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Terry
18-07-2008, 16:25
I would just like to say hi from Honiton Devon.
No doubt i will be along with a few annoying questions soon enough. :lolsign:
So i thank you in advance .:):)

Mike
18-07-2008, 16:26
Hi Terry,

Welcome to AoS. Ask away! :)

Beechwoods
18-07-2008, 16:44
Hi there Terry! Us folk with annoying questions should stick together!

Welcome from Bristol :)

Filterlab
18-07-2008, 19:06
Hi Terry and welcome, any questions - annoying or not - please fire away. :)

Mike Reed
18-07-2008, 20:40
Greetings, Terry.

Lovely neck of the woods, Honiton, with access to some beautiful countryside and coastline.

What kind of system do you have?

Terry
18-07-2008, 21:52
Thanks for the welcomes everyone.

Yes i am lucky to live here and doing the job i do keeps me outside most of the time to enjoy my surroundings, i am a photographer for the local newspapers here.

Now then as to my kit - well i am a complete beginner when it comes to decent amps and speakers etc. I do have a setup for the TV that gives me the sound i want for films and TV programs and that is (don't laugh) a Onkyo TX-SR606 AV Receiver and a pair of Bose Acoustimass - 3 Series for the fronts (To keep the wife happy - As they are 'NICE AND LITTLE' :() Kenwood CM-7ES rear speakers and a kenwood powered sub SW501,center speaker is a B&W LCR60 S3. For me this is fine for general TV watching and the odd film watched on my Sony SACD player. But when it comes to just wanting to play some music well it leaves a lot to be desired.
So i have a blank canvass to start with, regarding building up a system just for music. I know that i want to try a valve amp and was thinking of the Yaqin MC 100B and changing the Chinese valves for some better ones (will ask for your thoughts on this as to which ones to go for), as to speakers i am also open to suggestions to compliment this amp ?
Your experience on this will be greatly appreciated.

Steve Toy
19-07-2008, 01:54
You need to do quite a bit more to the Yaqin than just change some valves as Marco and AnthonyTD will no doubt explain.

Marco and Ian Walker's amp of choice is a modified Yaqin MC 100B. Mine is a modified Puresound A30 valve amp which in turn is a modified Bewitch.

Note the modified theme running through all of these amps.

Terry
19-07-2008, 09:02
You need to do quite a bit more to the Yaqin than just change some valves as Marco and AnthonyTD will no doubt explain.

Marco and Ian Walker's amp of choice is a modified Yaqin MC 100B. Mine is a modified Puresound A30 valve amp which in turn is a modified Bewitch.

Note the modified theme running through all of these amps.

Thanks Steve !

I would be very interested to know what other mods need doing to the Yaqin i wait with bated breath. Just hope i understand what is needed to be done as i said i am a complete beginner. Anyone on the forum offer a service to do the mods ?

Marco
19-07-2008, 09:51
Hi Terry,

Welcome to the forum, btw :)

How did you hear about the Yaqin?

The best procedure, since the Yaqin is now available in a much nicer chrome version with upgraded mains transformers, is to order one direct from here in France:

http://www.tubophile.com/

Scroll down to the bottom and click on 'Yaqin'.

Then send it directly to Anthony Matthews of Tube Distinctions (who's on the forum) here:

http://www.tubedistinctions.co.uk/main.htm

for him to test and check everything is ok. It should be because you're not getting the 'raw' version direct from China, but it's best just to make sure. Anthony can then modify it further if you wish in terms of valves, capacitors, output transformers, etc.

It's a bit more expensive (I think about £600 inc shipping) compared to ordering it direct from China, which costs roughly £300 including shipping, but you get a much nicer looking amp that's also 'sorted' for UK voltage, and the performance is superb!

If you need any more info just ask. Anthony may perhaps wish to add some advice of his own.

Marco.

Ali Tait
19-07-2008, 14:02
Another option is to look for a Mr Liang 845.This needs no mods to work on UK voltage and sounds excellent straight out of the box.Sounds even better with some NOS front-end valves,and can be taken to another level with just a couple of simple mods,changing 4 caps and two resistors.

Marco
19-07-2008, 14:10
I agree with Ali. The Mr Liang is also excellent. The decision to be made here is whether to go for SET or push-pull.

To work that one out you need to listen for yourself! :)

Much will depend on what speakers you use.

Marco.

Terry
19-07-2008, 16:22
Hi Terry,

Welcome to the forum, btw :)

How did you hear about the Yaqin?

The best procedure, since the Yaqin is now available in a much nicer chrome version with upgraded mains transformers, is to order one direct from here in France:

http://www.tubophile.com/

Scroll down to the bottom and click on 'Yaqin'.

