What makes me wonder is why N.P. takes the credit for being the first person to bias a speaker with a direct current.In just one book from 1974 I found more than 5 schematics of commercial amplifiers tape machines, portable tv sets and amplified turntables made in the 60's and 70's that used to derive the driver's current through the speaker using a form of cheaper bootstrap at the same time , avoiding thus the use of a capacitor.In some cases a 470 ohms resistor was in parallel with the 8...16 ohm speakers to limit the current through speaker.Those in the pictures were made by germans , polish and romanians...most of the basic designs being actually german(telefunken, saba, grundig) designs from the 60's.Those currents were in the order of tens of milliampers with a 24 v supply , but the speaker's maximum power was below 5 or 10 watts having some 4...16 ohms impedance so they were considerable for speaker's wellness...especially in the case of a short circuit...
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typical case of insufficient attention in class
Nelson is too smart and experienced to ever claim for anything doing first in history
quite contrary - he said several times - it happened that he found - something he made was already invented eons ago
I understand that , it happens to me every day - I'm full with ideas
Nelson is too smart and experienced to ever claim for anything doing first in history
quite contrary - he said several times - it happened that he found - something he made was already invented eons ago
I understand that , it happens to me every day - I'm full with ideas
Are you sure about that? I don't see any refference to old push pull germanium amplifiers that already had a severe imbalance by design using two very different devices for npn and pnp while pushing or pulling a dc current through a speaker(both positive and negative supplies were used for that matter ) and yes...that current was fixed too simillarly to NP CCS cause you'd need specific bias for the final stage through the NTC resistor and the driver is class a fixed current.I only see a refference to Barry Thornton using UA 709 op amp externally loaded with a resistor to imbalance its class B output stage.
I am sure that I didn't heard Papa's claim about inventing that
now, be serious, there are enough articles covering effect of DC to speaker function; I believe you'll find at least one in every year of, say, Voice Coil
you're speaking about a Guy having several patents, be sure that he's aware of procedures - what's real novelty , what's novelty in application, what's novelty in specific design
use his breadcrumbs, if you want ........ and be happy that he re-invented some of forgotten ones
now, be serious, there are enough articles covering effect of DC to speaker function; I believe you'll find at least one in every year of, say, Voice Coil
you're speaking about a Guy having several patents, be sure that he's aware of procedures - what's real novelty , what's novelty in application, what's novelty in specific design
use his breadcrumbs, if you want ........ and be happy that he re-invented some of forgotten ones
You can listen to the interview by yourself as anyone else...I'm not making anything up. I was actually looking for that exact interview where he'd talk about germanium transistors, but I couldn't find it yet.
I can appreciate him for promoting simplicity and philosophy, but I can't appreciate him for promoting expensive complementary j-fet devices based front ends that you can buy almost exclusively from one place and hear only a handful of guys ever talking about when speaking about expensive and huge Mark Levinson , Mckintosh and Parasound amplifiers as the quintessence of the audio realm.
Mosfets are cheap, but not that cheap when driven by interstage transformers. So it took some time to get from interstage to direct coupled jfet to mosfet with applied current feedback...10 years or so, isn't it? Was it all because interstage transformers are expensive to make or debatable about their quality?...If I'd make the effort to manufacture interstage transformers I'd surely use them with tubes not with transistors as the amount of work and design is quite simillar while no transistor will ever sound like a tube in a serious circuit, but I can admit having fun is the main diy drive.
Yet, if it's about having fun then we should take it as it is and fun classes aren't exacly what i' m looking for when listening to a big name in anything.When I listen to a big name I look for precision and JC or PS audio style videos always lack precision in a DELIBER(W)A(S)TE way. I only saw three videos with NP , all of them today and I see the same style where he quotes the other well known gold balls of the industry ...Until anyone hears NP talking anything about Peter Quilter and the only simple topology that was able to hold for 50 continuous years in production in more than 30 or 50 models I'm out of his channel.I really wait his opinions about QSC simplicity and philosophy .
Maybe I'm promoting the cheap side of things myself. That's why i bought about 200 germanium transistors while I still could for less than 0.5 $ /piece, but if NP is going to advertise them too, their price will go sky high as well as everything else that was advertised by a well known personality of audio industry and in the end we'll settle for the fact that 2000 bucks class d purify amplifiers are normal because class AB amplifiers are nonsense as they aren't very expensive class A amplifiers being too clean or having too many components and 1000 jfet amplifiers are the only way to go for "true audiophiles" who aren't on the Cheap side because Purify "isn't still there", that's why its cheaper class d models still cost "only" 2000 bucks... when they should cost about 1...200 bucks.
While waiting for the cheerful event I should probably consider buying tons of cheap germanium transistors and sell them later for good money and with such good marketing I have good chances of becoming rich overnight.By the way i have about 100 ac188/187/180/181 measured...Someone make me an offer cause i'm sick of being poor !
I'm still gathering the money while waiting for the opa2132 price going down significantly cause 1000 of them are about 6000 bucks at mouser for the moment so I don't see it making a 1000 j-fet op amp monster amplifier any soon unless some Saudi arabian sheikh will want it.
