alone & pedagogic side of analyser, computer solution will come after.

 

[bembel]

Some more news from the vendor on the Bruel&Kjaer:

* Oscillator (called beat generator) the same as 1022 ( Xstor) but with tubes (preceding model) 1 fix.osc@1MHz 1 fix.osc@1.02MHz, internal small PAmp.

* tracer model 2305

* Unit 2112 (or tube equivalent like the oscillator) it's the mic preamp or selective voltmeter.

in addition some info: the selective voltmeter (tubes) as filters for octave, 1/3 octave & fullband, oscillator is limited to 20kHz. Strange features as "hoot generator" ??? (french translation) & others.

Any info stiil welcome ! (the unit is 300 Km from me & I got no car, I prefer be informed before have a look)

 

[bembel]

Here are all infos I could grab:

Brüel & Kjaer 1022 Beat Frequency Oscillator

Schwebungssummer Typ 1022

Dieser Schwebungssummer ist Teil eines Electroacoustic Telephone Transmission Measuring Systems Type 3350/51 (OBDM)
vermutlich aus dem Jahr 1967 oder etwas später.

Technische Daten:

* Frequenzbereich: 20 - 20.000 Hz
* Skala: logarithmisch über 3 Dekaden
* Automatische Regelung des Ausgangspegels
* Frequenzmodulatio: Hub intern/extern einstellbar
* Eichteilerausgang (max. 12 V/2,5W
* Impedanz: 6/60/600/6000 Ohm
* Metallgehäuse 48 x 38 x 20 cm
* Gewicht: 15 kg
-------------------------------------------------------------------

Brüel & Kjaer 2112 Audio Frequency Analyzer

Tonfrequenzanalysator Typ 2112

Das Gerät verwendet 33 LC-Filter/Terzfilter, die mit einem Drehschalter einzeln ausgewählt werden

Technische Daten:

* Frequenzbereich: linear 2 - 45.000 Hz
* 33 Filter von 25 Hz bis 40.000 Hz Mittenfrequenz
* Bandbreite 1/3 Oktave, Terzfilter
* Bewertung: A,B und C nach DIN 45633
* Anzeige: 100µV Vollausschlag in 10dB Stufen bis 100dB abschwächbar
* Eingänge:
1. "Direct"
2. " Input Potentiometer"
3. " "Condenser Microphone" 7 pol. B&K Kondensator-Mikrofonbuchse
* Ausgang: Ri = 50 Ohm, max. 45 V
* Externe Filter anschließbar
* Anzeigen: Drehspulisnstrument mit Spiegelskala, Effektiv/Mittel/Scheitelwert
* Metallgehäuse 48 x 38 x 20 cm
* Gewicht: 25 kg

-----------------------------------------------------------------

Brüel & Kjaer 2305 High Speed Level Recorder

Potentiometerschreiber mit motorischem Vortrieb

Technische Daten:

* Writing Speed: 2 mm/s - 1000 mm/s
* Paper Speed: 0,003 mm/s - 100 mm/s
* Antriebskette für Schwebungssummer 1022
* Logarithmisches Potentiometer: 50dB 10mV - 3,16V
* Papierbreite: bis 12,5mm
* Inking Kit QI 0001 mit 4 Röhrchenfedern und eingetrockneten Tintenpatronen (Standard ?)
* Metallgehäuse 48 x 39 x 20 cm
* Gewicht: 25 kg


--------------------------------------------
IS THERE ALSO ? (MAYBE with luck)
--------------------------------------------

Brüel & Kjaer 2603 Microphone Amplifier

Mikrofonverstärker 2603

Dieser Mikrofonverstärker ist Teil eines Electroacoustic Telephone Transmission Measuring Systems Type 3350/51 (OBDM)
vermutlich aus dem Jahr 1967 oder etwas später.

Technische Daten:

* Buchse für B&K Kondensatormikrofon
* Input Selector
* Buchsen für externe Filter
* Bewertungsfilter: A/B/C Lin:20-40.000/Lin.2-40.000
* Level Meter -60dB bis +40dB / 10mV bis 1000V
RMS/Average/Peak/Slow/Fast
* Metallgehäuse 38 x 38 x 20 cm



PS: I've read somewhere that tubes models have PCB problems (tracks "ungluing" from the phenolic PCB). Anyone can confirm ?(It could turn to nightmare) but the vendor claim "mint" cosmetic state.

 

[Kay]

What do you think about this?

http://www.thomann.de/de/the_tmeter_mpaa1.htm

Alternative look foor Minilyzer

 

[cerrem]

The new Tektronix series of inexpensive scopes has a FFT function in the MATH menu... It changes the SCOPE screen into a "real-time" Spectrum Analyzer.... goes from Time to Freq scale... I couldn't belive how good it was... I have 200MHz version Sampling at 2GS/s...
I bought the TDS2024B ..... The B means it has USB ports for connecting to computer with software provided..In front it has another USB for flash drive....
You can set generator to do a slow sweep and save the data files to the PC then you can do more Math function in the PC such as in MatLab or Excell and plot the graphs....
If you use two channels to measure audio difference...send both channels data to PC....Subtract the LOG of each channel to get the Gain of amp vs frequency....

