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Post by derekrumble on Mar 21, 2005 10:44:05 GMT
I have had the V3 now for a few months and I am very pleased with it. I have read the X Can V2 valve audition page and was keen to know how the V3 would respond to similar changes.
Yesterday I bought a pair of Voskhod ecc88/6922 replacements and have just fitted them to my V3. Even without running in, the sound is at once improved. Bass, mid, treble and imaging have all gone up 'a point or two' And this from two unmatched, low cost valves.
As I had the V3 apart I took some photographs. When they have been developed I will be happy to share them with follow X Can fans.
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Post by creeky on Mar 21, 2005 20:55:01 GMT
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Fergus
100+
Done a David Ike and is now known as Godkin
Posts: 197
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Post by Fergus on Mar 29, 2005 19:08:36 GMT
Read Derek's posting with interest. It has inspired me to think about replacing the "bog-standard" tubes in my X-CANS. Since I haven't the foggiest idea about where to buy Derek's recommended VOSKHODS, I am considering a matched pair of SOVTEK 6922s or ELECTRO-HARMONIX 6922s. Thanks to Creeky for the pic. And in answer to his question, both the above valves can be sourced at www. hotroxuk.com. Fergus.
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Fergus
100+
Done a David Ike and is now known as Godkin
Posts: 197
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Post by Fergus on Apr 1, 2005 13:02:01 GMT
Have just replaced the stock tubes on my X-CAN with a pair of matched ELECTRO-HARMONIX 6922s, which I'm now told are a "slightly upgraded" version of the SOVTEK 6922. On first listening, the sound has better presence and integration; bass is considerably deeper, tighter and more articulate; and resolution is also significantly improved. Opening the X-CAN and removing the old tubes wasn't too painful, even for someone as "kack-handed" as me. In fact, MF seems to have gone to some lengths to make the procedure easier: the front fascia, for example, is on a separate circuit board and so can be pulled to the side to allow the main circuit board to slide out. I'm afraid to say that the capacitors are still mainly the old JAMICON SK types found in the X-CAN V2, which the ROCK GROTTO calls "far from audiophile": six of these "cheap caps" are rated at 2200uF/35v; 4 are 1000uF/35v; 2 are 10uF/63v; 4 are 100uF/50v; while 4 others - JAMICON bipolar NK types - are 220uF/6.3v. I also fear that at least two of these caps have started to leak, although there has not yet been a noticable degradation in sound quality. An upgrade to the PANASONIC FCs caps is therefore necessary. Thanks to the guys at HOTROX for a great service. Ordered tubes yesterday at 2 o'clock (31/3/05) and they arrived at 9.30 this morning (1/4/05). I've some low resolution pics of the internals of X-CAN and the valve changing procedure. I'll post them soon. Fergus
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Post by derekrumble on Apr 11, 2005 8:37:16 GMT
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Post by derekrumble on Apr 11, 2005 8:43:29 GMT
The V3, of course, uses two valves. But you can clearly see a number of transistors inside. The large ones along the front are part of the power supply, as far as I can tell. Are the remaining trannys also part fo the power supply, or this this amp a valve / transistor hybrid? I notice that MF say that the XCAN V3 'contains' valves, or words to that effect. They do not call it 'valve' amplifer.
Anyone?
Derek
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Post by creeky on Apr 11, 2005 13:47:53 GMT
The V3, of course, uses two valves. But you can clearly see a number of transistors inside. The large ones along the front are part of the power supply, as far as I can tell. Are the remaining trannys also part fo the power supply, or this this amp a valve / transistor hybrid? I notice that MF say that the XCAN V3 'contains' valves, or words to that effect. They do not call it 'valve' amplifer. Anyone? Derek Hello, I am pretty sure the x-can v3 is a hybrid design.
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Post by derekrumble on Apr 6, 2006 19:05:22 GMT
OK then - so if the X Can 3 is a valve / tranny hi-brid.. and so ar ethe mark ones and twos... then....
what are the valves doing there? Is it for marketing reasons - or is there a sonic purpose?
Derek
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Post by derekrumble on Feb 8, 2007 15:17:15 GMT
Yesterday I bought a pair of Voskhod ecc88/6922 replacements and have just fitted them to my V3. Even without running in, the sound is at once improved. Bass, mid, treble and imaging have all gone up 'a point or two' And this from two unmatched, low cost valves. I found the Voskhod tubes to be very microphonic... if I tapped the X-Can casing then I could hear ringing through my headphones. Also the amp made different noises than before on switch on and off. Lots of whooshing and thumping through the cans. Then, a couple of months back my X-CanV3 developed a fault.. one channel developed a distortion; as if the input on that channel was overloading something. Anyway, had it repaired and all is fine - I put the original JAN tubes back in before the repair so that the guy wouldn't see what I had done. I don't use the Voskhod tubes now. I wonder if using them caused the fault? Incidentaly the JAN tubes sound fine - I may have imagined the improvement above... it's so hard to compare the sound of before with after isn't it?
