I have been reading with interest the mods for the pre amps in another thread. I am in the proces of becoming flat and have so far got my sources sorted ( aaa5 and garrard 401) I am now moving onto pre amp. My question is which naim is the best to go for to mod at a later stage. I would like a phone card (for denon DL 103) to be part of the package. I want to buy second hand,could someone point me in the right direction to 32/32.5/42 etc etc. I will probably be partnering it with A260 kit from Les or similar again in the future when funds allow. Any thoughts/advic would be welcome Clive Smith
Naim pre amps-best for modding ?
- Thread starter clive7164
- Start date
Fatmarley
"It appears my intelligence circuits have melted"
One thing i'm finding very helpfull is http://www.neilmcbride.co.uk I printed all of the pre amp tweaking pages and sat with the pre amp lid off and stared at the circuit board for what seemed like hours.
I'm modding a 62 but i don't know if it's the best one to mod
I'm modding a 62 but i don't know if it's the best one to mod
Fretless Eric
Musketeer Bathos
My experiences relate to a 72 and are a few considerations.
I found that the individual boards gave a very quick and easy insight into just what does what inside the preamp.
It is easy to pull a board and modify it and you don't have to work on a mother board.
Some people even have a duplicate set of standard boards to replace and compare against.
32.5s and 72s were, in their day, the top of the range and, presumably, benefitted from better component selection [cough].
42s, 62s and 92s were built to a lower budget.
If you want to use phono, record buffers and Super-regs it gets mighty crowded in a 72; a 62, for instance, has space to use.
If youre going to change components on a large scale I would suggest that there would be little to call in the long run and may only be down to the differences in track layout.
Not a definitive answer but some things to think about... and of course - money.
Cheers.
I found that the individual boards gave a very quick and easy insight into just what does what inside the preamp.
It is easy to pull a board and modify it and you don't have to work on a mother board.
Some people even have a duplicate set of standard boards to replace and compare against.
32.5s and 72s were, in their day, the top of the range and, presumably, benefitted from better component selection [cough].
42s, 62s and 92s were built to a lower budget.
If you want to use phono, record buffers and Super-regs it gets mighty crowded in a 72; a 62, for instance, has space to use.
If youre going to change components on a large scale I would suggest that there would be little to call in the long run and may only be down to the differences in track layout.
Not a definitive answer but some things to think about... and of course - money.
Cheers.
markzb
pfm Member
Clive
I agree absolutely with fretless. I ended up with a 32. The card swapping feature is a HUGE benefit, at least when you are trying to learn how to fiddle.
You have to remove the mother board in the 42 - 62 preamps to solder out and in whatever you want to change. By the time this is done, and you get it fired up again, it is sometimes difficult for me to remember if the sound is better before or after.
And if it was a small amount, you just aint going to be bothered to change back. Pulling that motherboard out once in a while...no problems. After a frequent while...that task becomes such a pain in the ASS! I have never touched my 42 since.
Speaking from experience, you can then end up with a progressive "slow drift" and end up heading towards less musical satisfaction. I did this with my 42. It ended up having great definition and clarity....noticeable on quick A-B's...but less musical satisfaction resulted.
The late model 32 to me was what I chose.
It has tape buffers which can be useful.
It has extra inputs. Yay!
It is easy to bypass all the boards with wire links applied to the singal input and output pins.
You can do real quick A-B's when you get yourself a spare set of cards to baseline against.( It enables you to easily see that you are drifting away in the wrong direction)
It looks much better then the 42 or 62. IMHO. I used to think otherwise...but having them side by side...32 looks slick.
If your in another country, like me, you can ship them cards to be tweaked by Les without having to ship the whole thing thus saving mucho casho on postage.
