Sorry about that - I'd already put a "Best Offer" for US$250... which was accepted before I'd noticed you have posted it here...
I know nothing about these units but need a simple Sig Gen with "knob" for amplifier development etc. - maybe if I get time I'll see how much it can be improved as has been mentioned here with newer opamps etc.
RNM,
Our paths might have crossed in earlier lives, my father was a physicists at the Plasma Physics Dept. at Imperial collage London - where he researched and built High Vacuum / high voltage electronics that ended up your direction State side. High Energy Lasers, X-ray Streak Cameras, Picosecond HV pulsers... I spent my childhood building the HV Avalanche pulsers for these lasers and Streak cameras... this is where I grow so attached to the Tek 7000 series mainframe oscilloscopes - I've still on occasions use the TEK 7104 & 7934 mainframes, I still recall the first time I blow a S6 sampling head by attaching an open circuit coax cable that was statically charged... that was the end of the sampling diode bridge - and bang 10K GBP gone... its alot of money when your only 12 to 13 years old
When I think that these pulsers operated at 10's Kv's I'm not sure my father was very "protective" of me! A very different age then today, could you imagine today's child services?
My father used to have a High vacuum pump system in the kitchen pantry that would sit there for days on end pumping out the very last few atoms of air, with a wire mesh cages over the Glass envelope in case of implosion... and there I was testing thousands of Zetex transistors to characterises there "undocumented" avalanche mode - each pulser would have chains of these avalanche transistors in a HV stack to generate the require energy levels.
Well, guess it was a better childhood then playing football or some such
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@JohnW
No Problem, I just quoted the Ebay link.
I already have a 4400A and a 4402B and the Service Manuals.
People regular ask me about, so I sent them to Jan Dupots site,
which is unfortunately closed now.
Any tip where I can upload them again ?
No Problem, I just quoted the Ebay link.
I already have a 4400A and a 4402B and the Service Manuals.
People regular ask me about, so I sent them to Jan Dupots site,
which is unfortunately closed now.
Any tip where I can upload them again ?
Kindly forward by ghg:-
Krohn Hite 4400A Service manual:-
https://dl.dropboxusercontent.com/u/86116171/KROHN_HITE_4400A_service_manual.pdf
Krohn Hite 4402B Service manual:-
https://dl.dropboxusercontent.com/u/86116171/KROHN_HITE_4402B_service_manual.pdf
Krohn Hite 4400A Service manual:-
https://dl.dropboxusercontent.com/u/86116171/KROHN_HITE_4400A_service_manual.pdf
Krohn Hite 4402B Service manual:-
https://dl.dropboxusercontent.com/u/86116171/KROHN_HITE_4402B_service_manual.pdf
Kannan,
Download via this link (as posted above):-
https://dl.dropboxusercontent.com/u/86116171/KROHN_HITE_4400A_service_manual.pdf
Look to the Linear Technology App Note AN43 -Bridges. Several Wien Bridge Sine generators were designed, extremely low distortion. For obtaining tandem and good tracking potentiometers the best way is to make a gear coupling with two multi turn linear pots. I bought several stereo pots to choose the best one, no hope. Either not equal or not good tracking.
RNM,
Our paths might have crossed in earlier lives, my father was a physicists at the Plasma Physics Dept. at Imperial collage London - where he researched and built High Vacuum / high voltage electronics that ended up your direction State side. High Energy Lasers, X-ray Streak Cameras, Picosecond HV pulsers... I spent my childhood building the HV Avalanche pulsers for these lasers and Streak cameras... this is where I grow so attached to the Tek 7000 series mainframe oscilloscopes - I've still on occasions use the TEK 7104 & 7934 mainframes, I still recall the first time I blow a S6 sampling head by attaching an open circuit coax cable that was statically charged... that was the end of the sampling diode bridge - and bang 10K GBP gone... its alot of money when your only 12 to 13 years old
When I think that these pulsers operated at 10's Kv's I'm not sure my father was very "protective" of me! A very different age then today, could you imagine today's child services?
My father used to have a High vacuum pump system in the kitchen pantry that would sit there for days on end pumping out the very last few atoms of air, with a wire mesh cages over the Glass envelope in case of implosion... and there I was testing thousands of Zetex transistors to characterises there "undocumented" avalanche mode - each pulser would have chains of these avalanche transistors in a HV stack to generate the require energy levels.
