@anatech I agree on your comments re the PC sound cards and their limitations - please don't think that I was actually recommending them, just saying that they were at least a cheap option. Kinda matching the test equipment to the modifications being attempted 😗
IMO - and please add suggestions here - one of the best options that that has decent performance but is actually available at a reasonable price point is one of the vintage HP 33x series. As you know, this type of distortion measurement is not really something that I do much of (I have several 334's sitting on a shelf unused and getting dusty) but is pretty much your bread and butter so please make recommendations - I would be interested as well. For some reason I'm remembering that you used a 339 but, then, this is my memory I'm talking about so who knows?
Hal
IMO - and please add suggestions here - one of the best options that that has decent performance but is actually available at a reasonable price point is one of the vintage HP 33x series. As you know, this type of distortion measurement is not really something that I do much of (I have several 334's sitting on a shelf unused and getting dusty) but is pretty much your bread and butter so please make recommendations - I would be interested as well. For some reason I'm remembering that you used a 339 but, then, this is my memory I'm talking about so who knows?
Hal
I think so. Old style devices. Good ft (10MHz) but second breakdown quite limiting. BDY56 starts at 35V, about 0.9A at 50V and 180mA at 120V.
BDY58 "175W" but Is/b started at 25V/7A 1A at 54V and 200mA at 120V.
Suspect folks tried using them on too high a power rail voltage for their capability.
Probably the best amplifier with 2N3055 was the Bedini 25-25. But let's not forget the integrated Lenco L900 combo turntable +15+15 2N3055 amp.
Hi Hal!
No, I didn't think you were recommending them at all. I was just pointing out the possible issues with them. Jan designed a "front end" for sound cards that I hear is pretty good. A THD meter also makes an excellent "front end" for a sound card, noise floor being the biggest issue with some.
I have used a Heathkit THD meter (and IMD meter), HP 331A through 334A, and the 339A. One thing I found out is the high frequency response on the HP extended way up there, while some Japanese THD meters topped out less than 100 KHz. In other words, they lie measuring 20 KHz distortion. I had a Tek AA5001 (I think) as well. The ShibaSoku AD725C I have works very well, but it needs a low distortion oscillator as a source. Then I bought an RTX 6001 that Jens designed here, that is an extremely good audio analyzer.
What's really cool about the HP 339A is the performance can be improved (thread here). It contains an excellent oscillator and you only set one frequency, a time saver. So if you can grad an HP 339A, you're doing well. The ShibaSoku units are great, but expensive. The HP 8903A/B are great, but I prefer a meter movement.
Now for tricks. Use the monitor output of a THD meter into an oscilloscope and you can see crossover notch distortion on the 'scope. You can run that into a spectrum analyser or sound card to see the audio spectrum, and that is informative.
You can't beat an audio analyzer though. Look at the noise floor and various spurs. That tells you a lot. Note an FFT on a digital oscilloscope doesn't come close. Not even my Keysight MSOX3104T can compare to an audio analyzer. I almost forgot, I also have an HP 35665A FFT audio analyzer, and a couple HP 3580A (audio spectrum analyzer) and 3581A (selective voltmeter) that were amazing devices. I think noise floor might be the limiting factor for those, and speed. I use an HP 3585A (spectrum analyzer) as well.
One thing for sure, a less expensive THD meter beats the heck out of nothing, or the FFT function on a 'scope. You cannot responsibly service any audio equipment without a decent THD meter - minimum. These were required equipment in order for almost any warranty contract, and expensive as sin back when I started.
No, I didn't think you were recommending them at all. I was just pointing out the possible issues with them. Jan designed a "front end" for sound cards that I hear is pretty good. A THD meter also makes an excellent "front end" for a sound card, noise floor being the biggest issue with some.
I have used a Heathkit THD meter (and IMD meter), HP 331A through 334A, and the 339A. One thing I found out is the high frequency response on the HP extended way up there, while some Japanese THD meters topped out less than 100 KHz. In other words, they lie measuring 20 KHz distortion. I had a Tek AA5001 (I think) as well. The ShibaSoku AD725C I have works very well, but it needs a low distortion oscillator as a source. Then I bought an RTX 6001 that Jens designed here, that is an extremely good audio analyzer.