I did just that (line cards)...and am really looking forward to having the phono boards marked LW
Anyway Clive..whatever choice...with the help of many here, your bound to be a winner. I think you will have a wonderful time....its just a lot easier with the 32s & 72s
Cheers
Mark
P.S. I live in Malaysia. I have become so hooked on baroque music via LP and am trying to set up a small non profit listening club to promote baroque music here. If any of you see some good condition boxed LP sets that feature period instruments or small scale performances and are bargains....that sorta thing...could you let me know? Thanks. I could send the money to you. Cheers
P.P.S. Looking back at my mistakes with the 42, I remember Les commenting on something here to the effect that you can end up with so much detail none of which has anything to do with music. Andy said a similar thing that your modifying efforts can be an apparent great success...but you end up prefering to watch more telly. The point Im making here is that im beginning to discover that you need to be vigilant that your modifying efforts are improving your systems musical and emotional thruput, and not hifi round earth artifacts.
I agree absolutely with fretless. I ended up with a 32. The card swapping feature is a HUGE benefit, at least when you are trying to learn how to fiddle.
You have to remove the mother board in the 42 - 62 preamps to solder out and in whatever you want to change. By the time this is done, and you get it fired up again, it is sometimes difficult for me to remember if the sound is better before or after.
And if it was a small amount, you just aint going to be bothered to change back. Pulling that motherboard out once in a while...no problems. After a frequent while...that task becomes such a pain in the ASS! I have never touched my 42 since.
Speaking from experience, you can then end up with a progressive "slow drift" and end up heading towards less musical satisfaction. I did this with my 42. It ended up having great definition and clarity....noticeable on quick A-B's...but less musical satisfaction resulted.
The late model 32 to me was what I chose.
It has tape buffers which can be useful.
It has extra inputs. Yay!
It is easy to bypass all the boards with wire links applied to the singal input and output pins.
You can do real quick A-B's when you get yourself a spare set of cards to baseline against.( It enables you to easily see that you are drifting away in the wrong direction)
It looks much better then the 42 or 62. IMHO. I used to think otherwise...but having them side by side...32 looks slick.
If your in another country, like me, you can ship them cards to be tweaked by Les without having to ship the whole thing thus saving mucho casho on postage.
I did just that (line cards)...and am really looking forward to having the phono boards marked LW
Anyway Clive..whatever choice...with the help of many here, your bound to be a winner. I think you will have a wonderful time....its just a lot easier with the 32s & 72s
Cheers
Mark
P.S. I live in Malaysia. I have become so hooked on baroque music via LP and am trying to set up a small non profit listening club to promote baroque music here. If any of you see some good condition boxed LP sets that feature period instruments or small scale performances and are bargains....that sorta thing...could you let me know? Thanks. I could send the money to you. Cheers
P.P.S. Looking back at my mistakes with the 42, I remember Les commenting on something here to the effect that you can end up with so much detail none of which has anything to do with music. Andy said a similar thing that your modifying efforts can be an apparent great success...but you end up prefering to watch more telly. The point Im making here is that im beginning to discover that you need to be vigilant that your modifying efforts are improving your systems musical and emotional thruput, and not hifi round earth artifacts.
Andrew L Weekes
Reverse Engineer
These are by far the easiest as the ability to pull a card, do a quick mod and put it back is a big bonus.
The downside is that space is tight.
For a box with lost of space, but still quite inexpensive, a NAC92 could be a winner, I've not modded one myself though.
Andy.
The downside is that space is tight.
For a box with lost of space, but still quite inexpensive, a NAC92 could be a winner, I've not modded one myself though.
Andy.
RichardH
Bodging pleb
...However, if you run a turntable, you can always pull the phono cards and power them separately in an external box, which will gain some space.
Which leads me on to any tips people have for splitting the power rails to allow seperate power supplies for each board. How have you done it? Cut the PCB and run wires under the PCB back to the DIN socket? Removed the blade connector from each board and run power lines in over the top of the PCB, direct to the board? Does everyone agree that putting the regulators insid the pre is beneficial?
Good point in your P.P.S, Mark.
Which leads me on to any tips people have for splitting the power rails to allow seperate power supplies for each board. How have you done it? Cut the PCB and run wires under the PCB back to the DIN socket? Removed the blade connector from each board and run power lines in over the top of the PCB, direct to the board? Does everyone agree that putting the regulators insid the pre is beneficial?
Good point in your P.P.S, Mark.