Chris

 

[HollowState]

Hi bembel,

With the exception of the 2305 chart recorder, none of these units are listed in my oldest (1971) Bruel & Kjaer catalog, which means they are older then that. Your estimate of early 60's vintage is probably correct. All of this early equipment did use phenolic circuit boards. So depending on how many hours it has on it, or how many times it was repaired (and by whom) the boards may, or may not, be in good shape. Most of these did not have heat related problems.

but the vendor claim "mint" cosmetic state.

Perhaps from the outside. Who knows how the inside looks.

can you comfirm me that B&K and Bruel&Kjaer are two different brands ?

I was using the intials B&K to mean the same Bruel & Kjaer.
(Not to be confused with the low end "B&K Precision" in the U.S.)

The 2305 paper chart recorder was made for many years. It uses plug-in heads in the top for different ranges. (gain, lin/log, etc.) The early versions were tube, but at some point there was an upgrade to solid-state. This recorder did have some heat issues on the circuit board around the tubes that drove the mechanical pen assembly. (EL84s I think?) I used to repair this stuff years ago and have forgotten some of it.

I do not know of any source for Bruel & Kjaer manuals except to watch eBay. There are some sellers that put them on discs. And I don't know if B & K still supports the 2305 or sells the paper rolls. I only know that everything they sell is very expensive!

Do you really want a 1½ meter (5 foot) 65+ Kg stack of old equipment? (Unless you've got a boat)

Victor

 

[bembel]

Do you really want a 1½ meter (5 foot) 65+ Kg stack of old equipment? (Unless you've got a boat)

Victor, As I ain't got any boat, I think, from less to less.

Anyway, for me, it was an opportunity to look at.
I'm still working on a project on that way (have to got one)
---> see thread http://www.diyaudio.com/forums/showthread.php?threadid=88582

thanks you very much Victor for your great help. maybe I'd spend a 600km trip & time without you.

from Kay
What do you think about this?

It's a nice idea but I'm always in doubt face such little devices. And there is a definitive lack of informations about it (what about noise floor, dynamics, Z ). Anyway 20kHz is definitely to low (hp & bk were 45-50kHz, I need al least 4th harmonic of 17kHz, (know you a lot of babies buying tube amps ? )).
Any more experience ?

From Chris

The new Tektronix series of inexpensive scopes has a FFT function in the MATH menu... It changes the SCOPE screen into a "real-time" Spectrum Analyzer.... goes from Time to Freq scale... I couldn't belive how good it was... I have 200MHz version Sampling at 2GS/s...
I bought the TDS2024B ..... The B means it has USB ports for connecting to computer with software provided..In front it has another USB for flash drive....
You can set generator to do a slow sweep and save the data files to the PC then you can do more Math function in the PC such as in MatLab or Excell and plot the graphs....
If you use two channels to measure audio difference...send both channels data to PC....Subtract the LOG of each channel to get the Gain of amp vs frequency....

WHow that sounds cool How much is that beast ?
I'm very impressed is in my budget ? (I'm looking for a job now)

Thank you all again

 

[cerrem]

The Model I purchased was $2,100 + tax....
But that was a 4 channel 200MHz and has color display..
You can get lower bandwidth and 2 channels with Black and White display for mucho cheaper... In fact I seen one like that discounted for $800 at the local store because the box was previously opened by a customer... a same-day -return... Unit still is like new...

Chris

 

[bembel]

Chris, it's seems that the low end B&W 2x40MHz mdl is < 800€ (I hope getting better @ my corner shop) but this one is spec'd @500 MS/s
while the B&W 2x60MHz mdl is spec'd @1.0 GS/s (then 930€ & 4x60(color)=1400€)

How do you think the bandwidth difference alters spectrum analyzis precision < 100kHz ?

I'm also wondering about the following specification:

Maximum Input Voltage:300VRMS CAT II; derated at 20 dB/decade above 100 kHz to 13Vpk-pk AC at 3 MHz

What about tube lovers & parasistic oscillation ? is it covered by the lifetime warranty ? Anyway think I'll ask a quote (I've found the prices @farnell in one; they are not the cheapest, and I my corner shop owes me a favor(oscilloscope fixing), maybe they can leave aside some profit).