Then send it directly to Anthony Matthews of Tube Distinctions (who's on the forum) here:

http://www.tubedistinctions.co.uk/main.htm

for him to test and check everything is ok. It should be because you're not getting the 'raw' version direct from China, but it's best just to make sure. Anthony can then modify it further if you wish in terms of valves, capacitors, output transformers, etc.

It's a bit more expensive (I think about £600 inc shipping) compared to ordering it direct from China, which costs roughly £300 including shipping, but you get a much nicer looking amp that's also 'sorted' for UK voltage, and the performance is superb!

If you need any more info just ask. Anthony may perhaps wish to add some advice of his own.

Marco.

Hi Marco and thanks for your thoughts. I heard about the Yaqin MC 100B by just a google search on 'tube amps' as i have said before i am a complete novice when it comes to this but am learning fast about 'rolling tubes' etc just by reading posts on the internet. Thanks for the links, i have had a look at the French site and emailed them to ask what tubes and transformers they use on their version of the amp. They also offer a Yaqin MC 110B for £660 but i don't know what the difference is between this and the 100B.
Where abouts is Anthony in the country ?
Thanks Again :)

snapper
19-07-2008, 16:26
Hi Terry

He's in South Wales

http://www.tubedistinctions.co.uk/contact_info.htm

Terry
19-07-2008, 17:01
Hi Terry

He's in South Wales

http://www.tubedistinctions.co.uk/contact_info.htm

Thanks David !!!

Mike
19-07-2008, 17:47
They also offer a Yaqin MC 110B for £660 but i don't know what the difference is between this and the 100B.

I belive the 110B is a dual mono version of the 100B, seperate power supplies etc for each channel.

Cheers,
Mike.

Marco
19-07-2008, 18:17
Can't be that, Mikey. Mine is an MC100-B and it's dual-mono. I think the guy in France calls it a "110" after he's chrome finished it and upgraded the mains transformers.

Marco.

Mike
19-07-2008, 18:28
How many mains transformers has your Yaqin got marco?

Marco
19-07-2008, 19:15
Two big boys parallel to the two output ones. It's a dual-mono design, dude :)

Marco.

Terry
19-07-2008, 21:13
Hi Marco

Here is the email that i just got from Marc in France - So my question in regards to this, is it worth the £200 extra for a different power performer and some different capacitors ? Also i thought looking at the Hong Kong version on the website that they supply in either 110v or 240v which i believe is ok for the uk (240v) so really it seems that the £200 extra is for just the capacitors ? What do you think ?

Regards Terry


Dear Terry,

we have the MC100B in gold and in silver.
This is the same electronic diagram than Hong-Kong ones, but we make agreement with factory to some parts like capacitors we want.
Our power transformer is made on special request : voltage is 235V so it can meet all european requirement : UK who go up to 245V and some part for France who go to 225V.
The valve and output transformer is the same, but upon your request and extra price we can put the valve of your choice.

We have the MC110B which is a special edition for us with high grade output transformer. This one is in black. The price is higher. 799€ + shipment.
It also includes JJ KT88 in standard and NOS russian 6SN7. This price is now and I can't promise we can keep it in september because the yuan is increasing day after day.

The MC100B in silver would be around 499 GBP shipped to england with 1 year warranty which is a real warranty because you have just to send back the item to France and not to hong-Kong which cost is same price as the amplifier.

Don't hesitate if you need more details.

Best regards,
Marc
www.tubophile.com

lurcher
19-07-2008, 21:51
UK who go up to 245V

Nope, it can go up to 253 and be within spec.

Mike
19-07-2008, 22:43
Yep! - 230V +10%, -6%

Mike
19-07-2008, 22:44
Two big boys parallel to the two output ones. It's a dual-mono design, dude :)

Marco.

Cool! :smoking:

Marco
19-07-2008, 22:49
Terry,

Interesting email.

I'll come back to you tomorrow, mate. Just off to bed :)

Marco.

Terry
20-07-2008, 12:53
Hi Marco - so what are your thoughts om my post # 19 ?

Marco
20-07-2008, 13:18
Hi Terry,

Sorry about that - too much vino for lunch!


Hi Marco

Here is the email that i just got from Marc in France - So my question in regards to this, is it worth the £200 extra for a different power performer and some different capacitors ? Also i thought looking at the Hong Kong version on the website that they supply in either 110v or 240v which i believe is ok for the uk (240v) so really it seems that the £200 extra is for just the capacitors ? What do you think ?