I've just disconnected the upstream leg of the 27r and connected the +ve and +ve sense from the Sreg direct to the resistor. I must admit I got a bit fancy and reconnected one resistor to the back of one of each pair of boards so I could make a 'bridge' with a linking wire across and connected the SReg to the link since I'm using one Sreg per pair of boards (soon to change to one each )
C
ced
Guest
Tried it withthe 27R in briefly and it totally dulled the sound- less dynamics clarity and space by quite a way (with onboard regs for each board though). I say get rid of the 27R and don't look back. That said some have recommended keeping it in but I scratch my head as to why. If you're getting a touch of brightness or brittleness replace the electrolytic caps on the boards and that should sort it out. The only reason I can see to keep it in is if you only have say 2 regs powering 6 boards; then you'll get interaction between them.
Either way its easy to try out- desolder the powerrail side of each 27R resistor so it floats and just solder the reg output to either side of the resistor then. Takes about 2 mins of soldering to do an AB comparison.
cheers
Ced
Either way its easy to try out- desolder the powerrail side of each 27R resistor so it floats and just solder the reg output to either side of the resistor then. Takes about 2 mins of soldering to do an AB comparison.
cheers
Ced
Andrew L Weekes
Reverse Engineer
Ced and others,
There are several interactions going on here that need to be understood: -
The 27R provides several functions and they all interact in some way.
It raises the impedance of the power supply at frequencies where the capacitor following it is not of sufficiently low impedance - this is generally a bad thing.
BUT, the relevance of low impedance is related to two things, how constant the current demand of the preamp is and the number of circuits being powered and their interactions.
Intuitively the constant current sinks will work better at LF, so the higher impedance down there may not matter quite as much as first thought.
BUT again there's more
You also have to consider the effect of the local capacitors on the regulators. In the case of super regs adding extra output capacitance degrades certain parameters, so there's a balancing act here between improving rail impedance by lowering the R (which does improve sound) and applying too much cap load directly to the regulator, worsening it's performance.
This then starts to determine the values used here, with an LM317 it's performance starts dropping off at a very low frequency (circa 100Hz). Augment this with an RC that's improving as frequency rises and furthermore prevents interactions between the different stages of the amp and things may work better this way.
With the super reg's things are different, it's performance is maintained to a higher frequency before it degrades and starts from better point anyway. In this case there is some advantage to reducing the series R, whilst lowering the rail capacitance to form a higher rollof, reducing the sonic signature of the capacitor from the end result.
It even allows the rail cap to change to one of far higher quality, with great sonic reward.
From my own perspective, when using 1 reg / circuit I would dramarically reduce the series R and the C, but if powering more than 1 circuit / reg I would use a modified RC, determined for a specific application.
For those who don't already have this info, feel free to mail me and I will offer advice privately.
Re: Mark's P.S. I agree here, time is the great determinant to whether things are better, but I disagree more than ever about the flat / round thing. Often changes seem to improve both elements and you can have your round earth elements alongside your flat earth bits. Now we always want the FE as the primary elements, but when you add the two together, as opposed to the diametrically opposed camps that so often appear, it makes for an incredibly involving and engaging experience.
For example the ability to hear the acoustic around the recording, whether artificial or real, does not have to be some artificial element added to the music, but can be due to a very real increase in low-level resolution that brings to the fore previously hidden information.
This gives very real insights into the nature of the recording and the music, you get lots more details and clues about the music, the byproduct of which also manifests itself as what some would refer to as round earth stuff.
I don't listen to this and think 'air', 'space' or whatever, but think how much more accurate and convincing things sound when these elements aren't to the exclusion of the underlying musical elements of pace, rythm and timing.
Andy.
There are several interactions going on here that need to be understood: -
The 27R provides several functions and they all interact in some way.
It raises the impedance of the power supply at frequencies where the capacitor following it is not of sufficiently low impedance - this is generally a bad thing.
BUT, the relevance of low impedance is related to two things, how constant the current demand of the preamp is and the number of circuits being powered and their interactions.
Intuitively the constant current sinks will work better at LF, so the higher impedance down there may not matter quite as much as first thought.
