Vintage is all about feeling and sense of art. Can be a soothing pass time. Still a Genesis four tower loudspeaker system with class D servo active bass (some British ingenuity involved in its elaborate PSU side of things I believe), plus a Spectral DMA 260 amp for the dipole ''wings'' manages landing me to the present very nicely. I had set up one, I would have to win the lottery to ever own one. Yes you can contact me freely, by all means.
SEMICOA vas the . . .
If I remember those vintage days before Naim start to print theirs logo on the OP semis the orig. driver and OPs were made by US manufacturer SEMICOA and the marking on the metal TO3 was SM2xxxx and SM3xxx (compl) similar marking was on the VAS TO220 drivers with SMxxx markings, Semicoa make on those days the first semis with huge 25A-120V + 30MHz Ft TO3 compl. trannies, and Naim for their design was chose only NPN TO3 device.
cheers
Hello Nigel,
If I remember those vintage days before Naim start to print theirs logo on the OP semis the orig. driver and OPs were made by US manufacturer SEMICOA and the marking on the metal TO3 was SM2xxxx and SM3xxx (compl) similar marking was on the VAS TO220 drivers with SMxxx markings, Semicoa make on those days the first semis with huge 25A-120V + 30MHz Ft TO3 compl. trannies, and Naim for their design was chose only NPN TO3 device.
cheers
Hi Nigel,
That's what I suspected, they balanced the harmonic spectrum by tweaking the LTP with this resistor. I guess, for us DIY-ers, not having the same LTP and VAS transistors available, the whole thing is useless or at least unpredictable. We should probably try to decrease the distortion as much as possible by balancing the LTP the best way possible, as shown in the books.
I'm interested to know what is the "Hiraga treatment"
Do you have some sort of approximative calculation of distortion in LTPs? I have read many articles from J. Hiraga, but don't remember anything related to calculations. He's a journalist, DIY-er and audiophile as far as I know, I have never seen formulas in his articles. But that was in the 90s in "La Nouvelle Revue du Son" ... I'm curious to see what you mean...
Limiters
I'm interested in what to do about other design features and parts (ok-nothing about certain caps)
So, what to do about Naim VI limiter action and it's intrusion on audio. Realistically, they're the only protection available here. Many DIYs simply remove the limiter components from their originals or clones and "wing it", ignoring safety concerns. I assume it still is used in some form, so how does the sound of new and original products escape deeper criticism?
Is this just imagination or a matter of actual user power levels being lower than those approaching limiting action? I understand that objectionable effects with many applications begin much earlier than design predictions suggest.
I'm interested in what to do about other design features and parts (ok-nothing about certain caps)
So, what to do about Naim VI limiter action and it's intrusion on audio. Realistically, they're the only protection available here. Many DIYs simply remove the limiter components from their originals or clones and "wing it", ignoring safety concerns. I assume it still is used in some form, so how does the sound of new and original products escape deeper criticism?
Is this just imagination or a matter of actual user power levels being lower than those approaching limiting action? I understand that objectionable effects with many applications begin much earlier than design predictions suggest.
Salas I will risk that anyone can contact me and hope they preserve the etiquette of the forum . nigelpearson@*****. I know a bit about many British amplifiers and hi fi 1964 to 1997 ( and after , and before ) and happy to give my time . I helped a freind put together a system using a 2 x 300 W class D amplifier ( Tri path ) driving old Leak 12 inch bass units . The mid / top by Fostex full range unit . The main amplifier is a valve single ended design using KT 88 ( 8 Watts ) . All in all it approximates to a Naim system with walk in depth . The weird bit is the active crossover costs about $35 and was for car stereo . It has been the most transparent component of all ! It is run from bypassed motorcycle batteries and has been hot rodded . Many DACs costing big money have failed to impress ( the transport cost big money ) . FFT has been used to analyze the performance ( especially the speakers ) . I am not sure I would have put a system like this together , the Leaks are the precious part and as you say vintage .. However it is now starting to be just a little bit specail . Make no mistake the Fostex and valve amp are not very typically vintage except in concepts used . The DAC is Flying Calf which refuses to be replaced ( mildly modified , very very clean supply to the clock ) . It has 1/4 inch outputs !!!
