[BenBau]

Well, there actually IS a dedicated pin for the input relay switching. It's on pin 4 of the DB9 and is called DA3 (according to Kingwa). I measured it from the control panel (with the blue display) to the amp-box and it's intact and not shorted to ground. Now the strangest thing: I turned on the Phoenix but I forgot to connect the serial cable. I connected the serial cable without turning off the Phoenix. The input relays are clicking again, but only inputs 1, 2 and 3 (is that normal?). The volume is a bit louder, but still too soft and still the same on all inputs (=signal leakage). Another thing: on inputs 1 and 2 the volume relays keep clicking if I keep turning the knob "under 0" or "over 70".
 
There has to be something wrong with the control panel. The primary problem was the broken voltage regulator with 7V on the right-side output. I soldiered in a new one provided by Kingwa. The voltages are fixed now. Somehow the control panel must have gotten "messed up" or maybe also a short-circuit. It's just not logical that there's a fault in the amp box, it must be in the power box.
 
Les, I know of the oil issue in the encoders. That's not the issue here. I use the remote for control.
 
Pricklely, I don't think there a problem with the relay banks under the circuit board in the amp box. There IS control of volume and I hear the volume relays clicking, but the max. volume is far too low. The input relays are also clicking, but not the way they should i.e. connecting the input signal to the amp circuit. The preamp button is properly working: my balanced connected C1 Masters produce unfortunately also too soft sound in preamp mode.
The biggest part of "free floating" cast-aluminium from the power connector was 5mm! Also a lot of smaller debris inside the power box. "Clean working" or better, the lack of it, really is an issue Kingwa has to fix (still); it's high-end unworthy!

 

[Currawong]

I agree he does need to start using much better power connectors, and preferably ACSS connectors as well.

 

[pompon]

I tried something few days ago ...
 
I was using my Phoenix as preamp on my speaker setup,
 
 
I tried my dac directly on my poweramp (adjusting my numeric volume control in foobar to avoid to have something too loud,).
 
 
Result : More bass and mid bass this manner.
 
If Phoenix is really neutral, I should not notice difference in tone level right ? I am pretty convinced the Phoenix suck some amount of bass to give it's sound.
 
 
My speaker don't have a great mid-bass and I am using subwoofer for the deep bass. I prefer my DAC directly on my poweramp over the Phoenix acting as preamp.
 
BTW, the Phoenix still for me my best headphone amp ... it's my only balanced anyway.
HD800 and HD800 balanced ... we tested that few days ago in my home (meet I was hosting) ... we had 2 pair of HD800. The only thing bad ... no reterminated stock cable ... I was using DHC XLR. Balanced was hand down better in every way.
 
What give the cable itself ? I don't know but for sure, it's was smooter in balanced with the DHC with more bass and punch.
 
 

 

[BenBau]

Tomorrow I will ship my Phoenix back to China. I did not succeed in repairing it myself. I hate that; my new C1 Master(s) are waiting!

 

[Pricklely Peete]

Quote:

I tried something few days ago ...
 
I was using my Phoenix as preamp on my speaker setup,
 
 
I tried my dac directly on my poweramp (adjusting my numeric volume control in foobar to avoid to have something too loud,).
 
 
Result : More bass and mid bass this manner.
 
If Phoenix is really neutral, I should not notice difference in tone level right ? I am pretty convinced the Phoenix suck some amount of bass to give it's sound.
 
 
My speaker don't have a great mid-bass and I am using subwoofer for the deep bass. I prefer my DAC directly on my poweramp over the Phoenix acting as preamp.
 
BTW, the Phoenix still for me my best headphone amp ... it's my only balanced anyway.
HD800 and HD800 balanced ... we tested that few days ago in my home (meet I was hosting) ... we had 2 pair of HD800. The only thing bad ... no reterminated stock cable ... I was using DHC XLR. Balanced was hand down better in every way.
 
What give the cable itself ? I don't know but for sure, it's was smooter in balanced with the DHC with more bass and punch.
 
 

Were the levels matched for the test between the two ? Sometimes a small difference in level can give a false impression.
 
Peete.
 

 

[Currawong]

PP: More so, what do the outputs of both the Phoenix and the DAC measure?  I know there seems to be a conventional wisdom that an active pre-amp is better than a passive one (I'm slightly over-generlising here considering the circumstances) but there are some fantastic rigs that purely use passive pre-amps, such as the one Van Den Hul made.  I doubt that would work well in every system. I have tried the Phoenix as an active pre with various headphone amps and the result wasn't always as good as directly from the DAC.  I wish I had more gear to experiment with in this regard though.

