reducing weight? 
this is not sport car like zonda , this is more like freightliner truck in car world
and I think there can be changed few parts to achieve better sound-
1)transformer- to tribute audio custom with internal shield
2)diodes- to newest ,fastest
3)resitors- to audiophyle types with low noise, inductance, and discortion (caddock mk132,mp 930/850, dale, etc)
4)power suply capacitors to siemens/epcos sikorel 125/105 series
5)shunt power supply with silver oil foil capacitors
6)replace panasonic caps to black gate n/nx
also extra folowing modifications can be done with some minor improvvements(audible or just phycological-depends on your setup ant personality )
7)replace xlr and/or rca wires to audiophile types(kimber kcag for example) to sockets from pcb
8)replace all power supply wires to kimber 8tc for example or some monocrystal wires.
9) replace power, rca and xlr socket to better quality(speaker terminals for my opinion is very good)
this is not sport car like zonda , this is more like freightliner truck in car world and I think there can be changed few parts to achieve better sound-
1)transformer- to tribute audio custom with internal shield
2)diodes- to newest ,fastest
3)resitors- to audiophyle types with low noise, inductance, and discortion (caddock mk132,mp 930/850, dale, etc)
4)power suply capacitors to siemens/epcos sikorel 125/105 series
5)shunt power supply with silver oil foil capacitors
6)replace panasonic caps to black gate n/nx
also extra folowing modifications can be done with some minor improvvements(audible or just phycological-depends on your setup ant personality
)7)replace xlr and/or rca wires to audiophile types(kimber kcag for example) to sockets from pcb
8)replace all power supply wires to kimber 8tc for example or some monocrystal wires.
9) replace power, rca and xlr socket to better quality(speaker terminals for my opinion is very good)
1)transformer- to tribute audio custom with internal shield
2)diodes- to newest ,fastest
3)resitors- to audiophyle types with low noise, inductance, and discortion (caddock mk132,mp 930/850, dale, etc)
4)power suply capacitors to siemens/epcos sikorel 125/105 series
5)shunt power supply with silver oil foil capacitors
6)replace panasonic caps to black gate n/nx
minor improvvements(audible or just phycological-depends on your setup ant personality )
7)replace xlr and/or rca wires to audiophile types(kimber kcag for example) to sockets from pcb
8)replace all power supply wires to kimber 8tc for example or some monocrystal wires.
9) replace power, rca and xlr socket to better quality(speaker terminals for my opinion is very good)
There are high quality parts in this unit. Sit back and enjoy it. If you want to $#%# around with an amp build a DIY AX.
2)diodes- to newest ,fastest
3)resitors- to audiophyle types with low noise, inductance, and discortion (caddock mk132,mp 930/850, dale, etc)
4)power suply capacitors to siemens/epcos sikorel 125/105 series
5)shunt power supply with silver oil foil capacitors
6)replace panasonic caps to black gate n/nx
minor improvvements(audible or just phycological-depends on your setup ant personality
)7)replace xlr and/or rca wires to audiophile types(kimber kcag for example) to sockets from pcb
8)replace all power supply wires to kimber 8tc for example or some monocrystal wires.
9) replace power, rca and xlr socket to better quality(speaker terminals for my opinion is very good)
There are high quality parts in this unit. Sit back and enjoy it. If you want to $#%# around with an amp build a DIY AX.
Not having a schematic or actual unit in front of me, I'd be reduced to guessing. The only...and I mean only thing I would consider is if the unit uses Panasonic metallized polyester coupling caps (very likely 10uF 100V, brown in color) at the input, then you might think about either bypassing them with a polystyrene cap or replacing them with another good film cap. I have not done a scorched earth comparison of all the film caps on the market in quite some time, but I did a limited comparison between the Panasonic caps and a couple of others a few years ago. All I can say is that the Panasonic caps are okay in the bass, but get less impressive as you go up in frequency. For a modestly-priced film cap, I recommend WIMA polypropylene. The best film caps I have worked with--though expensive--are the MIT RTX polystyrene. MIT is also known to some as Rel Cap (Reliable Capacitor).
I know of few people who have actually gone to the trouble to buy samples of a wide variety of caps and compare them. As a result, you tend to get a lot of people telling you that they like Brand X. If you ask them what they compared Brand X to, they start mumbling and making excuses to the extent that 'everybody knows that Brand X is the best.' I've already given my disclaimer, though you'll find MIT/Rel Cap parts in a lot of high end gear. Of course, you can find Hovland, and any number of other brands as well. If you have a favorite film cap, feel free to try that.
If the amp doesn't use coupling caps, I withdraw my suggestion, but I seem to recall Nelson saying that there were caps at the input.
If your amp is under warranty it would be wise to see what Pass Labs' policy is regarding modifications to their equipment before warming up your soldering iron. There was another thread here just within the last week or so wherein (if I understood correctly) someone modified a Pass Labs amp. Nelson's comments in that thread sounded pretty grim to me. Don't say you weren't warned.
Grey
I know of few people who have actually gone to the trouble to buy samples of a wide variety of caps and compare them. As a result, you tend to get a lot of people telling you that they like Brand X. If you ask them what they compared Brand X to, they start mumbling and making excuses to the extent that 'everybody knows that Brand X is the best.' I've already given my disclaimer, though you'll find MIT/Rel Cap parts in a lot of high end gear. Of course, you can find Hovland, and any number of other brands as well. If you have a favorite film cap, feel free to try that.
