Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 29, 2009 21:52:32 GMT
Krisno
If you want to make the volume control action a little less abrupt, try replacing R107 and R207 (27K) with 47K metal film resistors. (a few cents each) This should reduce the overall gain from 9 to about 5.7, and in theory, should also give a small amount of improvement as well..
SandyK
|
|
|
|
Post by krisno on Jan 29, 2009 22:26:23 GMT
The source I use is NOS, which uses Philips Tantalum and oil output caps. It just cannot be sharp, and I tried it with the Yulong(SS), and it is the sweetest DAC I have ever heard in my life.
The X-canv2 is just plain bright and harsh atleast with AKG K 701. Will see if PSU helps.
SandyK, great advice. But R107 and R207.. does it say on the board which it is?? Are they difficult to swap out? ... Can you or Mike send me those 47K metal film resistors which I need? I tried to google it and did not understand anything of it.... !! Reducing the gain would be great.
GUYS, the V3 was less harsh... can I swap out the transistors(mosfet's) with something better to make it sound less sharp?? anyone tried anyhting like that?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 29, 2009 22:32:34 GMT
Krisno
Being a valve amplifier, I don't have one, but the PCB appears to have clear labelling for the components. It is quite easy to remove and replace resistors. Perhaps Mike or Dejanm , being more familiar with this amplifier can guide you with the exact location etc.? Surely there are many electronics stores/service centres where you could obtain a couple of the resistors to try?
If Mike still has his on the bench,and his has gain to spare, perhaps he could try this and let you know if it is worthwhile or not. Bear in mind though, that Mike likes his music LOUD !
SandyK
|
|
|
|
Post by dejanm on Jan 30, 2009 9:14:23 GMT
Mike Are you able to confirm the value of the input resistor R102 as 2K2 ? I would have expected something more like 22K (or higher) Alex Alex, The value of R102 is 220K. I am just measuring it with the Unimer ... |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 30, 2009 9:28:04 GMT
dejan
Thanks. That makes a lot more sense for a piece of valve gear.
BTW, does yours have too much gain too ? If so, are you able to try 47K for R107/207 instead of 27K ?
Alex
|
|
|
|
Post by krisno on Jan 30, 2009 9:43:18 GMT
The gain is tremendous... nothing like the V3 or V8. On high volumes, it is just unbearable, no matter what kind of music (very harsh and bright).
1: PSU might be problem... but it was bright in the beginning, but maybe that was caused by old tubes?? Now that I got new tubes, maybe PSU is the thing, especially after the mod.
But the thing is fun to listen too! I agree..
2: AKG K 701 might be too bright/sensitive... I think a better headphone for the amp would be the dark sennheisers, OR maybe Audio Technica WD1000 wooden headphones. The wood softens/darkens things..
I will wait for PSU, give it a go, might sell it, or if I choose to keep it, order the Shanling HP1000 discrete headphone amp, pure SS. Probably best match for AKG K701. The Yulong was actually quite good, and with the NOS dac, probably best I have ever heard.
This tube amp is much more realistic, but fatiguing... tubes in general are fatiguing, V8 was somewhat too(even with the built in dac). Though the V2 is a disaster !
K
|
|
|
|
Post by PinkFloyd on Jan 30, 2009 11:07:17 GMT
I'll whack in some 47K's this afternoon and, if satisfactory, will send you a couple Kris.
|
|
|
|
Post by PinkFloyd on Jan 30, 2009 11:20:51 GMT
I will take photos today.... looking at the board sideways with the volume pot facing the right the resistors are adjacent the the yellow 1uF film caps....... R107 and 207 are clearly marked on the PCB.
|
|
|
|
Post by dejanm on Jan 30, 2009 11:23:37 GMT
I do not have problems with gain. I am listening usually on 10 o'clock, sometiumes at 11. On 9 o'clock I have also decent but bit more silent sound. Nearly the same situation I have with my Naim Headline 2, which is Solid State headphone amp, running in separated HiFi system. That is why I believe that the gain in my case is ok.
I believe that Krisno has a problem with harshness and I also believe that he will probably have to do 2 things in order to get rid of it. First one is to go for better power supply. That will improve things enourmously and remove a lot of distrosion that he has (and I also had it) especially in the higher registers. The second thing is to replace tubes.
