[FauDrei]

Well, not me... but Curra got this from KingWa.
 
Happy tinkering.

 

[Pricklely Peete]

Quote:

Well, not me... but Curra got this from KingWa.
 
Happy tinkering.

Thanks FD for digging that up for me.
 
Peete.

 

[Currawong]

It's worth checking the bias at least once the Phoenix has burned in IMO as mine had drifted from the default 15V.  IIRC I set it to 18V for the LCD-2s and the result is fantastic. It changes the sound a little so is worth experimenting with.

 

[Pricklely Peete]

Quote:

It's worth checking the bias at least once the Phoenix has burned in IMO as mine had drifted from the default 15V.  IIRC I set it to 18V for the LCD-2s and the result is fantastic. It changes the sound a little so is worth experimenting with.

Definitely, good point Curra ....I bet mine has drifted a bit from all of the changes. I need to figure out a way that I can adjust the bias in real time while listening to the main rig...tune it by ear for the ET/Maggie panels.
 
Peete.

 

[Pricklely Peete]

It might be a very useful resource if  those that have futzed with their bias settings to list those settings, what gear they are using with the amp (speakers/headphones), and the voicing impressions of the chosen V range ( with the stock V range voicing used as a reference point ).
 
Maybe a separate thread for such in the DIY section perhaps ?
 
Peete.
 
 

 

[Pricklely Peete]

Yesterday was spent (the afternoon for the most part) investigating + - bias V settings (from 15 V to 18 V in 30 mV increments) using a Denon 3910 as source (down mix 2 channel analog outs) and HD650's as the sub for the speakers, into my Phoenix. I could not test the various settings in real time on my main system (there was no way to reliably set it up given the space restrictions between the hifi rack and the L channel banks of speakers and the related amps/cabling ).....at any rate after fiddling for a number of hours trying out a myriad of settings (using a single ref track throughout) I settled on a bias setting of + - 17.1 V . It sounds great with the speaker setup restoring my doubt about using the 650's to voice an amp that will be used primarily on planar/ribbon transducers. Phew...I really did not want to take the Phoenix out of the rack today to redo that whole process. I must have spent 2 hours dialing in the + - 17.1 V settings once settled upon (initial setting, then full warm up, adjust again after some drift and then final setting once fully warmed up and tested with the ref track a few times). At least this tweak was easy to access and perform (compared to pulling pcb's etc).
 
At the same time since I had the PSU chassis back on the workbench it gave me an opportunity to snap a few pics of the last mod done (the swap of the 4 x Solen caps for the K42/K40 PIOS).  I'll let the pic do the talking
 

 
 
I really like the changes using the new bias V setting...it's very subtle in nature (vs stock 18V) ...I opted for a compromise between the strengths of the stock V while adding a fair taste of the attributes brought to the table by the lower bias V .
 
Thanks to both Curra and FauDrei for bringing these details WRT tweaking the amp in this manner to light. !!!!

 
As an aside I had not bothered to check bias V after the MAX mod (it never occurred to me at that time) so before getting into the various settings yesterday I did note what the settings were ( L channel was - 17.78 + 17.98, R channel - 17.69 + 17.92). That wasn't too bad I suppose....getting these settings all uniform sounds much better (IMO and to these ears at least).
 
Peete.

 

[dukja]

Thanks for the sharing on your experience.  One day I'll get to the bias...
 
On another topic, recently I used Phoenix as preamp to my NAD216 and then to power HE-6.  The sound is good but not as good as I would like.  Suddenly, I remembered that my previous experience with SE headphone output, which wasn't as good as balanced headphone output.  So I wonder if the same principle also applies: the SE preamp output may not as good as XLR preamp out?
 
I'd appreciate someone has used balanced power amp (e.g. some Audio-gd offerings or others) with Phoenix may confirm my suspicion.  If that is the case, then I'll need to hunt down a balanced power amp.
 
Quote:

I really like the changes using the new bias V setting...it's very subtle in nature (vs stock 18V) ...I opted for a compromise between the strengths of the stock V while adding a fair taste of the attributes brought to the table by the lower bias V .Thanks to both Curra and FauDrei for bringing these details WRT tweaking the amp in this manner to light. !!!!

