Audio Note M2 Riaa.

[Ciampa]

Considering this Audionote M2 has a 6SN7 gain stage after the ECC83 and ECC88, it is difficult to see why you need to increase the gain; have you rewired the 6SN7 stage as a follower?

No 6SN7 follower at all. This is a stand alone riaa mm, two stage ecc83 and ecc88 for 37db gain and a rather high output impedance.

 

[soulmerchant]

Actually the riaa shd gain 37db with the ecc83 at first stage.

Pretty much correct with that. Most of the signal is going to ground with that wimpy 120k load for the ECC83 - but with the chosen B+ it would be tough to make any reasonable change. Also, it would include changes to the passive RIAA Network too.

I'm am actually surprised by the design - it must be a kit.. Since its on a board, changing to tubes with different pinout is going to be really annoying too.

I think maybe Merlin's idea might be worth a shot. That is, if shorter cables don't help... Where are you located?

Ian

 

[SY]

6KN8. Drop in, and you'll get about 5dB more gain.

 

[Ciampa]

Tnks SY. Is anything I can do to lower Z out other than using an external buffer ?

 

[Ciampa]

Pretty much correct with that. Most of the signal is going to ground with that wimpy 120k load for the ECC83 - but with the chosen B+ it would be tough to make any reasonable change. Also, it would include changes to the passive RIAA Network too.

I'm am actually surprised by the design - it must be a kit.. Since its on a board, changing to tubes with different pinout is going to be really annoying too.

I think maybe Merlin's idea might be worth a shot. That is, if shorter cables don't help... Where are you located?

Ian

I live in Canton de Vaud, u ?

 

[soulmerchant]

I live in Canton de Vaud, u ?

Zurich. I will however be in Genolier tomorrow.

The MOSFET follower works very well, doesn't take much space either. Doesn't "sound" any worse than a resistor imho...

http://www.geofex.com/Article_Folders/mosfet_folly/mosfetfolly.htm


Ian

 

[soulmerchant]

Also check out how Eli Duttman uses a mosfet follower in this phono design:

 

[SY]

Tnks SY. Is anything I can do to lower Z out other than using an external buffer ?

Significantly? No. Use a buffer, there's no harm in it and much good.

 

[Ciampa]

Significantly? No. Use a buffer, there's no harm in it and much good.

There are good replicas of Musical Fidelity X10D. Some time ago I had bought one of these, do u think is ok for the purpose ?

1set ECC88 6922 6DJ8 6N11 Tube Buffer Preamp X10D PCB Assemble Kits | eBay

 

[famousmockingbird]

If you are buffering the output how about a 6EV7?

 

[SY]

There are good replicas of Musical Fidelity X10D. Some time ago I had bought one of these, do u think is ok for the purpose ?

If a vendor is that dishonest, I wouldn't trust that their design is done competently.