If anyone from Saudi Arabia or Emirates here...please call me if you want to spend some 20k $ on a 2 channel 1 watt amplifier cause you can afford a Tannoy 15 inch monitor any hour! I can do it with fantastically low distortions that you can't even hear, but you'll know the difference after buying it cause it will be 24k gold plated too, yet I don't offer dc current bias with this model because i can't risk 8000 bucks Tannoy monitor pair ... The blue LED's are free though and i'm happy that NP didn't cover it with a patent .
Most probably this is the last time i visit NP's corner...Too expensive diy perspectives here for me and I don't wanna find that germanium amplifiers can have a sound of themselves only with Papa's touch cause at least for the moment my germanium headphones amp with no global feedback makes TPA6120 envious for its clean sound while supplied with +-2.8v and I couldn't go lower than that with the supply because of the op-amp driving the transistors not being able to work below +- 2.7 v.At least that is what the datasheet says, but i might have a surprise whe the batteries go lower, hopefully a pleasant one full of H2 when asymmetrical clipping find its way in.
I actually asked the diy community to suggest me some good op amps working with even lower supply and I got no answer ...So i need to trust Google more than the diy community...at least up until two days ago I was never curious to see how lm4562 sounds at +-2.8v ...Well it sounds fantastically well and that nobody told us before because we are supposed to believe only into what big names in audio industry tells us...
Personally I don't believe anyone about anything ! Feel free to do the same and check the video before saying anything back about it.
I can appreciate him for promoting simplicity and philosophy, but I can't appreciate him for promoting expensive complementary j-fet devices based front ends that you can buy almost exclusively from one place and hear only a handful of guys ever talking about when speaking about expensive and huge Mark Levinson , Mckintosh and Parasound amplifiers as the quintessence of the audio realm.
Mosfets are cheap, but not that cheap when driven by interstage transformers. So it took some time to get from interstage to direct coupled jfet to mosfet with applied current feedback...10 years or so, isn't it? Was it all because interstage transformers are expensive to make or debatable about their quality?...If I'd make the effort to manufacture interstage transformers I'd surely use them with tubes not with transistors as the amount of work and design is quite simillar while no transistor will ever sound like a tube in a serious circuit, but I can admit having fun is the main diy drive.
Yet, if it's about having fun then we should take it as it is and fun classes aren't exacly what i' m looking for when listening to a big name in anything.When I listen to a big name I look for precision and JC or PS audio style videos always lack precision in a DELIBER(W)A(S)TE way. I only saw three videos with NP , all of them today and I see the same style where he quotes the other well known gold balls of the industry ...Until anyone hears NP talking anything about Peter Quilter and the only simple topology that was able to hold for 50 continuous years in production in more than 30 or 50 models I'm out of his channel.I really wait his opinions about QSC simplicity and philosophy .
Maybe I'm promoting the cheap side of things myself. That's why i bought about 200 germanium transistors while I still could for less than 0.5 $ /piece, but if NP is going to advertise them too, their price will go sky high as well as everything else that was advertised by a well known personality of audio industry and in the end we'll settle for the fact that 2000 bucks class d purify amplifiers are normal because class AB amplifiers are nonsense as they aren't very expensive class A amplifiers being too clean or having too many components and 1000 jfet amplifiers are the only way to go for "true audiophiles" who aren't on the Cheap side because Purify "isn't still there", that's why its cheaper class d models still cost "only" 2000 bucks... when they should cost about 1...200 bucks.
While waiting for the cheerful event I should probably consider buying tons of cheap germanium transistors and sell them later for good money and with such good marketing I have good chances of becoming rich overnight.By the way i have about 100 ac188/187/180/181 measured...Someone make me an offer cause i'm sick of being poor !
I'm still gathering the money while waiting for the opa2132 price going down significantly cause 1000 of them are about 6000 bucks at mouser for the moment so I don't see it making a 1000 j-fet op amp monster amplifier any soon unless some Saudi arabian sheikh will want it.
If anyone from Saudi Arabia or Emirates here...please call me if you want to spend some 20k $ on a 2 channel 1 watt amplifier cause you can afford a Tannoy 15 inch monitor any hour! I can do it with fantastically low distortions that you can't even hear, but you'll know the difference after buying it cause it will be 24k gold plated too, yet I don't offer dc current bias with this model because i can't risk 8000 bucks Tannoy monitor pair ... The blue LED's are free though and i'm happy that NP didn't cover it with a patent .
Most probably this is the last time i visit NP's corner...Too expensive diy perspectives here for me and I don't wanna find that germanium amplifiers can have a sound of themselves only with Papa's touch cause at least for the moment my germanium headphones amp with no global feedback makes TPA6120 envious for its clean sound while supplied with +-2.8v and I couldn't go lower than that with the supply because of the op-amp driving the transistors not being able to work below +- 2.7 v.At least that is what the datasheet says, but i might have a surprise whe the batteries go lower, hopefully a pleasant one full of H2 when asymmetrical clipping find its way in.
