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Yaqin VK-2100 mods
Yaqin VK-2100 mods
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Old 14th July 2009, 01:32 AM   #1
Rockmore is offline Rockmore  United States
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Default Yaqin VK-2100 mods

Have a Yaqin (Yaoin) VK-2100 hybrid. Really like it and squeezing all the mods in I can.

Taking suggestions for a matched quad of 6n1 or 6dj8's (would prefer the 6dj8's) to replace the stock Shauguan (or however you spell it) 6n1's. The stock 6n1's just don't seem very "good".... There is no manual bias adjust.

Would prefer NOS, but only can seem to find reasonably priced NOS in matched pairs...
Looking for something REALLY good in a matched NOS quad, or other suggestions.

Thanks guys!
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Old 14th July 2009, 01:44 AM   #2
leadbelly is offline leadbelly  Canada
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Yaqin VK-2100 mods
Those are the INPUT tubes. A manual bias adjust would be a little comical. There's no need for them to be matched, for the same reason.
There are still unbridgeable divisions between cultures. How can two peoples ever come to understand each other when one of them is ignorant of TotÚ? Umberto Eco
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Old 14th July 2009, 08:04 AM   #3
soulmerchant is offline soulmerchant  Switzerland
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I would look for some reasonably priced JAN 6922's if possible. A couple of matched pairs could work very well.

Nicely matched input tubes (channel to channel) are desireable and you can hear the difference.

Most sellers on the net match tubes by output (Ia). This is useful for end-stage tubes, but for small input tubes I find it much more relevant to match channels by mutual conductance (gm or ma/V ).
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Old 14th July 2009, 09:58 AM   #4
Klimon is offline Klimon  Belgium
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It won't raise any prices if I tell you that pcc88/7dj8 is a much cheaper equivalent, albeit with 7v heater. You can perfectly run it at 6.3v, leading to a much prolonged life without any sonic penalty.

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Old 14th July 2009, 04:50 PM   #5
soulmerchant is offline soulmerchant  Switzerland
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Originally posted by Klimon
It won't raise any prices if I tell you that pcc88/7dj8 is a much cheaper equivalent, albeit with 7v heater. You can perfectly run it at 6.3v, leading to a much prolonged life without any sonic penalty.


Those are also fetching much more than in the past these days. But sometimes you can get the JAN 6922 (US made version) for an OK price. Quality on these are good too with decent ma/V readings (at least on the batch I bought last year).

But I do have a few philips 7dj8's that were cheeep a few years back doing nice service in a nice little phono stage...
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Old 16th July 2009, 02:28 AM   #6
Rockmore is offline Rockmore  United States
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I realize they are for my input stage.... just thought a matched pair of quads could not hurt....

Thanks for the ideas- will probably go with some cryo's in matched pairs from tubeman... "he's" got some decent Russian ones, and some Phillips that seem pretty good. I'm still keeping my eye out for some really old NOS if they ever pop up somewhere.
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Old 16th July 2009, 04:33 PM   #7
feralmeida is offline feralmeida  Spain
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Default Chinesse 6N1 vs 6DJ8... and Russian 6N1P-EB!

It has proven 6N1P-EB Russian (nothing common with the Chinese)
they demystified, or they stopped to me being so good of best 6DJ8 (Telefunken E88CC/6922 Gold Pind Diamond ) (adjus R katode)

one assumes that it will sound a type or another one better, according to the configuration, 6N1P-EB only needs the more tension and current to distort the less, if the tension is low, will do 6DJ8s better
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Old 9th August 2009, 06:08 AM   #8
shuggi67 is offline shuggi67  Australia
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RockMore what are your thoughts on the sound of this amp ?.
I am thinking of purchasing one and also modifying, I was originally planning on doing complete DIY bronski Hybrid but don't have any experience in Electronics.
I have had a look around the Net for some buyers of the amp, but not much out there and the ones I found seem to only keep in for a short time and ditch it for a MC-10L.

