macka said:
Sorry, you are right ofcourse! If I had an original, I wouldnt modify anything....
🙂
macka said:
First, thank you for taking the time and share the photos with us.
Assuming yours is X250.5 and not the X150.5, then I'm confused. The caps shown (50V) do not add up for 250W/8ohm, for me. From my rough cal., they should be rated >60V. Unless the thing is in balance mode at the output. I guess I'll never know.
"CN8": 2 larger white wires are the output.
2 smaller wires, red and blue, come straight the the rectifier's
output ? (or are they coming off from another bank of capacitors
from the bottom some where)
If direct, I strongly disagree with your statement. I highly repect the
designer of this unit. I admire his innovated designs. However, 20K for each rail at less than 50V is hardly enough (for me) for an amp at this caliper. There must be a reason somewhere.
I, also, repect what you're hearing. However, I still stand firm on my
previous posts.
BTW, when you say "they are strategically placed where they need to be. While there is nothing small about 10,000 uf, multiple use of these at the high speed rectifiers and on the board right next to the output stage is brilliant",
I assume you mean physically. The rectifier is approx. 10" away some where. IHMO, whichever the case, it's not an issue. Electrical distance is the thing. These have very low energy storage and by no mean low ESR (they are general purpose Panasonic as far as I can tell from the pictures).
The way it looks, if I have do it myself, I step up to 40-50mm (low ESR) size caps assume the current ones is 30-35mm caps. Go as high as I can to the ceiling. While I'm at it, hang a couples of high quality film caps somewhere.
As they say, you never know until you try.
Regards.
macka said:
Thank you for answer my balance puzzle.
macka said:
Perhaps to achieve better sound based on one's preference.
With all respects, I don't share your view of x250.5 being the best sounding amp neither, as I sense. What about the newer XA and XA .5 series amps. Are they for better or for worse ? What I'm certain is they correct some short falls of previous series. IMHO, it's all about best compromises. And I truly admire Mr. NP for his compromises to seemingly make their products highly musical to happy customers.
Now that's business.
Regards.
Zen Mod said:
if nothing else - thing is in balance mode at output .........
Thank you.
BTW, what does this mean
? 😀 😀 😀 I should have look more closely at the PCB traces lead to the output wires. So, balanced output, 3 pairs each phase !
Regards.
PS (to all): who owns one of these things. I don't. Just try to be helpful.
diy_Qui said:
diy_Qui,
The intent of my posts here are some helpful advise on an enquiry into the X250.50. I never said it was the best or the worst but its okay if you want to think that.
To introduce and encourage diy modifications into the commercial product is neither desirable or productive.
If you want to tweak and play around there are many diy amps that Nelson has generously offered. I have built numerous diy Alephs over years, a Zen V9, a JLH, and an SKA.
I love them all but I am long past tweaking them as they are what they are. When someone comes along with a better active gain device , ie a 100 watt Jfet I might re-visit them.
The key point here was don't mess with the commercial product by being a diy smarty and destroying it then expect free help from the factory.
As often happens these threads drift off topic
iMac
As a foot note and for the benefit is diy_Qui who appears to be unfamilair with the product there appears to be a total of 100,000 uf filter capacitance per channel in this model with local bypassing of 2200 uf if you care to count.
By virtue of a soft start device and a clever stand-by circuit the capacitors remain charged after initial switch on.
Mert,
Here is the X2.5 preamp which is quite compact and functional.
iMac
By virtue of a soft start device and a clever stand-by circuit the capacitors remain charged after initial switch on.
Mert,
Here is the X2.5 preamp which is quite compact and functional.
iMac
Attachments
macka said:
Perhaps, we misunderstood one another on this point.😉
macka said:
If you look at my posts again,
- I can not afford the thing
- Many IFs and MUSTs were given to mert
- Surely, one must be an idiot to do these things if not technically competent. Worse, expects the manufacturer to honor such action.
- Even though some products are better designed/engineered than others, in no way your first statement above can be true, generally. After all, how many threads on this board have to do with tweaking commercial products ?
- "diy smarty" I never try to be. If it appears that way. Be it ! Just try to be helpful to mert.
macka said:
I've not been able to afford such unit (x250.5). Usually, I don't tweak for the shake of tweaking. And never seem to have time for these things. I'm aware of those amps, thank you.
Can you share why "100 watt Jfet" is kindda special for you ? I assume you mean power Jfet as output devices.
BTW, how are we so sure x2.5 is better than the Boulder 810 in this setup as you seem to suggest, can we share this point ?
BTW, you can verify this for me, 60K of those 100K capacitance is from the front end PSU ? If so, I was referring to output PS.
That 2K cap must be low ESR Pan. cap ? FC ?
Regards.
Mert,
for having listened to the Sophias and the pass amps, with many combinations, I have to admit that I am surprised that you suspect the amp to limit your system, hopefully the wilsons you run aren't much dependant to the local size or acoustic(at least not as much as some other kind of spkrs using biggest woofers), but they have the qualities of their defaults, they sound smooth and are well toned, but highs are really coloured, and the spkr does not extend really deep in low end, also this spkr, whatever amp you'll use will sound a bit dark on many pianos recordings.
and you can't ask the amp to correct for all of those specificities.
as they are really expensive spkrs you should consider keeping them, and explore another side of the fun:
build a high end kit spkr, this will be fun, relatively inexpensive considering the kind of bucks you may spend for the gears you have, and you'll enjoy your Pass amp by exploring all the richness of it's sweet sound with high efficiency system...
why am I advising not to tweak your actual gears is that they are fully optimized , and your ressearch of sound would make a biggest step if you'd consider building yourself a second pair of spkr...