BUT again there's more
You also have to consider the effect of the local capacitors on the regulators. In the case of super regs adding extra output capacitance degrades certain parameters, so there's a balancing act here between improving rail impedance by lowering the R (which does improve sound) and applying too much cap load directly to the regulator, worsening it's performance.
This then starts to determine the values used here, with an LM317 it's performance starts dropping off at a very low frequency (circa 100Hz). Augment this with an RC that's improving as frequency rises and furthermore prevents interactions between the different stages of the amp and things may work better this way.
With the super reg's things are different, it's performance is maintained to a higher frequency before it degrades and starts from better point anyway. In this case there is some advantage to reducing the series R, whilst lowering the rail capacitance to form a higher rollof, reducing the sonic signature of the capacitor from the end result.
It even allows the rail cap to change to one of far higher quality, with great sonic reward.
From my own perspective, when using 1 reg / circuit I would dramarically reduce the series R and the C, but if powering more than 1 circuit / reg I would use a modified RC, determined for a specific application.
For those who don't already have this info, feel free to mail me and I will offer advice privately.
Re: Mark's P.S. I agree here, time is the great determinant to whether things are better, but I disagree more than ever about the flat / round thing. Often changes seem to improve both elements and you can have your round earth elements alongside your flat earth bits. Now we always want the FE as the primary elements, but when you add the two together, as opposed to the diametrically opposed camps that so often appear, it makes for an incredibly involving and engaging experience.
For example the ability to hear the acoustic around the recording, whether artificial or real, does not have to be some artificial element added to the music, but can be due to a very real increase in low-level resolution that brings to the fore previously hidden information.
This gives very real insights into the nature of the recording and the music, you get lots more details and clues about the music, the byproduct of which also manifests itself as what some would refer to as round earth stuff.
I don't listen to this and think 'air', 'space' or whatever, but think how much more accurate and convincing things sound when these elements aren't to the exclusion of the underlying musical elements of pace, rythm and timing.
Andy.
Ron The Mon
Location: Detroit
Andy,
Fantastic post above! Not only very informative from a DIY perspective but very well written.
I find it depressing when reading many posts at pfm that they are rushed with poor verbiage, spelling, etc. Yours are always a good example.
Every time I do a DIY project now, I always ask the question, "What would Andy Weekes think of the quality of this?". You've mentioned before that photos of poor DIY work do a disservice to our hobby. I would like to add that poorly written posts also do a disservice to our hobby.
BTW, instead of "Lifetime Underachiever", how about "Slowly but Surely Achieving My Goals"?
Richard asked:
I have simply unsoldered the 27-ohm resistor's input end from the board and soldered the PS right to it.
To take it a step further, it's worth noting that the Naim phono stages are actually two separate circuits. Naim does it a bit different than most by actually amplifying the RIAA treble reduction and bass boost separately. In the MM boards, you can simply get an additional 27-ohm resistor and cut-n-peel the foil on the board. The improvement is significant.
I have yet to try this with satisfaction to the MC boards as there are more complications with the power supply input coupled with the filter Naim uses. After reading the above posts, it may be probable that local regulators with separate grounds, the right capacitors, and a 27-ohm resistor might do the trick. Sounds like a good Winter project. How do I get those Super Regs?
Ron The Mon
Fantastic post above! Not only very informative from a DIY perspective but very well written.
I find it depressing when reading many posts at pfm that they are rushed with poor verbiage, spelling, etc. Yours are always a good example.
Every time I do a DIY project now, I always ask the question, "What would Andy Weekes think of the quality of this?". You've mentioned before that photos of poor DIY work do a disservice to our hobby. I would like to add that poorly written posts also do a disservice to our hobby.
BTW, instead of "Lifetime Underachiever", how about "Slowly but Surely Achieving My Goals"?
Richard asked:
I have simply unsoldered the 27-ohm resistor's input end from the board and soldered the PS right to it.
To take it a step further, it's worth noting that the Naim phono stages are actually two separate circuits. Naim does it a bit different than most by actually amplifying the RIAA treble reduction and bass boost separately. In the MM boards, you can simply get an additional 27-ohm resistor and cut-n-peel the foil on the board. The improvement is significant.