Regards Terry


First of all, there is next next to no chance that any Yaqin bought direct from China is going to be safe on UK voltage without a step-down transformer. Even if the mains transformers are 'sorted', the other components won't be able to handle the over-voltage that's likely. As Nick says, it can go up to 253V, or so, here in the UK.

SO DO NOT RISK THIS - IT IS VERY LIKELY THE AMP WILL GO ON FIRE!!!

I do hope I've made myself clear!

My advice would go for the MC-100B in sliver for £499, with the 'upgraded mains transformers'. I use inverted commas because I've got no personal experience of how good they are, but I know the standard ones in the Yaqin are more than decent so higher quality ones *should* be even better. For £200 more (if they're good) that's a bargain, because it would cost far more in the UK to have new mains transformers supplied and fitted.

Again, if you order one of these, I would send it straight to Anthony for safety testing before plugging it in, just to be on the safe side. Any adjustments that are needed can then be carried out.

The MC-110B with "high-grade output transformers" is an unknown quantity, but that's not saying it's not excellent - it could well be. I believe Anthony has got one of these (or perhaps the sliver MC-100B) belonging to my mate in his workshop at the moment so I'll ask him later (if he doesn't see my post first) to comment and help you in this matter.

What I would stress is that all this effort is well worth it, whichever one you go for, because you will end up with a very special valve amplifier that will outperform many much more expensive 'hi-end' commercial designs - I'm not kidding!!!

If there's anything else you need to know, Terry, just ask :)

Marco.

Terry
20-07-2008, 15:04
Fantastic answer Marco !! I really appreaciate it, so glad i found you guys on this forum, very informative and helpfull just like the guys on the Cobra website ! I think i will go for the one from France in the Silver, ok now to get a pair of speakers to do it justice any recomendations ? any anything that i should be looking out for in terms of power handling etc ?. Oh and I here you loud and clear - re the fire thing. Just one thing Marco that you say above -

''Again, if you order one of these, I would send it straight to Anthony for safety testing before plugging it in, just to be on the safe side. Any adjustments that are needed can then be carried out.''

If there was still a problem with the voltage have i not wasted my time getting this one and paying the extra £200 as well ?

Thanks Again

Terry

Marco
20-07-2008, 18:04
Hi Terry,

Sending the amp to Anthony is simply just to have complete piece of mind that everything's ok. You don't have to do this because, as you say, having paid the extra for decent capacitors and mains transformers, everything *should* be ok.

However, I know that these amps in basic form can vary wildly in overall component quality, so despite Marc from Tubophile having caps and transformers upgraded unless he's given the WHOLE amp a thorough testing (who knows - he might or he might not) then if it were me I'd feel happier that it's been tested as safe by a qualified UK valve engineer, such as Anthony.

Furthermore, you still need to address the valve situation as the Chinese ones supplied are only of mediocre quality, so when your amp is at Anthony's he can replace and re-bias a new set of output valves, such as cryo'd Svetlana KT88s, which I would recommend, and perhaps some NOS (new old stock) 6SN7s and 12AX7s if Anthony has any in stock. If not I can advise you where to obtain some of both. You should allow approximately £350 for a complete set of new valves (£200 for the Svets, which are brand new, and the rest roughly for the NOS ones).

The other thing is I presume you intend to use the Yaqin as an integrated? That's fine (when you've sorted out new valves) and it will work very well that way, but it really comes into its own when used as a power amp with a top-notch valve preamp. This is something you should seriously consider later, and there are a number of available options for you without spending a fortune, particularly the new range of Croft preamps which are soon to be released.

Ok, I hope that helps. Again, if there's anything I've missed or something you're unclear about, just ask! :)

Marco.

Terry
21-07-2008, 07:52
Hi Marco thanks for your explanation on the 'getting it checked' subject all clear now, i will ask you now on how a preamp will hook up to the Yaqin amp ?
As i have never seen how they fit into the system !
On the capacitors in the Yaqin amp i asked Marc from France what he had the factory change and here is his answer, it will make sense to you i am sure but to me :scratch::scratch::scratch: !!!!!

Dear Terry,

at the moment our special attention is to the power chemical capacitors. We ask samsung 560uF instead of 470uF
Also for all capacitors inside we ask 105° quality.

On special request, we can change the link capacitors to SCR or Solen with additional cost. In a a near future, we will put them in sery.

Best regards,
Marc

Do you think that i should ask him what are the 'capacitors inside of 105 quality' ?

Thanks Again

Terry

lurcher
21-07-2008, 08:18
Electrolytic caps are normally rated with a maximum temperature. The two normal temperatures are 85 deg C and 105 deg C. All things being equal the 105 are better to have in a valve amp, but that assumes all else is the same.

I can't remember what voltage the caps in that amp are, or if it has a couple of chokes or not.

