Hallo, I read somewhere that the stasis serie of Nakamichi were designed by Nelson himself...
Is it completly true? I'm asking that, because I need a new tuner and I've found the following item on internet and from "next door" sellers:
Kenwood KT-400 (but no-one knows anything abpout this model)
Technics st-s1 (a 190$ model from 1980)
a newer Kenwood model (quartz locked, it also come from 1980, but I don't remind the name, this is a photo link: http://i15.ebayimg.com/04/i/07/19/11/24_1_b.JPG )
a Sansui t-60
and a Nakamichi sr-3a,
in some review I read that it has a weaked tuner
...but it has an headphone output and I love this thing!
(surely, ..if it is not a merely crancky opamped one...)
Can any one help me to choose one of these???
Cheers,
Domenico
Is it completly true? I'm asking that, because I need a new tuner and I've found the following item on internet and from "next door" sellers:
Kenwood KT-400 (but no-one knows anything abpout this model)
Technics st-s1 (a 190$ model from 1980)
a newer Kenwood model (quartz locked, it also come from 1980, but I don't remind the name, this is a photo link: http://i15.ebayimg.com/04/i/07/19/11/24_1_b.JPG )
a Sansui t-60
and a Nakamichi sr-3a,
in some review I read that it has a weaked tuner
...but it has an headphone output and I love this thing!
(surely, ..if it is not a merely crancky opamped one...)
Can any one help me to choose one of these???
Cheers,
Domenico
Far as I know, Mr. Pass did indeed contribute the Stasis circuitry used by Nakamichi.
I have a TA2A myself and it's very good sound, though lately I have a component that is constantly building new solder bridges and introducing a nifty buzz in one channel (not to mention throwing the balance).
C
I have a TA2A myself and it's very good sound, though lately I have a component that is constantly building new solder bridges and introducing a nifty buzz in one channel (not to mention throwing the balance).
C
I think NP posted years ago something in the line that it was a money deal. Also that though the design of the power amplifier was basically that of the Threshold S-model, the components, layout and construction used were all Japanese.
I've heard both the Nakamichi 5A and the 7A Stasis power amplifiers when they were on the shelfs, definitely not the same as a Threshold amplifier.
Interesting that topology can be identical, and there can be such a big difference.
Mind you, in those days i was seriously thinking of getting a Nak, viewing that it was the only Pass amp i could afford with great difficulty. (and an ocassion at that)
I thought the receiver was just a license deal.
Would be nice if the Great Evil One himself has some additional bits of the Nakamichi Stasis story for history preservation sake.
I've heard both the Nakamichi 5A and the 7A Stasis power amplifiers when they were on the shelfs, definitely not the same as a Threshold amplifier.
Interesting that topology can be identical, and there can be such a big difference.
Mind you, in those days i was seriously thinking of getting a Nak, viewing that it was the only Pass amp i could afford with great difficulty. (and an ocassion at that)
I thought the receiver was just a license deal.
Would be nice if the Great Evil One himself has some additional bits of the Nakamichi Stasis story for history preservation sake.
From what I saw servicing the PA-7 and 5 amplifiers, they sounded very good. They were extremely reliable as well. The input circuit was totally different to the Threshold designs. I'm not surprised it sounds different. I wouldn't mind having one (Nakamichi).
-Chris
I have a TA-2 as well. Great sounding little set. Does not like low impedance loads in that it affects the sound quality. There is an under rated resistor that feeds the current source circuit. One per channel. It opens up over time. Replace it with a higher power rating metal oxide resistor. I can't remember the value off hand right now.
-Chris
Wait...
you say it sounds bad on low impedance loads?
Ooh boy, I can't wait to get my X-GC finalized, 'cause my mains hit 2.8ohm and they already sound excellent with the TA-2A, so I really wonder what their potential is (one other has built 'em - actually picked the drivers and had me do crossover and I ended up building 'em too - and they've picked up rave reviews from his visitors)
.
And the Nak is the only amp in the house that handles it. The buzz issue has existed far longer though.
The problem item (or, where the bridge forms) is between two legs of a TO-220 case so not a resistor - I'll see if I can find a toasted R though.
you say it sounds bad on low impedance loads?
Ooh boy, I can't wait to get my X-GC finalized, 'cause my mains hit 2.8ohm and they already sound excellent with the TA-2A, so I really wonder what their potential is (one other has built 'em - actually picked the drivers and had me do crossover and I ended up building 'em too - and they've picked up rave reviews from his visitors)
.
And the Nak is the only amp in the house that handles it. The buzz issue has existed far longer though. The problem item (or, where the bridge forms) is between two legs of a TO-220 case so not a resistor - I'll see if I can find a toasted R though.
Hi cjd,
The little Nak TA-2 will dump a lot of current for it's size. A little better than a Marantz integrated it seems. Because it doesn't have a lot of paralleled outputs, the sonic performance into low impedance loads suffers. The PA series is much more forgiving that way.
