| Deoreo |
Hello,
I just picked up these two items, but cannot find
much information about them. Ideally, I would like
some basic operating instructions, and original
specifications. A couple particular questions -
there are two main outputs,is one pair inverting?
In order for me to get the preamp to work with a
stereo amp I must use the right output from one
set, and the left output from the OTHER set, why?
There are two phono inputs - do they both offer the
same amount of gain, or is one dedicated to MC use
with the M1 unit? The quality of components, and
construction appear to be of very high quality. Are
there any details on the design topology, and components
avaliable? Would this be a good preamp to check over,
and replace any out of spec. items, or should I spend
money on a more current design (coda maybe)?
Finally, this preamp dates from 1977, how long was it
in production, and were very many of them produced?
Lots of questions, I know, but I believe this is a
Nelson Pass designed product, so I hope I came to the
right place!! :) Any help would be great,
Steve |
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| roddyama |
:cop:
Hi Steve,
I thought you'd have a better chance at an answer here in the Pass Labs forum since Mr Pass did own Threshold at that time.
:cop: |
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| Nelson Pass |
Actually, it sounds like it has been modified or is broken.
For help and information, I recommend Jon Soderbeg
vintageamp@earthlink.net |
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| roddyama |
Nelson,
They're like having kids, even though they have long since left the nest, they will always be your kids.:) |
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| Deoreo |
Thanks for the information, I was unsure
if Jon did work on preamps, so I started here.
The pre. works and sounds good, so I bet since
the outputs are not correct this is probably from
a past service - the filter caps in the power supply
were replaced - I'll bet the output jacks were
removed from the chassis and replaced incorrectly.
Thanks again for the info.
Steve |
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| yeoldestereo |
Just had Jon Soderberg of Vintage Amp go through the NS 10 I have.
Jon advised this was a prototype NS 10, not the standard production NS 10.
Was fully operational when I received it, but being some 28 years in service, decided to send to Jon for a check out and any needed service. Replaced all non film caps and additional work done of the modules. Sounds fabulous, great build quality, as we have come to expect.
Connected to a Threshold 400A power amp. Amazing to me that after 47 years in this hobby, I keep going back to the early Threshold gear. For me there is just something special about this gear, and now when I can afford most high end gear, its become back to the future - Kinda weird in some respects.
Anyway I highly recommend Jon for any and all service work on Threshold products. Great work,price is right, and knows what he is doing. Hard to find today. |
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| Nelson Pass |
I'm very pleased to hear that the NS10 is still working out for
you. The M1 remains a unique circuit that no one seems to
have copied, much like the I/V converter of the D1.
Also, I'm pleased to hear good things about Jon, as we continue
to recommend him for Threshold service issues. |
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| yeoldestereo |
Nelson, hard to believe that someone hasn't ripped off this design, as your designs have been ripped of more times than I can remember in the past 30 years or so.
Jon has worked on several Threshold items for me and have always been most impressed with his work. I recommend him very highly and have sent him many clients.
Forgot to tell Jon to replace the Volume pot. But I can handle that chore. Any ideas on which one to use? I have a Noble 50K around here somewhere, use that or something else?
For me the NS 10 is just magical. Perhaps not everyones cup of tea, but for me and quite a few others it remains after all these years a bench mark pre amp. As the 400A power amp remains a bench mark power amplifier. |
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| lumanauw |
| quote: | | For me the NS 10 is just magical. |
NS 10 is known as the first Threshold preamplifier. I don't know much about Threshold history (but I can ask Jacco :D)
From several Threshold preamp schematic floating around here, like NS10, Fet10, SL10, I REALLY suspect that NS10 is the best sounding one (even it is the first released).
I make a "back-engineered" NS10 preamp using the schematic provided by NP (no values), and use the first transistor with Jfet (K30), the sound is MMMAAARRRVVVEEELLLOOOUUUSSS.
I think about it for several weeks. Why? It is a single transistor system (not differential), and the more you look at the schematic, you will realize that it is essentially a CFP with gain (like JLH). CFP is considered 1 stage, right? So, it is 1 stage, with good linearity (there is feedback, current feedback-to emitors, very fast), no harmonic canceling. It's hard to have high order harmonics with this approach, but you can get super detailing and very fast response. What else do you want? |
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| choky |
| quote: | Originally posted by lumanauw
NS 10 is known as the first Threshold preamplifier. I don't know much about Threshold history (but I can ask Jacco :D)
From several Threshold preamp schematic floating around here, like NS10, Fet10, SL10, I REALLY suspect that NS10 is the best sounding one (even it is the first released).
I make a "back-engineered" NS10 preamp using the schematic provided by NP (no values), and use the first transistor with Jfet (K30), the sound is MMMAAARRRVVVEEELLLOOOUUUSSS.
