I could not tell a huge difference betwen the ST and AD version. There was one but it was subtle, but worth the $$. Apparently just a better opamp (AD has an AD8620, don't remember the ST version opamp)
The new HQ version is supposedly quite nice, but I have never heard one (way too expensive)
I built my own power supplies - as the Slit Foil HQ power supplies were too expensive. Nice pair of 10,000uf Nichicon LQ caps per rail with beefy rectifier always worked well.
For my "Ref" UCD400AD, I used two monster 56,000uf bypassed with a 4uf polypropylene cap per rail with beefy rectifier. Took almost a minute to drain down after shutting the amp.
The new HQ version is supposedly quite nice, but I have never heard one (way too expensive)
I built my own power supplies - as the Slit Foil HQ power supplies were too expensive. Nice pair of 10,000uf Nichicon LQ caps per rail with beefy rectifier always worked well.
For my "Ref" UCD400AD, I used two monster 56,000uf bypassed with a 4uf polypropylene cap per rail with beefy rectifier. Took almost a minute to drain down after shutting the amp.
Hi guys,
I know I should wait a while longer to get used to the sound of this amp & to let it burn in but I couldn't help myself because I'm an inveterate tweaker, so I started on some mods while waiting for parts to arrive. I figure the amp has already burned in as it was open box & I hear no change in sound the more I play it. Also I think I know the sound of it by now.
What I did was bypass some caps on the PS board with OsCon 2.2uF caps - these bypasses were mostly at PS supply to voltage regulators or before the SMPS trafos.
I also removed one of the 1,000uF XE caps at the output stage & replaced it with a socket to enable me to test a variety of caps that I have being sent to me, Black Gates,etc. I've tried a 2,200uF Panasonic FC here but highs are not as clear as with the XE caps.
I've done some other cap & wiring mods but I must go now & have a long listen to evaluate changes. Will report any findings here soon!
I know I should wait a while longer to get used to the sound of this amp & to let it burn in but I couldn't help myself because I'm an inveterate tweaker, so I started on some mods while waiting for parts to arrive. I figure the amp has already burned in as it was open box & I hear no change in sound the more I play it. Also I think I know the sound of it by now.
What I did was bypass some caps on the PS board with OsCon 2.2uF caps - these bypasses were mostly at PS supply to voltage regulators or before the SMPS trafos.
I also removed one of the 1,000uF XE caps at the output stage & replaced it with a socket to enable me to test a variety of caps that I have being sent to me, Black Gates,etc. I've tried a 2,200uF Panasonic FC here but highs are not as clear as with the XE caps.
I've done some other cap & wiring mods but I must go now & have a long listen to evaluate changes. Will report any findings here soon!
rha61 said:
This was also my experience with unmodded XR45 versus stock UCD180AD. The Panasonic was neutral... the UCD was just better.
ELD or anyone else, (ie: XR55 or XR57 speaker out board)
When you removed the stock speaker binding post assembly (with all the relays and such on it), and replaced it with the upgraded posts and wiring, do you notice and turn on popping or clicking now that there is no signal relays and the rest of the mess on that circuit board into the equation now??
Thanks!
When you removed the stock speaker binding post assembly (with all the relays and such on it), and replaced it with the upgraded posts and wiring, do you notice and turn on popping or clicking now that there is no signal relays and the rest of the mess on that circuit board into the equation now??
Thanks!
The UCD180ST was nice, UCD180AD nicer, and 400ST was better yet, and the 400AD was best of that bunch.
I would assume the 400HG would follow that trend, but moved on to class A before getting there.
I would assume the 400HG would follow that trend, but moved on to class A before getting there.
One comment that comes accross in my showcasing the Xr57 for a number of people is that it is super fast but maybe lacking in the presentation of harmonics of the instrument/sound - a bit more lingering on the inner detail of the tone rather than a rush onto the next note/tone!
Is this what you mean by the naturalness of the UCD versus the XR amps?
Has this ever been addressed by mods to the XRs? Is it a case of more second harmonic in the mix?