Anyone wanting a similar sound should buy a clone kit and Quad ESL 57's and write to me . My Pro Audio friends never loose an opportunity to say hi fi people have vivid imaginations . I love Naim gear because it would happily have been a Pro Audio product given it was scaled for the job . However what is anything without a little imagination ?As far as I know Alan Mornington West is now a Pro Audio consultant ( the originator of the NAP 250 ? ) !
Anyone wanting a similar sound should buy a clone kit and Quad ESL 57's and write to me . My Pro Audio friends never loose an opportunity to say hi fi people have vivid imaginations . I love Naim gear because it would happily have been a Pro Audio product given it was scaled for the job . However what is anything without a little imagination ?As far as I know Alan Mornington West is now a Pro Audio consultant ( the originator of the NAP 250 ? ) !
Smiley . Naim said to me that when BDY 56 ceased production that they had to pay for it to continue . They never out and out lied . However thinking back they were vague about it . I could hypothesis that 10 MHz Ft is ideal and 30 MHz might be too fast . JLH had this problem with his famous amp . Some modern transistors suited it fine and others not . JLH said he didn't know why and was eager to find out . I reckon it's the marginal stability which is so good and so bad in these designs ( a slightly over shooting square wave at 30 kHz and no output choke ) . You see , real music is not square waves . Naims drive Quad 57''s well , so no real world instability . BTW much of the ringing seen on square wave tests is the output choke . A 10 ohm resistor often used as a former damps that . It is said that the JLH needs no VAS cap . Not true if using a modern transistor . JLH is the opera lovers Naim . BTH if you think your Naims might be too fast use 0.6 mm solid core cable speaker cable ( handle it gently as it work hardens ) . If you want more slam use multiples of 0.6 mm . Try single first and live with it for a week . We are talking peanuts to find out . Transformer wire is OK . ( Litz effect if wondering ) . If you loose bass try repositioning the speakers . I reckon the IMF's Salas spoke of needs that?
Nigel thanks. There is a rule we don't post email addresses in public to avoid spam since these forums can be googled up by anyone for years to come, accessed by spambots etc. There is the PM (private message) system that members can use to address each other, exchange emails etc. Its available by clicking on the member's nickname to the left of his posts. If you got a PM the system notifies on the top right of the screen.
Ruwa . Someone had a real go at me saying I am full of contradiction , to which I said I am a Libra and it is natural for me ( we seek balance , I am not a believer , but it appeals to me ) . I said . As I understand it , Buddhism says life is full of contradiction and is good for us ( sorry , that's my own take on it ) .
Seeking balance in LTP is either low distortion or harmonic balance . Approximately the balance of the Naim is virtually equal 2nd and 3rd harmonics , very little 4 th and some 5th ( this is from memory ) . Within reason all LTP are the same and transistors will not change it very much ( complex to explain ) . I should point out that slew limits referred to in these things rarely exist in real music so don't loose sleep over a little bit of lost current . If you listen to only techno then disregard what I just said . You should increase the VAS cap by 20% if going for balance .
Approximately , if wanting to experiment . Fix the the 1K at 1K3 and 22K at zero ohms for complete balance ( if VAS vbe is 0.65 V ) . This will eliminate the second harmonic distortion and make the amp sound dry and ultra fast ( ask about current mirrors if this is your preference ) . Shorting the 22 K will tell you if you are heading the right way for you . .
If wanting a Hiraga effect you could make the 22K into 36 K and stick with 1K as now .
There is another way . Put a 8 R resistor between the emitter of the VAS and it's voltage rail . That makes the Niam into a popper transconductance amplifier and sits the VAS base up a bit future doing Hirage stuff . This is not about local feedback . I assume VAS beta to be 100 .
In theory the Naim requires a VAS beta of 1200 . One way to make a more Williamson style of trannmsconductance is to use a 16 R transistor in the emitter .