If the amp doesn't use coupling caps, I withdraw my suggestion, but I seem to recall Nelson saying that there were caps at the input.
If your amp is under warranty it would be wise to see what Pass Labs' policy is regarding modifications to their equipment before warming up your soldering iron. There was another thread here just within the last week or so wherein (if I understood correctly) someone modified a Pass Labs amp. Nelson's comments in that thread sounded pretty grim to me. Don't say you weren't warned.
Grey
mert said:
Mert,
What exactly do you dislike about the amp as it is? If you could discribe the aspects of what you're hearing that you'd like to change, it would be helpful. Also, it would help to know what is the source and what speakers you're using.
One other IMPORTANT thing, if you haven't Acoustically Treated your listening room you should do that first. I personally wouldn't do another thing until that's done, otherwise you'll be wasting your time and wouldn't be able to tell if any real improvements have occurred after the equipment mods.
Best Regards,
TerryO
the link for my setup:
http://forum.audiogon.com/cgi-bin/fr.pl?vopin&1178405064&read&3&4&
I believe Single Ended Solid State Class A amplifier concept is right way for best sound reproduction. X250.5 is a very good amp indeed. However, it has limited Class A performance(first 30 watts Class A I guess according to Mr. Pass) When you look X350.5, those figures will be around 40 watts in 8 ohm. Since There are not much powerfull stereo XA.5 series amps,(XA30.5), only way for me is playing with my X250.5. I am sure that this amplifier has potential of tunning. I don't think upgrading it to X350.5 will bring me marginal improvements since my setup has very interesting cabling and power conditioning that can compensate absence of X350.5.
I am looking for best of the best stereo amplifier from USA, right at this moment, there is no candidate; so , I may modify mine while Mr. Pass makes one
http://forum.audiogon.com/cgi-bin/fr.pl?vopin&1178405064&read&3&4&
I believe Single Ended Solid State Class A amplifier concept is right way for best sound reproduction. X250.5 is a very good amp indeed. However, it has limited Class A performance(first 30 watts Class A I guess according to Mr. Pass) When you look X350.5, those figures will be around 40 watts in 8 ohm. Since There are not much powerfull stereo XA.5 series amps,(XA30.5), only way for me is playing with my X250.5. I am sure that this amplifier has potential of tunning. I don't think upgrading it to X350.5 will bring me marginal improvements since my setup has very interesting cabling and power conditioning that can compensate absence of X350.5.
I am looking for best of the best stereo amplifier from USA, right at this moment, there is no candidate; so , I may modify mine while Mr. Pass makes one
Babowana said:
my speakers 4 ohm, 86-88 db, but may drop to 3.2 ohm. It seems around -45db, amp will switch to Class AB. However, recording quality of the Sacd/CD may vary: with some cd, you may make a critical listening -45db, amp will be still in Class A mode. With some cd's speaker require more power, matterfact , you make listening in Class AB mode.
I always tried to correct the things with powerconditioning and cables, using very reliable source as Accuphase, ....However, I reached theoritical limit. Recently, I purchased Acrolink 7N-PC7100 mexcel powercord(US retail 2400usd) for X250.5. This was the last thing that could be made on an amplifier which retails for 7500usd.
Now it is turn for internal modifications!
Hi Mert
This is probably not what you want to hear but if i were you i'd get rid of the pretty cupboard and buy a high performance rack, something with carbon/kevlar shelves and properly designed vibration dissipation. I'd bet anything the improvement will exceed many times a simple cap upgrade.
This is probably not what you want to hear but if i were you i'd get rid of the pretty cupboard and buy a high performance rack, something with carbon/kevlar shelves and properly designed vibration dissipation. I'd bet anything the improvement will exceed many times a simple cap upgrade.
mert said:
Papa says:
"The Pass Laboratories™ X250.5 is optimized for loads nominally rated at 4 ohms and above. You can run the amplifiers into a lower nominal impedance without difficulty, and we are not aware of a speaker on the market that presents unusual difficulty with these amplifiers."
The amp seems to have enough Class A bias current down to nominal impedance of 4 ohms. Nevertheless, if you are not satisfied fully, I would consider increasing Class A bias current and decreasing the rail voltages (considering the same heatsink temp) rather than any other mod. I believe that Papa would suggest how to do through e-mail if you kindly send him your question.
Good luck!
analog_sa said:
moe29 said:lovely equipment...
but, i can't imagine that those speakers are performing at their best placed like that.
I would say spend the money on getting a new room.
Let those puppies breathe! (or Sophia's)
My son is now 3 years old, I had to protect my gear for a while. I am changing my rack and speaker placement this weekend.(coincident)
All of you right.My current rack system only avoid potential damage from kid.
mert said:
While I see here a lot of talk about pressure levels, class A and B, power cords, price tags, you never mentiond what particular aspects of sound reproduction you'd like to improve. Without clearly defined objectives, modifications for a sake of modification have no sense at all.
And even if you know what you'd like to improve, it takes a lot experimentation, comparisons, listening tests to make a mod worthwile. It's almost like building brand new amplifier
If I modify a piece of equipment, it ususally takes 4 months or so of constant listening and changes. And there is some equipment I wouldn't touch, because modifications will certainly affect the resale value or simply are not worth the time invested.
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