Edit: oh BTW, I blew my beloved Rogers LS3/5A speakers with a late night test on the amp - Doh!
Is this what you mean by the naturalness of the UCD versus the XR amps?
Has this ever been addressed by mods to the XRs? Is it a case of more second harmonic in the mix?
Edit: oh BTW, I blew my beloved Rogers LS3/5A speakers with a late night test on the amp - Doh!
Hi guys,
Just wanted to report my latest round of mods and the results.
Mods:
1) Replace the stock C707 with a Jensen 4-poles 1,500uF/200V cap. Cut tracings to isolate input and output lines. ($62)
2) Replace the stock diodes bridge with a DIY Fairchild Stealth II diodes bridge. ($5)
3) Added two Panasonic TS-HA 15,000 uF caps after the ZE caps and before the Nichicon KZ/ Vishay caps. ($20)
4) Rewire the power lines to directly connect to the + and - tracings of the main board from the power board.
On a side note: I upgraded the power outlet to a FIM 880 (G)
After a week of listening from low to high volume, I can say that the results of the latest mods have elevated the Panny to an exceptional level. The 2nd harmonics are all there now in great details and depth. Violins and pianos sound natural and smooth. Imaging is rock solid. The stock sonic signature is still there, but the depth, smoothness, and soundstage are so much better. I'm very happy with the results. I think anything else that is done from this point on is just icing on the cake.
Crazy D,
I do notice a low clicking noise when I first turn the unit on.
Evad,
Both the Panasonic SAXR700 and the Sony DA7100ES are two units that have pre-outs. You might want to check into them.
Just wanted to report my latest round of mods and the results.
Mods:
1) Replace the stock C707 with a Jensen 4-poles 1,500uF/200V cap. Cut tracings to isolate input and output lines. ($62)
2) Replace the stock diodes bridge with a DIY Fairchild Stealth II diodes bridge. ($5)
3) Added two Panasonic TS-HA 15,000 uF caps after the ZE caps and before the Nichicon KZ/ Vishay caps. ($20)
4) Rewire the power lines to directly connect to the + and - tracings of the main board from the power board.
On a side note: I upgraded the power outlet to a FIM 880 (G)
After a week of listening from low to high volume, I can say that the results of the latest mods have elevated the Panny to an exceptional level. The 2nd harmonics are all there now in great details and depth. Violins and pianos sound natural and smooth. Imaging is rock solid. The stock sonic signature is still there, but the depth, smoothness, and soundstage are so much better. I'm very happy with the results. I think anything else that is done from this point on is just icing on the cake.
Crazy D,
I do notice a low clicking noise when I first turn the unit on.
Evad,
Both the Panasonic SAXR700 and the Sony DA7100ES are two units that have pre-outs. You might want to check into them.
Thanks ELD for the pics and update.
I noticed on the schematic for the XR-57 (I know you have the XR-55) that they have control lines for the dual amp purpose to open or close the relays. However I assume this could just be all bypassed with a direct point to point feed from the amplifier board outputs straight to the binding posts since I would only use the unit in that sense and nothing else.
BTW, change that row of blue, water based caps to Rubycon 1000uf/50v ZL's.
I wonder how those CREE zero recovery diodes would sound in this receiver? Someone should do a diode test and report back sometime.
thanks
I noticed on the schematic for the XR-57 (I know you have the XR-55) that they have control lines for the dual amp purpose to open or close the relays. However I assume this could just be all bypassed with a direct point to point feed from the amplifier board outputs straight to the binding posts since I would only use the unit in that sense and nothing else.
BTW, change that row of blue, water based caps to Rubycon 1000uf/50v ZL's.
I wonder how those CREE zero recovery diodes would sound in this receiver? Someone should do a diode test and report back sometime.
thanks
Well done eld,
I have a lot to do to catch up with you but I may well test out some 12V batteries I have spare, to power the output board. This might avoid the need for all the PS conditioning that this amp needs?