As one increases an emitter resistor you will find that slam is reduced , however spaciousness will increase . Lets be clear you can do this empirically between 0 an 47 R . Bias will become more critical as the size of the resistor increases ( set your bias by ear is fine as long as the transistors don't get too hot , I use a scope and my ears , it always works out identical ! and it will for everyone !! )_. A Douglas Self Bias idea would help .
Leave the VAS cap alone ( or increase if wanting to experiment ) . On Jean Hiraga . There is a saying . There is the right way , the wrong way and then there is the French way . The French way is rarely bad .
To be clear I would sit and listen to a Naim amp until eternity and it would be a Nait 2 . However at no risk ( if progressive and not rushing ) you can find out if you are JV's twin . My spell checker came up with " teatime " for eternity !
PS
I will tone down this technical stuff especially if asked . I have given my email out so will take more of a back seat now if people write directly .
About transistors , Ian knows more than me .
Seeking balance in LTP is either low distortion or harmonic balance . Approximately the balance of the Naim is virtually equal 2nd and 3rd harmonics , very little 4 th and some 5th ( this is from memory ) . Within reason all LTP are the same and transistors will not change it very much ( complex to explain ) . I should point out that slew limits referred to in these things rarely exist in real music so don't loose sleep over a little bit of lost current . If you listen to only techno then disregard what I just said . You should increase the VAS cap by 20% if going for balance .
Approximately , if wanting to experiment . Fix the the 1K at 1K3 and 22K at zero ohms for complete balance ( if VAS vbe is 0.65 V ) . This will eliminate the second harmonic distortion and make the amp sound dry and ultra fast ( ask about current mirrors if this is your preference ) . Shorting the 22 K will tell you if you are heading the right way for you . .
If wanting a Hiraga effect you could make the 22K into 36 K and stick with 1K as now .
There is another way . Put a 8 R resistor between the emitter of the VAS and it's voltage rail . That makes the Niam into a popper transconductance amplifier and sits the VAS base up a bit future doing Hirage stuff . This is not about local feedback . I assume VAS beta to be 100 .
In theory the Naim requires a VAS beta of 1200 . One way to make a more Williamson style of trannmsconductance is to use a 16 R transistor in the emitter .
As one increases an emitter resistor you will find that slam is reduced , however spaciousness will increase . Lets be clear you can do this empirically between 0 an 47 R . Bias will become more critical as the size of the resistor increases ( set your bias by ear is fine as long as the transistors don't get too hot , I use a scope and my ears , it always works out identical ! and it will for everyone !! )_. A Douglas Self Bias idea would help .
Leave the VAS cap alone ( or increase if wanting to experiment ) . On Jean Hiraga . There is a saying . There is the right way , the wrong way and then there is the French way . The French way is rarely bad .
To be clear I would sit and listen to a Naim amp until eternity and it would be a Nait 2 . However at no risk ( if progressive and not rushing ) you can find out if you are JV's twin . My spell checker came up with " teatime " for eternity !
PS
I will tone down this technical stuff especially if asked . I have given my email out so will take more of a back seat now if people write directly .
About transistors , Ian knows more than me .
Hello Nigel,
It was back in the 1976 at my friend in Wienna who bought a Linn LP 12 - Ittok-Troika Nac Pre + Naxos + 6 pack NAP250 + Linn Isobaric PMS speakers.
I was quite many times listening his system (ve make night sessions) and once one of his friend was so blown out of the sound presented
that he ask if it is possible to see the internal one of the NAP250 amp. At that time I saw the orig. markings on the semis I mention
- they were without Naim Logos. Next Year the same Guy made the Crimson 120W power amp with the same VAS & OPS semis,
available in that time at Cricklewood Electronics
(I saw in that time in theirs El. Catalogue (1977) the actual semis data).
In one of the next music listening session he bring his proto Crimson AMP & we make a comparative session with NAP250s. The Crimson proto was sounded more transparent with much better and deeper bass, also the vocals (mids) + (highs) were sweeter than with the Naim.
In the whole session he was 3 times replaced one NAP250 for each FX active range: - for the Lf and listening, for the Mids and listening, and for the Hfs and listening, each time one of the NAP amps was replaced with his Crimson Amp. In each position the Crimson was superior to NAP250. After some 6 months all NAP250 amps were replaced with that guy Diy Crimsons and as I can remember the full Crimson 6 pack sound was leave in my memory the second best Music playback experience till today.
