Hey Clint e. do you have a pic of your 6J1's?. You may have last years tubes, which have since been improved.

Thanks,
Ian

Here's the pic :

...and another pic.

I´m watching this Yaquin and this Musical fidelity X-10D buffers.

I´m hoping if I use one plugged in between my CDP and Passive-Pre I might get over the impedance problems and end up with the dynamic full bodied sound that is lacking with this combination.

What do you buffer experts think?

Jorge

What kind of impedance problems do you have? Any phase problems?

Not quite.

I own a very nice passive line pre-amp with a tube active stage for phono that I used to run before I bought the Beard CA-35.

I went as far as to replace the volume pot with a Sonic Frontiers stepped attenuator, and adding a second set of outputs to bi-amp, and although the sound is really, really clean, with an absolutely "black" background, and great detail and defenition, to me the sound lacks overall impact, particularly on the lower registers. Bass and drums on rock music sound light, and cymbals and double-bass on orchestras likewise. Turning the volume full up doesn´t solve the problem.

I bought this unit to replace my Audio research LS-7 tube pre which lacked a phono stage when I got back into vinyl with my Thorens TD-124. The sound, through the tube phono stage and the Sumiko Blue Point special cartridge was all I could hope for, and because I all but forgot CD´s, I was happy for a while.

Then gradually I got back into listening to CD´s, and more recently FM radio, and the shortcomings of this unit became apparent, and all the less positive things described above became overbearing. When I realized I should have bought a good external phono stage for the LS-7 it was too late.

So I went and got the Beard CA-35 for a decent price, and have been happy using it for the last few years. The line levell stage of the Audio Research was on an altogether different levell, though, and I have started missing its cristal clear, fast kind of sound.

Soooooo.......I have read quite a lot concerning this particular problem and its causes, which mostly lie in impedance mismatches between the output of the CDP and the input of the pre. It seems the best way to overcome this problems is to use a passive pre is with transformers or buffers.

This thread has aroused my curiosity and interest.

Jorge

Well, those tube buffers sure will help you lower the output impedance of your CD player but which one is better i have no idea so... since i have the two buffers you mention - one in my comp sound and the other in my main setup - we'll meet maybe this weekend at your house and we'll try both.

is your Sonic Frontiers stepped attenuator matched with your pre-amp? i didnt come up with this, but i remembered it when i was looking into attenuators ...

typical values are between 10K and 100K. just a thought, i have no idea what any of this means.

A great way to compare and see if it helps

I grabbed a couple of sets of the GE JAN 5654W and can't wait to try them, thanks for the tip.

Our B-283 only comes shipped with the Shuguang 6J1 72.2 C7 tubes, the la-*test*-('") spec from the factory, we noted with our first samples that the tubes were of different flavours (and in one case different physical size) so added that to our QC list.

Just a heads up on Chinese tubes in general, they are getting better sounding every year. A lot of customers have spent hundreds of dollars rolling and have come back to the stock tubes due to better overall balanced sound, not that it isn't fun . I always suggest rolling pre-amp type tubes first, much more bang for the buck.

Regarding impedance matching, the B-283 does not impedance match by design, but has helped out in mismatched gear. When used after a pre-amp it is suggested to keep the pre-amp's gain down and crank the amp up if possible.

The next logical upgrade to the B-283 is our P-307 Phono/CD Pre-amp, which I use for horizontal bi-amping. Jorge you may want to look into that to get back to where you where

Ian

Yesterday i was reading some "old" music magazines and i came across an article from Sam Telling in Stereophile about Anthony Michaelson, Managing Director of the British Musical Fidelity company, and here's what he says about the X-10 - and i quote :

"Essentially, the unit is an impedance-matching device," he explains. "It has a very high input impedance, of about half a meg [500k ohms—Ed.], and quite a low output impedance—we rate it at 200 ohms or less, but in fact it's about 15 or 20 ohms. What this does is allow a CD player to operate perfectly. You can take almost any old CD player, bang an X-10D on the end of it, and you can't believe the results you get."

I think the same could be applied to Yaqin, but instead the 6922 valves the X-10 have it has 6J1 witch gives another dimensionality and harmonics to overall sound.

This tube buffer looks similar to the Grant Fidelity unit. Is it the same?

Update: Maybe I should the entire post in the future. My question has been answered.

I am curious, though, about the working conditions and wages of the workers who make the tube buffer in China. What are these like and how does anyone commenting upon them as good actually know this to be true?

i believe so, but the Grant Fidelity units are modded for the North American market.

The GF B-283 is made by Yaqin. Basically cosmetic changes for now and the 110v transformer. New designs are in the works for later this year release, but the B-283 will always be with us as is.

Competition for skilled audio techs and quality assemblers is quite high in China, our factories employees enjoy a high living standard and excellent working conditions. Pics. GF pays our factories a fair price for our products which keeps the factories and their employees happy too and keeps the quality high.

hi i just bought Yaqin 6J1 i wanna ask any other alternative tube i can upgrade like Elite 6922 or JJ ECC88 because my country hard to find GE tube thanks

A friend of mine also have a Yaqin and he has 6J1P-EV from Russia. They are quite good.
Also you could try 6AK5W/5654 NOS Siemens or some Mullard EF95 or CV4010.