oldson
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Post by oldson on Feb 19, 2016 20:59:51 GMT
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Post by husafreak on Feb 20, 2016 17:50:02 GMT
I have the same question, I want to 'Y' connect my Polaris and Ember II to my pre amp tape out.
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solderdude
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Post by solderdude on Feb 20, 2016 19:33:41 GMT
Using a Y connector between a source (DAC for instance) which feeds a signal to 2 amplifiers is not a problem.
The output impedance of a source is usually very low and can deliver enough to feed many amplifiers at the same time.
The input resistance of amplifiers usually is 10k or higher.
You can also use a Y connector on the RCA output of the Polaris and split that signal to 2 other amplifiers as well.
The output R of the RCA out is low impedance as well.
Using a Y connector to combine 2 sources (say a CDP and a DAC) to one amplifier can be problematic.
2 low impedance sources will load each other heavily and when one is switched off there might even be a lot of distortion.
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oldson
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Post by oldson on Feb 20, 2016 20:56:53 GMT
Using a Y connector between a source (DAC for instance) which feeds a signal to 2 amplifiers is not a problem. The output impedance of a source is usually very low and can deliver enough to feed many amplifiers at the same time. The input resistance of amplifiers usually is 10k or higher. You can also use a Y connector on the RCA output of the Polaris and split that signal to 2 other amplifiers as well. The output R of the RCA out is low impedance as well. Using a Y connector to combine 2 sources (say a CDP and a DAC) to one amplifier can be problematic. 2 low impedance sources will load each other heavily and when one is switched off there might even be a lot of distortion. ok thats great, i think i already have some rca splitters somewhere so that is the headphone amp side of things sorted. i do have one other query, though. at the moment i am also using my Ember as a pre-amp to my marantz speaker amp. this speaker amp has only one pair of "power amp direct" inputs, which i currently feed from my Ember. if i add a Polaris and wish to compare it to Ember as a pre-amp for the marantz, can i split this line or should i use a switch box here? i guess as i intend to leave Ember and Polaris permanently on, it would need a switch. |
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Post by husafreak on Feb 22, 2016 7:34:38 GMT
Well, If you wanted to run the Polaris and Ember II off one Preamp tape out, would you daisy chain the two amps, say, Preamp to Polaris to Ember. Or would you use a Y connector from the Preamp to the Polaris and Ember II? I wouldn't listen to both at the same time but I might have them both running or I might not... If it doesn't matter that is good as I have extra RCA cables but would have to buy Y cables. Thanks!
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Post by husafreak on Feb 22, 2016 18:43:59 GMT
Actually now I think I should just get some kind of switching box. I also recently acquired an analog to digital converter to do needle drops and that makes three components that want to use my tape outs. Hopefully switching boxes are transparent affairs.
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solderdude
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Post by solderdude on Feb 22, 2016 19:31:15 GMT
they are
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Post by husafreak on Mar 5, 2016 7:01:47 GMT
I still have not received my switching box but while re rolling my favorite tubes in my Ember II and going back and forth comparing them to the Polaris I came to realize that I could use the Polaris as a goal for finding what the right tube in my Ember should sound like. I realized that some of the tubes I liked had colorations that were not neural. They sounded exciting in some ways but masked other information (music) that I also want to hear. But the really balanced or more neutral tubes made my Ember and Polaris sound very similar. I have to admit that I do like the Ember a bit better due to the sweetening of the sound overall and especially on vocals. But the Polaris sounds great too. It really gives a glimpse into what you golden eared designers are trying to achieve for us!
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oldson
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Post by oldson on Mar 5, 2016 18:34:58 GMT
I still have not received my switching box but while re rolling my favorite tubes in my Ember II and going back and forth comparing them to the Polaris I came to realize that I could use the Polaris as a goal for finding what the right tube in my Ember should sound like. I realized that some of the tubes I liked had colorations that were not neural. They sounded exciting in some ways but masked other information (music) that I also want to hear. But the really balanced or more neutral tubes made my Ember and Polaris sound very similar. I have to admit that I do like the Ember a bit better due to the sweetening of the sound overall and especially on vocals. But the Polaris sounds great too. It really gives a glimpse into what you golden eared designers are trying to achieve for us! surely if you were able to make them sound identical, there would be no point in having both? |
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Post by husafreak on Mar 6, 2016 18:06:00 GMT
Hmmm. "Similar" is not "identical". I doubt you could do that. But yes I agree, if the Polaris sounded identical to the Ember then there would be no point and I would go for the reliability and economy of the solid state Polaris. My goal was certainly not to make them sound identical but in the end I kind of used the Polaris as a benchmark to get the most balanced sound out of my Ember. I do enjoy my new hobby of "tube rolling" with the Ember but it is easy to focus on each tube's strong suits and lose sight of the overall picture. I quickly found myself bouncing back and forth. The Polaris is a bit of fresh air after a session like that! I like the Ember slightly better when tubed to sound like the Polaris, that is subjective. I like the Ember better when I want to listen to music through "rose colored glasses", that is very subjective! I like the Polaris for revealing the source in a very even handed, neutral, and consistent way, objective  |
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proid
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Post by proid on Jun 13, 2016 11:41:46 GMT
The led from my adapter keep turning on and off and so the amp. I think it's dead, any way to fix this?
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solderdude
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Post by solderdude on Jun 13, 2016 12:31:03 GMT
Most likely the power supply is the culprit, the amp may still be O.K.
Does the power supply work with another load ?
Can you try powering the amp from another power supply ?
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proid
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Post by proid on Jun 13, 2016 15:34:21 GMT
I don't have any other equipment that work with 48v so i can't test the adapter but seem like it's the problem because when i first turn the amp on, it working fine: after the red led turn off, it sound fine, but after about 20s, it start to turn on and turn off again and again, the led on the adapter also turn on and off as the amp.
Btw this amp does sound really great, it's very smooth and easy to listen to, great job Frans! I see in the schematic, the jfet in the voltage gain stage is a just intend for switching application, do you think it will be benefit from changing to low noise audio type like 2sk170bl? And i don't understand how to generate 2ma bias for the voltage stage, can you explain it for me? Thanks!
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solderdude
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Post by solderdude on Jun 13, 2016 17:20:30 GMT
Most likely it's the power supply.
Contact Jeremy about this issue.
The 2SK170 is no longer available, only through e-bay.
So we didn't consider it as a viable option.
We tried several FET's and these came up as best performing.
There is no current source in the FET path.
The FET biases itself by R13.
A current source would give an extremely high gain and poor frequency response.
Using R16 as a load also provides the proper amount of harmonics.
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Post by Asde on Jul 23, 2016 16:40:43 GMT
Is there any way to get Project Polaris in Europe?
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