Hi Conrad,
I remember thinking the HP 331A was nice, but clunky compared to my sparkling, new Leader LDM-171. After using both and looking inside I finally understand. The Leader I bought new can't compare to an HP 331A, never mind the 333A, 334A and the 339A. The same holds true for the HP oscillators. I'm rebuilding a 654A and it's going to be neat to see what performance can be squeezed out of it.
Magura, no need to be ashamed of that piece. I will say that the auto nulling models are much easier to use. This is especially true of signals that may drift in frequency.
-Chris
I remember thinking the HP 331A was nice, but clunky compared to my sparkling, new Leader LDM-171. After using both and looking inside I finally understand. The Leader I bought new can't compare to an HP 331A, never mind the 333A, 334A and the 339A. The same holds true for the HP oscillators. I'm rebuilding a 654A and it's going to be neat to see what performance can be squeezed out of it.
Magura, no need to be ashamed of that piece. I will say that the auto nulling models are much easier to use. This is especially true of signals that may drift in frequency.
-Chris
I have more than once. the most memorable was on top of downtown court building were all the repeaters for fire and police Dept were. Replacing a damage antenna , turning off transmiter was not a option . my boss wanted to smoke up there . But the city superviser keept checking on us. This was 1976.anatech said:
anatech said:
Hmm, well in that case I will show off instead
I got myself a HP650A and a HP212A as well.......and an Advanced Instruments OS25A scope, offering the excessive speed of 5Mhz
These instruments have though proven to be adequate for audio related electronics work, and I had them real cheap.
Magura
Hi Magura,
The main difference in 'scopes is the more sensitive vertical amplifier. If you want to service a CD player, the minimum is 20 MHz and 0.5 uS / Div. two channel. Those go for a song even new.
Your HP650A is very likely better than most audio oscillators out there. Sad, but true (and you know it!). I'd say that you have all you really need. It's just the toys, and I do love toys.
You might want to upgrade to a 331A or later, and a 652A or later. Being solid state, they settle down faster after turn on and will hold their calibration a little better. Not to mention there shouldn't be as much frequency and amplitude drift compared to your tube models. I think it's really cool that your instruments are still in daily use. Bravo!
-Chris
I can't argue with you there. I started with a 500KHz, single channel Stark 'scope. Learned a lot with that. I do keep a nice Gould (Advanced) OS255 around. A smoking 15 MHz.
The main difference in 'scopes is the more sensitive vertical amplifier. If you want to service a CD player, the minimum is 20 MHz and 0.5 uS / Div. two channel. Those go for a song even new.
Your HP650A is very likely better than most audio oscillators out there. Sad, but true (and you know it!).
I'd say that you have all you really need. It's just the toys, and I do love toys. You might want to upgrade to a 331A or later, and a 652A or later. Being solid state, they settle down faster after turn on and will hold their calibration a little better. Not to mention there shouldn't be as much frequency and amplitude drift compared to your tube models. I think it's really cool that your instruments are still in daily use. Bravo!
-Chris
Hi 70s music,
We did all kinds of stupid, dangerous stuff in the 70's. Can you imagine the workplace safety people hearing about that these days? I'm not sure your boss could even smoke on the roof these days in Ontario.
I had to replace 3 cartridge fuses in the main dimmer cabinet for the auditorium lighting, in the dark while the show was running. It was a 550 V 3 phase circuit and we couldn't turn off the main feed. I even dropped one on the buss bars and it luckily didn't short.
I'll never do anything close to that stupid again.
-Chris
We did all kinds of stupid, dangerous stuff in the 70's. Can you imagine the workplace safety people hearing about that these days? I'm not sure your boss could even smoke on the roof these days in Ontario.
I had to replace 3 cartridge fuses in the main dimmer cabinet for the auditorium lighting, in the dark while the show was running. It was a 550 V 3 phase circuit and we couldn't turn off the main feed. I even dropped one on the buss bars and it luckily didn't short.
I'll never do anything close to that stupid again.
-Chris
anatech said:Hi Magura,
Your HP650A is very likely better than most audio oscillators out there. Sad, but true (and you know it!).
I think it's really cool that your instruments are still in daily use. Bravo!
-Chris
I mainly do amps (no digital stuff), and I just need to get a relative measure to compare to my previous measurements. For this purpose those instruments are doing fine (though spareparts have become hard to find). I have to admit that they all need some time to settle, like 10-15 minutes or so if I need some sort of precision
Magura
Hi Magura,
I'd say you're good to go then. I like that you understand the value of your equipment.
One thing to consider. If you can pick up a 333A or 334A. they will make your life so much easier, just wait for a good deal. If you can score a 339A, you will be in heaven! The residual THD on a 652A ~ 654A would be lower also. Life would just be easier for you.
This is like getting a car with power windows. You don't need them, but they are very nice to have.
A question for you. Do you use Mullard tubes in your gear? They sound better it seems!
-Chris (being silly)
I'd say you're good to go then.
I like that you understand the value of your equipment.One thing to consider. If you can pick up a 333A or 334A. they will make your life so much easier, just wait for a good deal. If you can score a 339A, you will be in heaven! The residual THD on a 652A ~ 654A would be lower also. Life would just be easier for you.
This is like getting a car with power windows. You don't need them, but they are very nice to have.
A question for you. Do you use Mullard tubes in your gear? They sound better it seems!
