Hi I have a Nak PA7 for 8 months and am really enjoying it i my system driving a pair of of DQ10’s.
So I says to myself if the Nak sounds so good with the DQ10’s I wonder what the a real Nelson Pass amp would sound like with the DQ’s specifically the 400a.
Up until now I have found two 400a’s but I am confused , one guy says his unit was upgraded during the eighties to a stasis unit the other one says his unit has the S300 components.
So here is my question, did Threshold offer factory upgrades to original 400a and what upgrades were available and what were the benefits of the upgrades.
What did the stasis upgrade add to the 400a specs and qualities and future restoration.
I suppose there must have a an upgrade path for all threshold Amps.
Maybe Mr. Pass can chime in on this?
So I says to myself if the Nak sounds so good with the DQ10’s I wonder what the a real Nelson Pass amp would sound like with the DQ’s specifically the 400a.
Up until now I have found two 400a’s but I am confused , one guy says his unit was upgraded during the eighties to a stasis unit the other one says his unit has the S300 components.
So here is my question, did Threshold offer factory upgrades to original 400a and what upgrades were available and what were the benefits of the upgrades.
What did the stasis upgrade add to the 400a specs and qualities and future restoration.
I suppose there must have a an upgrade path for all threshold Amps.
Maybe Mr. Pass can chime in on this?
400a upgrades
Hi
Mr. Pass, thank you for your quick reply
Sorry for being so tardy with my response but l
Wanted to get a photo of this unit, and hope you can tell me whether it’s
400a, what has been upgraded and by whom.
Thanks you are the best, I do not any of any other designer that would what do
What You are doing with diy and that is so accessible.
Hi
Mr. Pass, thank you for your quick reply
Sorry for being so tardy with my response but l
Wanted to get a photo of this unit, and hope you can tell me whether it’s
400a, what has been upgraded and by whom.
Thanks you are the best, I do not any of any other designer that would what do
What You are doing with diy and that is so accessible.
Attachments
400a upgrdes
Mr. Pass
Sorry bad picture I was hoping it was a genuine “Threshold Skull and Crossbones”😀
Mr. Pass
Sorry bad picture I was hoping it was a genuine “Threshold Skull and Crossbones”😀
Threshold 400a and early Threshold amp upgrades
Hi Mr. Pass
This an excerpt from an interview you did with Thomas Norton of Stereophile Magazine in 1991.
I know that I can’t remember what I had for breakfast this morning let alone what I did in 1991.
I hope you are not offended I think that you it is great that you offered upgrades
I don’t recall any other manufacturer ever doing that
Love your designs
Best regards:
Norton: I've noticed recently that you have upgrades available for most of your early amplifiers. What do these upgrades consist of?
Pass: Within the context of the chassis, the original power supply, the heatsinks and so on, what we do is we replace the sonic circuitry. In the case of the older product, which was non-Stasis, and even the earlier Stasis models—the 1, 2, and 3—we replace the output stages completely with a later design. And we replace the front-end circuitry associated with the amplifier. If the power-supply capacitors have exceeded ten years of use we replace them, and the rectifier diodes, and those things which have a tendency to wear over time, so as to keep the device reliable for another 10 years or so. Basically the program encompasses everything except the CAS-1 and the CAS-2. Those are products where we haven't really perceived that there's going to be a significant market of people looking for upgrades.
Hi Mr. Pass
This an excerpt from an interview you did with Thomas Norton of Stereophile Magazine in 1991.
I know that I can’t remember what I had for breakfast this morning let alone what I did in 1991.
I hope you are not offended I think that you it is great that you offered upgrades
I don’t recall any other manufacturer ever doing that
Love your designs
Best regards:
Norton: I've noticed recently that you have upgrades available for most of your early amplifiers. What do these upgrades consist of?
Pass: Within the context of the chassis, the original power supply, the heatsinks and so on, what we do is we replace the sonic circuitry. In the case of the older product, which was non-Stasis, and even the earlier Stasis models—the 1, 2, and 3—we replace the output stages completely with a later design. And we replace the front-end circuitry associated with the amplifier. If the power-supply capacitors have exceeded ten years of use we replace them, and the rectifier diodes, and those things which have a tendency to wear over time, so as to keep the device reliable for another 10 years or so. Basically the program encompasses everything except the CAS-1 and the CAS-2. Those are products where we haven't really perceived that there's going to be a significant market of people looking for upgrades.
You are totally right. I'm just old and forgetful.
If you look at the photo, you can clearly see that the output of the amplifier
comes from the cases of the TO-3 devices, which was true only of the
later Stasis circuits. Further, 1 ohm resistors were never used on 400A's.
Clearly it was updated.
If you look at the photo, you can clearly see that the output of the amplifier
comes from the cases of the TO-3 devices, which was true only of the
later Stasis circuits. Further, 1 ohm resistors were never used on 400A's.
Clearly it was updated.
Sorry I hope I'm not hijacking if so Ill see myself out but I was wondering if there is a significant difference other then the cap on the inputs of the Nak PA7 vs the Threshold design. Not sure if I should upgrade.
The first versions of the Nak amps were pretty similar, schematic wise, but
used different transistors and other parts. Biggest difference I recall was a
lower bias figure, due to smaller sinks.
After a year or so they tarted the design up a bit on their own.
Thanks, suggestion for one of this old AB design ?
just to power on h24 as we can find cheaper...
just to power on h24 as we can find cheaper...
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It's my own opinion that all the warmup you need is in the first hour.
More that, it's largely wasted unless you are heating your listening room....
More that, it's largely wasted unless you are heating your listening room....
yes!
Sorry...what I mean is for play music all day near 15 hours ,
If you can suggest one model from your effort an AB in Naka, forte' ,Thre , this nice old stuff can be find at good price
Thanks in advance for the patience LoL!
Sorry...what I mean is for play music all day near 15 hours ,
If you can suggest one model from your effort an AB in Naka, forte' ,Thre , this nice old stuff can be find at good price
Thanks in advance for the patience LoL!
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