Has anyone tried this tube phone MM/MC Kit

[orrino]

Hello, I was wondering if anyone has tried this tube phono MM/MC
12AX7 MM/MC Phono Tube Preamplifier Kit ref VTL No Tube on eBay (end time 31-Oct-10 01:02:40 GMT)
or would have any input or thoughts on it. I was thinking of it for use with a Denon DL-103 low output MC.

Thanks. Ray

[Salas]

Don't do that. 0.25mV cart for that, it will never exploit it. Read SY's His Master's Noise article first. Article's link.

[wjlamp]

Originally Posted by Salas

Don't do that. 0.25mV cart for that, it will never exploit it. Read SY's His Master's Noise article first. Article's link.

Hi,

since I'm not to technical,could you please say why do you say that it won't work(noisewise).I read SY's article,and I saw that he uses input transformers for the phono in.

Do you mean that even if input trafos are used,the phono will not function properly,with a Denon 103,or any other low output cartridge?


B.L

[Salas]

It will never exploit properly any low mc cartridge I wrote. Its tube type's equivalent input noise and the gain it will take to bring such carts up to appreciable line level will smother crucial signal detail under noise. Not recommended.

[wjlamp]

Originally Posted by Salas

It will never exploit properly any low mc cartridge I wrote. Its tube types equivalent input noise and the gain it will take to bring such carts up to appreciable line level will smother crucial signal detail under noise. Not recommended.

Got it.

Thanks.

B.L.

[orrino]

Originally Posted by wjlamp

Got it.

Thanks.

B.L.

B.L. I am so happy that you got it, I am still trying to make sense of the very technical link, This is about my twentieth time I am reading it, hoping that it will eventually have some meaning.
If any one knows why this won't work or can explain in layman's terms please,,PLEASE put me out of this mental torment and just tell me
Ray

[Salas]

The link was to read about and appreciate the noise issues when low MC and valve phono are to be considered. To form a background so you can choose better. Having read that, lets see the VTL topology. Uses a grounded grid MC input stage. That will mean a very low input impedance. Maybe 200R and 26dB gain for a 12AX7. Less gain with Rk non bypassed. Creates the need for a large input coupling capacitor. Many would not think its best to pass your cart's 250-300uV through a dubious origin looking cap on that kit's photo, or any cap at all for that matter transparency wise. That stage is active, using a tube where most would use a transformer. Imposing noise from not the best tube choice for that even. Also 6 capacitive couplings from MC in to out to feedback return, and a wimpy follower for output. Look for something else IMHO. Has to be a kit? Why not copy Yaniger's if you have tubes in mind?

[orrino]

Salas, Thank you for your reply at length.
I have read the link you sent me several times.
I understand now what is meant, and you summed it up beautifully.
I would love to copy Yaniger's but I don't think I have gained enough knowledge to do that at this stage. I am happier stuffing boards with instructions.
I will read over the Yaniger's article again tomorrow and see if I feel more comfortable to try.

Thank You, Ray

[SY]

jackinnj (Jack Walton, Company Store) will be offering boards (maybe partial kits?) shortly.

Disclaimer: I don't make money from the sale of boards- Jack donates my "fee" to diyAudio.

[d to the g]

Originally Posted by SY

jackinnj (Jack Walton, Company Store) will be offering boards (maybe partial kits?) shortly.

Disclaimer: I don't make money from the sale of boards- Jack donates my "fee" to diyAudio.

I've already starting assembling some pieces, but this is definitely good news.