-Chris (being silly)
anatech said:
A question for you. Do you use Mullard tubes in your gear? They sound better it seems!
-Chris (being silly)
Thanks for the advice, much appreciated!
Nope, no Mullard tubes (or very few left...can't remember if the original tubes were Mullard, but there are a few of the original tubes still in operation). I got a bunch of russian tubes a couple of years ago, and have kept those ancient instruments afloat with those.
Magura
Hi Magura,
Since we are way OT, I'll continue.
I was joking of course. However there is a reason I joked about that, but I'll get to this in a minute.
I find that some Russian tubes are excellent. I tend to use New Sensor's Electroharmonix line. They are pretty close to a boogie tube (close to what the tube should be). So your tubes may be exactly what you should be using. You would know better than anyone.
I had some Heathkit instruments that came with Mullard tubes. What most people don't realize is that Mullard was just simply a well made tube, like many others out there. No magic. They certainly wouldn't be found in test equipment unless they were priced right.
-Chris
Since we are way OT, I'll continue.
I was joking of course. However there is a reason I joked about that, but I'll get to this in a minute.
I find that some Russian tubes are excellent. I tend to use New Sensor's Electroharmonix line. They are pretty close to a boogie tube (close to what the tube should be). So your tubes may be exactly what you should be using. You would know better than anyone.
I had some Heathkit instruments that came with Mullard tubes. What most people don't realize is that Mullard was just simply a well made tube, like many others out there. No magic. They certainly wouldn't be found in test equipment unless they were priced right.
-Chris
Well, in this application there is the beauty of the fact that a tube that gives the right measurement results is a good tube, regardless of name, reputation, audiophile mumbo-jumbo and origin....a tube that gives the right measurement results for a long time is an excellent tube
And so the conclusion is that the russian tubes are excellent tubes
I know very little about tubes in general. The only encounter I have had with tubes is maintainance of my instruments. The service manual from HP is very well written, and makes it possible to maintain the instruments with practically no background knowledge about tubes.
Magura/ who is contemplating the purchase of an A.I. OS250
And so the conclusion is that the russian tubes are excellent tubes
I know very little about tubes in general. The only encounter I have had with tubes is maintainance of my instruments. The service manual from HP is very well written, and makes it possible to maintain the instruments with practically no background knowledge about tubes.
Magura/ who is contemplating the purchase of an A.I. OS250
He got wiser.. he smoked before going up. But yet he never fell off a 400 foot comunication tower. 3 phase 480 volts sounds like a bomb when it shorts out and knock out the main breaker of the large bakery i work once. The electrician came out dazed. he never spoke a word and he walk back to the electrician room like a zombie. I never said anything to no 1 alse. I keept setting the machiney up. But i did see a large black spot on the wall between the main switch and wall after he had walk off. Another fun job was changing comunication tower light bulbs for warning low flying aircraft, You carry them inside your T-shirt. I miss those days!.anatech said:
Hi 70s music,
Stupid, stupid, stupid.
-Chris
Same as changing house lights in an auditorium. About 30 ~ 40 feet down. Our saying was "if you fall down, you have to clean up your own mess". The bulbs were changed while hanging upside down under the 2" struts. One hand and feet to hold, the other to screw in the light and also to remove the old one. Needless to say the lights had to be one for this operation. You could get about three lights under a shirt or sweater, then back for more.
Stupid, stupid, stupid.
-Chris
Hi Magura,
Okay, that's what I thought. Those are good 'scopes as long as that one is in good condition.
What do Tek 'scopes run for in your area? If you wait you may see one for 50 ~ 100. They are much better and you are almost there at $50. You may need to clean the switch contacts, or replace the filter caps by now. The connection to the power supply SCR (?) can burn too, so you simply solder the wires on. I bought a 2213A for $50 here at DIY. Switch contacts were bad.
-Chris
Okay, that's what I thought. Those are good 'scopes as long as that one is in good condition.
What do Tek 'scopes run for in your area? If you wait you may see one for 50 ~ 100. They are much better and you are almost there at $50. You may need to clean the switch contacts, or replace the filter caps by now. The connection to the power supply SCR (?) can burn too, so you simply solder the wires on. I bought a 2213A for $50 here at DIY. Switch contacts were bad.
-Chris
Around here any scope that just resembles something usefull and carries the name of either Tek or HP are at least 200$ and mostly more.
To be honest I find it hard to justify spending more than 100$ for some upgrade that I don't actually need.... you know...nice to have or need to have
Ohh, and one should not forget the fact that it's kinda good entertainment to see peoples faces when they see a lab that looks like the local technical museum, but delivers whatever I need
Magura
To be honest I find it hard to justify spending more than 100$ for some upgrade that I don't actually need.... you know...nice to have or need to have
Ohh, and one should not forget the fact that it's kinda good entertainment to see peoples faces when they see a lab that looks like the local technical museum, but delivers whatever I need
Magura
This is a Model C table top fan offered by The Lake Breeze Fan Company of Chicago, IL. This fan is powered by a Sterling engine enclosed in the motor housing just behind the blade. It has a small 2 cylinder motor and works by expansion and contraction of air. There is a compression piston and a displacer piston. .Conrad Hoffman said:People who see my lab are usually convinced that I can control worldwide weather patterns, and have at least limited control over the passage of time.
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