Has anyone tried this tube phone MM/MC Kit

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wjlamp

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Joined 2009
Salas said:
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.
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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

Salas

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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.
 
Salas

Salas

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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

orrino

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Joined 2009
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
 
jackinnj

jackinnj

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I've been compiling my list of mistakes from the prototypes I had made -- certain things like take-off points which I forgot to put in for the heaters, making dual power supply regulators (I'm using single). Spacing the depletion MOSFETs so their heat sinks don't touch...

SY get's the fame (deservedly). I'm just another lowly hod carrying Fenian anarchist who happens to own a CAD program for this stuff. When I get around to having them burned it'll be a GB for a year, net of the cost of the boards and transport, etc., etc. just like the Impasse boards. The input transformers are NOT inexpensive, but there are alternatives which should work pretty darned well.

My HMN is housed in the carcase of an Eico signal generator -- it had a rather beefy transformer and plenty of space to mount the power supplies. I did use the separate filament transformer which SY had recommended.

The amplifier itself can be on a floating suspension --
 
jackinnj

jackinnj

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Joined 2002
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Salas said:
When you come back from the NJ audio society meeting let us know how they liked it. Or give us a link if they will sum up their meeting on a url if you may. Cheers.

P.S. Or its done already? I see Oct 24th.
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We got really carried away listening to the modified Thors with a variety of source material. So a judgment of the HMN is left for another time.

We also got to listen to a couple of amplifiers which Bob Cordell had brought with him -- best darned gainclone I had ever heard, fwiw!
 
A

atreas2

Member
Joined 2011
I am just at the end of building a kit like this with tungsol reissue. Is for a customer of me with a good low output mc (tekaitora rue dynavector). I test it right now with a DL-103 (same output). I don't have thegain and dynamics/bass i want. I have good stage and i think nise open mid and highs. Is it somethink you sugest (other tubes, input transformers) to improve it the last time. I know that maybe is wrong choice but is impossible to change topology right now...

Thanks Stratos

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