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Post by jmpsmash on Oct 1, 2017 1:27:23 GMT
A little history first! I have had this V2 since 2001. I was really into headphone for a little while but life got in the way. Late I got some motivation after I was gifted a pair of NAD VISO HP20 so I dug out the old amp and started reading up. Little I know a lot happened in the last 16 yrs when it comes to the XCv2.  I went through almost all the info on modding the V2, mostly from Mike and others who have done similar mods. In the first pass I changed up all the PS caps. I went with the more is better philosophy and pretty much fit all I could in the small confine of the V2. 6x Panasonic NHG 3300uF 35V for the first stage and the heaters. 4x Panasonic FC 2700uF 35V for the 2nd stage. I am unable to source the short and fat 3300uF that Mike has, so ended up the fit is very very tight. I also changed some of the 100uF caps that sits on the +/- rails with Nichicon FG. The last thing was to change the 220pF cap right at the input and then to bypass the input coupling cap. It took around a week of daily listening at work for the mods to really open up. Bass extension, detail/texture and dynamics are most apparent changes. I listening almost exclusively to classical esp orchestral music so those can make a huge difference. It really makes listening "fun" which is what really matter.   |
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Post by jmpsmash on Oct 1, 2017 1:58:32 GMT
The next step is to continue and focus on the signal path and on things that I missed.
I put in a 1uF for the filter cap at the power input and 1uF to replace C103/C106 with some old Solen MKP-FC that I had left behind from a previous project. Those are huge thus the fit was very tight and I question if it is a good idea or not. I did end up with a bit more of a hum so perhaps the extra leads has something to do with it.
While I can and it was cheap, I changed C108/C109 with some WIMA.
I also changed the 2 transistor at the power board with higher current version.
And then I swapped out the 1N4007 with UF4007.
The last bit is to change the decoupling cap to Nichicon 1000uF BP.
That was earlier today so I am going to let it burn for a few more hours.
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Post by jmpsmash on Oct 1, 2017 3:38:16 GMT
some pics after today's mods:   |
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Post by jmpsmash on Oct 1, 2017 3:42:44 GMT
After burning this in for the past 6 hours. the sound opened up a bit more. I have not heard so much detail and texture from this amp before, and the base definition is tighter even though it doesn't sound as deep as before. instrument separation is better too.
Listening is getting more and more fun. But is this the end of the road for this amp? I don't know how much more mods can be done given the lack of space.
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Post by PinkFloyd on Oct 1, 2017 21:23:20 GMT
Everything you've done there is spot on Smash..... the only thing that's spoiling the party are those HUGE Solen caps.... no need for caps that size and the cornucopia of excess "lead" will, for sure, turn your V2 into a radio mast  Massive respect for the 3300uF squeezed onto the power board but the 1uF / 630V SOLEN caps are TOTALLY obscene and totally unnecessary, no way "in a million years" will they ever become the right part for the job in an X-CAN V2. You are introducing lead inductance and wasting money shoe horning those silly "obscene" caps into a V2..... save them for an application they are better suited in. Mike. |
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Post by PinkFloyd on Oct 1, 2017 21:30:50 GMT
Keep it neat, no loose wires...... It delivers the goods / trust me, I know  |
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Post by jmpsmash on Oct 2, 2017 4:09:47 GMT
Everything you've done there is spot on Smash..... the only thing that's spoiling the party are those HUGE Solen caps.... no need for caps that size and the cornucopia of excess "lead" will, for sure, turn your V2 into a radio mast Massive respect for the 3300uF squeezed onto the power board but the 1uF / 630V SOLEN caps are TOTALLY obscene and totally unnecessary, no way "in a million years" will they ever become the right part for the job in an X-CAN V2. You are introducing lead inductance and wasting money shoe horning those silly "obscene" caps into a V2..... save them for an application they are better suited in. Mike. Yes. They are gone. Put back the old caps. There was a buzz which has since disappeared. Now I need to figure out if I should find something else to replace them. Unfortunately I think the amp is near maxed out. I can add some bypass caps but those alone won't justify making any order as the shipping cost is nearly $10. I don't have any other mods in mind. |
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Post by jmpsmash on Oct 2, 2017 4:14:15 GMT
Speaking of which, this is a real limitation of the V2. Real estate is really lacking and that limits what can be done. It is a fun challenge in itself but I want to do more but cannot.
I also notice the V2 runs rather warm. The caps are hot to touch and the whole enclosure is rather warm after a long day.