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Old 9th August 2009, 08:38 AM   #9
Arnulf is offline Arnulf  Europe
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Originally posted by soulmerchant
Nicely matched input tubes (channel to channel) are desireable and you can hear the difference.
Sure ... when one half is about to die Many people can't even recognize a 3 db (almost 100%) diffrerence between channels when testing (= same input on both channels but only one playing at any given moment during testing), let alone when music is playing on both channels and the two halves aren't as grossly mismatched.

A random NOS twin tube with identical halves isn't likely to differ by even 1 db (25%) between channels.

Tubes have to be matched when symmetrical output is required because components included and principles of operation involved are MUCH more sensitive than your "golden ears".
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Old 11th December 2009, 05:18 AM   #10
Rockmore is offline Rockmore  United States
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Wanted to say Happy Holidays to everyone with getting this post/thread back into activity. I have modded, tweaked, researched and researched, and used my VK-2100 DAILY since July of this year. Not just because I own one, but because it is still the best bang for the buck anywhere worldwide. The hybrid engineering, especially with the Japanese better-end components, is hard to beat.

There still needs to be a definitive Yaqin (Yaoin) VK-2100 thread and "home". Maybe this thread should be it.

Let me post some info and facts since-

- There is STILL no official or credible professional review of this amp by any of the average or higher end magazines or incorporated sources. Most whom I have talk to voice on the phone STILL have a huge stigma about the Chinese companies and markets, and will not recognize them as credible until they go "mainstream". This may never happen, as companies like Yaqin (Yaoin) are still locked in marketing/trade/cost locks with and for the western markets. That's why you still only see them offered via Ebay with huge shipping costs (and hassle inherent warranty issues).

- In the non European markets for North America, it is still advisable to obtain this hybrid from the closest geographical location, Canada.

- There IS NO direct English speaking support from Yaqin in any form. If you can get one, the owners manuals are hand translations from Chinese by or from the source you purchased it from. NOT GOOD.

- There is still no exact official response on pre-amp tube replacement from Yaqin, other than the stock Shauguang(sp?) 6N1's. Depending on the "version" (and printed on the circuit board itself), officially, the VK-2100 only accepts 6n1 or the 12xxx series tubes.

- There is no recognition what-so-ever from mecca sources like Audiogon, etc. Western companies and brands like Jolida whom have been the mainstay for these mecca sources for decades are very threatened by companies like Yaqin, and they damn them absolutely. Such terms as "dangerous" and "poorly made" are commonly used when referring to Yaqin and the like. When in realty, it's all a cost vrs dollar vrs what-you-get-for-your-hard-earned-dollar issue.

- The only to-date mainstay issue with the VK-2100 is heat and heat dispersion issues. This continually come up anywhere worldwide (not just by owners in N. America). Any owner of the VK-2100 needs to be prepared to do case and cover modifications new out of the box.

- The following thread/link is STILL the only to-date hands-on tweak and balancing thread in English speaking forums. M jarve is still one of the few that has tackled this amp with some credibility: Yaqin VK-2100 tube integrated amp - Page 2 - AudioKarma.org Home Audio Stereo Discussion Forums

- There has been no professional made or met challenges from major label Western made and marketed companies to any of the Yaqin amps; the Yaqin VK-2100, MC10L, and the MC100b being the primary products the consumers and enthusiasts are buying in droves, compared to their Western world counterparts "retailing" at 3 to 20 times the cost.

I personally, using this hybrid daily 7 days a week, with various higher end speakers, have found the VK-2100 to meet or beat ANY amp in it's class for home audio or 2 channel home theater. It has been durable, refined, very musical, cosmetically appealing (compared to other tube/SS amps), refined, and the best bang for the buck I have found. The ONLY personal thing I have modified (not the confirmed heat dispersion issue) has been the excessively bright blue LED power light. It is excessively bright in candle power being right next to the warm orange glow of the stock pre-amp tubes.

Get the word out fellas- lets make this thread the worldwide point-of-contact with anything to do with this hybrid amp. Availability, costs, issues, tweaks, mods, problems, discussion, etc. etc.

I will also add a reply/response to Mike (M Jarve) I made about the VK-2100 last July.

Happy Holidays!