My tests of the voltage control gave me these figures
dB Voltage
-79 to -44 10.55
-43 11.28 (+0.63V)
-42 12.54 (+1.26V)
-41 14.18 (+1.64V)
-40 16.03 (+1.85V)
-39 18.08 (+2.05V)
-38 20.32 (+2.24V)
-37 22.76 (+2.44V)
-36 25.58 (+2.82V)
-35 28.99 (+3.41V)
-34 32.60 (+3.61V)
-33 36.61 (+4.01V)
-32 to 0 41.40 (+4.79V)
These might be different from others as I'm using a stepdown trafo to give 106V input voltage. So from this digital vol control operates from -79 to -44dB and at the louder levels -32 to 0dB. In between PS voltage is varied to achieve volume control!
So I listen at -41/42 for reasonable levels so that's about 1 battery & loud would be 2 batteries giving 24/25Volt for -36dB.
My question is to anyone who may have done this before - can I connect battery to output board before main PS is powered on?
I have a lot to do to catch up with you but I may well test out some 12V batteries I have spare, to power the output board. This might avoid the need for all the PS conditioning that this amp needs?
My tests of the voltage control gave me these figures
dB Voltage
-79 to -44 10.55
-43 11.28 (+0.63V)
-42 12.54 (+1.26V)
-41 14.18 (+1.64V)
-40 16.03 (+1.85V)
-39 18.08 (+2.05V)
-38 20.32 (+2.24V)
-37 22.76 (+2.44V)
-36 25.58 (+2.82V)
-35 28.99 (+3.41V)
-34 32.60 (+3.61V)
-33 36.61 (+4.01V)
-32 to 0 41.40 (+4.79V)
These might be different from others as I'm using a stepdown trafo to give 106V input voltage. So from this digital vol control operates from -79 to -44dB and at the louder levels -32 to 0dB. In between PS voltage is varied to achieve volume control!
So I listen at -41/42 for reasonable levels so that's about 1 battery & loud would be 2 batteries giving 24/25Volt for -36dB.
My question is to anyone who may have done this before - can I connect battery to output board before main PS is powered on?
Hey CrazyD,
Your post crossed with mine - I have the XR57 & have bypassed speaker board for Front L+R speakers - just testing now - too early to report findings.
Are you sure the Rubycon Zls sound better than the Blue XE caps - I have removed one and replaced with a socket to try out different caps - tried Panasonic FC = not nearly as good in the highs as the XEs
Are the CREE diodes better than soft recovery?
Your post crossed with mine - I have the XR57 & have bypassed speaker board for Front L+R speakers - just testing now - too early to report findings.
Are you sure the Rubycon Zls sound better than the Blue XE caps - I have removed one and replaced with a socket to try out different caps - tried Panasonic FC = not nearly as good in the highs as the XEs
Are the CREE diodes better than soft recovery?
jkeny said:
with a high resolution system ( mine has Esotar tweeters and all the contacts the signal passes through are regularly cleaned ) , there is something a bit artificial in the equibit midrange and treble although the modded 45 presentation is very nice and absolutely incredible for the price
the UCD needs some testings ( opamp in the input stage , separated PS for power stage ... )
sorry for your LS3/5
when i tweak an amp , i always measure the output voltage before connecting speakers because i have blown very expensive and rare woofer
A question I've been meaning to ask is what is the circuit on the output of each channel signal - I've ringed it in the attached PDF - the service manual calls it a switch comprising two transistors & surrounding parts.
Could it be a sound level switch for each channel? I'm wondering what sonic effect it might have on the amp.
I have checked XR45 schematic & it doesn't have this circuit!
Edit: thanks rha61, I know I broke my 2 golden rules - test for DC on cable before connecting speaker & only use cheap test speaker. What can I say I was tired, had done the mod on one channel already & got complacent.
Could it be a sound level switch for each channel? I'm wondering what sonic effect it might have on the amp.
I have checked XR45 schematic & it doesn't have this circuit!
Edit: thanks rha61, I know I broke my 2 golden rules - test for DC on cable before connecting speaker & only use cheap test speaker. What can I say I was tired, had done the mod on one channel already & got complacent.