 

[grhughes]

Dr. Jordon's WinAudioMLS

Check out Dr. Jordon's WinAudioMLS here;http://www.dr-jordan-design.de/Winaudiomls.htm

All you need is a good sound card like the RME and this is much more sophisticated than the old equipment you mentioned. Good luck! Ray

 

[jackinnj]

HP stuff, while long in the tooth, is the ne plus ultra. that being said, as the US Government purchased much of this stuff they second sourced so there is great Gen Rad stuff as well.

An HP 3581 Wave Analyzer has a frequency/tracking generator as well as a very acurate a.c. voltmeter -- when I broke my leg I scanned the manual and put it up on my website -- this is a great instrument which sells for about 1/300th of its initial cost. the HP 3581 has X-Y outputs which are very easily interface via a data acquisition card to your computer.

 

[kevinkr]

I'm with Jackinnj on this one and heartily recommend the HP3581, another very good option if you are really just looking for a precise generator, ac voltmeter, and thd measurement analyzer (meter based) is the HP339 in any incarnation. I have used this since nearly the beginning of my career, and IMHO there is nothing better/easier for daily use, and it has very good resolution and accuracy.

Another older, but still good choice would be the HP334A.

I have an Amber 3501A, sort of the poor mans HP339, it works well, but has been unreliable to the extent that I now keep a spare parts unit for it.. Otherwise it is pretty nice too.

Either of these will measure thd <0.01% and have switchable LPF/HPF filters.

 

[ilimzn]

Another older, but still good choice would be the HP334A.

I have a pristine HP334A and use it for coarse THD measurement - the fine stuff i get by attaching a PC soundcard to it's residual output.
I also have a HP3586, which is basically a 'manual sweep' spectrum analyser. This works great but is currently off the bench due to space restrictions - and it can also be usefully etended in functionality by connecting a PC to it's baseband output.

 

[SY]

A third on the 3581. I have a borrowed one and use it as a reality check for my soundcard spectrum analyzer, an ac voltmeter, and a knob-adjustable signal generator (the sinewave output in back has about 0.05% THD).

 

[bembel]

Thx again all, these informations are very usefull for me !!!

For now I'm more on the enrty level tektronix way. I'm now facing a pink pig (piggy bank) looking him in the eyes, He is not very fat but almost enough for the "tek cooking" (I'm sorry, but I can't integrate the english language, saying "it" for animals, I'm definitely their pair (with maybe an exeption for mosquitos)).
So ... maybe I could afford it (through I'm not in the bettrer position).
I'll prefer (for now) to grab an old HP308x , and even with having the tek (of witch I'd like precisely the TDS1002B model), I'd like to own a selective voltmeter anyway. But the fact is that I can't find any, and the sources of vintage gear around me, are either being cheap (or even free) ... or unfair.
But there don't seem to be any AF analyzer waiting me around nor selective voltmeter in a 400Km circle (while I have yet to see an old rascal OM). I'm not yet an eBay buyer, past experiences were not very good.

So here are some last few questions:

- Have you some experience of the TEK TDS1002B oscilloscope. especially for FFT analysis and other AF functions?
Have you some information about the "fold of FFT spectrum around Nyquist frequency" does it alters the reading of AF spectrum let's say under 100kHz ?
Are all the 2048 sampling points used for the the scope's bandwidth spectrum (ie: 60MHz), or the selected only spectrum (ie: 100kHz). This is quite important but not very clear in the manual) Chris if you're here I think you can help!

- Any experiences with the sophisticated little SPL analyser Kay's indicated (Though I don't think it's the tool for such jobs, am I wrong ?)

- Lastly what's about all those sound card software FFT analysers (I think then 200€ usb 24/96-192 with a good chip), what are the real facts under numbers, for me, a PC is near a noise source (AF as HF ), I can't believe it can make a mesuring tool ! (through I'm surely wrong); Has anyone compared to lab stuff ?. In all that plethora of software, is there a GPL winner ? (with window$ binaries, I had enouth headaches with my philips soundcard & unix).
Anyway I find this solution not convinient at all (were are the BNCs or banana plugs ?). But as I have to choose, I have to clarify.

salut tous !

 

[Kay]

It's a nice idea but I'm always in doubt face
such little devices. ...

of course, but it's cheap and "handy",
but YOU must decide, what you want.
This part is not for measure distortions.
Do you read the manual?

If you like more, you SHOULD use a PC, maybe with ARTA,
www.arta.com
with a good (maybe external) soundcard.
Try the demo first!

O.k. a compromise, NTI Minilyzer,
you find it at www.monacor.de
or looking with Neutrik.

I'm measure with the old IMP FFT-Audio-Analysator from
Liberty with DOS-Software on PC. Later I plan to go to
ARTA (Jordan is not a option!).



additional,

if you like to buy (very) old parts,
you need always a professional calibration!

and
1. for testing soundcards use Rightmark RMAA.
2. buy a external soundcard and mount BNC, if you like
3. don't forget, a PC has always earth connection