I just put NOS Telefunken E88CC instead of Reflektor 6N23P-EV and I could hear immediately two things: Tekefunkens have lower gain than 6N23P-EV (I have to turn it a bit more but not a huge difference though); and the second thing is much stronger bass and harshness does not exist even in traces. There are some disadvantages as well, but I will give them some time first before I make my mind with which ones to proceed.
P.S. I am using Grado SR325i headphones (32 ohms), which are more prone to harshness than AKG K701, by the way ...
|
|
|
|
Post by krisno on Jan 30, 2009 16:40:07 GMT
Mike, that would be great. See if those film caps does anything..
dejamn... great reply. PSU might help. Hmm, I thought the reflector was not harsh at all..... is harsh = grain ??
I got these very expensive Tungsram 6922 NOS, military grade. Will these tubes be less harsh tahn the reflector?? Remember, it was harsh also with Jan philipis, and the V3 had the same tubes but less harsh. Maybe the tungsram is the tubes to get, not the reflector. But everyone says reflector is great for v2-v3...... I will not buy expensive telefunken.
Maybe I dont want the realisticness and musicality of tubes, just the sharpness, details, positioning and SPEED of a discrete solidstate. I just have to try that shanling amp !! see on headfi many likes it with akg..... k701 + nos + discrete SS with tons of power might be the one . but I will keep this i guess. It really is one of the best tube amp for headphones, if you use some dark headphones. I never heard tubes more alive than in this modded v2.
K
|
|
|
|
Post by dejanm on Jan 30, 2009 18:34:29 GMT
Krisno,
Reflektor 6N23P-EV are not harsh. They are very accurate, fast, detailed (very detailed) and very, very linear, especially in the mids. Great tubes. In my case though they had quite modest bass. It is tight, with lot of details but the bass drum kick was not deep and "volumineux" enough. Bass drum kick must hit you in the belly; it must have full bodied, deep sound - with Reflektor you get only indication of it. Reflektor 6N23P-EV also produce quite open, light musical picture. I am assuming that one of the reasons is that slight inbalance in the reproduction with dominating high frequencies, very neutral mids but rather timid bass. That was the reason why I am trying these Telefunkens ... searching for more balance and above all, for more bass kick.
I guess that these observations depend also very much on the musical taste. I am listening to a lot of R&R, drum & rhytm based modern music ... For female vocals for example, Reflektors are combination made in heaven.
After putting better PSU I cannot hear any remenesence of any kind of "tuby" sound. Practically I am not able to say whether tubes are inside or not (if I wouldn't know it). Actually, my Naim Headline 2 (solid state thing) sounds very similar to MF X-Cans V2 with Telefunken inside ... that is what I am listening at the moment ...
These are some observations which might help you. I do not know about Tungsram but try them ... and let us know how they fit this amp ...
|
|
|
|
Post by PinkFloyd on Jan 30, 2009 19:44:03 GMT
I have adjusted the gain using Alexs method and it works a treat giving you slightly better "travel" with the volume control (more usable) here is how you go about it: www.rock-grotto.co.uk/X-canv2-gain-adjustment.htmlKris, another thing you may want to try is to fit axial ferrite bead inductors in place of the 10uF caps... these help cut down any RFI resulting in a very quiet background see diagram:  I am experimenting with my ELNA version "open frame" v2 (I have a Panasonic version too) so should sound identical to yours:   |
|
|
|
Post by PinkFloyd on Jan 30, 2009 19:46:48 GMT
Alex, one thing I have noticed since altering the gain is the transistors are running pretty scorchio.... I will probe them and see what they are running at.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 30, 2009 20:12:35 GMT
Mike
Are small heatsinks as used in the SC HA an option, or are they already used ? I' m unsure as to why they should be running hotter, as no DC changes were made due to the presence of the series 1uF capacitor to earth.
