Thank you for that report!
At this point I am trying to solve for lowest noise from the gain stages of the Io.
(Yes, Kedar, I have conceded I have to tube "roll.")
Hi there,
I have had my Io Signature with volume controls and 2 supplies for some time. Starting with Albert Porter's post on Audiogon some years ago ( I think that post evaporated) I began to tube roll my Io from the start.
My unused stock tubes are in a box. I have accumulated mass amounts of vintage small signal tubes to roll. If you are not inclined it is definitely worth the price to pay for a properly matched set for the Io. It is worth the price because the time and culling involved can be massive if you don't have stock to pull from.
I have Telefunken smooth plates up front , I have used Tung sol round plates for the 6Sn7 position but settled on the the red based 5692. For the 6dj8s I use the amperex USN CEP 6922 gold pin. Siemens ECC83 in the front are nice too - they are harder to find. I have a Vaccuum Tube Valley small tube characterizer to check for noise and balance.. that helps. Not many tubes in my testing are balanced. IMO this is less important than noise. Telefunkens last for ever and typically are more balanced than most types.
I'm not even talking about the NOS 12AX7 RCA's ( Mullard origin) and Mullard XF2 El34's in the two supplies.
As to cartridge I use a Koetsu Rosewood Signature Platinum , Lyra Etna SL which are about the same output at .23mV , I have the new Goldfinger Statement and Lyra Atlas too.
While noise is definitely a function of the design , tube quality, gain required,associated room interface , speaker sensitivity , amp input impedance and sensitivity come into play. I have no problems with noise. I run Beveridge electrostatics Directly Driven- no output or step up transformers . Would I notice with horns?.... maybe. My room is largish at about 19'x42'.
You pay the price for a design like this with , I think 22 tubes, in the signal path. The results are stupendous when they work. People ask- why torture yourself? , you can drive a Ferrari or a Lexus - the Ferrari will cost you more and aggravate you more. The Lexus will just get you there in luxury and comfort.. which one can you live with? That is a personal choice.
Have fun be prepared to be frustrated some times... and don't listen to those that say the Io can't run with the best. I have heard it lately against the CH precision and Tenor.. Would I trade-- no ... not enough to make me do so right now. Very different in presentation but the competition certainly does not run away with it - not by a long shot.