Vince
for having listened to the Sophias and the pass amps, with many combinations, I have to admit that I am surprised that you suspect the amp to limit your system, hopefully the wilsons you run aren't much dependant to the local size or acoustic(at least not as much as some other kind of spkrs using biggest woofers), but they have the qualities of their defaults, they sound smooth and are well toned, but highs are really coloured, and the spkr does not extend really deep in low end, also this spkr, whatever amp you'll use will sound a bit dark on many pianos recordings.
and you can't ask the amp to correct for all of those specificities.
as they are really expensive spkrs you should consider keeping them, and explore another side of the fun:
build a high end kit spkr, this will be fun, relatively inexpensive considering the kind of bucks you may spend for the gears you have, and you'll enjoy your Pass amp by exploring all the richness of it's sweet sound with high efficiency system...
why am I advising not to tweak your actual gears is that they are fully optimized , and your ressearch of sound would make a biggest step if you'd consider building yourself a second pair of spkr...
Vince
Hey guys!
those are some schweet pics!
Steenoe,
those are my kind of heatsinks AND caps! I briefly looked for Rifa in the US a few years back, here they go by Aerovox and it's not the same stuff. Anyways I could never find the supplier. Where do you get yours?
As for the 250.5 the balanced design allows to keep the PS voltage lower for the same amount of power, so 2x50V is plenty for a 250W amp.
The last time I heard a Pass Amp was a 250 hooked up to the open baffle proac speakers (don't remember the model) and it produced the best sound in the whole audio show. I think the speakers were not well designed since the scan speak woofer unit was moving +/- 10mm still the whole thing sounded great.
I imagine the .5 version would be giving better highs if nothing else.
those are some schweet pics!
Steenoe,
those are my kind of heatsinks AND caps! I briefly looked for Rifa in the US a few years back, here they go by Aerovox and it's not the same stuff. Anyways I could never find the supplier. Where do you get yours?
As for the 250.5 the balanced design allows to keep the PS voltage lower for the same amount of power, so 2x50V is plenty for a 250W amp.
The last time I heard a Pass Amp was a 250 hooked up to the open baffle proac speakers (don't remember the model) and it produced the best sound in the whole audio show. I think the speakers were not well designed since the scan speak woofer unit was moving +/- 10mm still the whole thing sounded great.
I imagine the .5 version would be giving better highs if nothing else.
macka said:
Sometimes they're right. Wilsons can be quite demanding of
control on the bottom end.
I have owned Watt/Puppies and I could hear a large difference
between and Aleph and an X amplifier, even though both were
operated in their linear region and had the same nominal specs,
including damping factor and bandwidth.
Where does the difference come from? We can only guess.
Nelson Pass said:
Thank you for the information Mr. Pass.
There we have it. I have no further question !
Regards.
grataku said:
As this seems to address to "Steenoe", but I take it as to counter my point due to its context.
"plenty" NOT. As we have new info. from Mr. Pass, I don't believe the increase is just for the shake of spending more money into a product.
Regards.
analog_sa said:
b-square said:
Wow, I just joined this board recently. Read more closely and found these. How friendly and helpful we are at diyaudio.
And some one has already called me "diy smarty".
So I'll know. All of this is fine on this Board ?
It is still unclear to me of what the original poster has intended to improve or what is that his system is lacking. I doubt that he will be able to hear any dramatical difference with any mod he does. The amp is already maxed and this is the first time in my life that someone stated that transformer in Pass Lab amp is not big enough or that there is not enough capacitance. Believe me - that is not the case with Pass Lab amps.
My advice would be not to waste the money and time in modding X250.5, but to go for additional XA amp, if you are after pure class A sound. Even XA30.5 will do great job in active set up just for the tweeters. Obviously it would be without any benefit running class A for the base speakers, and that fact enables you to have smaller amp for the tweets in the active set up.
If the case is that you are trying to gain more punch from the base - no tweeking will accomplish that short of adding one more amp or changing existing amp for X600 or x1000 (X600.5 or X1000.5) Only other option that could change the character of your base is adding EQ.
Besides above mentioned options, sometimes changing position of the speakers to the opposite set of walls instead of where they are now could be eye opener. I do understand the fact that you cannot move them from where they are right now. If you never tried you should do it jut for the sake of test. It is sometimes equal to astonishing revelation in just positioning speakers to opposite set of walls in regards to the bass performance. In some cases it is equal to almost doubling the power amp or adding new set of speakers. Like I mentioned - try it just for the kick, you will be surprised.
My advice would be not to waste the money and time in modding X250.5, but to go for additional XA amp, if you are after pure class A sound. Even XA30.5 will do great job in active set up just for the tweeters. Obviously it would be without any benefit running class A for the base speakers, and that fact enables you to have smaller amp for the tweets in the active set up.
If the case is that you are trying to gain more punch from the base - no tweeking will accomplish that short of adding one more amp or changing existing amp for X600 or x1000 (X600.5 or X1000.5) Only other option that could change the character of your base is adding EQ.
Besides above mentioned options, sometimes changing position of the speakers to the opposite set of walls instead of where they are now could be eye opener. I do understand the fact that you cannot move them from where they are right now. If you never tried you should do it jut for the sake of test. It is sometimes equal to astonishing revelation in just positioning speakers to opposite set of walls in regards to the bass performance. In some cases it is equal to almost doubling the power amp or adding new set of speakers. Like I mentioned - try it just for the kick, you will be surprised.
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