I remember there is a thread here that talks about making a custom PCB that clones the V2. Not only providing more space for mods and experimentation, but also better quality traces. That will open up a lot of opportunities. Did anything come out of that?
Or is that called the V3? I looked at the V3 pics and PCB, and topologically that looks quite like the V2 but in a larger space. I do wish they have a version with separate power supply sections. That will give so much better separation and headroom.
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Post by jmpsmash on Oct 2, 2017 4:15:55 GMT
Is there any upgrade possible with the output FETs?
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Post by PinkFloyd on Oct 2, 2017 20:28:03 GMT
Speaking of which, this is a real limitation of the V2. Real estate is really lacking and that limits what can be done. It is a fun challenge in itself but I want to do more but cannot. I also notice the V2 runs rather warm. The caps are hot to touch and the whole enclosure is rather warm after a long day. I remember there is a thread here that talks about making a custom PCB that clones the V2. Not only providing more space for mods and experimentation, but also better quality traces. That will open up a lot of opportunities. Did anything come out of that? Or is that called the V3? I looked at the V3 pics and PCB, and topologically that looks quite like the V2 but in a larger space. I do wish they have a version with separate power supply sections. That will give so much better separation and headroom. Yup, the available space is the problem, it's already "tight" with the stock parts but it is what it is and shoehorning crazy large parts in is going to provide no sonic benefit whatsoever and totally subtract rather than "add" to the sonic stakes smash. If we are going along the lines of making a custom PCB to accomodate "larger" components then it's no longer an X-CAN V2...... it's much like saying "the Mini Cooper engine is OK but let's make the car a lot bigger so we can shove a V8 engine under the hood". I actually like the V2 and think it's a classic (I know it's a classic!), I like the cylindrical housing (it was totally world class when it was introduced / still is) so I like to keep any upgrades / mods sympathetic with the original design. I think you'd be happier doing an amp build from scratch Smash (what is your name by the way? I'm Mike.) Start from the beginning and, essentially, design your own amp where there is enough real estate to populate with parts of your choice. The V2 is already very cramped for space and not really up for continued "in and out" component evaluation thanks to the pretty flimsy traces. It is what it is and you CAN max it out but you've got to max it out sympathetically with parts that FIT..... the 630V / 1uF caps are total overkill (as you now know) perfectly good in "another" amp but absolutely useless in a V2 The V3 has a bit more real estate but it's not a Made In England V2, it's a designed in England "Made in Taiwan" job........ I'm happy to Frankenstein a V3 all day long but prefer to keep classics like the X-CANS (V1) and V2 pretty close to their roots. Hope this helps. Mike. |
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Post by PinkFloyd on Oct 2, 2017 20:32:28 GMT
Is there any upgrade possible with the output FETs? Yes, Buy 50 of them and match a pair up (hfe)..... a good pair of matched TIP110 / TIP115 will be as good as it gets IMO. Mike. |
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Post by jmpsmash on Oct 2, 2017 21:10:28 GMT
yeah. those Solen caps.. I had a few left over from a previous project.. let's leave it at that.  I totally agree with the V2 being a classic having a character. No doubt about that. I am likely to keep mine like it is for now. The sound has opened up a little more with a few more hours burning in since yesterday. But I am at a loss how much more can be done. (I do have some NOS Russian tube to roll in but that's about it) But there is also the urge of try to make something and do what can be done sonically beyond the V2. Unfortunately I don't have the circuit design skill to design an amp circuit from scratch. Best I can do is to find a circuit and try to build it up and then tweak the component to make it sound best. That's why I thought of doing something with the V2 circuit since the schematic is available. I believe trying to design a PCB from scratch is doable but will be a decent project on its own already without adding more variables. I am just afraid it will be just like building a V3 though. |
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Post by jmpsmash on Oct 2, 2017 21:17:31 GMT
More thoughts and observation.
Looking the V3, I see a couple of changes compared to V2.
- topology is mostly similar.
- input voltage is now 24VAC instead of 12VAC? Did the V+/V- change?
- output now has 2 pairs of thermally coupled darlington instead of 1 in the V2.
- that transistor at the PS is more beefy looking than the ZTX653/753. (the V8p has something different again)
Thoughts for improvement other than putting in higher caps:
- put heater in parallel instead of series like that Spanish mod
- separate out the PS section. one per channel to make it dual mono
- bypass all electrolytic caps everywhere.
