That's the name Klaus has come up with as it's sort of a one off amp.
This is part review and part update of my amplifier adventure, of which the problems were described here:
Part one: last July, I had Klaus convert my Stereo Stratos with cap upgrade (additional standard grade power supply caps, not the reference ones) to a Dual Mono (with additional transformer and double the caps per channel - still standard grade). It ran hot though the sound quality was much improved over the previous Stereo Stratos. Much more bass slam, better projection of the SDA effect, generally sweeter overall. After about 6 months of use I heard a loud pop one Saturday morning while playing the system at a moderate level. Left channel gone, amp too hot to rest your hand on. So the unit went back to Klaus.
Part two: While he had it in for repair, I had him upgrade most of the power supply caps to reference grade. Couldn’t use those for the four on the upper most board as they’re too tall. To make a long story short when I put the amp back into service it could only be used with my 2.3tl’s without the SDA effect. In other words, no IC cable between the speakers, and no AI-1. We went back and forth trying everything we could think of, but could never get the amp to play well with the SDA speakers. I had to connect the speakers in conventional stereo mode. It still ran hot, but the improvement in SQ with the reference caps was stunning.
Part three: I finally gave up on the Dual Mono because the SDA effect is important to have to really hear what these speakers can do. Back it went to Klaus for the re-conversion. In order to give me the bang for the buck I paid with the Dual Mono conversion for he did more upgrades: the Stereo Stratos now has the black Kismet board, the caps on the board are now reference grade too, plus some other tweaks I can’t think of right now. All of this was at no additional cost.
With only about 30-40 hours of burn in the sound quality is even better than before. I thought I might lose some of the authority of the Dual Mono, but it’s still there along with an even sweeter mid range. Vocal and instrument textures seem a little more enhanced, the sounds seems to emanate from within the room rather than from the speakers.
There’s one fly in the ointment though. I have a horrible grounding problem when the Odyssey Candela Pre is in the system, even when the IC’s are d/c’d from the power amp so that the only thing connected to it are the speakers and the AI-1. It’s a buzz/hum that increases with the volume level.
I’ve tried the following, and nothing helped:
- Cheater Plug on the Stratos to lift the ground
- Cheater Plug on the Candela to lift the ground
- Pulled out the Candela and swapped tubes
- Swapped in shielded IC’s (the ones I use are unshielded)
- Checked continuity on all IC’s
- Plugged the Stratos into an outlet on a different circuit
- Unplugged all other components (DAC, CDP, Subwoofer, Candela Pre) from the wall and d/c’d the IC’s
- Unplugged cable coax and turned off cable box, though the HT is on a separate circuit
- Unplugged cordless phone
- D/c’d the AI-1 so the left and right speakers were only in stereo mode (no IC cable either)
- Made sure all PC’s crossed IC’s at right angles
- Made sure all speaker wires are away from PC’s
- Checked outlets for correct polarity
And here’s what solved the problem:
swapped out the Candela pre from the system and put an older NAD C160 ss pre in its place using all the same IC’s. Voila! An absolutely dead silent background, no hiss-buzz-hum even with your ear on the speaker.
Of course it doesn’t have the beautiful imaging and harmonic richness of the Candela, but at least I’ve narrowed down the problem. Don’t know why I’m having this issue now when I didn’t have it before, but it’s going back to Odyssey for repair.
Love the new Special Fred Edition, even with the NAD