Marco
21-07-2008, 08:20
Hi Terry,

You can connect a preamp via any of the source input terminals on the back - it works that way, but in practice the gain appears to be too high through those terminals and it can induce some hum, so I use the two inputs on the front and this works fine. You may need some longer interconnects (1.5 or 2m) to compensate for the connections being further away from the preamp than normal, though. All you do then is flip the toggle switch on the front to the 0.6V position when using the unit as a power amp only. Once done, the volume control on the front acts as a gain control. This is usually set to the 'full on' position but adjustment can be made depending on the sensitivity of the preamp. There are also full instructions explaining all this in the enclosed manual.

As an integrated amp (once modified as described) it is very good, but as a standalone power amp with a top-notch preamp at the helm it is absolutely stunning. Therefore if you can afford to purchase a suitable preamp to use with the Yaqin you will indeed have a very formidable pre/power combination.

What Marc is saying regarding capacitors is that he has specified ones with a higher reservoir capacity, which should (although not necessarily) improve performance. I'm sure the ones he's chosen are a genuine upgrade on the standard ones (it wouldn't take much because they're fairly low grade) but much depends on the circuit. Sometimes you can go OTT with caps and make things worse instead of better, or you're just wasting money for the sake of it.

The "105°" is simply relating to the capacitor temperature handling capability. The capacitors he's selected are high temperature ones which are necessary on the Yaqin due to their proximity to the mains transformers, which can get a bit hot, although in practice the transformers are operating well within their manufactured tolerance. In reality the only thing that gets really hot are the KT88s! These kick out a phenomenal amount of heat if left on for prolonged periods, which is not so good in the summer months... I can turn my (admittedly smallish room) into a mini greenhouse just by keeping the Yaqin on for a few hours! :eyebrows:

As a result you should bear in mind that the electrical consumption of a valve amplifier like the Yaqin is considerably higher than that of anything solid-state (it's almost akin to running one of those two or three bar electric fires that used to be made - not quite but close enough) so remember to factor higher running costs into the equation. For that reason, and also one of safety, it's best to turn it off when not in use.

You just have to get into a different routine with valve gear, and treat it with respect, but you soon get used to it and the sonic rewards of doing so are substantial.

Marco.

anthonyTD
21-07-2008, 09:08
hi terry,
the yaqin 100b and 110b are both very capable amplifiers once the weak points have been addressed, the french version is indeed a better option out of the two as the better output transformers alone I would guess would cost you around the same price as the whole amp to get them made in this country! as they say the mains transformers have also been upgraded to a higher primary voltage spec, but, untill I have fully tested the one I have here I cannot comment on that at the moment. the power supply caps [nick] are rated at 470uf 450v and there are a pair in series to share the full ht in each channel, but the standard ones are absolute cr#P, and as marco discovered can and will catch fire if left in. there are other parts of the power supply that can and do get upgraded, also, a lot of the original resistors etc are terrible,so, again need addressing. the original mains transformers in the 100b are supposed to be rated for 220v but on test i found that 210v was about the limit for all the voltages to be right on the secondaries! nick is also correct by saying that the voltage in some parts of the uk can be in excess of 250v at certain parts of the day, so, as you can see, it's no wonder these amps go bang when people put them straight on our mains supplies.
this is why i recommend anyone contemplating buying one of these amps to not even switch it on before getting them upgraded for uk useage.
anyway, I hope I have helped with your decision on whether or not one of these amps may be right for you, if I have left anything out, or you want to know more let me know and I will do my best to help in any way I can.
anthony...:)

Terry
21-07-2008, 16:46
Marco and Anthony.

You are both Gents, i thank you for all your help on this.

I will be in touch just as soon as i have sorted things out.

Thanks Again

Terry

Ali Tait
21-07-2008, 18:26
Yes,as it is a class A device,it's running full-tilt all the time so to speak.Class A amps valve amps are less than 10% efficient in general as far as I know.Mostly wasted in heat.

Marco
21-07-2008, 18:32
Marco and Anthony.

You are both Gents, i thank you for all your help on this.

I will be in touch just as soon as i have sorted things out.

Thanks Again

Terry

You're welcome, Terry. It's what the forum is for :)

Marco.

Terry
22-07-2008, 19:45
Hi Guys
Just thinking about a turntable and how i would hook it up to the Yaqin as it has inputs for cd/tape etc but no phono.
Any ideas ?

Thanks

Terry.

Marco
22-07-2008, 19:54
Hi Terry,

Either go for a preamp with a phono stage built-in (eg. Croft) and connect that to the Yaqin, or use a separate standalone phono stage, which will connect to one of the line inputs of the Yaqin when used as an integrated or whatever preamp you use that doesn't have a built-in phono stage.