Do You maybe remember those Crimson Amps? (Symetr.PP) they were designed with SMxx BJT and Hita. LatFets (very easily oscillated at 20Mhz) designed by some British enthusiasts?
Cheers,
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Salas I thought that . I just didn't want to turn into Alex Kitic ( much admired by me ) . I don't mind spam and get buckets full , I must claim the various fortunes I have waiting for me one day . I use Avast free virus checker which I would recommend to help avoid ill effects . If people don't say about audio I delete it anyway if I don't know them .
Smiley . If you look back through the thread I mention I was torturing my Pro Audio Chums by a discussion about Crimson . I know they don't dare criticize them . Crimson is a mixture of Naim , Amcron and Quad 303 . C Audio is how to get them excited if wondering .
C Audio Power Amplifiers
An example , with my chums I have to agree that cables don't matter as long as they are not rubbish . Well that is subjective isn't it ?. What is rubbish ? I was even told of a customer specifying a certain cable for a mixing desk , buying it for them and them not fitting it . Then being smug he didn't notice . Now that is going too far .
Sorry Naim Clone guys we are well off track . Still Smiley is absolutely right .
People who know me will think I am being a bit of a traitor to write on this Forum . Not at all . The Naim Circuit was more or less public domain before Naim Audio existed . Within the design is mostly what anyone would want from an amplifier . We are just doing what a group of guys were doing in Cambridge in 1970 and one from Oxford joining them ( JV ). .
C Audio Power Amplifiers
An example , with my chums I have to agree that cables don't matter as long as they are not rubbish . Well that is subjective isn't it ?. What is rubbish ? I was even told of a customer specifying a certain cable for a mixing desk , buying it for them and them not fitting it . Then being smug he didn't notice . Now that is going too far .
Sorry Naim Clone guys we are well off track . Still Smiley is absolutely right .
People who know me will think I am being a bit of a traitor to write on this Forum . Not at all . The Naim Circuit was more or less public domain before Naim Audio existed . Within the design is mostly what anyone would want from an amplifier . We are just doing what a group of guys were doing in Cambridge in 1970 and one from Oxford joining them ( JV ). .
Ian . Two things implied about Naim in the early days which they never challenged was that they went down to DC and they didn't use VI limiting , neither is true . The VI limiting is very intelligent on the Naim . Salas was saying about flying wire transistors . If I was to remove the VI limiting I would use flying wire transistors . If thick wires from the PCB I could put in new transistors fast ( and drivers ) and it would look and work like normal gain clone . You will loose your speakers , that's the rub ( fit a DC crowbar protection ? ) .
Hello Nigel,
I was just read some of Yours posts and see You'r the man from the old good days when fashion didn't enter yet into the world of the music lovers . .
I'm from the same time also and will probably never try or wish to understand the (trendy fashion) words - High End.
I'm deeply impressed with Yours broad base knowledge of good Audio rules from the past. If I've with a little lucky I'll ask my old chap in Wienna if he still have the Schs from those Crimson Amp and will provide it here for the old nostalgia minded guys just to not to be forgotten another great sounding Amp design from the past.
Cheers
I was just read some of Yours posts and see You'r the man from the old good days when fashion didn't enter yet into the world of the music lovers . .
I'm from the same time also and will probably never try or wish to understand the (trendy fashion) words - High End.
I'm deeply impressed with Yours broad base knowledge of good Audio rules from the past. If I've with a little lucky I'll ask my old chap in Wienna if he still have the Schs from those Crimson Amp and will provide it here for the old nostalgia minded guys just to not to be forgotten another great sounding Amp design from the past.
Cheers
Hi Ian , I gave out my email , it was declined so sorry to hog this . The first Naims which I had forgotten were like a Quad 303 and had wires from the PCB to the transistors . It makes life easier to replace them . I reckon just fitting small posts on the PCB would do the same . I seem to remember latter Naims used this idea and the transistors were sweated onto the PCB and not through a hole . Then a metal bar clamped the transistors down .