Well, guess it was a better childhood then playing football or some such
All sounds very familiar to me. wasnt it the 22N697 that could be used in avalanche mode without destroying it. very fast. My father was a science teacher. So my fate was known before I was born. Nice to know people in high energy physics are here, too.
-RNM
The "Boat Anchor Manual Archive" -- the repository of all things (except Heathkit)
http://bama.edebris.com/manuals/
The archive is updated almost every day.
BTW -- the Tektronix 79xx scopes
You can play with any kind of combination. I tried to make a good tracking pair with photo resistors, again no hope within budget. The low "light" resistance having ones are expensive and the reasonable ones have high "light" resistance, far ahead of 10kOhms. That's why I suggested the multiturn-linearpot(5% tolerance)-gear combination. By the way, any wienbridge sine generator has low distortion. If the feedback arm has thermistor or incandescent lamp, during frequency change oscillation will stop, as soon as you stop turning the pot, oscillation starts. Because the thermistor (or lamp) has a big time constant. If the feedback arm has a FET or other semiconductor-IC combination, then you can get a continuous frequency sweep during pot turning. If you are looking a real low distortion sine generator for audio test purposes, just go with a wienbridge oscillator. None of those IC generators will get close to wien bridge oscillator. I built with MAX038, XR2206 and XR8038, and none of those are as good as wienbridge. Some more complicated circuits, built as square-triangle generator, then with a diode-resistor network rounded the peaks to make sine. NOP, won't work. All have minimum 1% distortion. Don't waste your time, you won't get any better than wienbridge. Just build one and see the beauty of sine(0.02% distortion). From 16Hz towards 20kHz you'll be fine. In the year 1976 I built one with discrete components, from 10Hz towards 100kHz. That era to find a good tracking stereo pot was not difficult.
The AD8400 potentiometers from Analog Devices track very, very closely -- but you'll need a little help from an Arduino or Basic Stamp as they talk using the SPI protocol. You can also use the low noise 8-bit switches to create a linear potentiometer which will track to a very close tolerance with only 8 resistors.
Is the linearity of the resistors important in a Wien Bridge design? - I doubt the Voltage coefficient of the on board resistors is going to be very good (THD is quoted at 0.003%)... But I really don't know what effect (if any) this will have on the Wien Bridge design? - but I suspect the resistor linearity will be important.
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RNM,
this is where I grow so attached to the Tek 7000 series mainframe oscilloscopes - I've still on occasions use the TEK 7104 & 7934 mainframes, I still recall the first time I blow a S6 sampling head by attaching an open circuit coax cable that was statically charged... that was the end of the sampling diode bridge - and bang 10K GBP gone... its alot of money when your only 12 to 13 years old
I have a newer and more compact TEK scope with the built-in FFT option (TDS3032) and a TEK 7904 with a variety of specialized plug-ins for it. I have a S6 if you need one replaced
I much prefer the TEK 7904 if I have the bench space when working. I also have a spare parts 7904 to be sure I can keep it running forever.
THx-RNMarsh
RNMarsh,
If you get a chance try and pick-up the later 7904A - its basically the 7104 but without the MCP tube - its a much more modern mainframe the then non A version. The only thing I miss on the 7904A is the current probe calibrator - the little plastic "Handle" on the 7904 front panel. It tock me about two decades before I realised what the "little plastic handle" was for, but bare in mind I first started using the 7904 when I was about 12years old - and had never seen a current probe!
Thank you for the very kind offer of the S6, but I've moved on from the 7S12 / 7S11 & 7T11 combinations, I've bought some rather nice Agilent 86100C's mainframes with the 20GHz & 50GHz plug-ins... Also, I'm not so involved in ultra fast pulse work these days... I do miss the cutting edge - but Audio's OK, but lacks that small community of really cutting edge research.
It saddens me that there are so few "true" designers in Audio - thinking back to the days of Quad current dumping etc. Today you see someone just rediscover some prior topology that no one would have battered an eyelid for, and now its like they are Semi Gods in the world of HiFi...
The times I look at old Tektronix schematics and you have to admire the amazing creativity! Yet, in HiFi people still flog old Class A/B designs with all the Phase / Gain modulation that occurs around the zero crossing point - such is our "Art"...
I just get alittle disillusioned as there is so little genuine creativity to stimulate the mind and go - Erh, that's clever!