"... Thanks for the replies and help, Mike.

Please feel free to post my exact experience with
the VK-2100. Forgive the attached pics. I have not
finished my "fine tuning" on the case and other mods,
but wanted to get this out and to you ASAP for anyone else.

Bought mine from Song in Canada @Canada
Online. Took 8 business days to get the midwest
USA. Song was VERY selective to ensure who
he was selling to, and NOT TO sell a VK-2100
unless "we" knew exactly what we were getting into.
He (or she) stated they tested three of them and
send the right one for us. Don't know what that means.

Was semi-double boxed and that cheap thin Chinese
cardboard thats about the same as a single North American

No factory manual- but a printer type, 10 or so pages
of stapled paper.

Worked fine out of the box, but Yaqin (Yaoin) is right
when they say 100 hours of break-in, 3 hours at a time.
Sounded terrible for the first three hours. Don't know if
it's getting better or not.

In three hours at one quarter volume (8 ohm load for
the speakers), I LITERALLY burned my forearm on
the aluminum front faceplate. There is no adequate stock
cooling to the pre tube area. and the rest is woefully
inaduaquate for ambient cooling.

Still waiting to see if this thing is truley 85WPC; seems
a little milktoast so far.

It looks nice. But on mine, after pulling the cover, the interior
is not like the stock photos. There is no interior covered area
behind the huge heatsinks. Either something is different (possible
no need for power conversion to 220v), or this is a "version".

**The stock tubes are their toned down amberish color, enclosed
on the back and sides with a cheap mirrored metal. The blue LED for
power is AT LEAST 30 times in candlepower brighter than the what
the tubes ambience is, and is very, VERY distractive, since they are
close together. The seemingly bluish color behind the tubes is not
from the tubes, but reflection form the overly bright blue LED also.**

At a minimum, this is what is critical and needs to be done by
any consumer buying or owning the VK-2100:

- After removing the cover, carefully remove the 2 mini-screws
holding the mirrored metal surrounding the tubes and remove it.
My (US) version, the screws are attadhed into those PC motherboard
type brass threaded risers. Cut the sides of the mirrored metal
completely off, to allow cross airflow.
I also drilled two vertical 1/4" holes directly behind and above each
tube for air flow.

- The case cover metal is not as "tin foil" as mentioned by others.
About the same gage thickness as any PC cold pressed metal.
The tubes can not be boxed in like that, and needs at least ambient
air flow above. I cut a small retangle out of the case above the tubes
and added aluminum screening and side bump tubing.

- Side airflow is absoloutely necessary. I cut "slots" 1 inch
wide and about 7 inches long on both sides and added aluminum
screening and bump tubing.

- I heat tolerence glued a standard, low RPM 80mm 12vdc PC case fan
to the huge heatsinks. Behind them and flush for height. My US version has plenty of open room for the fan behind these heatsinks. It faces up and outwards. Cut a square out of the case metal and added the same screening and bump tubing. This fan will draw air for airflow from the top above the tubes. from the sides, the bottom, and a little from the back.

- Drilled and added a 3/8" hole on the back as shown and added a rubber grommet for external fan wiring for the fan using the "wort or wart" method (external 12vdc power adapter). Would of rather wired the 12vdc fan internaly, but no one as of yet can state exactly how to effectively and safely do so and draw power from the board itself.

- Drilled a 1/4" hole on back for a simple SPST on-off switch for the fan.

These mods all for cooling has AT LEAST reduced basic
operation for temps by -30 -40 degreef F, if not more.
Running the amp for an additional 4 hours at less than half
volume without the fan on has been nominal and acceptable so
far. With the fan on, haven't noticed any interference at all,
and is very cool compairably.

I penned the eye blinding power blue LED using a black
Sharpie completely, and the candlepower brightness is STILL
20 times brighter than what it should be, bleeding through.
Still working on a fix other than to masking tape it over
(blinding blue will still bleed through).

Again, can't state enough how bad, if not actual defective, stock
cooling is (was) for my VK-2100. Cooling mods must be done for
anyone using this hybrid amp!

~Rockmore ..."
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