I think about it for several weeks. Why? It is a single transistor system (not differential), and the more you look at the schematic, you will realize that it is essentially a CFP with gain (like JLH). CFP is considered 1 stage, right? So, it is 1 stage, with good linearity (there is feedback, current feedback-to emitors, very fast), no harmonic canceling. It's hard to have high order harmonics with this approach, but you can get super detailing and very fast response. What else do you want? |
hm-I know my sh#t with tubes,just because I put more than just few years in passion for various tube stages and topologies .....but I have not equal knowledge (ie - feel ) with transistors or I just have not enough time to use same approach (reading,lookin' thinkin' , buildin' and tweakin.... ;) ) .........
can you share that "back-engineered " schmtic with us (me) ?
dumb Choky |
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| lumanauw |
If you are a "dumb", then I'm the "dumber":D
You got the blind NS10 schematic in your hands?
If you do, then here's what I do.
-First, I use symmetrical power supply, +/-25V with 0 gnd. So, I do not use R5, R6, R7 in the schematic. If you got only single supply 0/50V, then R7=200k, R5=R6=100k, C4=47uF.
- R13=20k potentiometer, for volume adjust. The wiper goes to left of C1 (470nF MKT), R12 is moved after C1. The bottom of VR13 goes to ground via additional 1k resistor, the upper is fed with input.
-The right of C1 connected to voltage divider (R6-R7), thus to R12=1k, and this R12 connects to gate of Q1, or if you got symmetrical supply, you can put the right of C1 with 100k to gnd (0V).
-R12=1k, is placed after the voltage divider (that is after C1) and before the gate of Q1 (2sk30y).
-I also put 470pf WIMA from gate to drain of Q1 (2sk30y).
-R4=10k, Q2=mpsA92, Q3=mpsA42, R8=470ohm, C2=C3=22uF non polar elko. R1=10k, R2=2k2 (makes gain=10k/2k2), R9=2k7 1/2watt.
- put base stopper at base of Q3, I use 1k there.
- R3 is for adjusting DC output, it is about 100k-470k, depends what device you use for Q1. I myself don't mind DC offset at left of C2, I got only 0V5 there, so I don't use R3. Sounds better without R3, even it has DC.
-R10=100ohm, R11=100kohm.
I tried various devices for Q1, MPSA06, MPSA42, 2n5401, BC550C, BC546, they sound differently. The best sound is 2sk30y (you can also buy 2sk30gr suffix). |
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| tmblack |
Hey Choky,
what's your favorite tube preamp design?
I have some 6922 and 6SN7 still in box.
Tom |
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| tmblack |
lumanauw,
I see a single stage (Q1) with level shifter followed by power stage (Q3). Very clever like JLH.
But what do you mean leave out R3?
This connects Q1 emitter to gnd and seems to be needed in my simulation.
If its as good as you say I will have to try it!
Tom
EE |
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| lumanauw |
Hi, Tmblack,
I don't invent the schematic, it is NP who make it. :D So, I really don't know the values of each component and its main function.
From my backengineering (I don't use SIM, I go straightly to the real thing), it seems R3 is only for determining DC point at output, and in my real cct, it works without R3 at all, but it has slight DC. Sounds better too without R3.
Without R3 : Example Q1=bipolar with VBE=0V6. The current flowing through Q1 is 0V6/R4. I use R4=10k, so the current flowing is 6E-5A. Without R3, this current will flow from emitor of Q1 to R1 then to R9. This means if the base of Q1 is hold at 0V, and R4=R1=10k, then at the output (before C2) it will be -1V2. |
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| choky |
| quote: | Originally posted by tmblack
Hey Choky,
what's your favorite tube preamp design?
I have some 6922 and 6SN7 still in box.
Tom |
hehe-just click at button bellow...
look for WOT
easily made with one 6922 per channel,with both sections paralleled
unsurpassed type of music presentation,if not anything else ...
:clown: |
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| tmblack |
Hi Lumanauw
you are correct, good job at figuring out the values.
I plan on trying it and Choky's preamp.
Tom
EE |
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| Nelson Pass |
Here's the basic NS10 circuit.
Since the M1 is basically the same as the the SL10 MC input
stage, you can see it on the SL10 schematic which is posted
at www.passlabs.com/np |
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| choky |
| quote: | Originally posted by tmblack
Hi Lumanauw
you are correct, good job at figuring out the values.
I plan on trying it and Choky's preamp.
Tom
EE |
like I say-use ECC88 or 6922,both sections in paralel;
Ua around 100V on top of your OPT ( OC3 is pretty handy there,even if I dont know exact current capacity in this moment (little bookie is not near me) so you;ll need maybe even two OC3 per channel ......