What's really cool about the HP 339A is the performance can be improved (thread here). It contains an excellent oscillator and you only set one frequency, a time saver. So if you can grad an HP 339A, you're doing well. The ShibaSoku units are great, but expensive. The HP 8903A/B are great, but I prefer a meter movement.
Now for tricks. Use the monitor output of a THD meter into an oscilloscope and you can see crossover notch distortion on the 'scope. You can run that into a spectrum analyser or sound card to see the audio spectrum, and that is informative.
You can't beat an audio analyzer though. Look at the noise floor and various spurs. That tells you a lot. Note an FFT on a digital oscilloscope doesn't come close. Not even my Keysight MSOX3104T can compare to an audio analyzer. I almost forgot, I also have an HP 35665A FFT audio analyzer, and a couple HP 3580A (audio spectrum analyzer) and 3581A (selective voltmeter) that were amazing devices. I think noise floor might be the limiting factor for those, and speed. I use an HP 3585A (spectrum analyzer) as well.
One thing for sure, a less expensive THD meter beats the heck out of nothing, or the FFT function on a 'scope. You cannot responsibly service any audio equipment without a decent THD meter - minimum. These were required equipment in order for almost any warranty contract, and expensive as sin back when I started.
Wow, that collection of test equipment in anatech's shop would have looked great in the back of the local house-painter-for-cash's Cherokee when he carried off everything I owned electronic that was not disassembled. Also every hand or power tool. Does anatech work in a bank vault? I put 1000 hours into the insurance claim then gave up. $41000 is not worth that.
I own guns ... and a 65 pound doggy. 🙂
Yeah, I was very sorry to hear what you went through. On the plus side, there is so much here, and it's heavy. Plus bolted into 19" racks. Anyone breaking in wouldn't know what things were, or could decide. Then they have to work on removing it. The police would probably assist them into their own specialized transportation. If they defeated the alarm, neighbours would have called it in already anyway.
Your issue is curious. Test equipment is difficult to sell compared to stereos and TVs. It is easily traced as a result. So only a complete idiot would steal anything specialized, they want to turn stuff into cash quickly. Test equipment is something way beyond what most thieves would understand. Of course I guess we aren't talking about Mensa members here (they just think they're smart).
In short, it isn't worth the attempt. My insurance has pictures, serial numbers etc ...
One thing I was careful of was the insurance company I'm with. Insurance isn't worth anything at all if they won't cover you, so go with a reputable company that will back you up.
Yeah, I was very sorry to hear what you went through. On the plus side, there is so much here, and it's heavy. Plus bolted into 19" racks. Anyone breaking in wouldn't know what things were, or could decide. Then they have to work on removing it. The police would probably assist them into their own specialized transportation. If they defeated the alarm, neighbours would have called it in already anyway.
Your issue is curious. Test equipment is difficult to sell compared to stereos and TVs. It is easily traced as a result. So only a complete idiot would steal anything specialized, they want to turn stuff into cash quickly. Test equipment is something way beyond what most thieves would understand. Of course I guess we aren't talking about Mensa members here (they just think they're smart).
In short, it isn't worth the attempt. My insurance has pictures, serial numbers etc ...
One thing I was careful of was the insurance company I'm with. Insurance isn't worth anything at all if they won't cover you, so go with a reputable company that will back you up.
Something you should all know,....... Chris's 65 lb. dog (Sterling) will lick you to death. Sterling is especially fond of blueberry muffins, if you're ever in the neighbourhood.
The steel scrapyard will pay $200 a ton for anything metal. MJ15025, J174, dead lawnmowers, $200 a ton. I suppose the perp did get a little higher for the 80 lb of wire. In the on-topic 2n3055 department, the perp left the Dynakit ST120 because the cover was off. The Peavey speakers & amps maybe went for tenth ebay price.
I saw the perp riding a bicycle 8 days after the arrest. He did not receive enough cash to retrieve his Jeep Cherokee from the impound lot. He did have enough brains not to steal the codiene tabs left over from a couple of root canals.
I stay in the city a couple or 3 days a week for medical & business reasons. 4-5 days I spend on 24 acres 2000' from anybody. Except airplanes, 800'. I would not enjoy being an armed guard for either house. The houses are beginning to resemble bank vaults. Steel doors, 3/4 polycarbonate sheet inside windows. You know you can buy used teller windows on ebay?