Alex
|
|
|
|
Post by PinkFloyd on Jan 30, 2009 21:27:39 GMT
Mike Are small heatsinks as used in the SC HA an option, or are they already used ? I' m unsure as to why they should be running hotter, as no DC changes were made due to the presence of the series 1uF capacitor to earth. Alex Actually Alex, to be honest, it's the first time I've actually touched the v2 transistors with my fingers for ages.... they have probably always run this hot and bugger all to do with reducing the gain. No, there are no heatsinks on the stock v2, they run naked.... just out of interest, I'll measure the temperature and see what they're running at. Reducing the gain seems to have slightly improved the SQ at my preferred listening level, this could be down to better tracking of the pot....... A very nice little tweak and it'll be interesting to experiment with different values of resistor in this area (47K upwards) ..... by the way, Alex, I gave you credit for this on the website article www.rock-grotto.co.uk/X-canv2-gain-adjustment.htmlGain was never a problem with me and X-Cans but, I must confess, I'm already preferring it with the 47K in situ.... nice to have that extra bit of pot excursion  Kris..... I emplore you to remove those 10uF input capacitors, it'll take you all of 5 minutes and I guarantee you will reap sonic rewards as a result.... they are pretty much a belt and braces incorporation and not required in most applications.... they do degrade the sonics (albeit marginally) and are better out than in. I am experiencing no harshness, or any of the other things you describe, from my ELNA version of the v2.... in fact, the sonics are pretty much spot on and well "rounded".... I am running 6N23P at the moment and they are performing beautifully. I'd still be looking toward the source, if I were you, I have experienced many x-cans and opinions from X-Can owners over the years and "brightness" is not one of the words I hear a lot...... the stock 6922 can sound a tad bright in some amps but, again, this can be sorted out at source. No way are you going to tame a bright source ampside. The K-701 are pretty eargasmic with the v2 so it's definitely NOT the headphones that are the weak link here.... in fact, I'd go so far to say the K-701 / X-Can v2 are a perfect match..... beautifully extended bass, articulate mids and silky smooth highs.... extremely listenable and enjoyable The vast majority of guys I know who rate the v2 (literally hundreds of them) are in their 40's / 50's so it's also possible that your hearing is more acute and are picking things up that our older lugholes are missing..... don't discount this....... I had my hearing tested a couple of years ago and it was pretty much as it should have been but that's not to say that your ears are a lot more sensitive than mine to high frequencies....... You could also be experiencing the opposite from placebo effect Kris.... ie: it's your first attempt at soldering and sub consciously you're thinking "It can't be good, I must have done something wrong".... whereas if I appeared in your living room and performed the mods you may be thinking differently...... Without actually listening to your amp all I can do is guess.... from the pictures you posted it would appear you've done a good job on the soldering front..... yet you find the sound to be "bright"? I could tell you to "give it 600 hours" and "let it burn in" but I doubt you have the patience for that  Really, that's all I "can" say..... give it a couple of hundred hours to cook (same goes for the 6N23P) and report back then. No point in trying to reinvent the wheel in the meantime.... trust me when I say the components require time to bed in. Mike. |
|
|
|
Post by PinkFloyd on Jan 30, 2009 21:32:42 GMT
Transistor temp. = 49C / TIP 110 53C / TIP 115 so not as hot as my finger told me  |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 30, 2009 22:32:47 GMT
Mike Looking good then. ;D The slight improvement in SQ could also be partially due to the small additional amount of negative feedback available after the gain reduction. dejan Because the feedback ratio set by the 220K and 27K/47K and 1uF,controls overall gain, using valves with slightly different mu shouldn't make any difference to the pot setting, at least not due to the gain. Some valves may sound "cleaner" (lower noise) than others, so that a slightly lower potentiometer setting may be used. Alex XTRProf So this old fart doesn't know anything about valves,eh ?  I was playing around with valves, when you were still in nappies. |
|
|
|
Post by PinkFloyd on Jan 31, 2009 11:12:53 GMT
Mike, if you have not sent me the tubes/psu would you include a couple of the 47K resistors as well as a couple of the ferrite beads. Send me a PayPal bill using my email address as the user no. Thanks. Hi Miguel, Your PSU shipped on Wednesday ( I fitted the evolution cable on it ) You don't have to pay for a couple of resistors and ferrite beads mate, I'll stick them in a jiffy bag today for you. Mike. |
|
robertkd
Been here a while! 
Electronics Engineer from sunny Queensland
Posts: 111
|
Post by robertkd on Jan 31, 2009 11:16:13 GMT
Hey Mike how much are those gassy Russian light bulbs you got recently anyway ?
can they really do 30mA plate current?
