I've noticed a few things about HP signal generators on E*bay.
1) It's mostly HP signal generators on E*bay. More than other brands. How come? Did HP corner the market on signal generators? Perhaps all the crappy generators didn't last and went in the trash.. :P
2) I've concluded the most popular price paid for HP generators seems around $300US. And applies to a wide range of models too.
300.00??? Can I take that as a hint that a new signal generator (maybe other brand) starts at around $600.00.. But what?
3) Is it me or do some HP signal generator models have an ugly front panel design?
HP's first product was the 200A Oscillator. It (and its follow-ons) Truly Rocks.
Whoa, you have to stop saying "signal generator" and tell us what you're talking about. RF, Microwave, Audio, programmable, modulation ???
Agilent's cheapest new generator is circa $9000.
List price for benchtop and handheld 5 or 10 or 20 MHz function generators (sine, square, triangle) is circa $200-$300 new from B&K. Used they'll be lucky to be fetch $10-$20.
HP 200AB, 200CD's etc. (Wien bridge audio oscillators) typically go for $30-$40. Off-brands even cheaper - and they don't sell at all!
Ewwww...I botched this post. (I think I need a vacation..) Almost as bad as the dude that did that Hakko post. :P
Let me try that again... I've noticed over several months that ~300US is a popular bidding price for the HP 3324A HP function generator. Examples HP 3325A 20Mhz $301 Item number: 220201270184 HP 3325A " "$375 Item number: 290207698486 " $301 220199053599 " $370 220190335121 Could list more but E*bay only keeps 100 watch items. The rest is from memory and rough stats.
Let's say the bidding price for a HP3325A compresses around $300. I suspect that means people know there's something else new not far away.. I'm wondering what it could be.
You mentioned B&K so I checked out..
formatting link
A 20Mhz B&K signal generator 20Mhz Newark: $732.00 Not too far away...and is some evidence to my theory why ~300.00 is a popular bidding price for a HP 3325.
Besides all that... What I'm really thinking about is: Is it worth it to get an old 20Mhz function generator?
If you are working in an area where you don't need anything faster than 20MHz, why not?
Enough people got enough value out of the old gear to buy it and replace it and if you are doing pretty much what they were doing, you won't need anything better.
If, on the other hand, you've ever be tempted to put together something programmable or faster, it might well be worth working out what you can buy today that you couldn't have bought five or ten years ago.
Fifteen years ago the software guys needed a programmable Guassian- shaped test pulse, and I cobbled something for them from a DAC, and EPROM and a counter - they had to program the EPROM.
We probably should have used an audio card, but nothing we could get our hands on was all that suitable.
I get tripped on 'cool factor'. I mean, do I want an old boat anchor on the bench with needles, red leds, clunky switches, a bulky box and a noisy cooling fan... Sad... Or do I make the bench look sporty with a sleek box that has a colour LCD display and a modern interface. Something that says 'This is a kickass work area'. Not something that says 'Boat anchor recycling bench'. Sure it costs more, but new equipment is posh.
So...I'm struggling a bit with saving $$$ on old vs new cool.
Cool. So _YOU're_ the guy who buys all the gold plated new stuff so that I can corner all the great retro equipment. My hat's off to you, sir--you're a public benefactor. I have lots of instruments, but the only two new ones I've bought in the last 4 years are a 7 GHz sampling scope and (just last week) a new lock-in, because all the old ones I had were so horribly out of calibration.
When the boat anchors kick the butt of the sleek and stylish, it's no contest. Function over form.
The 9,000 brands from one factory china specials go for $107-270 on e*bay, brand new, buy it now (no need for auction drama). And I'm pretty sure that I mentioned this months ago. The cheaper ones top out at 2MHz, though. But you can get a new, mystery-crap-brand 20MHz generator for under $300. Feel free, see if it impresses your date.
As for the prices of 3325As, it's what's called "the going price", "what the market will bear", etc. I got mine a bit cheaper (under $200 delivered) because it had some minor cosmetic issues and really blurry pictures, or else the mythical cabal of used equipment dealers that plagues you missed it, or leaves me alone. If the fan noise bugs you, invest in a new fan.
Fact - the 3325A beats the pants off the China special. The tiny little box couldn't even hold all the connectors on the 3325A. Despite only claiming to go to 20mHZ, the 3325A will actually go to 69.99 MHz (but not into 50 ohms). The opposite end goes to absurd limits of slow.
Well, the 3325 came out some time in the early '80's, I believe. One problem with the A version is that you won't be able to get repair parts for certain items inside. The B version (early 90's I think it was) will be a bit easier. Reliability is good, though, so that's probably not really an issue. You'll want to make sure the frac-N loop is properly calibrated if you get one, else you'll have spurs (that you may not really care about that much). The 3325 went out of production quite some time ago now. The "new improved" model is the
33250 and its relatives, much smaller, goes to 80MHz, and is generally a very nice little generator. I was sad when the one on loan from the fellow putting together a test system had to go back to him, when he was ready to put it into the test system, but boss-man didn't have any trouble getting my group a couple of our own.
The 3325 has no pointers, dials, analog meters or stuff like that-- it's all synthesized, controlled with pushbuttons, and LED readout of frequency and level. To me, it's a bit of a pain that it DOESN'T have a knob you can turn to raise and lower the frequency or level. I'm not sure, but it may have been the first instrument to use the fractional-N PLL that was patented; it was done (in essence anyway) by adding a ramp to the phase comparator output. These days you can buy frac-N PLL chips that do it a different way, but at the time it was certainly a pretty important patent to HP.