I have yet to try this with satisfaction to the MC boards as there are more complications with the power supply input coupled with the filter Naim uses. After reading the above posts, it may be probable that local regulators with separate grounds, the right capacitors, and a 27-ohm resistor might do the trick. Sounds like a good Winter project. How do I get those Super Regs?
Ron The Mon
RichardH
Bodging pleb
Ron, I second your comment on Andy's post above, and your general comments on the importance of spelling, verbiage etc.
I'm afraid my previous comment is an example (rare in my case, I hope) of a poorly worded post - when I said "splitting the power rails to allow seperate power supplies for each board", I was actually meaning the splitting of the power rail on a single phono board to allow for supplying each half of the circuit with a separate supply, as you mentioned as your winter project. Apologies!
I'm currently at the stage with my phono board twiddles where they each have a single power rail feeding them from a hicap clone. I'm currently building another power supply which will hopefully end up being a 4 channel supply just for the phono cards. Any pointers on where to split the circuit (MC in my case) so that each half can have it's own supply would be appreciated - perhaps we should all use the PDF from Neil McBride's site as a common reference. Your comment re seperate earths is interesting too.
I am also intending to try removing the regulator section from the MC card once I have locally placed regulators.
I think we're starting to get to the point where this discussion is best taken to another thread!
Richard
I'm afraid my previous comment is an example (rare in my case, I hope) of a poorly worded post - when I said "splitting the power rails to allow seperate power supplies for each board", I was actually meaning the splitting of the power rail on a single phono board to allow for supplying each half of the circuit with a separate supply, as you mentioned as your winter project. Apologies!
I'm currently at the stage with my phono board twiddles where they each have a single power rail feeding them from a hicap clone. I'm currently building another power supply which will hopefully end up being a 4 channel supply just for the phono cards. Any pointers on where to split the circuit (MC in my case) so that each half can have it's own supply would be appreciated - perhaps we should all use the PDF from Neil McBride's site as a common reference. Your comment re seperate earths is interesting too.
I am also intending to try removing the regulator section from the MC card once I have locally placed regulators.
I think we're starting to get to the point where this discussion is best taken to another thread!
Richard
Andrew L Weekes
Reverse Engineer
Ron,
Thank you for the kind words!
Your suggestion of splitting the phono stages, adding an additional RC is exactly what Naim do to the Prefix.
This is the 'improved power supply' arrangement. They also use better quality caps for the prefix (the gold ones used in the more expensive kit).
Unfortunately I'm out of stock of reg's 'til the new year - I'm taking a little break for Xmas to catch up on some outstanding tasks I need to finish.
Andy.
Thank you for the kind words!
Your suggestion of splitting the phono stages, adding an additional RC is exactly what Naim do to the Prefix.
This is the 'improved power supply' arrangement. They also use better quality caps for the prefix (the gold ones used in the more expensive kit).
Unfortunately I'm out of stock of reg's 'til the new year - I'm taking a little break for Xmas to catch up on some outstanding tasks I need to finish.
Andy.
Patrick Dixon
Imagineer
Shit, better not post any more pics!
Ron The Mon
Location: Detroit
Richard,
I worded my previous reply the way I did because I thought you meant splitting one board to two circuits ala my project.
The Naim phono boards have changed over the years. The circuits essentially remain the same but what has changed is the layout. On the older boards the components are arranged close to the schematic. Later versions have the components rearranged such that component leads and board foil paths are shorter lengths (less RF, better sound).
In other words, you need to find the point on the schematic where they need to be separated. On my MM project, it was simple as my MM cards (version 1) only needed one piece of foil cut out. The only other thing is to add a second cap across ground and the second power supply rail on the board.
As I alluded to in my above post, I'm not sure if the RC network in the stock MC boards are necessary if local regulation is used. Ideally, you do need the grounds separate. The phono boards use a "star" earth so it's relatively easy to cut the copper foil down the middle. Andy mentioned that power rail caps affect the regulators. Shared grounds will affect the 0-volt reference for the regulators too. Unfortunately working with a finished product like a Naim MC phono card makes that a challenge. Considering I have mine hardwired inside my LP12 with a bottom board makes it near impossible. That's why I said "Winter" project.