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Post by jmpsmash on Oct 2, 2017 21:18:36 GMT
I think you'd be happier doing an amp build from scratch Smash (what is your name by the way? I'm Mike.) Call me Kev. |
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Post by PinkFloyd on Oct 2, 2017 21:37:51 GMT
I think you'd be happier doing an amp build from scratch Smash (what is your name by the way? I'm Mike.) Call me Kev. Hi Kev, I'm off to bed........ 22.30 hrs here in the UK so time for a cup of Horlicks and a bottle of Scotch (chaser)...... Kev "rhymes with Kev", I'll forget your name overnight....... "Andy" rhymes with Mandy (or Pandy)...... "Bob" rhymes with Rob, "Mary" rhymes with "fairy", Pete rhymes with "sheet" etc. etc. etc. etc. Anyhoo........ Hello Kev, nice to meet you |
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Post by PinkFloyd on Oct 2, 2017 21:51:17 GMT
I need to get some sleep BUT, after a lot of thinking, "Kev" is probably a non rhyming name. Really quite rare. Mike / Bike Peter / Meter Luke / Fluke John / Gone Simon / Flugel horn Nigel / bass drum Samuel / tambourine erm......... I need to re-evaluate this one |
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Post by jmpsmash on Oct 2, 2017 22:04:53 GMT
Haha. what it is, I am having what you are having!
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Post by jmpsmash on Oct 2, 2017 22:06:09 GMT
there a unmodified V3 for sale US$220. tempted but not sure if that's the correct route to go. certain good for learning but at this rate, I will end up spending a lot more than $220 to upgrade that.
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Post by jmpsmash on Oct 3, 2017 21:14:18 GMT
it is either I f*cked up something or the new components from the weekend is not fully burning in yet (after 12+ hours?)
coz the sound from the V2 is downright weird today. it was great yesterday (I swear). but today, while still detailed, seems to have lost the low end and some salt and pepper noise (for lack of a better description). maybe clipping? but it doesn't sound like clipping though. or maybe clipping at a certain frequency.
the only thing I changed was the rectifier diodes, the two PS transistors, and the output cap to 1000uF, and then a couple of small caps (47pF) on the signal path.
I am leaning towards rolling back some of the mods I did or should I give it a couple more days?
anyone has any clues?
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Post by PinkFloyd on Oct 5, 2017 19:17:24 GMT
it is either I f*cked up something or the new components from the weekend is not fully burning in yet (after 12+ hours?) coz the sound from the V2 is downright weird today. it was great yesterday (I swear). but today, while still detailed, seems to have lost the low end and some salt and pepper noise (for lack of a better description). maybe clipping? but it doesn't sound like clipping though. or maybe clipping at a certain frequency. the only thing I changed was the rectifier diodes, the two PS transistors, and the output cap to 1000uF, and then a couple of small caps (47pF) on the signal path. I am leaning towards rolling back some of the mods I did or should I give it a couple more days? anyone has any clues? Hi Kev, Definitely a case of rolling back mate..... if it was fine and all of a sudden "not fine" after fitting different parts then go back to where you were before fitting the new parts. If the amp sounds shitty then no amount of "burning in" will make it sound less shitty..... roll back to where it was before Reminds me of a friend who bought a fake Krugerrand..... I weighed it and informed him that no way was it gold..... he said "I'll put it in a drawer for a few years" and I said "you can put it in a drawer for 100 years and it still won't be gold!!". Best regards, Mike. |
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Post by jmpsmash on Oct 5, 2017 19:28:23 GMT
I don't know dude. Today my ears are happy again. Didn't do a thing!
Anyway, the V3 that I saw was sold. I guess that seals my fate.
in the hope of trying to learn/build something, I am tracing the V2's PS board schematic. I have a pretty good understanding of it now with some help. I will put it up when I have it looking pretty, hopefully it will benefit future modder.
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Post by PinkFloyd on Oct 5, 2017 19:44:41 GMT
I don't know dude. Today my ears are happy again. Didn't do a thing! Anyway, the V3 that I saw was sold. I guess that seals my fate. in the hope of trying to learn/build something, I am tracing the V2's PS board schematic. I have a pretty good understanding of it now with some help. I will put it up when I have it looking pretty, hopefully it will benefit future modder. I'll send you the schematic Kev...... give me five minutes, I'll fire it over in an e-mail to you Best regards, Mike. |
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Post by PinkFloyd on Oct 5, 2017 19:48:19 GMT
Sent.....
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