Whether it's worth it or not to you -- is up to you.
When the option exists, get a generator that can be hooked up to a
10Mhz reference. I don't know if the Chinese junk can do that. Most HP gear can do this. [The 8903B is one that comes to mind that doesn't, though I wouldn't classify it as a function generator.] Second best is to make sure it is synthesized, even if it won't lock on an external reference. A lot of HP gear isn't synthesized. Some synthesized signal generators will at least provide their reference, s you can sync something else to it. All that comes in handy if you want to build sampled data systems out of bench components.
It been my experience that Wavetek stuff is poorly made. I won't buy it used or even new for that matter. Philips gear can be touchy. I haven't had any issues with their DMMs, but I have a PM5191 that no longer does anything but TTL. Granted it wasn't expensive ($125, but a long time ago).
I've used a lot of SRS (Stanford Research) gear and found it to be good, though often the operation seemed awkward.
I'd say the HP 3325A 20Mhz function generator is best of the boat anchors for function. It's probably why I've watched it so much on E*bay and not the china boxes.
I just find it mysterious how the E*bay HP 3325 price seems to level off around $300.00. Why not 600 or 700 or 1000? It suggests there's something better at those prices. What that is,I dunno yet. Maybe there's nothing..Perhaps it's just a huge price jump to the latest DDS or arbitrary function generators. I'll have to shop around.
Funny...you recalled my theory about used equipment dealers gobbling up HP equipment.. Yah never know :)
Neato...I didn't know the 3325 goes to 69.99Mhz.. Makes it more worth it.
Early 80's!! That's like 200 years ago in techno time :P (Consider $60.00 for that Australian 85Mhz DDS USB board on E*bay.)
About the 80Mhz Agilent 33250A... As on
formatting link
Yikes $4963! Certainly not a boat anchor :P And it's got a good honking knob too...The way I like it.. :) Not like the pecker operation on the HP 3325.
I think I saw an E*bay Wavetek generator with all membrane pad control. Membrane pads can have little tactile feedback to know how hard to press. I'll probably be chasing after the Wavetek keypad with each poke that moves the unit further away. :P
Yes, those keypads suck, but not for the reason you think. When they get old, the debounce circuit can't handle the signal The SRS gear is probably membrane too, but it isn't crappy.
formatting link
I don't own any SRS gear, but I never complained about using it at various labs. The DS345 or old DS340 are kind of cool. I did a complicated setup using two of them and a DSP analyzer all running off of one reference. You can vary the phase between generators, though IIRC it takes a scope to do this. That is, the generators are not "aware" of each other enough to set up relative phase via GPIB. If you look at the website, you will notice the low distortion generator can't be synched (no reference jack). This is really common. The only low distortion generator I ever saw was a B&K (the Danish company).
I have HP gear so old it uses the old style IEC cords. They really built them back then. Of course, everything will break your back since the definition of portable back then was man-movable.
Note much of the HP RF gear is really high distortion. I have the old
8660C series that is much cleaner, plus has 1Hz steps so you can test crystal filters. These trade on ebay all the time, but I got a broken "unable to test" unit. I did some deals with the plug ins plus cash to get it fixed from a local guru. Freakin' heavy is a kind description.
You can download the manual from Agilent. Stick 3325A into the search box. Triangle waves and ramps are limited to 10.999999999KHz, square waves go to 10.999999999MHz, and sine waves to 20.999999999 Mhz (all will drive 50 ohms). Minimum is 1 uHz for all.
The auxiliary sine output goes from 19.000000001MHz to 60.999999999Mhz (misremembered by 9Mhz) and does drive 50 Ohms (also misremembered) but at a fixed amplitude (0 dBm)
The lack of a dial is not a big deal. There are up/down buttons, and you can select which digit you would like to manipulate to control the speed/step size of going up/down. The sweep functions are delightful, as compared to some other sweep generators I've muddled with.
I used a 3325A almost daily for two years, and never missed any knobs. Also, it can be computer controlled for SATE or ATE applications. the ability to set the output by voltage or dB level is VERY handy, and the digital DC offset was great for doing precision measurements on slow AGC systems where the level was integrated up to a ten second period.
Another place that it was great was doing bandwidth measurements on video filters where you could read the frequency to the nearest Hz. The only problems we had were a few failed relays in the output attenuators.
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
There were piles of spare, and dead Wavetek crap in the cal lab. The function generators were temperamental, the DC offset drifted, and the pots to set the frequency wore out. They RF sweep generators were even worse. Spurs, and too often, the end of the band was right where you needed to work. After Microdyne stopped building C-band equipment, it was pretty much retired.
--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
Sane yourself the time and put your trashcan behind the bench. United Video had a bunch of Wavetek crap to align CATV equipment. We also had a tektronix spectrum analyzer plugin for a scope. I tried the new wavetek stuff once, and left it sitting on the shelf over the bench for the next four years I worked there. They had a 12" 'scope' made with a B&W TV CRT. That, with their sweep generator and a diode detector was supposed to be usable to align trunk and bridging amplifiers.
--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
Yes, barring that last microhertz. Labeled for 10 Khz, but actually works to 1 uHz less than 11 KHz. I presume it's got to do with generating nice linear ramps being somewhat trickier than sine and square, at least with the technology of the day.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.