 

[Pricklely Peete]

Well Curra the problem with using the active pre into a headamp is the simple fact that most headamps (almost all of them) already have a preamp section built in...so double amping the line level signal will give less than an ideal result. So for the headamp application a passive pre is almost a must (if you plan on using one). An interesting quirk of the KHA amp is the lack of preamp section which made it fun for me to try out any pre I have on hand. Most headamps are nit built like this though. It might be possible to alter a SS design (to bypass the pre section) far easier than tube based one but that is just guessing on my part.
 
In a lot of ways the passive vol control provides a very clean attenuation of the line level signal but and this is a big but, the output level is almost always compromised as is the impedance curve in some way (with conventional pots) as you adjust the Vol up or down. The impedance changes as the vol is adjusted which is a problem an active pre stage overcomes. The active pre stage also has a fixed output impedance (usually 47Kohms for SS and 100Kohms for tube) A mismatch with the amp (tube or SS) can cause audible problems which is why folks need to pay attention to such things when selecting gear. Remember those MIT IC's I bought  for my ref system, they are impedance matched between the preamp/Xovers and amps. It makes a big difference to these ears.
 
My active/passive GFP-750 is a good example of the differences...in passive mode it outputs 1V whereas in active mode it's the standard 2.0V. It drives the amp stages to what I call the sweet spot (every amp has an area where it's most comfortable operating) far easier than the passive setting, so it's possible you are not driving the amp to it's fullest capability in passive mode. This depends on the input stage sensitivity of the amp being driven, some like lots of juice to get there while others require less and the output V of the passive control should adequate to fully drive the amp stages. Not all passive units are the same WRT what they output (vs input level) and of course the quality of the attenuators,wiring, jacks etc all play a crucial role in the end result. At any rate as far as setting levels it's very difficult to set them by ear alone, you'll almost always be off by a few db (which is critical for a fair evaluation) so I use an SPL meter for such things.....just a cheap little RadioShack unit which does a decent job.
 
An interesting passive device is this one .....  http://diyaudioprojects.com/Solid/DIY-Lightspeed-Passive-Attenuator/   which eliminates the problems conventional attenuators bring to a passive pre. As always there are trade-offs to be considered. I bet the Van Den Hul is a nice unit provided it's matched to the right amp. That is the key to any of these systems...another advantage the active pre has over the passive...it can be used with just about any amp made and the result will be predictable (as long as there is not a gross impedance mismatch). Of course you could add a zero gain buffer after the passive pre if need be but that is somewhat counterproductive to the idea of the passive unit.
 
As for the outputs on the Phoenix and RE1 I haven't measured them but I would guess they are double the 2.0V standard (for balanced mode) I'd have to guess they are anywhere from 4-5.0V and 2.0-2.5V SE'd. I should measure them and find out.
 
Peete.

 

[Charnwood]

BenBau: How much time do you have on your C1 Masters?
 
I've had my C1 Masters for nearly a month and for about the first 30 hours they sounded lean and too quiet and I'm wondering if this is what you are hearing with your C1 Masters. This is 30 hours with music playing, just leaving them powered on seemed to have little effect. Just after I passed the 30 hour mark I left them powered on over night without any music playing only to discover the next they had lost much of what they had gained the previous day. But a couple of hours playing music at low volume and they were sounding better than they had the previous evening. Since then they have settled down somewhat and have sounded okay even from power on. They are still running in and sound better some days than others but are improving as time goes on.

 
Quote:

 
 
Pricklely, I don't think there a problem with the relay banks under the circuit board in the amp box. There IS control of volume and I hear the volume relays clicking, but the max. volume is far too low. The input relays are also clicking, but not the way they should i.e. connecting the input signal to the amp circuit. The preamp button is properly working: my balanced connected C1 Masters produce unfortunately also too soft sound in preamp mode.
 

 

[BenBau]

I have.... about 10 minutes on them!
 
Awaiting my new C1s I took my gear apart to clean. The Phoenix was kaput when I reconnected it. It's on its way to China as we speak......

 

[les_garten]

Quote:

I have.... about 10 minutes on them!
 