Don't forget, the feedback is taken before the output transistors, so they are running open loop. The non-linearities are not corrected for and they are a larger magnitude than in a multi-output situation. There, the change in current is spread out over many transistors.
I am trying to visualize the problem you are having with "bridges" on the PCB. The solder should not be hot enough to flow. Picture?
-Chris
The little Nak TA-2 will dump a lot of current for it's size. A little better than a Marantz integrated it seems. Because it doesn't have a lot of paralleled outputs, the sonic performance into low impedance loads suffers. The PA series is much more forgiving that way.
Don't forget, the feedback is taken before the output transistors, so they are running open loop. The non-linearities are not corrected for and they are a larger magnitude than in a multi-output situation. There, the change in current is spread out over many transistors.
I am trying to visualize the problem you are having with "bridges" on the PCB. The solder should not be hot enough to flow. Picture?
-Chris
I already removed the old solder and re-soldered but there is a fair amount of solder bulk at the pins (I wish I knew what actual device it was - heatsinked, TO-220 package [could be larger actually - is that TO-5? don't remember]) since it sort-of "floats" into place. This solder is bridging along a path between two of the pins.
If it is indeed happening yet again I'll see if I can snap a pic. I'm more sure that it's happening again than I am sure I can get a pic that's clear of something that small.
C
If it is indeed happening yet again I'll see if I can snap a pic. I'm more sure that it's happening again than I am sure I can get a pic that's clear of something that small.
C
Far as I know this unit sat in a cabinet (in use - mind, it was cramped so had poor cooling) at my grandparents place for its first many years of life and was never serviced. It also has only one channel of the phono input working. I've had it for only about ten years now (wow, has it been that long?!)
And, maybe "whisker" is a better term to be using - it just grows enough to bridge eventually.
C
And, maybe "whisker" is a better term to be using - it just grows enough to bridge eventually.
C
Nakamichi Stasis ...
I sold the recievers and amps when new. They were quite nice to listen too. At the time one of my favourite setups to sell, an SR2, OMS2 (or 3), a Revolver turntable and DCM or B&W speakers--DM1600s. (I'd love to get a pair if I could find them and/or afford them). Really a very nice set up--and lower B&W speakers worked well to.
Compared directly to the then current NAD 3240PE, and the HK PM635(?), and a Bryston 2BLP/.5 combination, the Nak ran a close second to the Bryston setup. Yes, the Bryston had better bass. (the 2BLP/.5B was combined into the BP20 or whatever the intergrated was/is called).
I recalled the SR2 , and decided to buy one. I think I paid under $50 USD including shipping off of epay. The little reciever still sounds very good.
Is it a threshold? nope. But it held it's own against the Bryston pair and at a substantially lower cost. Currently I use it in my bedroom, but hope one day to create a "museum" of equipment in my livingroom. Kinda like pick and play.
anyone interested in a more modern look at the Nakamichi SR4 should look here , at the Feb 06 issue.
I sold the recievers and amps when new. They were quite nice to listen too. At the time one of my favourite setups to sell, an SR2, OMS2 (or 3), a Revolver turntable and DCM or B&W speakers--DM1600s. (I'd love to get a pair if I could find them and/or afford them). Really a very nice set up--and lower B&W speakers worked well to.
Compared directly to the then current NAD 3240PE, and the HK PM635(?), and a Bryston 2BLP/.5 combination, the Nak ran a close second to the Bryston setup. Yes, the Bryston had better bass. (the 2BLP/.5B was combined into the BP20 or whatever the intergrated was/is called).
I recalled the SR2 , and decided to buy one. I think I paid under $50 USD including shipping off of epay. The little reciever still sounds very good.
Is it a threshold? nope. But it held it's own against the Bryston pair and at a substantially lower cost. Currently I use it in my bedroom, but hope one day to create a "museum" of equipment in my livingroom. Kinda like pick and play.
anyone interested in a more modern look at the Nakamichi SR4 should look here , at the Feb 06 issue.
Hi Nelson,
I imagine you have a better idea than most of us, but I'll confirm that you are dead right.
H9,
Hi Nanook,
But you can't compare it to amps of normal design really and it does have much better mid and high resolution. Yes, it has it's characters, but all in all I'd rather listen to a PA-x over any Bryston of that period (horrid construction BTW).
I still use a TA-2 in my bedroom.
-Chris
How can you be so sure??
I imagine you have a better idea than most of us, but I'll confirm that you are dead right.
H9,
I think you have that backwards. Those speakers need a solid ground between channels or it will smoke the input stage grounds. Trust me on this.
Hi Nanook,
Yup, just a little different and mechanically cleaner in build quality.
The Statis design takes the feedback from the drivers a little further back. The output is therefore running open loop with zero feedback. It will have a lower damping factor due to this. One of the advantages is that the amplifier only has one input (instead of two) now and does not respond to a speakers antics. It also doesn't receive radio stations quite as well as other amps may.
