Ricardo: july 20th- Aug 1st, staying at Villa Gale..... but I don't want to impose at all...
Anyway the news is...... it works!!!
Sound is very smooth, clean and clear, and certainly is not dull (some concern with the silver mica 15.7 instead of 15.0nf). Smooth, big open soundstage with very good depth.
This is good progress!! I do have some noise pick up, but I know a good amount of that is due to me bringing raw AC into the box - the noise rises and falls as I wiggle the AC cable inside the box. So I will move the rectifiers and filter caps to the transformer box. I also need to fit a grounding lug for the TT (forgot it!). I also have some microphonics - if I tap the box or valves I can hear the ringing, but its not bad really - no worse than some other 6SN7 I have had in the aikido.
Its a good day!!
Fran
Anyway the news is...... it works!!!
Sound is very smooth, clean and clear, and certainly is not dull (some concern with the silver mica 15.7 instead of 15.0nf). Smooth, big open soundstage with very good depth.
This is good progress!! I do have some noise pick up, but I know a good amount of that is due to me bringing raw AC into the box - the noise rises and falls as I wiggle the AC cable inside the box. So I will move the rectifiers and filter caps to the transformer box. I also need to fit a grounding lug for the TT (forgot it!). I also have some microphonics - if I tap the box or valves I can hear the ringing, but its not bad really - no worse than some other 6SN7 I have had in the aikido.
Its a good day!!
Fran
Off to a good start then. Yet it needs getting it together for those AC runs. Maybe some anti vibration rings on the 6SN7s also. Trying some different quality coupling and Riaa capacitors in the near future, also fine tuning the HF Riaa cap value will give you some happy evaluation & tuning hours for sure.
More progress:
I changed around the power supplies and added the grounding lug. Good reduction in the noise, but still some there. So my next port of call was the inputs - noise here would be severely multiplied I thought. I had wired in an extra set of inputs for MM which went to the other side of the input transformers. Cutting these out made for another reduction in noise.
I still get some noise pickup, and it seems fairly sensitive to electrical stuff - eg, my wife turned on a light and there was quite a noticeable "click". Positioning the amp on the rack also makes a difference. None of this is new to me - the Ono is the same.
So to make the story shorter:
Put diodes and filter caps in transformer box for all supplies.
Don't wire both MM and MC at the one time - can try using a switch or something maybe?
Watch your grounding and layout in the case.
Its is now pretty quiet - almost as quiet as my DAC - little bit of "rush" at max volume on the DAC, have that too with the itch, but little bit of hum as well, plus sensitivity to electrical stuff (like light switch above).
For anyone else: the steps up (partridge 977 with 1:6) seem to give me more than enough gain, initial try out with zyx cart with 0.48mV output, using DCB1 and moderate gain power amp. Should satisfy most systems I'd say.
Fran
I changed around the power supplies and added the grounding lug. Good reduction in the noise, but still some there. So my next port of call was the inputs - noise here would be severely multiplied I thought. I had wired in an extra set of inputs for MM which went to the other side of the input transformers. Cutting these out made for another reduction in noise.
I still get some noise pickup, and it seems fairly sensitive to electrical stuff - eg, my wife turned on a light and there was quite a noticeable "click". Positioning the amp on the rack also makes a difference. None of this is new to me - the Ono is the same.
So to make the story shorter:
Put diodes and filter caps in transformer box for all supplies.
Don't wire both MM and MC at the one time - can try using a switch or something maybe?
Watch your grounding and layout in the case.
Its is now pretty quiet - almost as quiet as my DAC - little bit of "rush" at max volume on the DAC, have that too with the itch, but little bit of hum as well, plus sensitivity to electrical stuff (like light switch above).
For anyone else: the steps up (partridge 977 with 1:6) seem to give me more than enough gain, initial try out with zyx cart with 0.48mV output, using DCB1 and moderate gain power amp. Should satisfy most systems I'd say.
Fran
Rearranged TT grounding. I remembered that I tied the grounds together for the pass pearl - made it quiet at the time. Now its floating all the way to the SUTs. I grounded primary of SUT to the circuit - it was a bit quieter this way.
Moving the phono box around the noise changes. So its like the circuit is an antenna for noise. Also, the box is open, so when it goes in its sleeve, it might be quieter too.
More experiments tomorrow night - I'll try it with the other TT too.
Fran
Moving the phono box around the noise changes. So its like the circuit is an antenna for noise. Also, the box is open, so when it goes in its sleeve, it might be quieter too.
More experiments tomorrow night - I'll try it with the other TT too.
Fran
mmm. I think I have discovered a problem. Maybe the problem. The heater sharing won't work out - I'm getting unequal drops across the 6N2 and 6H8. The result is that the 6N2 is seeing ~9V and the 6H8 only 3V.
So I need to set some different transformers now and see can I fix this issue.
Fran
So I need to set some different transformers now and see can I fix this issue.
Fran
200V are no good for the Itch. The Riaa is DC biased around there. 250-600V for coupling and Riaa for the Itch.