Marco.

Terry
30-08-2008, 11:16
Hi everyone.

Just thought i would give you an update.
At the moment i am still tubeless !!! I have emailed the guy in France telling him that i would like to purchase his uprated Yaqin 100B for £499 and have not had a reply. If you go to his website its still says that he is in ill health but when i emailed him to give me the info about his product last time he answered with no problem. So i hope that he is ok, but in the meantime i am stuck as to what to do. I could watch a 100B that is on ebay (already in UK) now and if cheap enough send it to Anthony to sort out but i guess it would need new transformers as well as caps etc !!.

ps, Anyone know anything about these - Avreavox Arcana 82 Monoblocks with matching Arcana 81 Pre-amp.

Thanks Again !!!

Steve Toy
30-08-2008, 20:46
Tubophile makes false claims about the uprated specs of their transformers on the Yaqin, so it would seem. You would be better off buying direct from China and sending it to Anthony.

Terry
30-08-2008, 21:59
Tubophile makes false claims about the uprated specs of their transformers on the Yaqin, so it would seem. You would be better off buying direct from China and sending it to Anthony.

Thanks for your thoughts on this Steve, think i need to have a chat with Anthony to get prices etc ! The only thing that concerns me about getting one from China is that i have been hearing that you will get a bill from our lovely customs people that make it not worthwhile !!! Any comments on the Arcana 82 Monoblocks + 81 Pre-amp ?

Marco
30-08-2008, 22:01
Hi Terry,

I'll come back to you tomorrow regarding this. I'm off to listen to some tunes before going to bed.

Laters,
Marco.

Terry
31-08-2008, 09:01
Hi Terry,

I'll come back to you tomorrow regarding this. I'm off to listen to some tunes before going to bed.

Laters,
Marco.

Thanks Marco.

Look forward to hearing from you !
By the way i cannot find any info on the Arcana 82 Monoblocks + 81 Pre-amp as to wpc or price etc ?
I have also found this one for sale, PrimaLuna Prologue One any thoughts on price etc ?

Terry
31-08-2008, 12:56
Heres a couple of pics of the one's i have found.

Marco
31-08-2008, 19:10
Hi Terry,

I have no knowledge of the Arcana 82 monoblocks so I'm afraid that I can't advise you there.

As for Primaluna, I've heard a couple of their amps and wasn't particularly impressed. In standard unmodified form the Yaqin outperformed them in my system.

As for Tubophile in France, after recent experiences I wouldn't use them. They're advertising the Yaqin as having upgraded mains and output transformers, but after testing the former is completely untrue and the latter very unlikely. The only difference with the Yaqins sold by Tubophile is that they're supplied with JJ Tesla KT88s, which are better than the usual Chinese output valves, and the brass top-plate and transformer container cans have been sprayed black - not much for the extra expenditure!

I'm not sure if it's the case that Tubophile specified upgraded transformers from Yaqin in China and they were not supplied or the French chap is at it. I suspect (and hope) the former. However, as you've discovered, he's currently ill in hospital (or so he says) and unable to reply to emails. My advice in any case is to stay clear. If you want to go for a Yaqin, buy one from the many vendors on Ebay and send it straight to Anthony for making safe and modifying. You will then end up with a superb and safe amp! :smoking:

Marco.

Terry
31-08-2008, 19:27
Thanks Marco.

I will keep a lookout for a Yaqin and as you say send it to Anthony for any mods that need doing. I thought it strange as to why the chap in France hadn't replied to my emails, especially as i was giving him business.
Anyway i will keep you informed as to which path i take.

Marco
31-08-2008, 19:30
Excellent, Terry. Yes the fact that he's not replying to you even though you were giving him business sort of proves that he's genuinely ill. If I discover any new information on this situation I'll let you know.

Marco.

Terry
03-09-2008, 15:51
Hi Marco

Just one more question regarding the Yaqin 100B from china.
I have atached a picture of their wiring, does this look right to you ?
As i thought that these amps used point to point wiring but as you can see theres have pcb's ?
Thanks.

Marco
03-09-2008, 16:41
Hi Terry,

Point-to-point wiring as standard on a cheap Chinese valve amp? If only! :eyebrows:

No, that's spot on. Proceed with pleasure!

Marco.

Terry
03-09-2008, 17:38
Hi Terry,

Point-to-point wiring as standard on a cheap Chinese valve amp? If only! :eyebrows:

No, that's spot on. Proceed with pleasure!

Marco.

OPPS !!!!!!!!!! :lolsign:

Told you this was a steep learning curve for me !!!!!