I suggest that you use grid stoppers of circa 100 ohms per each grid, both anodes tyed together with ferite bead right at base -as must ;I also always put that bloody 1M resistor from grid to ground,just because I can't trust to any pot to hold grid at gnd potential forever .......
both cathodes tye together and use one mutual resistor in range 43 to 51 ohms ,and you'll be in current range of some 25 to 30 mA per channel ;some 1000 micro/6V sh#ty BG cap or other (choice is yours) across cathode resistor is your choice also
you can also try NiCD (at least 4Ah/1V2 ,NiMH also) in cathode ( as battery charger instead of preamp hehe) but be prepared that some cells are bad for that use-oscillations can arise if you use "bad " accu .....
in final breadboarding try to rotate just secondary leads (rotate-swap, whatever you call it) -just because in one position capacitive parasitics in OPT are smaller than in other position.
loading secondary with some resistor can be usefull also (sonically wise) but that depends solelly of your particular OPT.....
I hope that some of this will help ....... |
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| choky |
| quote: | Originally posted by Nelson Pass
Here's the basic NS10 circuit.
Since the M1 is basically the same as the the SL10 MC input
stage, you can see it on the SL10 schematic which is posted
at www.passlabs.com/np |
:clown:
just rename that *.zip to *.gif |
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| lumanauw |
In this NS10 schematic, there is hidden another elegance, NP's style. Look at the arrangement of Q2, Q3, R8. If you look at it, there's nothing special, just ordinary connection. But it really clever. This arrangement makes the Q2 works towards a CCS with value of 0V6/R8. Q2 doesn't experience current fluctuation, it works in steady current, even the output current is fluctuating with signal (because the load is Resistor, R9).
Look at the attached schematic.
The designer wanted to have steady current for Q53's load. He put Q8, D15, D16, R104, R110, Q42 (that's 6 components) for achieving that effect. NS10 only puts Q2,Q3,R8 (3 components) to have the same effect.
The final load is the same, plain R, R9 for NS10 and R112 for the attachment.
Beautifull, right....... |
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| choky |
| quote: | Originally posted by lumanauw
In this NS10 schematic, there is hidden another elegance, NP's style. Look at the arrangement of Q2, Q3, R8. If you look at it, there's nothing special, just ordinary connection. But it really clever. This arrangement makes the Q2 works towards a CCS with value of 0V6/R8. Q2 doesn't experience current fluctuation, it works in steady current, even the output current is fluctuating with signal (because the load is Resistor, R9).
Look at the attached schematic.
The designer wanted to have steady current for Q53's load. He put Q8, D15, D16, R104, R110, Q42 (that's 6 components) for achieving that effect. NS10 only puts Q2,Q3,R8 (3 components) to have the same effect.
The final load is the same, plain R, R9 for NS10 and R112 for the attachment.
Beautifull, right....... |
huh-you confused me for a moment...then I realize that attached shmtc is just for comparison......
couldn't agree more with you about elegancy......
simple things are most hard to make it right........ |
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| tmblack |
Have a look at this review:
http://forum.audiogon.com/cgi-bin/f...14&zzlFerrari&&
Amazingly low distortion and speed for such a simple design but should we expect anything less from NP?
Can you measure the specs of your re-engineered unit to see if they are similar?
Tom
EE |
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| yeoldestereo |
That review is from yours truly. Have always thought that this NS 10 from Threshold, was often under appreciated and over looked as a genuine break through in solid state preamps.
By the look of this thread it appears that there is a renewed interest in the NS 10.
With the work that Jon Soderberg has done on the NS 10, it will serve my needs for the foreseeable future. The overall sonic signature of the NS 10 is incredible. And to think that this was NP first preamp is nothing short of a tour de force.
If you can find one of these, the search is worth the effort. In 47 years have had a lot of amps and preamps including other Threshold pre amps. But I gotta tell'ya the NS 10 is something special, although it came out in 1976 or 1977 or so. |
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| lumanauw |
Hi, Tmblack,
| quote: | | Can you measure the specs of your re-engineered unit to see if they are similar? |
I don't know how to measure those specs like in the review. Can you show me how to measure those numbers?
From the review, yeoldstereo = ferrari?
This NS10 is special. If you look for a transistor based preamp that sounds like tube, this is the one, because it is a singleton system, not a differential system. That's why the sound is more "complete" like the review said.
If you have heard this preamp, and go back to ANY (yes, I mean ANY) preamp that based on differential system, you will feel that something is "missing" in the differential based system (compared to this singleton based system). But remember, the choice for Q1 is important, it dictates what pattern of the harmonics, by the input/output transfer function of this Q1. I like Jfet better in the place of Q1.
Another important aspect : FAST. It has feedback to emitors, current feedback, it's much faster than feedback to opposite base (inverting input in differential system). This feedback ensures linearity (if you compare it to non-feedback system)
It consist only a single stage, make it faster and have minimal phase shift. No wonder the review said the response is up to Mhz number. If the frequency response is up to Mhz numbers, the phase shift within the first 20khz bandwith should be very small.