I will only be using the XR57 via BI-AMP/BI-WIRE to drive my speakers as this is the best sounding method so I have to get confirmation that bypassing the speaker output board is going to work.
also, I will report back when I change out the apparent high jitter clocking circuit that feeds into the Audio DSP chip with a aftermarket ultra low jitter clock. I am also considering replacing the HDMI RX chip clock out as well but thats further down the road.
The ZL's are also a water based solution capacitor and I perfer them to the blue XE caps. I took the Blue XE caps I took out of my XR-55 and tried them in other electronics for testing and thought the ZL's were better across the entire frequency spectrum. But thats just my own experience and listening experience so mileage might vary with different systems..?
also, I will report back when I change out the apparent high jitter clocking circuit that feeds into the Audio DSP chip with a aftermarket ultra low jitter clock. I am also considering replacing the HDMI RX chip clock out as well but thats further down the road.
The ZL's are also a water based solution capacitor and I perfer them to the blue XE caps. I took the Blue XE caps I took out of my XR-55 and tried them in other electronics for testing and thought the ZL's were better across the entire frequency spectrum. But thats just my own experience and listening experience so mileage might vary with different systems..?
Crazy_D said:
they think here that ZL are better than Blackgate :
http://www.referenceaudiomods.com/M...Screen=CTGY&Store_Code=RAM&Category_Code=RUBY
Oops, forgot to include attached file with last post - this is the output circuit circled in PDF that I think has to do speaker distance setting (delay) + whatever else.
If you're only using this for stereo then this is not needed - removing two 220K resistor on each channel would disconnect this circuit, I think
Edit: CrazyD, have you figured out how to connect pin 30 of the DIR AK4114 with the new clock? I'm looking to do the same
If you're only using this for stereo then this is not needed - removing two 220K resistor on each channel would disconnect this circuit, I think
Edit: CrazyD, have you figured out how to connect pin 30 of the DIR AK4114 with the new clock? I'm looking to do the same
One other issue that may have an impact on us XR57 owners - the digital input SPDIF circuit is different to the models that went before - before, a pulse transformer was used, now just an inverter is used with no transformer.
Can any owners of 55 or before confirm the DIR that is on the DSP board? - on the XR57 it is an AK4114 & the SPDIF schematic given in the AK4114 datasheet is pretty much the one used on the Panasonic - I just wonder if previous models used a different DIR?
Can any owners of 55 or before confirm the DIR that is on the DSP board? - on the XR57 it is an AK4114 & the SPDIF schematic given in the AK4114 datasheet is pretty much the one used on the Panasonic - I just wonder if previous models used a different DIR?
I have been thinking about how I can power the output stage using one or more batteries. I believe battery power with caps will represent a stiff, clean PS & even if not left in permanently will give the reference by which mods to the PS can be assessed!
Two concerns I have (I don't want to blow an amp after blowing my speakers):
1 - Does the power-up sequence matter? ie. can the power to the output stage be on before the low level power is applied from the PS?
2 - How do I make sure the sense signal is OK? The +sense & -sense are the voltage value (I think) which is fed back from the output stage & used in conjunction with vol control to ensure the correct voltage for the dB level.
I think the answer to 1 above was given on the "Anyone for a digital amplifier" thread and the sequence doesn't matter? Can anyone confirm?
I believe I have the answer to 2 - as I'll be disconnecting the flat cable that brings PS to the output board & this cable has both Sense & PS, I thought that I could just loop the PS to the sense on that cable! Again can anyone see a flaw with this?
I know the vol control will be flat in the -43 to -33 region of the vol but I can see what this works out at, soundwise!
Two concerns I have (I don't want to blow an amp after blowing my speakers):
1 - Does the power-up sequence matter? ie. can the power to the output stage be on before the low level power is applied from the PS?
2 - How do I make sure the sense signal is OK? The +sense & -sense are the voltage value (I think) which is fed back from the output stage & used in conjunction with vol control to ensure the correct voltage for the dB level.