Robert
|
|
|
|
Post by PinkFloyd on Jan 31, 2009 11:19:38 GMT
Hey Mike how much are those gassy Russian light bulbs you got recently anyway ? can they really do 30mA plate current? Robert Dirt cheap Robert... a couple of quid each specs here: www.tubes.ru/techinfo/HiFiAudio/6n6p.html These are genuine NOS too / 1974 vintage |
|
|
|
Post by PinkFloyd on Jan 31, 2009 11:28:02 GMT
By the way Alex, I've had this puppy on all night and she sounds absolutely fantastic.... gorgeous in fact! beautifully smooth, flowing and mellifluous just the way a finely tuned v2 should sound..... certainly more air around things since the 47K / ferrite tweak.... nice |
|
|
|
Post by PinkFloyd on Jan 31, 2009 16:01:22 GMT
Kris........ the soundstage (v2 + K701) is expansive, you could drive a double decker bus through it.... the music is flowing, natural and extremely detailed without a hint of this harshness you describe.... can you try another source with yours as I can find nothing at all with the sound of the amp using CDP as my front end. In fact, v2 / K701 is a near perfect combo and hard to fault in ANY department.
|
|
|
|
Post by krisno on Jan 31, 2009 17:30:41 GMT
I bought this X-canV2 used, and it was bright out of the box, but it don't look used at all. It had no scratches or anything at all. So it should be OK. It was bright, and at higher volumes it just kills my ears, very fatiguing... I am using NOS dac based on 8xTDA1543(based on Lite DAC! should not be sharp)... I used this with the Yulong Dah1 'mark' and it was MUCH sweeter and not sharp at all, running through the yulong. Actaully, nos dac's are famous for being 'dark' and abit rounded in the treble. I just cannot understand that the fault is in the DAC? I will try with my £50 CD player and we will see. I have to comment that, when using the NOS dac through the Yulong I heard the 'colors' and atmophere of the music so nicly, through the V2 this is removed.... I honesly think stock V3 with stock tubes was alot 'nicer' on the ears... Mike, you have shipped the PSU, but could you ship me 2x 47ohm resistors needed for the 'gain' mod, and 2x ferrite bead 'links' to replace input transistors? Though I am not sure if it has DC around on the dac output.. The ferrite beads need to be on 'link', as I have no spare 'metal' to use as a link... bad enligsh. Btw, the Tungsram E88CC 'HOVEDSEG' 6922 1971 100% NOS just arrived. They look very nice.. will post pictures later on, but I don't dare to try them. I think I am going to sell them instead, as I will use the much cheaper russian. Don't htink the tungsram will fix the brightness anyways.... Still V2 is not usable as it is right now with AKG K701..... The yulong solidstate, or even analog output on laptop sounds less harsh. The yulong was not harsh at all actually.. will change source and see if it helps, but I doubt it... K |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 31, 2009 17:45:56 GMT
Kris,
I'm going to have join the frey here and further back up what the guys are telling you. I have no preference for valves or SS, I just know what I like, any kit that gets me there is good enough for me.
The V2 (modded/Pinkie) + K701 (well run in) combo is NOT bright in its own right. (Tho' before mod/pinkie/run-in I did find it bright)
Articulate, detailed, dynamic etc., yes.
I usually have my 'phones amp in the tape loop, as I listen mainly via the 'speakers but, for reasons too boring to go into, I'm reduced to CD/'phones amp/'phones at the moment, therefore, running direct. Using Nordost Blue Heaven interconnect, NOT known for being dull!
I have no ingress of brightness at all, just a better version of went before, if anything has been inreased it is depth of bass!!!
Beg or borrow a different source, something of reasonably well known character/reputation, see what you think then...
|
|
|
|
Post by krisno on Jan 31, 2009 17:58:17 GMT
Yes, Pinkie might solve my problems... anyways I think I will keep this. I am not going to get another for 'modding' , and remove the brightness, if you do - it is the best tube amp I ever heard.
but still it lacks some of the 'drive' i heard with the NOS + yulong... watching that James bond HD movie trailer. It is the best I have heard in my life....... and that yulong is based on 2134 opamps, not even discrete.
|
|
Really, that's all I "can" say..... give it a couple of hundred hours to cook (same goes for the 6N23P) and report back then.