Try this test. Play this preamp to the fastest musical programme you have. Maybe a heavy classical full orchestra, maybe a heavy jazz with that big bass guitar with the fastest finger playing it, maybe the fastest piano+cymbal combo you have, or anything you can find. This preamp will pass all that musical test with excellent grade. You can hear each musical instrument clearly without mud, no matter how fast the whole music is. |
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| tmblack |
| quote: |
I don't know how to measure those specs like in the review. Can you show me how to measure those numbers?
|
You need a radio frequency generator and at least 50Mhz oscilloscope
I would think to measure propagation delay and freq. response of real unit but my simulation says it only goes to a Mhz or 2.
But I can't buy the 2SK30. How about 2N5458 or 2N3819?
I can't get the output transformer for Choky's preamp, so maybe an actual tube like 6922 would make a real sweet replacement for Q1?
Regards,
Tom
EE |
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| yeoldestereo |
To truly appreciate the NS 10 listen to the early Telarc digital to LP recordings, although most of these are in CD format now, the LPs were truly over the edge recordings. Most of these were done in late 70s and at that time provided a glimpse into the then coming digital medium.
Theshold supplied many preamps and power amps to Telarc for these recordings, as they were the only products at that time that were capable to handle these extreme recordings.
The Telarc LPs were cut at 1/2 speed in pure digital and transferred to analog LP. Absolutely no compression,limiting or editing was used in this process. The muscians had to be right on from the start and play without fault. Several of the early Telarc LPs won grammys for their technical achievement. I was with CBS at the time and this type of recording caught us of guard and soon after we started developing the digital to LP process.
When the early Threshold gear made its debut, many of the High End salons of the time used these Telarc recordings to demo the Threshold product.
One such was the Frederick Fennel Telarc 5038. This is a glorious piece of work not only to listen to, but as an use to evaluate a system. It is difficult to play properly and will tax all components to their maximum response. Picture of this LP appears with this post. This album has powerful low and high frequency transients and I urge due caution in playing this for the first time. Over the years I have seen this album destroy a lot of gear due to lack of caution. If you find this LP, be most careful and use very moderate volume settings, till you are comfortable that your gear is capable of the demands placed upon it by this recording. At times this recording is frightening, the hair will stand up on your neck and you will swear the anvil strikes and snare drum passages are about to literally come through the speakers!
However a properly operating Threshold NS 10 will handle this piece like a knife through hot butter, with that being said this recording has a way of exposing other weakness's in the audio system.
Yep yeoldestereo is Ferrari on Audiogon. Been in this hobby since 1957 when it was kits,tubes and mono. I haven't done any building or modding for quite some time. In fact last kit I did was a Hafler DH200 for a friend of mine and that was 1984 I think.
Without question the membership here is far more gifted than I when it comes to actual execution of these designs. With that being said my hat is off to the respondents of this thread. In a short time now I have learned a lot on the technical side.
My best to all of you. |
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| mlloyd1 |
this Leach design preamp from many years ago had a non-differential line stage:
http://users.ece.gatech.edu/~mleach...eb77article.pdf
i wonder how it sounds in comparison; i used a duplicate differential stage as my line dirver when i built this years ago.
mlloyd1
| quote: | Originally posted by lumanauw
Hi, Tmblack,
...This NS10 is special. If you look for a transistor based preamp that sounds like tube, this is the one, because it is a singleton system, not a differential system. That's why the sound is more "complete" like the review said.
... |
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| Nelson Pass |
| quote: | Originally posted by yeoldestereo
That review is from yours truly. Have always thought that this NS 10 from Threshold, was often under appreciated and over looked as a genuine break through in solid state preamps. |
By the photo I see that it was indeed one of the originals, as the
later units had blue anodizing on the circuit shields and did not
also have a mu-metal case on the transformer.
The published specs: |
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| lumanauw |
| quote: | | But I can't buy the 2SK30. How about 2N5458 or 2N3819? |
I've also tried K117 Jfet for Q1. I still like K30 better in place of Q1.
You can try various devices for Q1, they will sound different. Most Jfet or bipolar will fit, because the voltage is only +/-25V, Q1 willl only experience half of that or 25V. |
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| choky |
| quote: | Originally posted by tmblack
I can't get the output transformer for Choky's preamp, so maybe an actual tube like 6922 would make a real sweet replacement for Q1?
Regards,
Tom
EE |
?
nope with just 2x25V
in fact-I think that will be just hopeless mix from two good approachs;
key factor in WOT preamp is :
1. OPT approach- meaning that signal energy preservation is No.1 (or primary thing-if you wish )
2. decent active element (even EC8020 if you can find ,or triode wired 7788) with absolute minimum of surounding elements , and
3.gorgeous supply,both for anode and for heating
seems to me that NS10 is simillar type of jewell, and it's sacrilege to spoil it with sort of bstrdizing,if you know what I mean ;)
and now-only if Emperor of latheral thinking think to say something about Lumanauw's component values.............. :clown:
contrary to my usuall approach to every seen schmtc- I don't feel any urge to change anything in Emperor's values or ideas ,even on microplan..........except his sneakers,maybe. ...... ;) |
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| choky |
RIAA part ?
