Yaqin MC10L and KT88

[megalodementia]

Hello Everyone .
It is my first time on this site and people sound cool and the website is totally what I was looking for !!!

1-I bought a Yaqin MC10L 3 months ago and i never had any Problems on this amp but I want to upgrade this Amps with KT88 ( Or Equivalent ) without touching the elecytroni components , I would like to know if someone already tried this operation .

2-In the meantime what can happen if I change the Tube without modifying the components ( If Needed) Is there something which gonna Burn or ruin my Amp ( Or Lamps )?

3-I was told to check the bias and If the current in the Amps is Powerful enought I was told I could change it without any problems? Is That True (If Yes do you know a good tutorial that shows how to make that Operation ?

Sorry for so many question But I am a beginner and I am looking for a lot of Info
In case of need Here is My Amp : http://www.yaqin.cn/en/products_hf.html
Thankls in advance for your Help
Ben

[SY]

Welcome to the forum! You're living in my favorite city in France.

Now the bad news: there will almost certainly be changes to the circuit required in order to successfully and safely swap output tubes. To start with, you'll need a schematic of the circuit. Do you have one or have you traced it out yourself?

Do you have the basic tools necessary to do this right? At minimum, a good multimeter, a signal generator, an oscilloscope, and a dummy load.

Do you have experience working in high voltage circuitry? If not, don't even think about doing this; death is easy to find and hard to get rid of.

Do you have a clear reason for why you want to change the output tubes? Random tube swapping might be entertaining, but it is unlikely to bring you audio nirvana.

edit: Here's some copy from the linked site that I find amusing:

Grade has enlarged circuit and " long end type " phase inverter for SRPP ago, output transformer adopt Japan produce audio frequency special-purpose silicon steel sheet (Z10 ) and high strength enameled wire and special to is it make craft make to wind.

[megalodementia]

Hello SY

Thanks for your reply , Nice to know that you like the city !! Are you American 'cause I ve been living in NYC for 3 Years and I loved it so much ...

Anyway , The reason of the upgrade is that I tried the almost the same Amps equipied with KT88 and the sound is way better than Mine : Clearer , more muscal and deeper .

I do not have the circuit unfortunately and I really do not know how to get it .

I never experienced something like that before thats why i was asking advice in order to avoid ... Death !!

Well Can you tell the risk I can encounter if I Change the lamp without changing some component ( By the way ; What are generaly the components you have to change for such an Update ? Any idea? Transformers / Resistors ??? )

Thanks For your help And if you are in LYON soon , you are more than Welcome... Anytime
Take care
ben

[Yvesm]

Hi Ben,

I can't tell what could be changed in your amp nor how.

I'm probably not as fluent as more guys over here, but I'm certainly one of the nearest

Some lives in Napa Valley, other in the Vallée du Rhone.

Yves.

[SY]

Typically, some minor socket rewiring is needed. The bias network will need to be changed to accommodate the new tubes. The output transformer may not be suitable- the optimum load impedances are different between KT88 and EL34. Compensation and feedback will need to be reworked.

Yes, I'm American, but about 5000km from New York. I'm near San Francisco, which is very similar to Lyon in some important ways (physically beautiful, sitting between two great wine regions, and a culinary center). We even have a Michelin *** nearby.

edit:

Some lives in Napa Valley, other in the Vallée du Rhone.

Coincidently, we drank some Brezeme last night. (sorry for the bad orthography, accents are difficult on an English keyboard)

[bibster]

Originally posted by megalodementia

I do not have the circuit unfortunately and I really do not know how to get it .

Salut Ben,

You *DO* have the circuit, and you *DO* know how to get it...
You just have to take look inside your amp, and (try to) draw a schematic!

If you think you're not able to accomplish such a task, just make some good, sharp, well focused, close up photos of the inside!

I'm pretty sure Sy only likes Lyon because it's neatly between the northern and the southern côtes du Rhône.

Paul (Côtes du canal du midi)

[megalodementia]

Hi Guys

Thank you all for your Support ... For the 2 french guy That Would be great If I could get your Phone Number by email megalodementia@yahoo.fr

For the Pics I will take some pics tonight and post it later tonight , that would be great if i could change those Tubes , Sound so much better with KT88

Ben

[megalodementia]

Hey Guys
there you go for the pics .
I believe it should be ok ....Hoping you ll be backwith good news and away to upgrade the amp take care

[jarthel]

Originally posted by SY


edit: Here's some copy from the linked site that I find amusing:

thank nothing compared to:

VK-2100 description

First class-B gall stone is combined , grade is SRPP circuit before the gallbladder.

[woodturner-fran]

for some reason valves in chinese are always translated as gallstone or bladder by the likes of babel fish!

Anyway, I noticed in the for sale section that there is now a dealer for yaqin products in the UK and he will do repairs etc etc. Would be a good resource for those with these amps. At least you won't have a language barrier


Fran