 
As an aside I had not bothered to check bias V after the MAX mod (it never occurred to me at that time) so before getting into the various settings yesterday I did note what the settings were ( L channel was - 17.78 + 17.98, R channel - 17.69 + 17.92). That wasn't tool bad I suppose....getting these settings all uniform sounds much better (IMO and to these ears at least).
 
Peete.

 

 

[Pricklely Peete]

I'm running my main system's amps ( 4 mono blocks and 1 stereo amp, 4.2  setup) off the Phoenix SE'd preamp outs, it's sound quality is fantastic dukja FWIW.
 
Peete.

 

[FauDrei]

Originally Posted by Pricklely Peete /img/forum/go_quote.gif
Thanks to both Curra and FauDrei for bringing these details WRT tweaking the amp in this manner to light. !!!!

Enjoy Peete.

 
I suppose those K42 and K40 are from e-bay? I might me sourcing them soon...
 
...and BTW & OT - Peete, if you are still in planning phase of diode swap project - do also consider Schottky SiC "zero recovery" diodes. I am pleased with my "stealths", but they do get darn hot...

 

[Pricklely Peete]

Quote:

Enjoy Peete.

 
I suppose those K42 and K40 are from e-bay? I might me sourcing them soon...
 
...and BTW & OT - Peete, if you are still in planning phase of diode swap project - do also consider Schottky SiC "zero recovery" diodes. I am pleased with my "stealths", but they do get darn hot...

Thanks FD !....I think I bought these off eBay...it was quite awhile back. I do know one thing for sure, I bought a boatload of the 200V .033uf K40's and a fair number of the 1.0 uf 160V K42's from a vendor based in the Ukraine (way better than dealing with vendors from the Russian Federation).
 
PS: Thanks for the diode tip !!! 

 
Peete.

 

[drez]

Quote:

 


X2,  I tried the HE6 (balanced) and the LCD2 (SE) on the Phoenix and preferred the HE6 by a wide margin. I felt like the HE6 could've possibly benefited from more power, so I'm thinking the HE-500 might be a better match with the Phoenix.

I wouldn't jump to that conclusion until you try the LCD-2 balanced.  Out of the NFB-10 the LCD-2 sounded really sluggish when driven single-ended.  Not the same amp I know but its not a fair comparison SE vs. balanced esp on Phoenix.
 
 

 

[lmswjm]

Thanks, I'd really like to hear the LCD-2 in its optimum envirornment...........

 

[Currawong]

PP: Stock bias is 15V according to Kingwa. I settled on 18V in the end. I wouldn't mind trying a pair of HE-500s, especially since I've been so pleased with the Phoenix + LCD-2s, but a certain pair of Stax has done in my interest in those for now anyway.

 

[dukja]

OK, so the SE preamp out of Phoenix may not to be blamed for the plain sound... But are preamp SE out and headphone SE out share most of common circuit and hence similar SQ?
 
Thanks!!
 
Quote:

I'm running my main system's amps ( 4 mono blocks and 1 stereo amp, 4.2  setup) off the Phoenix SE'd preamp outs, it's sound quality is fantastic dukja FWIW.
 
Peete.

 

 

[tim3320070]

Quote:

Thanks for the sharing on your experience.  One day I'll get to the bias...
 
On another topic, recently I used Phoenix as preamp to my NAD216 and then to power HE-6.  The sound is good but not as good as I would like.  Suddenly, I remembered that my previous experience with SE headphone output, which wasn't as good as balanced headphone output.  So I wonder if the same principle also applies: the SE preamp output may not as good as XLR preamp out?
 
I'd appreciate someone has used balanced power amp (e.g. some Audio-gd offerings or others) with Phoenix may confirm my suspicion.  If that is the case, then I'll need to hunt down a balanced power amp.
 


 

I used 2 different Emotiva amps with my Phoenix- the UPA-2 (RCA) and the XPA-2 (XLR). Both sounded great but not to the level of the AGD amps. But for about $700, providing massive power and XLR inputs, the XPA-2 is a good value. The UPA-2 is also good value but it sounded pretty colored (warm) which I liked on a lot of music and not so much on others.