Meixing Mingda tubes

by ac2 Mon Mar 31, 2014 6:21 am

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Post n°1

Meixing Mingda tubes

by ac2 Mon Mar 31, 2014 6:21 am

Hey guys,

Was wondering if anyone has tried these cool looking KT90 or 6SN7's? They win on looks but sound quality? Sure are pricey too but wow do they look good!

by sKiZo Mon Mar 31, 2014 4:23 pm

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Post n°2

Re: Meixing Mingda tubes

by sKiZo Mon Mar 31, 2014 4:23 pm

Way I understand it, Electro Harmonix has a lock on KT90 production, so I imagine these are EH in a cute bottle ...

One thing you should consider is that the KT90 doesn't bias up like a KT88 ... maybe some of the gurus can chime in as to whether that would be an issue. Worse comes to worse, you can always plug in the "mystery resistor" in R39 to adjust the range if you're using a VTA board.

They are extremely good looking tubes though.

PS ... pricing doesn't seem all that bad ... I found a matched pair at Psvane for $75 ... where it gets weird is pricing for a quad is MUCH more. Probably better off getting two matched matched pairs if you need four. Nice to have them close, but perfect isn't a requirement long as you have separate adjustment pots for each tube.

by ac2 Mon Mar 31, 2014 5:52 pm

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Post n°3

Re: Meixing Mingda tubes

by ac2 Mon Mar 31, 2014 5:52 pm

The Chinese have the market locked down on the best looking tube amps/preamps by far in my opinion, now they are even making the glass to match.

A set of those KT90's would look nice in my M-125, dang I wish it used 6SN7's.

So far I have two quads of KT120's, had I seen these KT90's I would have opted for them instead..... wheels are spinning, need Chinese KT-90's Smile

Going to have to check but I think the ST120 has option for 6SN7's right? Or is it the MK3? I'll check but I would love to build an amp with the Chinese KT90's and the Meixing 6SN7's.

My next project is the SP9 with 6SN7's but I don't know if the center to center spacing allows for the big bottle on the Meixing 6SN7's. My chassis will be custom to match my custom M-125's (will post new thread when I start building, still in design stage)

I was doing a little reading last night and from what I hear that 6SN7 is a good sounding tube. They remind me of the old Frankenstein movies I loved to watch as a kid. Smile

by pmarcin Tue Apr 01, 2014 2:19 pm

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Post n°4

Re: Meixing Mingda tubes

by pmarcin Tue Apr 01, 2014 2:19 pm

The 6sn7 is a mixed bag. Ed Schilling of The Hornshoppe does not like them. In order to prove him wrong, I built a 6n7, Aikido with a Janus shunt psu. I used excellent and it tested spot on. This unit sounded fine on jazz, rock, electronic and vocals. I then tried my XLO test record and, voila, I found something, I called up Ed and matched notes. They were exactly the same. I sold the unit. In summary, I hope you're not going down a primrose path with the 6sn7s. IMHO, it's Jekyll/Hyde tube.

by corndog71 Tue Apr 01, 2014 2:59 pm

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Post n°5

Re: Meixing Mingda tubes

by corndog71 Tue Apr 01, 2014 2:59 pm

I've heard there are very few quiet 6SN7's left out there. I tried some newer EH tubes years ago in a line stage and they did somethings good but eventually succumbed to microphonics. It could've been my circuit but I was steered away from them by my research and really haven't looked back.

by **Bob Latino** Tue Apr 01, 2014 3:02 pm

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Post n°6

Re: Meixing Mingda tubes

by Bob Latino Tue Apr 01, 2014 3:02 pm

ac2 wrote:

A set of those KT90's would look nice in my M-125, dang I wish it used 6SN7's.

The use of octal 6SN7's in the driver circuit of an amp does not guarantee "better sound" in relation to 12**7 noval tubes.

Case in point > the McIntosh MC2301 monoblock amps. These are 300 watt monoblock amps using EIGHT KT88 or 6550 output tubes. These amps cost $22,000 USD for a pair. At the price these amps sell for and their "cost is no object" construction, they could have used ANY driver circuit for "best sound". The MC2301 is now their "statement" tube amp. What driver tubes do they use on the driver board for this amp ? TWO 12AT7 driver tubes per monoblock driving EIGHT output tubes. These 12AT7's are NOVAL driver tubes not octal driver tubes ..

As an aside > I had someone Email me and "give his opinion" that the VTA M-125's with just TWO 12AU7/12BH7 driver tubes could not possibly "provide enough drive" to drive FOUR output tubes and reach rated output. (125 watts). I sent him a return Email with a short note and a pdf of the McIntosh 2301's ... I never heard from him again ..

McIntosh MC2301 brochure

Bob

by Guest Tue Apr 01, 2014 3:41 pm

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Post n°7

Re: Meixing Mingda tubes

by Guest Tue Apr 01, 2014 3:41 pm

Bob Latino wrote:

ac2 wrote:

A set of those KT90's would look nice in my M-125, dang I wish it used 6SN7's.

The use of octal 6SN7's in the driver circuit of an amp does not guarantee "better sound" in relation to 12**7 noval tubes.

Case in point > the McIntosh MC2301 monoblock amps. These are 300 watt monoblock amps using EIGHT KT88 or 6550 output tubes. These amps cost $22,000 USD for a pair. At the price these amps sell for and their "cost is no object" construction, they could have used ANY driver circuit for "best sound". The MC2301 is now their "statement" tube amp. What driver tubes do they use on the driver board for this amp ? TWO 12AT7 driver tubes per monoblock driving EIGHT output tubes. These 12AT7's are NOVAL driver tubes not octal driver tubes ..

As an aside > I had someone Email me and "give his opinion" that the VTA M-125's with just TWO 12AU7/12BH7 driver tubes could not possibly "provide enough drive" to drive FOUR output tubes and reach rated output. (125 watts). I sent him a return Email with a short note and a pdf of the McIntosh 2301's ... I never heard from him again ..

McIntosh MC2301 brochure

Bob

holy smokes!....can you believe those prices??...highway robbery is all I can say...no offense meant, but any fool laying down that kind of money for these amps has more money than brains!

by corndog71 Tue Apr 01, 2014 3:47 pm

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Post n°8

Re: Meixing Mingda tubes

by corndog71 Tue Apr 01, 2014 3:47 pm

[quote="MontanaWay"][quote="Bob Latino"]

ac2 wrote:
holy smokes!....can you believe those prices??...highway robbery is all I can say...no offense meant, but any fool laying down that kind of money for these amps has more money than brains!

Some people have money to burn. I kinda think any audio item over $20K becomes more of a status symbol. Hell, anything over a couple of grand is out of my league.

by Guest Tue Apr 01, 2014 3:50 pm

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Post n°9

Re: Meixing Mingda tubes

by Guest Tue Apr 01, 2014 3:50 pm

corndog71 wrote:

MontanaWay wrote:

Bob Latino wrote:

ac2 wrote:
holy smokes!....can you believe those prices??...highway robbery is all I can say...no offense meant, but any fool laying down that kind of money for these amps has more money than brains!

Some people have money to burn. I kinda think any audio item over $20K becomes more of a status symbol. Hell, anything over a couple of grand is out of my league.

you got that right. I put that in the same category as a Porsche Cayenne!!

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