Hi wiseoldtech,
Yes, this was probably the worst thread you could have popped up in with your viewpoint. Our discussion is off topic in this thread.
However, I am talking from a practical standpoint from real world experience. I would tell you the same thing standing right in front of you. If you skim the thread on "what's on your work bench", you will see actual pictures of benches that people actually use. You would be welcome to add to that collection. Mine is also posted there so you can see that I put my money where my mouth is. Your bench is probably mid field, not the least populated one.
My posts are intended to help you, nothing more. I hope you took them that way as I don't "beat members up". The intentions were positive.
I have some of these oscillators. If you put together one at 1 KHz, you would probably use it a lot. You might even be able to hear the difference between these and your variable sine oscillator. Also, as was mentioned, sound cards will put out pretty good signals. Just be careful not to put the output of an amplifier into a sound card. They normally will only withstand 5 Vp-p.
Best, Chris
-Chris
Yes, this was probably the worst thread you could have popped up in with your viewpoint. Our discussion is off topic in this thread.
However, I am talking from a practical standpoint from real world experience. I would tell you the same thing standing right in front of you. If you skim the thread on "what's on your work bench", you will see actual pictures of benches that people actually use. You would be welcome to add to that collection. Mine is also posted there so you can see that I put my money where my mouth is. Your bench is probably mid field, not the least populated one.
My posts are intended to help you, nothing more. I hope you took them that way as I don't "beat members up". The intentions were positive.
I have some of these oscillators. If you put together one at 1 KHz, you would probably use it a lot. You might even be able to hear the difference between these and your variable sine oscillator. Also, as was mentioned, sound cards will put out pretty good signals. Just be careful not to put the output of an amplifier into a sound card. They normally will only withstand 5 Vp-p.
Best, Chris
-Chris
The SX-1250 I serviced was completely restored, having tons of old capacitors replaced, some transistors, diodes, lamps, and extensive mechanical parts serviced/lubed. A complete tuner section alignment was performed as well, it's standard procedure. Improvements/upgrades included LED lighting, increases in output bias currents, and various detailing of the entire unit.
The customer had 2 of these, and called me to inform me that the unit I serviced blew the socks off the other one he owned (all stock).
I don't mess around, never have, and this is why my customers choose me for my reputation. I was even given a 5 star rating on a reviews website, and the only reason I know about it was a notice from the website mailed to my shop. I had no idea of that previously.
Bottom line, you do good work, and it rewards you in the end.
For the record I was able to tune up an old Luxman with a very cheap (<$10) RF oscillator that was swept by having a coil wound on a core that had its mu modulated by a 60Hz co-wound coil. Chris are you familiar with one of these, I forgot who made it (Boonton?)
@wiseoldtech
No one here is disputing what a great tech you are. You not the only one who takes pride in thier work. When I had my shop in Vancouver I was, at the time, the only tech in North America to be awarded a gold certificate from Fender Musical Instruments. All this meant is I could bill them a max of two hours labor on warranty repairs. No one else was authorized to do that. I could go on but this is really off topic for this thread.
Maybe you can start a thread on what it means to be a great audio tech.
No one here is disputing what a great tech you are. You not the only one who takes pride in thier work. When I had my shop in Vancouver I was, at the time, the only tech in North America to be awarded a gold certificate from Fender Musical Instruments. All this meant is I could bill them a max of two hours labor on warranty repairs. No one else was authorized to do that. I could go on but this is really off topic for this thread.
Maybe you can start a thread on what it means to be a great audio tech.
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Chris, I can appreciate your suggestions and sincerity, as well as your enlightenment of the member society.
However, your mention to things like sound cards imply that I'm uneducated in that area. Well, I've built my own computers since Windows 3.1 was popular, and familier with the facts of computer/digital technology. (I run Windows 10 now, with others on XP due to programs requiring that)
And after 45 years of being in the service business, I've got plenty of experience behind me - I'm now 66 years old, and still going strong. My customers all know how "detail oriented" I am, and appreciate that, knowing full well they're getting proper attention for their money.
What's on my workbench is a substantial amount of equipment for all my needs, including equipment that I designed from scratch, for specific purposes. Some of my equipment is vintage, some is "new digital" stuff. I know when an amp for instance is experiencing a problem, even if "inaudible" - and take measures to correct it, particularly for reliability reasons.
However, there are just some things I choose not to "obsess" over like worrying about 0.00000001% distortion figures of something. Because that's rediculous in my field, unnecessary, and inaudible to normal people. - Unless you are some Alien Being from another planet.