Marco
03-09-2008, 17:59
No worries. Keep us posted with how you get on, and let Anthony know he's got another Yaqin on the way to him! :)

Marco.

anthonyTD
05-09-2008, 15:07
Fantastic answer Marco !! I really appreaciate it, so glad i found you guys on this forum, very informative and helpfull just like the guys on the Cobra website ! I think i will go for the one from France in the Silver, ok now to get a pair of speakers to do it justice any recomendations ? any anything that i should be looking out for in terms of power handling etc ?. Oh and I here you loud and clear - re the fire thing. Just one thing Marco that you say above -

''Again, if you order one of these, I would send it straight to Anthony for safety testing before plugging it in, just to be on the safe side. Any adjustments that are needed can then be carried out.''

If there was still a problem with the voltage have i not wasted my time getting this one and paying the extra £200 as well ?

Thanks Again

Terry

hi terry,
the mains transformers on the French versions are still not right for our voltage in the UK where the voltage [measured] can be anything from 238v to 253v [260v in some extremes] so my advice would be if you buy one either from eBay [Hong Kong] or from France, be prepared to have the mains transformers changed, as even running these amps 10% over what they say they are rated for is still too much for long term reliability. As for cosmetics, I agree that the chrome/black finish can be more appealing in some listening areas, but both versions are aseptically pleasing. The valves in both are not the best, so some nice new old stock drivers and a set of Svetlanas in the output stage will be a definite upgrade of standard performance, but even then the sound of the yaqin in standard form leaves a lot to be desired, but when seriously modified, they offer huge potential.
I hope this helps.
regards,anthony,TD...:)

Terry
05-09-2008, 16:17
hi terry,
the mains transformers on the French versions are still not right for our voltage in the UK where the voltage [measured] can be anything from 238v to 253v [260v in some extremes] so my advice would be if you buy one either from eBay [Hong Kong] or from France, be prepared to have the mains transformers changed, as even running these amps 10% over what they say they are rated for is still too much for long term reliability. As for cosmetics, I agree that the chrome/black finish can be more appealing in some listening areas, but both versions are aseptically pleasing. The valves in both are not the best, so some nice new old stock drivers and a set of Svetlanas in the output stage will be a definite upgrade of standard performance, but even then the sound of the yaqin in standard form leaves a lot to be desired, but when seriously modified, they offer huge potential.
I hope this helps.
regards,anthony,TD...:)

Thanks Anthony !
What kind of figures are we talking about for these upgrades ?
I am keeping my eye on one at the moment.
Thanks.

Terry
06-09-2008, 08:44
Hi Anthony

Thanks for the info yesterday.
Just to let you know that i asked one of the chinnese sellers on ebay about the voltage issue and this is their reply,

Hello,

The input power that we supply is 230V, if you want 240V we can special order from the factory, thank you.

Best regards,
Leshele

I then asked about the price and they said it would be the same, what do you think ? If i order one how can i tell if it is of the correct voltage ?

Thanks Again !!

anthonyTD
06-09-2008, 09:52
Hi Anthony

Thanks for the info yesterday.
Just to let you know that i asked one of the chinnese sellers on ebay about the voltage issue and this is their reply,

Hello,

The input power that we supply is 230V, if you want 240V we can special order from the factory, thank you.

Best regards,
Leshele

I then asked about the price and they said it would be the same, what do you think ? If i order one how can i tell if it is of the correct voltage ?

Thanks Again !!

hi terry,
difficult, the only real sure way is to have it tested when it arives.
regards,anthony,TD...:)

dr.larkos
05-11-2008, 18:05
Hi Terry,

Sending the amp to Anthony is simply just to have complete piece of mind that everything's ok. You don't have to do this because, as you say, having paid the extra for decent capacitors and mains transformers, everything *should* be ok.

However, I know that these amps in basic form can vary wildly in overall component quality, so despite Marc from Tubophile having caps and transformers upgraded unless he's given the WHOLE amp a thorough testing (who knows - he might or he might not) then if it were me I'd feel happier that it's been tested as safe by a qualified UK valve engineer, such as Anthony.

Furthermore, you still need to address the valve situation as the Chinese ones supplied are only of mediocre quality, so when your amp is at Anthony's he can replace and re-bias a new set of output valves, such as cryo'd Svetlana KT88s, which I would recommend, and perhaps some NOS (new old stock) 6SN7s and 12AX7s if Anthony has any in stock. If not I can advise you where to obtain some of both. You should allow approximately £350 for a complete set of new valves (£200 for the Svets, which are brand new, and the rest roughly for the NOS ones).