I actually asked the diy community to suggest me some good op amps working with even lower supply and I got no answer ...So i need to trust Google more than the diy community...at least up until two days ago I was never curious to see how lm4562 sounds at +-2.8v ...Well it sounds fantastically well and that nobody told us before because we are supposed to believe only into what big names in audio industry tells us...
Personally I don't believe anyone about anything ! Feel free to do the same and check the video before saying anything back about it.
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oh boy, you did knock in wrong hood ..... main reason you getting it all wrong
anyway, I wish you all the best, whatever business or/and hobby arrangement you choose
anyway, I wish you all the best, whatever business or/and hobby arrangement you choose
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While I was reading about a Tek 576 curve tracer I came across an ASZ16 PNP Germanium transistor.
What I did not know is that it seems normal by "nerds" to test what happens if voltages are "reversed" (unless it is by accident).
On a curve tracer it is just a switch to test it "reversed". With ASZ16 tested as a NPN it seems to be acting like a very linear "follower"?
If you want to have a look go 4/5 down here and look for the headline "A GERMANIUM TRIODE!":
https://jacmusic.com/Tube-testers/TEK-576/Tek-576-3-Measurements.html
Maybe some of you have ASZ16 to "play with"?
What I did not know is that it seems normal by "nerds" to test what happens if voltages are "reversed" (unless it is by accident).
On a curve tracer it is just a switch to test it "reversed". With ASZ16 tested as a NPN it seems to be acting like a very linear "follower"?
If you want to have a look go 4/5 down here and look for the headline "A GERMANIUM TRIODE!":
https://jacmusic.com/Tube-testers/TEK-576/Tek-576-3-Measurements.html
Maybe some of you have ASZ16 to "play with"?
A Tek 576 would be a nice hobby tool for DIY-play if it is possible to find one of the latest built (1990) at a reasonable price in good working condition.
Does Soundhappy has one?
It can do a bit more than my DCR 75 pro tester. Much higher voltages/currents. But it takes up a lot more space and difficult to repair if it breaks down.
Does Soundhappy has one?
It can do a bit more than my DCR 75 pro tester. Much higher voltages/currents. But it takes up a lot more space and difficult to repair if it breaks down.
@ Twichie and Diyers
Congratulations !! Those are beauty vintage
2SB206 genuine source link https://www.diyaudio.com/community/...-nos-to-79-sit-v-fet-from-japan-tokin.327309/
Enjoy
Congratulations !! Those are beauty vintage
2SB206 genuine source link https://www.diyaudio.com/community/...-nos-to-79-sit-v-fet-from-japan-tokin.327309/
Enjoy
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I don't but Mr. Rothacher get Tek 577
Nicely restored , calibrated stand alone toolno need computer , software and service manual was included 😉
2SB Ge curves looks like "hallucination" on Tektronix green turquoise colour screen.
I guess yes haha
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It is a nice one and good the VFETs from China was real ones and not fakes.
They also looked quite old and not new and shinny as the fakes often do.
They also looked quite old and not new and shinny as the fakes often do.
You're welcome. From my point of view its a very good amplifier. Its hard work to restore but woth it. Cheers
Ps: i really have to thank you guys from Russia for poiting me out another Ge gem from hifi.ru i think. Also fantastic soundig.
Hey guys please try to include as much power Ge variants as possible, and dont stick only to those hard to get japan stuff. Of course they are very good and robust but i would like to see others constructing diy fun projects because that's all about it isnt it?
As i see it there are:
*USA made 2N series wich i still dont know (somebody please help here);
In a power amp 3db noise is ok (audio ksa 992 Si has this much and is very ok).
So please lets keep it accesible.
Cheers
As i see it there are:
*USA made 2N series wich i still dont know (somebody please help here);
- UE made AL 101,102,103 (1-3mhz) from SGS aka ST; AD166, 167(1-3mhz) Siemens; ADZ 12 by Valvo (20A@80v@100khz@90*C); SFT250, 214, 213 (french) ; EFT 250, 213,214 also AD series by IPRS (RO) ; also Tungsram series, OC series and so on.
- japanese where the 2SB/2SA lower suffix (one hundred, two hundre, three hundred) ;
- russian very robust series made till the '90s P and MP (please add examples) ;
In a power amp 3db noise is ok (audio ksa 992 Si has this much and is very ok).
So please lets keep it accesible.
Cheers
Please bare in mind that my Grundig has 200khz Ge outputs, phase splitter tr and allot of caps in the signal path and it doesnt have problems with the hights or base response and actually feels very fast..............
German hifiists loved Grundig in those days. Max Grundig's philosophy was »HiFi for everyone«, and indeed you got a lot of bang for the bucks. Grundig's gear wasn't badly engineered either, quite the contrary, I'd say. It was cleverly designed. E. g., radio receivers set the landmarks in terms of sensitivity. I still own my all-tube RT 50 tuner, one of the first stereophonic standalone devices available in Germany. And it still works sufficiently. Grundig even hadhis own loudsepaker R&D department, they didn't need to buy LS chassis from other manufactrers and throw them into boxes, as other German manufacturers did. Despite of that, they were affordable.
Best regards!
Best regards!