Ron The Mon
I worded my previous reply the way I did because I thought you meant splitting one board to two circuits ala my project.
The Naim phono boards have changed over the years. The circuits essentially remain the same but what has changed is the layout. On the older boards the components are arranged close to the schematic. Later versions have the components rearranged such that component leads and board foil paths are shorter lengths (less RF, better sound).
In other words, you need to find the point on the schematic where they need to be separated. On my MM project, it was simple as my MM cards (version 1) only needed one piece of foil cut out. The only other thing is to add a second cap across ground and the second power supply rail on the board.
As I alluded to in my above post, I'm not sure if the RC network in the stock MC boards are necessary if local regulation is used. Ideally, you do need the grounds separate. The phono boards use a "star" earth so it's relatively easy to cut the copper foil down the middle. Andy mentioned that power rail caps affect the regulators. Shared grounds will affect the 0-volt reference for the regulators too. Unfortunately working with a finished product like a Naim MC phono card makes that a challenge. Considering I have mine hardwired inside my LP12 with a bottom board makes it near impossible. That's why I said "Winter" project.
Ron The Mon
Ron The Mon
Location: Detroit
Andy,
Have you (or anyone else here) updated your Prefix? I'd especially be interested in a before and after photo though a description would suffice.
Ron The Mon
Have you (or anyone else here) updated your Prefix? I'd especially be interested in a before and after photo though a description would suffice.
Ron The Mon
Ron The Mon
Location: Detroit
Patrick said
I wasn't singling out anyone about photos. In fact, the worst pink fisher photo shows better work than some of the best I've seen on other dedicated DIY sites.
Even though I haven't seen it written here explicitly, most of us understand the importance of good quality components, wire, soldering, and layout to the "flat earth" sound. Most DIYers on other sites believe that just copying a schematic gets you the same sound.
Also worth noting is pink fishers have the safest DIY hi-fi I've seen on the net.
Ron The Mon
I wasn't singling out anyone about photos. In fact, the worst pink fisher photo shows better work than some of the best I've seen on other dedicated DIY sites.
Even though I haven't seen it written here explicitly, most of us understand the importance of good quality components, wire, soldering, and layout to the "flat earth" sound. Most DIYers on other sites believe that just copying a schematic gets you the same sound.
Also worth noting is pink fishers have the safest DIY hi-fi I've seen on the net.
Ron The Mon
Andrew L Weekes
Reverse Engineer
First, I was wrong about the prefix PSU split, the extra caps are the 47u feedback caps in the signal path - I've never looked at mine, only a photo of a board!
It's still a viable option though.
Courtesy the Naim Audio Short Guide
As for the updates, I do plan to have mine done, but only when I have a standby alternative for whilst it's away.
To be honest I really want to design my own phono stage using a FET front end - these offer potentially better performance and should bring dramatic reductions in RF sensitivity, but obtaining the FET's is the hardest challenge in the UK, at sensible money.
Another job for the list of stuff to make and do
It's still a viable option though.
Courtesy the Naim Audio Short Guide
As for the updates, I do plan to have mine done, but only when I have a standby alternative for whilst it's away.
To be honest I really want to design my own phono stage using a FET front end - these offer potentially better performance and should bring dramatic reductions in RF sensitivity, but obtaining the FET's is the hardest challenge in the UK, at sensible money.
Another job for the list of stuff to make and do
Andrew L Weekes
Reverse Engineer
Anyone looked inside their Prefix?
Looking at that picture above, I've noticed there's 6 tantalum caps on the board.
4 will be input / output coupling - any idea what the other two are (they are at the bottom of the pic, close to the SNAIC output wiring)?
Andy.
Looking at that picture above, I've noticed there's 6 tantalum caps on the board.
4 will be input / output coupling - any idea what the other two are (they are at the bottom of the pic, close to the SNAIC output wiring)?
Andy.