:magnet:
Master?
:bawling:
ps. I just even don't need to make NS10 , I just love to droooooooool......
:clown: |
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| yeoldestereo |
Many thanks to Nelson Pass for posting the published specs on the NS 10.
My first NS 10 was a production model along with the 400A amp.If memory serves me correct the production NS 10 had a somewhat different circuit board, or at least it was different in color. This NS 10 prototype has the blue and gold circuit board and the previous one had,if I remember right had a yellow and gold circuit board. Not sure what the difference may have been.
Anyway had these until about 1981 when the house was broken into, so replaced these with another 400A, but by then the NS 10 and SL 10 was out of production. So went with the FET 2 for the preamp. The 400 A was very probably one of the last produced,but dealers was able to get one new.
This occupied my system for about 16 years or so, until another break in. Then tried several other amp, preamp combinations.Until I found a CM Labs 914 power amp and coupled that to a Forte Model 2 preamp, was the system until the world wide web tied us together.
Most of you will not remember CM Labs. It was a very small high end manufacturer in Danbury,CT. So no need to elaborate on CM Labs, but nonetheless made some terriffic power amps. Their pre amps on the other hand left a lot to be desired.
So recently I have been able to get back to what has made me really happy and that is the NS 10 and 400A. So the 400A I have now is another late production unit and to my surprise was able to find a NS 10 prototype. So I am set for a very long time. Being 62 now this should be last stop.
I will have to say that while the FET 2 preamp was very good, to my ears it fell short of the NS 10.
Many thanks to Nelson Pass for the extraordinay build quality on these Threshold products. These are true lifetime products, that only require minimal service some 20 years down the road. Damn few products built during that same period of time, have the outright longevity of the early Threshold gear. And it appears from these posts that these designs remain cutting edge to this day.
Like I said back to the future and once again I have that super silly grin on my face listening to this system.:D |
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| tmblack |
I don't know if NP was ripped off or not but these Naim preamp circuits look a lot like the NS10.
I was thinking of replacing R9 with a CCS and look at what someone already did:
http://www.acoustica.org.uk/t/naim/preamps.html
Comments?
Tom
EE |
|
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| yeoldestereo |
Apparently on this side of the pond, the Mundorf Caps are the latest buzz in caps.
With the apparent cancelled production of Black Gate Caps, are the Mundorf the next generation of caps to replace the Black Gates?
Anyone have any info or ideas on this?
Or better yet anyone here used the Mundorf Caps? |
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| apassgear |
| Someone interested on cloning the NS10?:D |
|
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| jacco vermeulen |
| quote: | Originally posted by apassgear
Someone interested on cloning the NS10?:D |
Excellent suggestion, Master Tony. |
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| lumanauw |
| NS10 is from 1970's, from what year is that for Naim? If Naim uses the same topology, this should add proof of how good NS10 is :D |
|
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| tmblack |
Naim NAC 42 1979-1985
Naim NAC 72 1989-2000
How does NS10 sound with CD source?
And what is good power amp to use with it?
Tom
EE |
|
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| yeoldestereo |
The NS 10 sounds fabulous with a CD Player. This was somewhat of a surprise to me. I knew from the start that the NS 10 was going to be great with analog sources, that was a given.
But to find out that it excels as well with digital sources was a suprise. But I guess I shouldn't have been, knowing the pedigree.
I am not a big fan of digital so I don't spend a lot in this area.The current CD Player is a Onix XCD88, which is same as the Music Hall 25 CD Player and use a Sony MD 501 Player/Recorder.
The NS 10 can handle the digital components with extraordinary ease that most preamps past or present have difficulty in presenting a liquid signature from the digital medium.For some reason it takes the edge off the digital signature. I can't remember how many times I thought I had an LP on only to realize it was a CD.:cool:
Using a Threshold 400A with the Threshold NS 10, overall I could not be more pleased with this combination.:D
Without question in my mind, the Threshold NS 10 is one of those ageless gems from the mind of NP. That pretty much says it all.:nod: |
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| yeoldestereo |
If the Naim in the link posted above appears to be a NAC 32.5,released in 1985. At $1,145.00 new in USD, now worth about $320.00 USD, used.
Other than that can't find much info on it. Doubt if it is worth the time and effort to do the mods though. |
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| lumanauw |
Everyday we hear a differential based system. NE5532, 4558, TL072, all opamps inside TV set, Compo, CD player, most commercial products, even HiFi equipment is using differential system.
You should listen to this NS10 design. No matter what source you have (CD, Tuner, PH, etc) and no matter what amp you use after that, as long as you are familiar with the sound. You will hear something in the music that you never heard all this time :D |
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| steenoe |
| quote: | | If the Naim in the link posted above appears to be a NAC 32.5,released in 1985. At $1,145.00 new in USD, now worth about $320.00 USD, used. |
Any idea what the NS10 is worth?