I see some people online choose to obsess over such things, fine. I suppose they have plenty of time on their hands for such issues, but it makes me wonder why? Why the obsession with such trivial "measurements"? - is it a driven compulsion, a sense of needing to feed some inner issue, like an addiction to drugs or booze?
There has to be a sensible line drawn for satisfaction at one point, is all I'm saying.
Hi Scott,
A Grid Dip Meter? That's all I can think of.
Hi wiseoldtech,
To align a tuner, you should have an accurate RF generator that can modulate the signal with an FM 1 KHz tone at 75 KHz deviation. That's to set up step #1 - tracking. There is no getting away from that as you typically use points just outside the FM band at either end. Later, along comes setting the front end trimmers using the same oscillator at reduced output level and measuring both audio output level and the distortion. The FM detector is set up looking at DC offset and ... distortion again. Then you go to separation (often out as well) which requires a stereo signal. You see, you can not align a tuner using nothing but a 'scope and the existing radio stations (although I use them as a sanity check).
You did not align the tuner. You messed with it and maybe made it a little better, but I wouldn't call that a good job. This has zero to do with your abilities, but with your lack of equipment. Sorry if that's harsh, but I have to clean up work like that pretty darned often. Once again, the customers weren't aware the tuner could be better until it goes across the bench of someone with the equipment and ability to use it. A tuner design expert couldn't align his own design without the proper equipment. So don't delude yourself that you can.
Without a THD meter, you couldn't possibly be certain that an amplifier was set up properly, and you should darned well have some equipment that would allow you to see if anything was oscillating, or if the power supply was healthy or not. Luckily, an oscilloscope with do that for you.
How about a normal meter? Digital I'll assume. Bias is set with readings in the mV across low value resistors. So you need a meter accurate to xx.xx mV. That excludes most cheap meters, and that is even if they can hold calibration. Most cheap meters cannot ant many are out of tolerance right out of the box.
So. No matter how good you are, or think you are, you cannot do a competent job without having the right test equipment. We will also assume the equipment is in tolerance. Otherwise you are both lying to yourself and your customers.
I also have a very high rating from my customers, and a credit on a CD too! Pretty cool, I didn't know until someone told me. But it is nice to be well regarded in one's field of expertise. It's now 21 years since I sold my shop (it was 6,000 sq ft) and I do not have to advertise to get work. I'm pretty full right now as it happens. So, what's on your bench? There is a thread for that type of information.
-Chris
A Grid Dip Meter? That's all I can think of.
Hi wiseoldtech,
To align a tuner, you should have an accurate RF generator that can modulate the signal with an FM 1 KHz tone at 75 KHz deviation. That's to set up step #1 - tracking. There is no getting away from that as you typically use points just outside the FM band at either end. Later, along comes setting the front end trimmers using the same oscillator at reduced output level and measuring both audio output level and the distortion. The FM detector is set up looking at DC offset and ... distortion again. Then you go to separation (often out as well) which requires a stereo signal. You see, you can not align a tuner using nothing but a 'scope and the existing radio stations (although I use them as a sanity check).
You did not align the tuner. You messed with it and maybe made it a little better, but I wouldn't call that a good job. This has zero to do with your abilities, but with your lack of equipment. Sorry if that's harsh, but I have to clean up work like that pretty darned often. Once again, the customers weren't aware the tuner could be better until it goes across the bench of someone with the equipment and ability to use it. A tuner design expert couldn't align his own design without the proper equipment. So don't delude yourself that you can.
Without a THD meter, you couldn't possibly be certain that an amplifier was set up properly, and you should darned well have some equipment that would allow you to see if anything was oscillating, or if the power supply was healthy or not. Luckily, an oscilloscope with do that for you.
How about a normal meter? Digital I'll assume. Bias is set with readings in the mV across low value resistors. So you need a meter accurate to xx.xx mV. That excludes most cheap meters, and that is even if they can hold calibration. Most cheap meters cannot ant many are out of tolerance right out of the box.
So. No matter how good you are, or think you are, you cannot do a competent job without having the right test equipment. We will also assume the equipment is in tolerance. Otherwise you are both lying to yourself and your customers.
I also have a very high rating from my customers, and a credit on a CD too! Pretty cool, I didn't know until someone told me. But it is nice to be well regarded in one's field of expertise. It's now 21 years since I sold my shop (it was 6,000 sq ft) and I do not have to advertise to get work. I'm pretty full right now as it happens. So, what's on your bench? There is a thread for that type of information.
