Yaqin MC-10l

[sacpul]

Today I received the this amplifier and I had a small problem concerning to the sound.

I'm using the same speakers which are eminence alpha 12 and motorola piezo tweeters with 40 years old philips midrage and crossovers.

When I'm comparing the sound between a Fisher amplifier with 5 band equalizer. The midrange and the treble of the yaqin is nicer but the bass seems to be flat compared to the fisher amplifier.

What can I do to improve this valve amplifier. The valves are factory default that are provided from the factory.

Thanks Alot and Best Regards

[adason]

if it's brand new amplifier, give it some time...

[PreSapian]

the valves are the sound in a tube amp. and since chinese tubes are the cheapest with the worst sound, i think you have pleasant surprises waiting for you as you start upgrading the tubes. my mingda 84a sounded painfully harsh at the start but turned into magic once i replaced all the tubes with nos mullards.

[sacpul]

All the valves are factory default. I was trying to replace them by 6L6's or EL34's of JJ Tesla as they are easy to buy them here locally. I was considering if the small valve driver's needs to be replaced also for a better sound.

[Ultima Thule]

Originally Posted by sacpul

...but the bass seems to be flat compared to the fisher amplifier....

Hi,

how about your Fisher amplifier, are you sure it doesn't have some kind of 'Loudness control', a bass compensation at low volumes built in?

I found a very nice review by a guy on the following link:
AudioKarma.org Home Audio Stereo Discussion Forums - View Single Post - Yaqin MC-10L mk II: It's here!
and from what I could read is it goes down quite deep.

According to PreSapians comment Chinese tubes being bad I just recently read somewhere they do have some good tubes too.
I don't know what tubes the Yaqin amp comes with but some Chinese eBay tube amps have Russian Harmonix tubes.

EDIT: Found another interesting link, this is a good read if you want to roll tube!
http://www.audioasylum.com/audio/tub...22/223047.html

Cheers Michael

[sacpul]

Well I have tried the fisher with the loudness control on because it sounds more beautiful for my ears. I'm using the same speakers and the same source.

Tomorrow I will try it again but the fisher without loudness control. I think that with out loudness controll it will have better bass the yaqin but I didn't noticed that little bass boost is extened and not naturally like the yaqin.

What I wished was a Valve amplifier with tone controls like the guitar valve amplifiers. Is there any valve equalizer to put between the amplifier and the cd player?

[Koifarm]

You can use this preamp with tone control and not to expensive.

NEW XiangSheng Improved 728A Tube Pre-amplifier Manufacturer exporting direct from Delhi, India

Ronny

[sacpul]

Today I have tried the amplifier but this time with a different cd disc. The fault was that I didn't noticed that the song had some distortion and on the valve will result more. Not a distortion that you will hear it but a kind of unbalance modern music that will result into distortion.

Today I have played a musical song only and the result was very nice. I have played it with the factory default valves and had a nice result. In the future I will try it will other 6l6's valves.

[Evers]

Originally Posted by sacpul

Today I have tried the amplifier but this time with a different cd disc. The fault was that I didn't noticed that the song had some distortion and on the valve will result more. Not a distortion that you will hear it but a kind of unbalance modern music that will result into distortion.

Today I have played a musical song only and the result was very nice. I have played it with the factory default valves and had a nice result. In the future I will try it will other 6l6's valves.

• After prolonged deliberations and a couple of weeks of intense study at some Danish and international forums, I chosen to bye a YAQIN MC-10L from Tube Amp / DJ Tech online shop - EL34, KT88, 300B, 845, 2A3, Valve, Amplifier, CD Player to 299th - £ = 2600 Dkr. incl. airplane shipping to Denmark.
  
  I must say that their service is on very high and highly professional level.
  The seller did made a fictitious invoice for USD160 and sent it as a gift.
  The day after I had paid, I received an email from a seller with 4 pictures of the package with the package label, invoice and everything ...
  Later that day there came a mail "in Danish" from UPS China containing track & trace number and a date of expected delivery.
  
  5 days later it was at my address without any extra payment :-)
  
  Out of the box the sound was a bit metallic and irritating, and after 2 days came the preamp tubes I ordered in Latvia.
  It sounds very lifted and removed a lot of hot midrange and made the bottom more cash, but it was as if the bass could not quite follow the "read sounded somewhat muddy"
  
  2 days ago so the the output I had ordered in Ukraine, and WOOOOOOUUUU, I can not get his arms down ...
  
  What a difference, the bass is now more than magic, even when I play at low power, and then it can now play at full speed without distortion.
  Sounds really good now at the old Sweedish RAUNA NJORD Concrete speakers from 1983 with my Harman Kardon CD player.
  
  (And yes, I did remembered to adjust the BIAS in the Chinese tubes) 35mA and 50mA at 6P3S-E :-)
  
  Replaced the 4 preamp tubes with 4 X 6N1P-EV which I had read is some really good tubes...
  6N1P, 6N1PVI, 6N1PEV (6H1n, 6H1nBN, 6H1nEB)
  
  and 4 X output tubes 6P3S-E as they say suggests most NOS and other more expensive tube with several lengths, and tested by several others in some MC-10L
  6P3S, 6P3S-E
  
  I had a set of Winged = C = SED Svetlana EL34 tubes (Price 1080 Dkr.) from half past eleven to noon, but they had to give way to 4 paragraphs 6P3S-Es to 24 - $ from Ukraine.
  
  And then I looked over the schem "and below" through with my TUBE GURO which recommend that I do as written here.:
  
  Much more lively it will sound when you change the resistor of the global feedback to something from 22k two 40k from 5.1k.
  But be aware there are High Voltage of about 440V nearby!!
  Install a lttle trimmer of 20-50k in series with the 5.1k and go up until the sound is the best for you (and your speakers).
  Then put in a metal film resistor 1W of the measured value of the trimmer in place where the 5.1k resides .- You will not bother about tube rolling or changing caps any more!
  
  
  
• I got my tubes from here
  
  http://cgi.ebay.com/6P3S-E-6L6GC-588...item3caa6ab1c8
  
  6N1P-EV
  
  RCA Tube items - Get great deals on GE Tube, Sylvania Tube items on eBay.com!
  
  You can save some $ on combine shipping by bying them from the same shop
  
  6P3S-E
  
  http://cgi.ebay.com/6P3S-E-5881-6L6G...item45f064fa59
  
  6N1P-EV
  
  http://cgi.ebay.com/6N1P-EV-6DJ8-ECC...item4399cb018a
  
  Also the 6L6 can be used in this amp I been told :-)
  
  
  
• 
  Had the cover of today, to see what really was below the 3 large transformer covers. To my great astonishment, I must break down and admit that everything I've read so far about these Chinese amps, with getoblaster trafo not quite hold true in this case.
  
  Neither resembles some of what I've seen on previous models, and can only rejoice that the 23 kg it weighs, obviously lies hidden in the 3 large and beautiful transformer that fills the houses well and thoroughly.
  
  I'm still more than very pleased with the amplifier, which still surprises me ...
  
  
  
  

[data]

I got the YAQIN MC-10L and after 60 hours of burn-in It's sounding much smoother than at first.

Also, to my pleasant surprise it has indeed a 240v power supply, even after 10+ hours of play the covers on the PS are just warm

I replaced the Chinese tubes that came with it after the first hour for all Russian NOS valves, 6P3S-E and for the pre section 6N1P (USSR-75).