Steen. |
|
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| lumanauw |
| If Mr.Pass don't give the values of components, this NS10 will be like antique SOTA. Will be more expensive (maybe even compared to the "new" price) as time passes by. :D |
|
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| yeoldestereo |
The NS 10 broke out at around $1,295.00 if memory serves me correct. They now bring an used average price of about $400.00 depending on condition. The NS 10 are becoming somewhat hard to find. Seems that audiophiles that have then keep them. Now thats validation.
However the SL 10(pic below) is generally easier to find and the cosmetics are just stunning. The SL 10 broke out at $1,290.00 and has an average used price of $420.00, but most go for near $500.00 now,or more depending on condition.
For late 70s retail prices, these were not inexpensive to say the least and not many audiophiles could afford them. Everybody wanted them, but few had the the price of admission.
When it comes to todays used prices for these, it becomes a no brainer to choose either one of these. One can do seriously worse in a preamp. It is the sonics and build quality of these early Threshold preamps, that make them a viable alternative to most anything today.
Just had my NS 10 gone through by Jon Soderberg and the service was $175.00, so it is good for another 20 years. Now thats value! Service prices are based upon what is needed to bring the preamp up to specification. So prices from Jon will be based upon service needed to a specific Threshold preamp. As most of you know Jon was at Threshold the same time Nelson Pass was there, so Jon has the knowledge and expertise to handle any and all Threshold service requirements. Thats all I need to know. Jon has worked on several of my Threshold amps and preamps and have always been more than pleased with his results. Very hard to find this kind of workmanship and integrity today.
So if your looking for a preamp consider the Threshold NS 10 or SL 10 have it serviced and your set for a very long time. I firmly believe that once you have one of these, your preamp needs are set for quite some time.
As far as I am concern these are like Ferrari. Once a Ferrari always a Ferrari regardless of when they were new. And certainly these early Threshold preamps more than fall into that category. |
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| tmblack |
Have you ccompared the NS10 to the Naim preamps?
Similar topography suggests similar sound.
The NAC 32 was introduced in 1977.
Tom
EE |
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| lohk |
| Naim topology is only similar concerning the non-differential input. Beyond that I dont see many similarities. Naim also relates strongly to the supply and grounding scheme, which is part of the whole topology. I am very familiar with Naim amps from the eighties, I can hardly imagine any similarities soundwise with Threshold preamps. |
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| steenoe |
Lumanauw, Yeoldestereo thanks a lot for the info:) I do consider
to find one for myself, and I think Í might be able to dig one up;)
Steen:cool:
Ps. Whats the black box, standing next to the preamp? |
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| Russ White |
| quote: | Originally posted by steenoe
Whats the black box, standing next to the preamp? |
My guess is its the PS. :) |
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| apassgear |
| quote: | Originally posted by steenoe
Ps. Whats the black box, standing next to the preamp? |
Power supply maybe? |
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| steenoe |
Thanks guys, but I thought mayby it some MC-RIAA or something like that. I did see a few of the old Thresholds and if memory serves me, they didn't have external psu.
Steen:) |
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| yeoldestereo |
The picture on the post is of the SL 10 which has an outboard power supply. Of which most other high end manufacturers later on copied. I think the SL 10 was the first high end preamp to use an outboard power supply. Although I cannot be a 100 percent on that statement.
However if one looks through these post, there is a picture of my NS 10 I currently use. The NS 10 does not have an outboard power supply. However it is sufficenlty isolated in the NS 10, particulary on this NS 10 prototype. |
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| yeoldestereo |
The NS 10 did have an optional outboard accessory called the M 1 and it was for Moving Coil phono cartridges and plugged into the back of the NS 10 via connector and umbilical cord.
Think the NS 10 is a hard find, try to find the M1 accessory!!!
I've been looking for five years for this.
As well there was the M7 power supply for the M1,so it could be used with other preamps, though not needed for the NS 10, as the M1 received its power directly from the NS 10 when connected. |
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| tmblack |
I just make up my NS10 version with JFET for Q1.
It works like a charm just like the simulation.
There is something that makes my CD's sound like LP's.
Good pace and ease in the sound.
| quote: |
Naim topology is only similar concerning the non-differential input. Beyond that I dont see many similarities. Naim also relates strongly to the supply and grounding scheme, which is part of the whole topology. I am very familiar with Naim amps from the eighties, I can hardly imagine any similarities soundwise with Threshold preamps.
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I see them almost exactly alike. Take the 2 transistors that fom a constant current source and replace with single resistor. Now both NAC 32 and NS10 have 3 transistors in almost identical configuration.
That is the line stage, no idea about the RIAA stage or the preamps.