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Post by bennyboy on Feb 8, 2007 23:02:48 GMT
Yesterday I bought a pair of Voskhod ecc88/6922 replacements and have just fitted them to my V3. Even without running in, the sound is at once improved. Bass, mid, treble and imaging have all gone up 'a point or two' And this from two unmatched, low cost valves. I found the Voskhod tubes to be very microphonic... if I tapped the X-Can casing then I could hear ringing through my headphones. Also the amp made different noises than before on switch on and off. Lots of whooshing and thumping through the cans. Then, a couple of months back my X-CanV3 developed a fault.. one channel developed a distortion; as if the input on that channel was overloading something. Anyway, had it repaired and all is fine - I put the original JAN tubes back in before the repair so that the guy wouldn't see what I had done. I don't use the Voskhod tubes now. I wonder if using them caused the fault? Incidentaly the JAN tubes sound fine - I may have imagined the improvement above... it's so hard to compare the sound of before with after isn't it? Thats a laugh! Those tubes are the best quality I've found in any tubes. I've tested over 100 and only one had a slight microphonic ring. The philips I've come across ring like church bells! :-/
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Post by PinkFloyd on Feb 9, 2007 0:12:40 GMT
I found the Voskhod tubes to be very microphonic... if I tapped the X-Can casing then I could hear ringing through my headphones. Happens sometimes, thankfully not the norm but you do get the occasional pair of valves that can be microphonic. The Voskhod are generally dead in this respect and I can honestly say I haven't encountered one that is microphonic. I've found a couple them (out of hundreds) which "whooshed" or hummed but the vast majority of them I've found to be 100% spot on. What did you fit was it the 6H23P-EB or the 6N1P-EB? A slight "whoosh" at power up and power down is perfectly normal.... "thumping" however is not. You go onto mention you had it repaired, what did the fault turn out to be? And? what was the diagnosis? I sincerely hope so.... if it were still not working after "repair" I'd be well pissed off ;) From that I can only assume the "repair" was carried out under warranty in which case you'll never know what was the cause of the fault. I would not like to hazard a guess but will say it's probably 90% certain the Voskhod valves weren't the cause of the fault.... the fact the fault occured when they were in circuit means nothing, it could have been a totally unrelated breakdown of another part of the circuit. I note you first posted about the Voskhod valves in your V3 "two years" ago (March 2005) I assume they've been in circuit all that time? We don't even know what the "fault" was yet. The majority of V3 faults are not associated with the valves, if the valves go they generally go and replacing them is all that's required....... do you have any photos of the PCB there may be tell tale signs of scorching that will help us pinpoint the culprit ;) better still, unless the repair was carried out by MF under warranty, ask the person who repaired the amp what the problem was! Voskhod are SUPERB valves and I certainly wouldn't point the finger of blame in their direction on this occasion.
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Post by derekrumble on Feb 9, 2007 8:38:52 GMT
Yes, the russian tubes had been in circuit since my original post.
It was my local MF dealer's in-house engineer who repaired the amp.... he explained it was rare to have an X-canV3 go faulty. I think he described the fault as being in the output stage - but then I suppose most of the x-can IS output stage!
And honestly, the russian tubes DID ring. And the JAN Philips do not. I will check the tube type and post the details here. I will also take a look inside to see if I can see where the repair was.
To be honest I can't remember clearly the start up and switch-off noises the amp made with russian tubes in place - I just recall that it was a noisier process than with the Philips. I will, at some time, put the russian tubes back in - and maybe record the noises and compare them more objectively.
When I said, after saying I had had it repaired, that 'all is fine'.. that was just informal conversational prose... I would have been disappointed too if all had NOT been fine. My local dealer always gives good service; Shropshire Music Centre in Shrewsbury UK for those interested. I bought an X-dacV3 there just few weeks ago and I was 'fortunate' to go there when they only had their demo model left in stock - so I was given a generous discount on it - I am enjoying its output now as I write.
Derek
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Feb 9, 2007 21:55:02 GMT
valves are the best voltage gain stage available so are providing the gain but valves are also the worst at driving any but a high impedance load being a hi-z output device while transistors excell in this area so
Valve voltage gain stage Transistor impedance conversion/current gain
Only a few ways to low Z output with a valve amp and ALL more expensive to implement than the cost of the X-Cans V3 hybrid design so makes good sense unless you want to treble the price of the amp
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