The other thing is I presume you intend to use the Yaqin as an integrated? That's fine (when you've sorted out new valves) and it will work very well that way, but it really comes into its own when used as a power amp with a top-notch valve preamp. This is something you should seriously consider later, and there are a number of available options for you without spending a fortune, particularly the new range of Croft preamps which are soon to be released.

Ok, I hope that helps. Again, if there's anything I've missed or something you're unclear about, just ask! :)

Marco.

Hello, just discovered and joined this excellent forum.

Marco, I have a question related to the post I am quoting above. In particular, the part discussing the virtues of using the Yaqin MC-100B as a stand alone power amp in combination wit a top notch valve preamp. I have such a preamp (an all valve Cary Audio Design) and I am contemplating buying a Yaqin MC-100B. Does the Yaqin have a true Pre by-pass or the Pre's circuitry will still be in the path of the signal coming from the Cary? If I understood the Canadian vendor correctly (I am in the US), it appears that there is no true by-pass in the Yaqin but an additional gain reduction circuitry (front inputs) with negative feed-back (I gather, to elminate potential added distortion from daisy-chaining preamps [??]). Now, I imagine that if it is correct that the Yaqin's preamp cicuitry is still in the path of the Cary's signal, then, one still has to address the issue of tube quality in the Yaqi's preamp section, right? In the light of all this, I would appreciate if you could throw some insights on this matter and, if possible, elaborate a bit more on how is that the Yaqin comes into its own when used as a power amp with a top-notch valve preamp.

Thanks and all the best......................dr.larkos

anthonyTD
05-11-2008, 20:24
hi dr larkos,
i have been asked to explain about the diffrences in using the yaqin as a dedicated power amp as apposed to the intergrated that it is in its standard form. i think what marco is refereing to is when the amp has been fully modified and the original preamp section is removed from the circuitry, not the diffrence between the front direct inputs and the rear switched inputs in its standard configuration!
hope this helps.
regards,anthony,TD...:)

dr.larkos
05-11-2008, 20:54
hi dr larkos,
i have been asked to explain about the diffrences in using the yaqin as a dedicated power amp as apposed to the intergrated that it is in its standard form. i think what marco is refereing to is when the amp has been fully modified and the original preamp section is removed from the circuitry, not the diffrence between the front direct inputs and the rear switched inputs in its standard configuration!
hope this helps.
regards,anthony,TD...:)

Anthony, many thanks for your prompt response. I am not so sure that Marco strictly meant what you suggest. The following quote from Marco's Post #30 (in this Thread) appears to indicate otherwise. Within the context of Post #30, Marco appears to be talking about conecting an external preamp to a standard Yaqin, not to one that have had its preamp section "removed":



Hi Terry,

You can connect a preamp via any of the source input terminals on the back - it works that way, but in practice the gain appears to be too high through those terminals and it can induce some hum, so I use the two inputs on the front and this works fine. You may need some longer interconnects (1.5 or 2m) to compensate for the connections being further away from the preamp than normal, though. All you do then is flip the toggle switch on the front to the 0.6V position when using the unit as a power amp only. Once done, the volume control on the front acts as a gain control. This is usually set to the 'full on' position but adjustment can be made depending on the sensitivity of the preamp. There are also full instructions explaining all this in the enclosed manual.

As an integrated amp (once modified as described) it is very good, but as a standalone power amp with a top-notch preamp at the helm it is absolutely stunning. Therefore if you can afford to purchase a suitable preamp to use with the Yaqin you will indeed have a very formidable pre/power combination.

It was the combination of Marco's Post #30 and the post I quoted in my original post that prompted me to try contact Marco through The Art of Sound Forum.

All the best................dr.larkos

Marco
05-11-2008, 21:36
Hi Dr Larkos, and welcome to AOS :)

Hehe...you're right - Marco didn't strictly mean what Anthony suggested! :lolsign:

This is the question I wanted Anthony to answer as he'll be able to do it better than me (particularly the bit in bold):


Does the Yaqin have a true Pre by-pass or the Pre's circuitry will still be in the path of the signal coming from the Cary? If I understood the Canadian vendor correctly (I am in the US), it appears that there is no true by-pass in the Yaqin but an additional gain reduction circuitry (front inputs) with negative feed-back (I gather, to elminate potential added distortion from daisy-chaining preamps [??])


I'll leave that one to Anthony when he comes back ;)

As for the rest of your query, particularly this:


Now, I imagine that if it is correct that the Yaqin's preamp cicuitry is still in the path of the Cary's signal, then, one still has to address the issue of tube quality in the Yaqi's preamp section, right?