The Naks are running great, however my Marantz 2325 is acting up, intermittent contact in both channels when powering up then losing one or both channels, so I suspect the relay is shot; last replaced in 1998. Needs some TLC, after all it's almost 50 years old.
@anatech - I've looked at the 339s but never pulled the trigger on one - I just don't see myself using one enough to justify the price... not that that has ever stopped me getting something before, but still... I have a 8903A that I've played with a bit but, again, just really don't have the need. I have a couple of 8970A's and a couple of 8970B's - one of which has the required noise gen and is calibrated. It's like my 8902A - don't really use it all that often but don't even want to think about having to replace it if I sold it and then wanted one again. Of course that is basically just me coming up with a justification to keep a cool piece if TE - something I am extremely skilled at doing 
I really would like a good LF analyzer, though - having my SA bottom out at 9K can be bothersome at times.
Hal
I really would like a good LF analyzer, though - having my SA bottom out at 9K can be bothersome at times.
Hal
Hi Hal,
Cool, want a 35665A? We can work something out. I haven't needed a noise figure meter. I wonder if I could find a use for one? lol! I have the very same sickness!! I may have another 339A also. The 8903 would be fun to play with, just to discover what it was all about. Don't need one of course!
The 8902A is extremely cool, and useful.
Cool, want a 35665A? We can work something out. I haven't needed a noise figure meter. I wonder if I could find a use for one? lol! I have the very same sickness!! I may have another 339A also. The 8903 would be fun to play with, just to discover what it was all about. Don't need one of course!
The 8902A is extremely cool, and useful.
Hey Angelo,
Well, I have a bunch of improvements for the 2325 that drops noise in the power supply, and drops distortion in the output section. I have to build mine up that way, it is original. The relay is no seat, minor issue.
I love the 2325 as a receiver. It looks amazing and performs really well. That's a keeper for sure. Plus the lamp upgrades I do (I make my own indicator LED assemblies) look just like the original lamps. New vellum (real, from Germany) make it look crisp and new.
Well, I have a bunch of improvements for the 2325 that drops noise in the power supply, and drops distortion in the output section. I have to build mine up that way, it is original. The relay is no seat, minor issue.
I love the 2325 as a receiver. It looks amazing and performs really well. That's a keeper for sure. Plus the lamp upgrades I do (I make my own indicator LED assemblies) look just like the original lamps. New vellum (real, from Germany) make it look crisp and new.
that happens because there are a lot of suckers out there, that are easy to fall pray to snake oil artists...
thank you for this advice - L900 is the integrated amp and the used turntable is the model L75 (sometimes the L78)
https://www.lencoheaven.net/forum/index.php?topic=16499.0
Also with integrated FM stereo tuner available (model "stereo 3040")
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lenco-3040FM+L78-III.jpg -
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lenco-3040FM+L78-IV.jpg -
lenco-3040FM+L78-VII.jpg -
lenco-3040FM+L78-rear.jpg -
lenco-3040FM+L78-V.jpg -
lenco-900+L75+speakers-II.jpg -
lenco-900+L75-III.jpg -
lenco-900+L75+speakers-I.jpg -
lenco-900+L78.jpg -
lenco-900+L75-rear.jpg -
lenco-900+L75-II.jpg -
lenco-900+L75-I.jpg
It was loud for the time, looks nice too. But the question is what output transistors it had? was it 2N3055?
Those early stereos were gruesome things. They did not perform well compared to real audio equipment. But, they were much better than something along the lines of a "Candle" having the same format. The earlier version of the Lenco used Germanium transistors. It was terrible, but people loved them.
question post #596:
according schematic for 900 under
https://www.hifi-archiv.info/Lenco/Lenco L 900 Manual/index.html
(also in the attachment)
sometimes 2N3055, sometimes BD142
stereo 3040FM is the same
https://www.lencoheaven.net/forum/index.php?topic=22168.0
according schematic for 900 under
https://www.hifi-archiv.info/Lenco/Lenco L 900 Manual/index.html
(also in the attachment)
sometimes 2N3055, sometimes BD142
stereo 3040FM is the same
https://www.lencoheaven.net/forum/index.php?topic=22168.0
Attachments
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