If you get a chance try and pick-up the later 7904A - its basically the 7104 but without the MCP tube - its a much more modern mainframe the then non A version. The only thing I miss on the 7904A is the current probe calibrator - the little plastic "Handle" on the 7904 front panel. It tock me about two decades before I realised what the "little plastic handle" was for, but bare in mind I first started using the 7904 when I was about 12years old - and had never seen a current probe!
Thank you for the very kind offer of the S6, but I've moved on from the 7S12 / 7S11 & 7T11 combinations, I've bought some rather nice Agilent 86100C's mainframes with the 20GHz & 50GHz plug-ins... Also, I'm not so involved in ultra fast pulse work these days... I do miss the cutting edge - but Audio's OK, but lacks that small community of really cutting edge research.
It saddens me that there are so few "true" designers in Audio - thinking back to the days of Quad current dumping etc. Today you see someone just rediscover some prior topology that no one would have battered an eyelid for, and now its like they are Semi Gods in the world of HiFi...
The times I look at old Tektronix schematics and you have to admire the amazing creativity! Yet, in HiFi people still flog old Class A/B designs with all the Phase / Gain modulation that occurs around the zero crossing point - such is our "Art"...
I just get alittle disillusioned as there is so little genuine creativity to stimulate the mind and go - Erh, that's clever!
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This topic started looking to me similar with the ones of .. Which banana plug and cable sounds better?
Then Semi Gods in the world of HiFi...came in to play too, and every one closing his eyes at the fact that crossover networks using 5% tolerance of capacitors, and that even the human ear it self is an imperfect instrument which it condition is not stable and constantly degrades.
My saying will be that sound amplification by the use of electronics is now matured and further research is not needed.
All that is needed when copying other people technology, because this is what DIY people do, is to test your design if it pass successfully basic tests, and for such testing you have to use recently made test and measurement equipment.
End of the story.
Then Semi Gods in the world of HiFi...came in to play too, and every one closing his eyes at the fact that crossover networks using 5% tolerance of capacitors, and that even the human ear it self is an imperfect instrument which it condition is not stable and constantly degrades.
My saying will be that sound amplification by the use of electronics is now matured and further research is not needed.
All that is needed when copying other people technology, because this is what DIY people do, is to test your design if it pass successfully basic tests, and for such testing you have to use recently made test and measurement equipment.
End of the story.
I dont agree that we have reach amplifier perfection - and I also don't agree that the typical measurement perimeters that we currently hold so dear are able to quantify sound quality.
In my experience time domain measurements such an Amplifiers Phase Margin and PIM (Phase Intermodulation distortion) are far more critical to sound quality then simply THD (once THD has been reduced to a reasonable level).
Anything that effects the Amplifiers Open-loop gain in a dynamic manor is also very negative to sound quality. Typical of this is ClassAB crossover distortion, during the transitional period your amplifiers output stage is effectively "high impedance" so you can kiss goodbye to any open-loop gain you believe you have to correct the issue.
In my experience, PIM is a performance matrix that helps characterises an amplifiers sound stage performance - yet when was the last time you have seen it measured and discussed in "popular" HiFI magazines?
Quads current dumping principle is very effective way to resolve this issue, and yet its advantages is not well understood by the industry.
Even THD is a pretty meaningless performance matrix as 0.1% second order THD I can live with, yet 0.1% of high orders would be unlistenable! so what does a claimed 0.1% THD really mean? It just says the total THD is 0.1% but says nothing of its sonic character.
An amplifier Phase Margin seems to have a direct impact on an amplifiers sound stage performance - yet I've seen very little mentioned on this subject - is there an ideal Phase margin?... (I don't think there is, as the whole systems final dynamic performance is what's important and the amplifier is just one element in the replay chain and an amplifiers PM needs to be factored into the systems overall "total"). What I mean by this is that you can have an over-damped speaker system, with an under-damped amplifier and together the combination works well... yet with an over-damped speaker and over-damped amplifier the system will sound lifeless and dead....
I do believe that ultimately we can characterise a unit performance with measurements, but not with simplistic THD and frequency response measurement, we first need to have a better understand of what's important to the ear / brain as otherwise we are just blindly stabbing about in the dark.
I probably have one of the very best audio measurement labs anywhere in the world, yet I cannot guarantee a units sound quality from simple measurements - and something I find hard to work with.
I will say, that if a design has good time domain performance then in my experience its far better positioned to sound good.
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