Tom
EE |
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| choky |
| quote: | Originally posted by yeoldestereo
The picture on the post is of the SL 10 which has an outboard power supply. Of which most other high end manufacturers later on copied. I think the SL 10 was the first high end preamp to use an outboard power supply. Although I cannot be a 100 percent on that statement.
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Quad QC (preamp for II) and numerous other tube pramps from that era-powering from power amp?
;) :clown: :devilr: |
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| choky |
i'm also interested in topology of Nelson's power supply for NS10;
not schm,just topology.......
when I have time I'll try that jewell with heeeeaavy shunt type supply (burnin' at least 10 times of steady current) :devilr:
btw- version with dual supply (2x25V) looks most promising -maybe even DC coupled on both ends ,and just nmaybe with sort of servo from SL10 |
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| apassgear |
| quote: | Originally posted by tmblack
I just make up my NS10 version with JFET for Q1.
It works like a charm just like the simulation.
There is something that makes my CD's sound like LP's.
Good pace and ease in the sound.
Tom
EE |
Great Tom,
Could we see the schematic of your clone? Rail voltage?
Sorry, but to which simulation are you refering to? |
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| lumanauw |
| quote: | I just make up my NS10 version with JFET for Q1. It works like a charm just like the simulation.
There is something that makes my CD's sound like LP's.
Good pace and ease in the sound.
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Good for you Tmblack......You can hear what I and Yeoldstereo wrote all this time? |
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| steenoe |
Googl'in for NS-10, I found this absorbing read:
NS-10, one happy owner.
I wonder who that guy is;) ;) Very enjoyable reading.
Steen:) |
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| yeoldestereo |
| Review is from yours truly. that was posted on Audiogon. Long live the NS 10.:D |
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| tmblack |
| quote: |
You can hear what I and Yeoldstereo wrote all this time?
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We should be hearing the same circuit, clean and loose sound.
Amazing for such a simple circuit.
Now try replacing R9 with a CCS like a N-JFET at 8-10mA.
I hear a tighter bass.
Now on to more evaluation!
Tom
EE |
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| lumanauw |
Hi, Tmblack,
| quote: | Now try replacing R9 with a CCS like a N-JFET at 8-10mA. I hear a tighter bass.
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If you replace R9 with CCS, that means = more OL gain = more feedback = more damping factor. You may hear tighter bass.
If you replace R4 (I use 10k) with smaller value, you will get more OL gain too, but I feel losing details with too small R4.
| quote: | | Now on to more evaluation! |
Try the "FASTNESS" test, with playing your system with the fastest musical program you have. This should add more smile on you. :D
To fine tuning the CCT, you can add "warmth" (=add more midrange response) by trying various values of cap (47pf-470pf) between G-D of Q1. This reduces the OL response, but in one pf value, you will find sweet spot where the whole tonal balance is perfect. |
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| lohk |
| Naim preamps have always used a CCS instead of R9 - for all output stages actually, for the gainless buffer or filter and the gain stage. |
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| tmblack |
I think we should stick with the original NS10 design for now.
It offer good balance of tone and speed. I am finding FET input is sweetening the sound and it should stay true to the source.
The single power supply needs to be very clean, otherwise hum can be heard.
Tom
EE |
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| yeoldestereo |
| Very nice production unit just sold on Audiogon for $750.00 USD,prices keep climbing on pristine Threshold NS 10. |
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| choky |
| quote: | Originally posted by yeoldestereo
Very nice production unit just sold on Audiogon for $750.00 USD,prices keep climbing on pristine Threshold NS 10. |
WTF we are doing here?
:D :clown: |
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| yeoldestereo |
Ah, yes for those of us that are diy challenged, the original NS 10 is the way to go. For me at 62 now, building once again not an option for yeoldestereo.
My hat is certainly off to those that can build this design from the ground up and I am indeed in very esteemed company.
All respondents to this thread have more than impressed me,with your knowledge and expertise and have more than enjoyed reading the posts. Without question the Threshold NS 10 will remain one of the cutting edge designs,even after 28 years in the field.
Many thanks to all,who have let this ole audiophile contribute to this thread, it has been enlightening to say the least:D |
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| jacco vermeulen |
A big thank you to you, for posting on the NS10, by others who see magic in Threshold gear.
Viewing pictures of preamplifiers with 8 inputs is already a treat, let alone something as rare as the NS10, seeing a pre-production model is unique.
Even though i find it more intrigueing to find out what is underneith a cover, understand and duplicate it, i truly envy you.
Forgering a Renoir is not the same as owning one. |
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| JC Fardo |
Yeoldstereo
Thanks for kind words. Fact is that I´m not familiar with this preamp and can not resist to ask what are those huge four blocks?
BTW, 20, 40, 55, 62 are just digits. A passion for something is far beyhond digital limits.
