After having tried these preamps with M2X:
Passive
Bluesound 2i (set to variable volumen)
Staving Student II (anode resistor)
Staving Student II (CCS)
…..it was now time for Korg Nutube. After some hours listening this is a very good combination (I still use Tucson with OPA 604 input board).
I remembered to reverse polarity of speakers to have correct phase.
Transients in classical music are very nice. Never aggressive. The high tones on a piano can be a challenge but is handled very good.
I think so far......the best combination. It is also two quite special "Pass" designs with two unusual ways to achieve voltage amplification (Nutube + Edcor).
Passive
Bluesound 2i (set to variable volumen)
Staving Student II (anode resistor)
Staving Student II (CCS)
…..it was now time for Korg Nutube. After some hours listening this is a very good combination (I still use Tucson with OPA 604 input board).
I remembered to reverse polarity of speakers to have correct phase.
Transients in classical music are very nice. Never aggressive. The high tones on a piano can be a challenge but is handled very good.
I think so far......the best combination. It is also two quite special "Pass" designs with two unusual ways to achieve voltage amplification (Nutube + Edcor).
Just spent the last month listening to the Norwood board and enjoyed it. Found that some classical albums were handled well with clarity between sections and a soundstage that was wide and deep. Also able to keep up with some of the fast tempos of some orchestras without smearing.
Went back to the Tucson with the OPA1611 and was reminded of the character I first enjoyed. Maybe not quite the clarity of the Norwood, but the same music presented itself more intensely, emotionally(?). Soloists seemed to pop out into the room.
Both boards are fantastic in the M2x. Am waiting for some FG or Muse caps for the Ishikawa.
Very interesting, please tell us any differences between the 3 preamps, I'm following this.
Hi, recently completed my build of this fantastic amplifier. Thanks .I have read quite a bit over last year, finally parts were in the store so proceeded with no problems.
Its playing very nicely and sounds unbelievable,wow!
I have a question concerning the zeroing of offset ,its unstable and wonder how much of a swing is normal?
Its playing very nicely and sounds unbelievable,wow!
I have a question concerning the zeroing of offset ,its unstable and wonder how much of a swing is normal?
M2X survived the initial +/- 30.5Vdc power up using SLB with 24-0-24vac trafo.
The 500VA trafo actually produced 26Vrms, so 30.5vdc is the lowest that i can adjust from the SLB ps.
It is singing.
Nice work, Meanie. How is the heat output with 30v rails? Your heatsinks actually look pretty big and should be able to handle it. How is the background noise level or hum/hiss with the SLB vs precious PSU?
The heatsink is a Conrad 350x155 model.
@+/- 30Vdc, temp is around 56 degC with an ambient temp of 22 degC room temperature. @ +/- 24Vdc. its around 48DegC.
With CRCRC ps, there is a little noise in both speakers (ear close to speakers), hum is bearable. With SLB, noise is very low or almost gone, but hums remains. Later i realised that hums was pick up by the Edcor near trafo, by moving both channels further away from the main trafo, all the hums is gone.
My M2X has never been so quiet before.
@+/- 30Vdc, temp is around 56 degC with an ambient temp of 22 degC room temperature. @ +/- 24Vdc. its around 48DegC.
With CRCRC ps, there is a little noise in both speakers (ear close to speakers), hum is bearable. With SLB, noise is very low or almost gone, but hums remains. Later i realised that hums was pick up by the Edcor near trafo, by moving both channels further away from the main trafo, all the hums is gone.
My M2X has never been so quiet before.
I tried substituting a pair of LT4320 based 'ideal' rectifiers for the bank of FEP30 diodes that were in my M2x. The synchronous rectifiers noticeably reduced the slight hum that I get. Measured ripple after the switch was 24 mV. I'm still using a 400VA Antek inside a steel case with a single diyA PSU board stuffed with 22,000 uF caps. The new recitifiers seemed to improve the imaging and instrumental detail in addition to reducing the hum.