-Chris
I know quite well of being a "warranty repair" station, the companies require you to do the needed work at their cheap rate offerings. I've had Samsung, Goldstar, RCA, etc, in the past - all worthless to me. To cover operating costs/overhead, it benefit me to be an independant servicer. And once the internet came along, and service info got online, things got even easier.
Hi wiseoldtech,
Just saw your latest post. No one is worrying about a ton of zeros in front of a number for THD, but you must be able to prove that something rated for 0.05% THD is in fact meeting or beating that standard. IF you can't, you don't have any business servicing audio equipment at all. As you've said earlier, for $150 you can have an oscillator. For similar money you can buy a THD meter. If you can find an HP 339A on Ebay for around that you owe it to yourself and your customers to buy one. You do need it, period. No ifs, ands or buts about this.
If you are doing tuners, you require an accurate standard RF generator, and some way of generating a stereo signal. You can get HP 8656B or similar out there, same for a stereo generator that tends to be pricey. But if you do want to service this stuff, you must pay the price of admission or be a hack when it comes to alignment.
Brands that I did warranty work for demanded I have the proper equipment (reasonably I might add). For example, to do Nakamichi warranty I had to buy $10,000 worth of jigs, tapes and equipment. I did and paid it off over time, but that was the cost of admission. The same with even the dummy loads. I had to buy the Dale 250W 1% 8R resistors. Still use them to this day. I had to buy three complete sets. They were $50 each at that time, plus machining the heat sinks flat to mount them on.
I would rather have not needed to buy that stuff, but there was no choice. There is a ton of other stuff I needed to buy. Everything from test tapes to video testing gear (LCD projector service). But, every investment more than paid for itself.
-Chris
Just saw your latest post. No one is worrying about a ton of zeros in front of a number for THD, but you must be able to prove that something rated for 0.05% THD is in fact meeting or beating that standard. IF you can't, you don't have any business servicing audio equipment at all. As you've said earlier, for $150 you can have an oscillator. For similar money you can buy a THD meter. If you can find an HP 339A on Ebay for around that you owe it to yourself and your customers to buy one. You do need it, period. No ifs, ands or buts about this.
If you are doing tuners, you require an accurate standard RF generator, and some way of generating a stereo signal. You can get HP 8656B or similar out there, same for a stereo generator that tends to be pricey. But if you do want to service this stuff, you must pay the price of admission or be a hack when it comes to alignment.
Brands that I did warranty work for demanded I have the proper equipment (reasonably I might add). For example, to do Nakamichi warranty I had to buy $10,000 worth of jigs, tapes and equipment. I did and paid it off over time, but that was the cost of admission. The same with even the dummy loads. I had to buy the Dale 250W 1% 8R resistors. Still use them to this day. I had to buy three complete sets. They were $50 each at that time, plus machining the heat sinks flat to mount them on.
I would rather have not needed to buy that stuff, but there was no choice. There is a ton of other stuff I needed to buy. Everything from test tapes to video testing gear (LCD projector service). But, every investment more than paid for itself.
-Chris
Chris, I assume you didn't read my previous reply, of course. That's ok.
My bench equipment consists of Sencore, Fluke,Tenma, B&K, Tektronics, RCA, and other stuff I can't state because I'm not in front of the bench right now. A slew of custom test fixures and equipment that I designed and calibrated is also cluttering my bench up. Trust me, I'm well-equipped for what I do. RF/IF alignment I've done over the years is something I can do blindfolded, so to speak.
My bench equipment consists of Sencore, Fluke,Tenma, B&K, Tektronics, RCA, and other stuff I can't state because I'm not in front of the bench right now. A slew of custom test fixures and equipment that I designed and calibrated is also cluttering my bench up. Trust me, I'm well-equipped for what I do. RF/IF alignment I've done over the years is something I can do blindfolded, so to speak.
Well, I know about making a tn of jigs to make life easier, or to do things that can't be done any other way. I have respect for well designed jigs and equipment as long as they can trace their calibration back to a known accurate commercially available source.
My bench is most HP / Agilent / Keysight. I have some Tektronix, Philips and even a Sencore SG80.
Have a look at "Whats on your bench?" (or something like that). You can see what others are working with, and even me. It might also be a good place to put pictures of your gear in case you suffer a loss and are trying to get insurance coverage. We don't critique benches, it's there for interests sake.
-Chris
My bench is most HP / Agilent / Keysight. I have some Tektronix, Philips and even a Sencore SG80.