But you can't compare it to amps of normal design really and it does have much better mid and high resolution. Yes, it has it's characters, but all in all I'd rather listen to a PA-x over any Bryston of that period (horrid construction BTW).I still use a TA-2 in my bedroom.
-Chris
anatech
well, I am, nor ever will be a technician.
I recall the explaination for "Stasis" as follows:
basically a high quality input driver (operating in class 'A' or near class'A'), that is used to drive a class 'AB' output.
really, kinda like using a class A tube amp as an input to an AB output that uses no or little feedback.
Really quite a good idea. And I do love my old SR2, it is an early production one as the ones I sold were after 1989, and the "2" had terrible spring loaded speaker connectors.
hmm if low dampening factor than a nice match for my Hemp FR8 drivers
well, I am, nor ever will be a technician.
I recall the explaination for "Stasis" as follows:
basically a high quality input driver (operating in class 'A' or near class'A'), that is used to drive a class 'AB' output.
really, kinda like using a class A tube amp as an input to an AB output that uses no or little feedback.
Really quite a good idea. And I do love my old SR2, it is an early production one as the ones I sold were after 1989, and the "2" had terrible spring loaded speaker connectors.
hmm if low dampening factor than a nice match for my Hemp FR8 drivers
anatech said:Hi Nelson,
How can you be so sure??
I imagine you have a better idea than most of us, but I'll confirm that you are dead right.
H9,
I think you have that backwards. Those speakers need a solid ground between channels or it will smoke the input stage grounds. Trust me on this.
Hi Nanook,
Yup, just a little different and mechanically cleaner in build quality.
The Statis design takes the feedback from the drivers a little further back. The output is therefore running open loop with zero feedback. It will have a lower damping factor due to this. One of the advantages is that the amplifier only has one input (instead of two) now and does not respond to a speakers antics. It also doesn't receive radio stations quite as well as other amps may.
I still use a TA-2 in my bedroom.
-Chris
You are right (as usual Chris) I used a double negative in the sentence and confused everyone, including myself. Polk SDA 1C's can only be used with a common ground amp unless you utilize a special cable (AI-1) which incorporates a transformer for non-common ground amps like mono blocks. This is of course for the inneraural crosstalk cancellation feature of the speakers. I don't have the special interphase cable ( I just have the std. SDA cable) and I don't want to build one. I've heard they degrade the sound anyways.
On the Adcom GFA5500, 5800, 5802, 565's and 585's you can tie the negative output terminals together and they can be used with Polk SDA's. I was just wondering if the NAK isn't common ground, could the negative speaker terminals be connected (with approriate size cable) if need be.
I sold NAK and Polk way back when and I don't remember this being an issue, but memory can fail so I figured this would be the most accurate place to get the info
Regards
-Brock-
Hi Brock,
You should be fine. The only issue is that the SDA's force heavier currents between the negative speaker terminals than was thought of when the amp in question was designed. A heavy wire link between the negative terminals is recommended (just like Adcom 555 type amps).
We were authorized warranty for both Polk, Adcom and many other amps. I still fail to see why Polk released these darn speakers on the market without very clear warnings. I can't tell you how many customers had to pay for repairs not covered under warranty due to these speakers.
-Chris
You should be fine. The only issue is that the SDA's force heavier currents between the negative speaker terminals than was thought of when the amp in question was designed. A heavy wire link between the negative terminals is recommended (just like Adcom 555 type amps).
We were authorized warranty for both Polk, Adcom and many other amps. I still fail to see why Polk released these darn speakers on the market without very clear warnings. I can't tell you how many customers had to pay for repairs not covered under warranty due to these speakers.
-Chris
Hi Nanook,
I used to be in audio sales and moved into service. Couldn't stand most other salesmen.
Anyway, the output of a Stasis amp is class AB, but biased on higher than normal AB. Nelson could give some rough figures off the cuff, and correct me if I'm wrong here (please, feel free to correct me!). The output stage is not contained in the feedback loop. The more output transistors there are run in parallel, the lower the distortion and the higher the damping factor will be. They do not sound as good into low impedance loads as they do into 8 ohm loads.
I must say that a Statis amplifier is darn hard to kill. It can be done, and I am impressed when it happens. My only repair of a PA-7 was the unfortunate victim of one of those really large copper box staples that fell inside. It's the only one I ever saw fail.
-Chris
I used to be in audio sales and moved into service. Couldn't stand most other salesmen.
Anyway, the output of a Stasis amp is class AB, but biased on higher than normal AB. Nelson could give some rough figures off the cuff, and correct me if I'm wrong here (please, feel free to correct me!). The output stage is not contained in the feedback loop. The more output transistors there are run in parallel, the lower the distortion and the higher the damping factor will be. They do not sound as good into low impedance loads as they do into 8 ohm loads.
I must say that a Statis amplifier is darn hard to kill. It can be done, and I am impressed when it happens. My only repair of a PA-7 was the unfortunate victim of one of those really large copper box staples that fell inside. It's the only one I ever saw fail.
-Chris
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