Yes of course you're right, and that is done (to an extent) by upgrading the two Chinese 12AX7 tubes on the front for something like NOS Mullards or Telefunkens, as these are related to the Yaqin's preamp gain section. However, addressing and significantly upgrading the quality of the Yaqin's overall preamp section requires more fundamental internal modifications, but (as far as I know) most (but not all) of the circuitry is bypassed when using an external preamp.

However, experience tells me that using a high quality separate tube preamp with the Yaqin and turning it into a 'pre/power' combination as I've described yields far superior results than those obtained by using the Yaqin solely as an integrated amplifier. The difference is far from subtle! I can go into more detail about this if you wish.

I hope that helps. If there is anything you feel we haven't covered just ask :)

Marco.

dr.larkos
05-11-2008, 21:59
Splendid, Marco (or as you chaps like to say, brilliant!). this is exactly the kind of insight I was hoping to get. many thanks. You are confirming that regardless of how much the Pre's circuitry is still present, when connecting to a top notch Pre to the Yaqin's front inputs, the benefits are there and they are not just subtle. Let's see what Anthony can figure out regarding those front inputs and if there is any additional circuitry associate with them besides gain reduction(negative feedback or whatever else).

Goes without saying, I will be more than happy to hear from you (whenever is convenient) about the benefits of the External Pre/Yaqin combination.

All the best...................dr.larkos

Marco
05-11-2008, 22:12
I'll put some thoughts together and post them tomorrow. Basically, what you should realise is that the power amp section in the Yaqin is where most of its talents lie. The preamp section in comparison is relatively poor quality and more of an 'afterthought', if you see what I mean.

Incidentally, what's your first name? :)

Marco.

dr.larkos
06-11-2008, 05:58
Look forward to those comments, Marco....yes sir, vey rude of me, my first name is Carlos and I live in New York.

anthonyTD
06-11-2008, 10:30
hi dr larkos,
sorry about the confusion, anyway, the preamp section in the yaqin is still in the signal path whether you use the front direct inputs, or the switched ones at the back, its just the gain is altered, and of course the signal is not having to go through all the switching. the only true way of bi-passing the preamp section in the yaqin is to remove it, and re-work the remaining circuitry.
regards,anthony...:)

dr.larkos
06-11-2008, 15:32
Thank you Anthony. Just a thought. I own another valve integrated amp made in China (fully designed in Australia), a 38 watt Melody SP3. This amp has two sets of RCA inputs. One set is a true by-pass that allows to connect an external preamp to the internal power amp section of the Melody. Not exactly a jumpered Pre-Out/Power-In set up but, basically, a set of RCA input jacks wired in parallel at the circuitry point where the internal preamp's L/R signal outputs enter the power amp section. Couldn't the same be done to the Yaquin rather than removing the pre section and reworking the remaining circuity, as I believe you are saying? Namely, would it be possible to disconnect one of the Yaqin's RCA input pairs from the input selector switch and wire the pair directly to the power amp's L/R circuit-path entry points?

All the best...........Carlos

anthonyTD
06-11-2008, 17:58
Thank you Anthony. Just a thought. I own another valve integrated amp made in China (fully designed in Australia), a 38 watt Melody SP3. This amp has two sets of RCA inputs. One set is a true by-pass that allows to connect an external preamp to the internal power amp section of the Melody. Not exactly a jumpered Pre-Out/Power-In set up but, basically, a set of RCA input jacks wired in parallel at the circuitry point where the internal preamp's L/R signal outputs enter the power amp section. Couldn't the same be done to the Yaquin rather than removing the pre section and reworking the remaining circuity, as I believe you are saying? Namely, would it be possible to disconnect one of the Yaqin's RCA input pairs from the input selector switch and wire the pair directly to the power amp's L/R circuit-path entry points?

All the best...........Carlos
hi DR,
this would not be possible with the original yaqin circuitry as the first gain stage is directly coupled to the second stage, also, in its standard configuration, if you just removed the preamp stage the gain would be too low, its a bit of an odity, but it works quite well, but its only when you reconfigure the circuitry in a paticular way that the true potential of these amps are recognised.
anthony...:)

dr.larkos
06-11-2008, 18:13
Clearly understood, Anthony, many thanks.

Carlos

dr.larkos
09-11-2008, 16:42
I'll put some thoughts together and post them tomorrow. Basically, what you should realise is that the power amp section in the Yaqin is where most of its talents lie. The preamp section in comparison is relatively poor quality and more of an 'afterthought', if you see what I mean.

Incidentally, what's your first name? :)

Marco.

Greetings, Marco. Did you or have you guys had the chance to compare the Svetlana's KT88 to the Genalex Gold Lyon's (New Issue) in the Yaqin (or in general)?

Best regards................Carlos