Have a look at "Whats on your bench?" (or something like that). You can see what others are working with, and even me. It might also be a good place to put pictures of your gear in case you suffer a loss and are trying to get insurance coverage. We don't critique benches, it's there for interests sake.
-Chris
We are way off topic but we are at least living up this old thread.
I do have a 1250 on the bench right know if you need me to check something out, it has 2 discriminators, one for the center tune meter and one for the ratio detector. most times it is the centering, but I can always fine tune the mono thd, usually around 0.15%, so I can use a HP 8656B with an external osc for that. It is not good enough for better tuners like a Yamaha T-85 for instance
I do have a 1250 on the bench right know if you need me to check something out, it has 2 discriminators, one for the center tune meter and one for the ratio detector. most times it is the centering, but I can always fine tune the mono thd, usually around 0.15%, so I can use a HP 8656B with an external osc for that. It is not good enough for better tuners like a Yamaha T-85 for instance
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As a favour I fix my neighbor's cherished JVC RM-90 blaster, he called it the king of the blasters, his dad freaked out over it. Ate "D cells. The Hitachi zener diode fix, thx god for hifi engine schematics, just to find the 10 cent diode. I did manage to graft it in there, it was PITA to take all apart to get at the bottom side of the pcb = madness = un-profitable. It rocks with new speakers. I can hear it at my place, probably this weekend again 
That's okay I can drown him out.
That's okay I can drown him out.
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Hi Guys,
I was lucky with warranty contracts actually. We got training and good rates compared to most other contracts. All in all, the contracts made us a lot of money, and the out of warranty referrals gave us a leg up. In the telephone directory, we listed all those brands and that drew in a great deal more people than just those brands.
As soon as we were forced to do low end stuff, or video products I would generally drop the line. A better line was always there to fill the gap it seems. The warranty contracts were the best things we could have done and they made us a much better service shop as a result. It was only when the market dropped out in 1998 that caused me to sell. I sold at exactly the right time and stepped off a rapidly sinking ship. The business lumbered along for a decade or so until they finally used up the last of the good will we had developed and the poor market swallowed them up.
Without the warranty contracts it would have been extremely difficult to become so successful in the Toronto market. I can look back with some pride to the company I built over a 16 year period. Too bad the new owners were so nasty and short sighted, otherwise they would still be around.
-Chris
I was lucky with warranty contracts actually. We got training and good rates compared to most other contracts. All in all, the contracts made us a lot of money, and the out of warranty referrals gave us a leg up. In the telephone directory, we listed all those brands and that drew in a great deal more people than just those brands.
As soon as we were forced to do low end stuff, or video products I would generally drop the line. A better line was always there to fill the gap it seems. The warranty contracts were the best things we could have done and they made us a much better service shop as a result. It was only when the market dropped out in 1998 that caused me to sell. I sold at exactly the right time and stepped off a rapidly sinking ship. The business lumbered along for a decade or so until they finally used up the last of the good will we had developed and the poor market swallowed them up.
Without the warranty contracts it would have been extremely difficult to become so successful in the Toronto market. I can look back with some pride to the company I built over a 16 year period. Too bad the new owners were so nasty and short sighted, otherwise they would still be around.
-Chris
While it was probably and older tube Boonton generator you could say a YAG tuned microwave sweeper spectrum analyzer is the same. . . There were some early RCA? sweepers for FM-TV that had a motor to rotate something to do the sweeping.
I think the confusion is stepping into the Distortion Nuts gallery where nothing is perfect enough. There is a Time Nut and a Volt Nut gallery just down the way where voltage measurement to 8+ digits and frequency to 14 digits are essential calling cards. Nothing useful in the real world comes out but at least no one is causing injury (except to pocketbooks and music).
We should all be playing Bocce Ball at the senior center.
We should all be playing Bocce Ball at the senior center.
Finally got around today to finish the home for a couple of Vicnic oscillators.
Stock except the power supply (a SilentSwitcher of course) and the output impedance lowered to 250 ohms each phase.
Finally something to give the AP a run for its money. Gets crowded on the bench!
Viktor if you are reading this: the inverted output on the 5kHz is a bit higher in amplitude than the normal single ended input. On the 1kHz they are both the same amplitude. Do you have an explanation for that?
Jan
Stock except the power supply (a SilentSwitcher of course) and the output impedance lowered to 250 ohms each phase.
Finally something to give the AP a run for its money. Gets crowded on the bench!
Viktor if you are reading this: the inverted output on the 5kHz is a bit higher in amplitude than the normal single ended input. On the 1kHz they are both the same amplitude. Do you have an explanation for that?
Jan
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