Please read here, here, here, here, and here before you continue reading this one. I believe that could give you an overview of this project.
Finally, we come to the day to have a listening test of this project. The comparison has been done with original Lundahl LL1673 (same Choke). Mine is potted, the other one is used as-is.
The system used is MP50Di power amplifier (a MOSFET amplifier). Originally, the preamp is Aikido based with 6AS7 and 6SN7 (correct me on this), but during this test, the tubes are changed with something new (compatible) which I can’t recall. This is a heavy 2-boxes preamp with marble enclosure. A big pain to move them from one place to another. So a big thanks to my friend DY who brings this today 😉
Another close up shoot of the main unit. The capacitors sealed in plastic. They are Jensen and Mundorf.
The back of the power supply box. We can see several chokes and high end parts inside. The main objective today is the Lundahl LL1673 hanging on one side of the box.
The original Lundahl deactivated for some time, then some jumpers are connecting the circuit to the potted version outside the box.
First we listen the original Lundahl, then we switch with the potted version, then return back again to the original Lundahl (well, we have to return the circuit to the original one which belongs to the owner of this preamp anyway).
The result is quite impressive. The potted version brings a significant improvement on the high extension. We can hear more details and resolution. The 3rd test which returns back to the original version of Lundahl also confirms the different. The high seems got more harmonic (crispier treble, sparkling high, more creamy, etc – I think that could describe what we hear). The different even could be heard from first few seconds.
Mid and low, probably not much different at this stage – or we are not paying extra attention on that part.
To be honest, I don’t expect such significant differences. We use Norah Jones, which the record is ‘just nice’, not a superb one. But definitely we can hear the lips detail more than what we used to hear with the original Lundahl – and that makes a significant different.
What I can’t say at this moment (and need more verification) is whether the potted version brings extra roughness/fatigue or not. I’m not familiar with the system, as I’m also not prepared to hear significant different. But definitely at this point, the original and potted one does sound different. An even more serious session could be very usefull.
It’s gonna be interesting to see how this will compare with other potted Choke like Tamura, Tango, or Hashimoto. It might not be an Apple-to-Apple comparison due to different inductance and resistance, but still gonna be an interesting finding. Will see.
triodethom
July 18, 2012 13:29My guess is that the potting of the choke added mass and damped the choke in the higher freq. Slowed or stop it from rubbing on the insulator thus reducing the cause of smear and impedance changes in that region of freq. Detail is no longer lose to a less than ideal choke behavior . Don’t get me wrong Lundahl makes a fine choke . I will be looking foward to hear what Mr. Lundahl thinks of your finding. Regards
stk
September 12, 2012 11:50Ndahsyaaattt Om satu ini ………..di Audiolifestyle juga di kupas ..hehehe.
Auw Jimmy
September 12, 2012 23:35Ngerame2in aja Om… 😉
Thanks.
Merijn
November 13, 2012 19:01Hi Jimmy,
Greetings from the other side of the globe 🙂
I just ran into your site and you’ve made some verry impressive modifications to the venerable Aikido I must say!
Currently I am working on a dual mono approach to the Aikido PS with the AZ1 rectifier /LL1673 10H in Improved Common Mode Rejection (as in: http://www.emissionlabs.com/html/articles/Power-Supply-1/App-note1.htm) and wonder why you’ve chosen for the stereo PS with one RF/multiple L in stead of dual mono?
Thanks for responding!
Merijn
Auw Jimmy
November 13, 2012 23:24Hi Merijn,
I think I just can’t afford to make it dual-mono, as with my configuration, adding dual mono would cost me double. What that kind of chokes and capacitors, I dont think that’s a good idea 😉
Thanks.