I think the answer to 1 above was given on the "Anyone for a digital amplifier" thread and the sequence doesn't matter? Can anyone confirm?
I believe I have the answer to 2 - as I'll be disconnecting the flat cable that brings PS to the output board & this cable has both Sense & PS, I thought that I could just loop the PS to the sense on that cable! Again can anyone see a flaw with this?
I know the vol control will be flat in the -43 to -33 region of the vol but I can see what this works out at, soundwise!
Hi jkeny - I got your pm but haven't had a chance to respond.
With respect to my battery experiments on the XR25, I found
a) I connected the bridge supply first (with low-level circuits off) and simply left it connected. Leakage even when powered on but with zero digital signal was neglibigle; I disconnected the charger for listening and reconnected it without disconnecting from the amp.
b) the xr25 does not have any output sense; I thought only the XR10 had this. If the XR57 has brought this back, you may be on your own for determining the characteristics.
With respect to my battery experiments on the XR25, I found
a) I connected the bridge supply first (with low-level circuits off) and simply left it connected. Leakage even when powered on but with zero digital signal was neglibigle; I disconnected the charger for listening and reconnected it without disconnecting from the amp.
b) the xr25 does not have any output sense; I thought only the XR10 had this. If the XR57 has brought this back, you may be on your own for determining the characteristics.
Thanks dwk123,
I guess I'm going to have to experiment!
Do you reckon the sense function is as I said like a Kelvin sense signal seen here in the Hypex HG linear regulators? http://www.google.com/url?sa=t&ct=r...lY4BrNng5MFdfWcNg&sig2=1c6QkcSQEx1suClVr8I1CQ
Edit: Also used in the Jung Super Regulator http://www.alw.audio.dsl.pipex.com/jung_schematic.htm
I guess I'm going to have to experiment!
Do you reckon the sense function is as I said like a Kelvin sense signal seen here in the Hypex HG linear regulators? http://www.google.com/url?sa=t&ct=r...lY4BrNng5MFdfWcNg&sig2=1c6QkcSQEx1suClVr8I1CQ
Edit: Also used in the Jung Super Regulator http://www.alw.audio.dsl.pipex.com/jung_schematic.htm
I connected the battery late tonight & need to listen for extended period but no obvious difference in the sound of the amp - maybe a little smoother, I'm not sure. I was expecting more of a diff,
Could be that I connect the battery direct without caps! (How much capacitance did you use dwk123?) Could be that the step-down trafo is providing a good clean PS feed from the mains? Could be that the PS in the XR57 is sophisticated ( I was impressed by the Kelvin sense used in the PS to take account of the inductance & resistance of the cables feeding PS to the output board)
I will put in some capacitance & have a longer audition.
I basically disconnected the cable from the PS board to the main board. This cable feeds PS & gnd to main board & takes back +sense & -sense from the main board as Kelvin sense. I connected the +sense to the +V on the cable & the -sense to gnd on the cable (basically connected pin 10 to pin 8 & pin 9 to pin 7).
This seems to work great - with just one battery of 11.35V the volume works as it did when connected to mains PS. I was expecting a flat area in the middle where variable voltage controls volume but I'm not sure I went into that area - didn't crank it all the way up as it was late at night.
Could be that I connect the battery direct without caps! (How much capacitance did you use dwk123?) Could be that the step-down trafo is providing a good clean PS feed from the mains? Could be that the PS in the XR57 is sophisticated ( I was impressed by the Kelvin sense used in the PS to take account of the inductance & resistance of the cables feeding PS to the output board)
I will put in some capacitance & have a longer audition.
I basically disconnected the cable from the PS board to the main board. This cable feeds PS & gnd to main board & takes back +sense & -sense from the main board as Kelvin sense. I connected the +sense to the +V on the cable & the -sense to gnd on the cable (basically connected pin 10 to pin 8 & pin 9 to pin 7).
This seems to work great - with just one battery of 11.35V the volume works as it did when connected to mains PS. I was expecting a flat area in the middle where variable voltage controls volume but I'm not sure I went into that area - didn't crank it all the way up as it was late at night.
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