Awaiting my new C1s I took my gear apart to clean. The Phoenix was kaput when I reconnected it. It's on its way to China as we speak......

Sorry to hear about your Phoenix!  That's a Drag.  Let us know what needed to be fixed on it when you get the Autopsy results!

 

[Pricklely Peete]

I wouldn't be surprised if the C1's take a really long time to settle fully. The FBI-500 I rebuilt ( a few months back) and gave to a friend for his BD has been running daily (6-8 hours or so) for the last 2.5 months (turned off at night) and it still isn't run in fully. The C1 Masters have 48 power transistors and 210,000uf of mains filtering each (IIRC, while the FBI-500 has 24 transistors, 12 per channel, and 140,000uf of filtering)....that means a long burn in period.
 
I wouldn't be surprised if the C1's take anywhere from 500 to over 1K hours to reach their full potential.
 
Sorry to hear of your amp return  BenBau, hopefully the turnaround is quick.
 
Peete.

 

[Charnwood]

Quote:

I wouldn't be surprised if the C1's take a really long time to settle fully. The FBI-500 I rebuilt ( a few months back) and gave to a friend for his BD has been running daily (6-8 hours or so) for the last 2.5 months (turned off at night) and it still isn't run in fully. The C1 Masters have 48 power transistors and 210,000uf of mains filtering each (IIRC, while the FBI-500 has 24 transistors, 12 per channel, and 140,000uf of filtering)....that means a long burn in period.
 
I wouldn't be surprised if the C1's take anywhere from 500 to over 1K hours to reach their full potential.
 
Sorry to hear of your amp return  BenBau, hopefully the turnaround is quick.
 
Peete.

Thanks for this. I'm managing about 40 hours a week so it could be 2011 before mine have fully settled.

 Still, they're sounding very good even now.
 
Edit: Just had some new longer balanced cables arrive so I can now connect the C1's to my Phoenix.  

 

[tim3320070]

That should sound very nice. I have my Phoenix hooked to an Emotiva XPA-2 and it sounds great (not sure if it's better than the FBI-500 I had but I may get a C10 amp someday to compare).

 

[Pricklely Peete]

I'm just about finished Phase 2 of the Phoenix Max mod. I had the preamp/headamp switch fail on me last evening (those bad caps from the first 10 units are the cause I'm almost certain). There are six of them near the jack panel that I replaced with exact value Elna cerafine/Panasonic FM and Nichicon FG same value as stock but the Panny FM caps are 470uf 35V rather than 470 16V.
 
Getting the relay banks off the underside is major PITA since the wiring on one end of them is custom with pins/socket on the other end.....as a result of that I can't decide if it's worth pulling the last Nover caps for Nichicon KZ Muse or just leave them be....it's a fiddly business to get to those 12 x 100uf cap pads.
 
Anyway having the amp go on me last evening gave me the kick in pants I needed to get the mod completed and to change those faulty caps out at the same time. Hopefully that swap will bring the amp back to proper function .....here's a pic of what has been done so far (just 12 caps to go if I decide to pull the relay banks). I'm waiting on a question that I asked of Kingwa to be answered before testing/reassembly.
 
In the pic are 16 x Nichicon 100uf 25V KZ Muse, 4 x 4700uf 35V FW, 2 x 100uf 25V FG, 1 X 2200uf 35V FG (back half of pcb out of view in this pic), 2 x Elna 4.7uf 50V cerafine, 2 x 470uf 35V Panasonic FM.
 

 
 
EDIT : Important note about polarity of the right hand pair of large caps (1500uf stock, 4700uf 35V Max mod). The silk screen of the cap's polarity is incorrect. As you see from the pic the negative pole of the FW caps (all 4) are installed facing left. The silk screen of the right side  pair has opposite polarity indicated on the pcb which is wrong. All other silk screen symbols are correct, it's just these two spots that are wrong. A good idea for reference is to take a pic of the entire pcb before getting started (if one decides to tackle this mod) that way you can double check cap polarity before first power up and avoid any costly errors. I'm not sure how many units have this error but I would imagine that has been taken care of by now. At any rate if you have an early production Phoenix this silk screen error in the event off a possible DIY mod, please keep this information in mind when installing the new caps.
 
Peete.
 

 

[les_garten]

As Usual...
 
Great Googly Moogly!
 
Lot of work there!
 
I was wondering how you were going to do those relays on the bottom.