JC :) |
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| Nelson Pass |
| The blocks are metal cans which cover the circuits. |
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| Malotron |
| Here's a shot of a M1 module if anyone was curious... |
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| Malotron |
| ...early production NS10 - too bad BlackGate caps don't come in anodized blue :cool: |
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| choky |
| quote: | Originally posted by Malotron
Here's a shot of a M1 module if anyone was curious... |
?
where it is |
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| yeoldestereo |
| Thanks for the pic of the M 1 Module. |
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| yeoldestereo |
Have located a late production unit Threshold NS 10, should anyone want to acquire, kindly e mail me.:D
Pic below:) |
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| choky |
| :bawling: :bawling: :bawling: :bawling: :bawling: |
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| yeoldestereo |
Have been informed that the original volume control on the NS 10 could be problematic.
At present I have ywo of these NS 10 preamps. If anyone knows,kindly advise. |
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| apassgear |
I guess the original NS10 are the wiper carbon track type pot and even new they won’t compete with the “audiophile type” we most likely use as DIY’ers, these are the “discreet” ladder or series resistors (stepped attenuators) mounted on a shorting switch.
Drawbacks?
Bigger, you must check if they will fit and more expensive too plus you usually only get around 23 steps.
:)
P.S. Another alternative is to try an Alps Black Velvet pot and see if that makes an inprovement. |
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| beppe61 |
| quote: | Originally posted by Malotron
Here's a shot of a M1 module if anyone was curious... |
Dear Sir,
I am very curious about this M1 "active impedance matching module".
Could you tell me anything about its schematic ?
Is it a buffer?
Maybe with a nice pot in front of it could be an even more basic line stage.
Thank you so much.
Kind regards,
beppe |
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| Malotron |
Hello Beppe,
I'm afraid my knowledge of electronics is limited and the manuals for my Threshold equipment was lost in a flooded garage in 1997. :bawling: What I can tell you is how the module works with the NS10. The M1 is for matching the impedance of various ( 900 to 1.5 ohms ) moving coil phono cartridges so, in my case, my Dynavector 23R plugs into the 1.5 -10 ohm input and out to the one of the NS10's magnetic cartridge inputs. It has one modification: I replaced the 6 47uF tantalum caps with Panasonic FCs. How does it sound? Real nice with quality vinyl, like say, "Art Pepper Meets the Rhythm Section,": solid, wide imaging through 15 ohm Rodgers Ls3/5a's and tight extended bass through custom Kef SP-200 EBS subs. So, yes, for impedance matching MC phono cartridges the M1 through the NS10 is great. I couldn't say for other applications.
Thank you Nelson Pass.
-Mal |
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| beppe61 |
| quote: | Originally posted by Malotron
Hello Beppe,
I'm afraid my knowledge of electronics is limited and the manuals for my Threshold equipment was lost in a flooded garage in 1997. :bawling: What I can tell you is how the module works with the NS10. The M1 is for matching the impedance of various ( 900 to 1.5 ohms ) moving coil phono cartridges so, in my case, my Dynavector 23R plugs into the 1.5 -10 ohm input and out to the one of the NS10's magnetic cartridge inputs. It has one modification: I replaced the 6 47uF tantalum caps with Panasonic FCs. How does it sound? Real nice with quality vinyl, like say, "Art Pepper Meets the Rhythm Section,": solid, wide imaging through 15 ohm Rodgers Ls3/5a's and tight extended bass through custom Kef SP-200 EBS subs. So, yes, for impedance matching MC phono cartridges the M1 through the NS10 is great. I couldn't say for other applications.
Thank you Nelson Pass.
-Mal |
Dear Sir,
thank you sincerely for your kind and very valuable reply.
Kind regards,
beppe |
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| apassgear |
Beppe
Check Nelson's list for Threshold SL10, you will find what your looking for on that schematic sheet.
http://www.passlabs.com/np |
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| beppe61 |
| quote: | Originally posted by apassgear
Beppe
Check Nelson's list for Threshold SL10, you will find what your looking for on that schematic sheet.
http://www.passlabs.com/np |
Thank you very much for the link,Sir.
Kind regards,
beppe |
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| Tyimo |
Hi!
Could somebody tell me the specs of the NS10?
How much gain has it? How many output voltage, impedance etc.?
Is it as strong as the BOZ?
Greets:
Tyimo |
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| yeoldestereo |
| See Pic below for specs |
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| BrianEno |
From YeoldeStereo| quote: | | The picture on the post is of the SL 10 which has an outboard power supply. Of which most other high end manufacturers later on copied. I think the SL 10 was the first high end preamp to use an outboard power supply. Although I cannot be a 100 percent on that statement. |
The Levinson JC-2 had a outboard powersupply in 1974 with the line cords vast attached to them. Later in 1975 I believe they used a PLS-150 Powersupply for it.
Can buy a NS10 pre for my second system to replace a Yamaha C2-a but I'm not sure because of the age of at least 30 years.
Greetings |
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