Smiley it is said Audio designers are aging with the customers . At the pub I was being universally blamed for the joke that Audio has become . I was horrified and said that it is customer led . The problem is it is putting off new people . I went to a Rock gig the other day and nearly cried . It was a time warp and everything was alright in the world ( girlfriends son's band ) . Marshall guitar amps and every expensive flovour of guitar . The kids still love music . So why don't they love hi fi ? We put them off . That's why I want to be doing this . They were on Radio Marlow ( we all have to start somewhere ) and were said to be a mix of the Arctic Monkey's and the Beatles , not bad I would say . .
Hi Nigel. We have private mail here on your User CP page. In fact you have a PM from a day or 2 ago, maybe more? It should meet most email needs unless you need to exchange large graphic files.
Thanks for the explanation - I didn't recognise the old mounting method I grew up with. Most large gear before the mid 70's was wired up that way and I even have a large Denon amp. I'm staring at that sports it on at least 200mm flying wires!
Thanks for the explanation - I didn't recognise the old mounting method I grew up with. Most large gear before the mid 70's was wired up that way and I even have a large Denon amp. I'm staring at that sports it on at least 200mm flying wires!
Thanks Smiley . I am doing a quiz at the school tonight and your comments will make me relax .
Alex Kitic I mention seemed to be to be a visionary . Somehow it all went wrong . I used to read his technical stuff . I have started another thread called how to Vary a Small Signal Pentode to Triode in steps , or something like that . . I am trying to finish his work . I am not a valve man so have to pretend . The guys are solving a problem proposed in 1936 by Alum Blumlein ( my hero ) and it looks like they are winning . Smoking Amp , Alfredo and The Gimp . Worth a look . They are all being hero's also .
I intend to build an amp like Alex Kitic with this refinement . It will sound a bit like a Naim amp !!!! It will be to listen to You Tube via whilst writing to you guys . One needs a special amp for that .
I read Kitic in Serbian now via Google translate . He is Alex Springsteen I think now !?
Alex Kitic I mention seemed to be to be a visionary . Somehow it all went wrong . I used to read his technical stuff . I have started another thread called how to Vary a Small Signal Pentode to Triode in steps , or something like that . . I am trying to finish his work . I am not a valve man so have to pretend . The guys are solving a problem proposed in 1936 by Alum Blumlein ( my hero ) and it looks like they are winning . Smoking Amp , Alfredo and The Gimp . Worth a look . They are all being hero's also .
I intend to build an amp like Alex Kitic with this refinement . It will sound a bit like a Naim amp !!!! It will be to listen to You Tube via whilst writing to you guys . One needs a special amp for that .
I read Kitic in Serbian now via Google translate . He is Alex Springsteen I think now !?
You know Ian if we don't put global feedback on we can have the wires as long as we like . A Chinese amp I had to redesign didn't have it . It was unsalable to our ears . It had mighty punch . I worked out how to do it using the same principle and sound OK . For that one I used an amp much like this with NPN PNP output .
Sorry about private stuff . I became a member years ago and just started writing this week . A bit like having a membership to a gym I guess .
I wrote about a gain clone technical solution when I started in 2007 . They were saying slight harness so I copied the internals of the chip in a screen grab and said why technically it would sound that way ( biasing problems and safe operating , thermal feedback inside the chip , move chip into class A was my plan ) . I offered a solution if they wrote back . I am still waiting .The solution cost $0.50. What they don't know is I made one of the quirkiest gain clones of all time ( I can not say which ) . It was a phono stage .
Sorry about private stuff . I became a member years ago and just started writing this week . A bit like having a membership to a gym I guess .
I wrote about a gain clone technical solution when I started in 2007 . They were saying slight harness so I copied the internals of the chip in a screen grab and said why technically it would sound that way ( biasing problems and safe operating , thermal feedback inside the chip , move chip into class A was my plan ) . I offered a solution if they wrote back . I am still waiting .The solution cost $0.50. What they don't know is I made one of the quirkiest gain clones of all time ( I can not say which ) . It was a phono stage .