Audio Asylum Inmate madalo's Franken - System

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madalo's Franken - System
Last Update: December 11, 2000 at 22:56:49 IP Address:
Amplifier: Sumo Ulysses - bridgable, 65W/channel...
Has new output MOSFETS that are good up to 10+A and boo-koo watts each (IRFP240 TO-247).

I can measure the voltage at the power supply caps (10,000uF) as +/-50v... nice headroom on a 65 Watt'r with a 40vac tranny.

My frickin tranny gets so hot. This leads me to believe when I crank my tunes up loud enough to rattle the walls and stuff, that I must be saturating the transformer and trying to suck more juice than it can give. I'm at a point now, where if I run it for more than an hour it (the transformer) gets so hot i cant touch it (from what I hear Sumo's run pretty hot), and I'm sure the reserve current is suffering to refil those caps fast enough. When I play at low volumes or soft passages the regulation on the caps is quite good, but I worry that this voltage might dip more toward the WVDC level and hose out all the gain stages except for the input buffer which I'm sure gets some ill effect.

So, I made a plan. I have ordered a Plitron toroidal tranny with dual secondaries at 55vac each @ 3.2A nominal (400VA rating) and 3% regulation, capable of instantaneous current "well in excess of rated spec." To this I added onto my order an electrostatic screen and a EMI shield option.

Once this baby arrives, its gonna get the once-over and go into action with a few friends. I will add a power supply board, with some qualitiy rectifiers (ditch the chassis mount BR), some RFI filtering, some juicy caps and largish inductors. Following that a nice set of bi-polar zener/feedback regulators keeping a nice steady +/-50vdc at about .5% regulation or better up to 4A and problably just as well up to 7 or 8 on the peaks... guess we have to wait to test that one though. Another thing i want to do is up the voltage from the input buffer (op-amp) from +/-15 to +/-18v (for headroom).

Other than that, the only other addition to the innards will be a small active circuit directly on the AC mains (basically a latch) to allow a solid-state switch to activate a solid-state relay for power on/off. Oh yeah, and change to a cool blue power LED!! ;)

Preamplifier (or None if Integrated): My own design - 3 inputs, 1 pre-out, 1 amp-out; dual-mono single gain stage; 5Hz-30kHz; 10Vp-p; low distortion buffers; RFI filtering, very linear 10kohm input impedance; cool blue power LED! ;-)
Speakers: My own design - small/satellite (10"x6"x8" HWD) 5" generic aluminum cone woofer - 30mm generic titainium tweeter, my own x-over: Lo=60Hz-2k Hi=variable 12dB/oct; L-pad; vented-enclosure; FR: about 45Hz-20kHz;
special features: all solid 16AWG internal wiring; bi-wired; small, but nice sound. Aluminum gives great bass control, the mids a bit soft. conversely the titaniums give sharp highs, but the 30mm dia. tweet really sounds like a nice mid-range.

Also have a set of RCA tower speakers with bunches-o-tweaks including being over-stuffed with poly-fil, rubberized gaskets around the driver mountings, custom made x-over. They sound quite flat, plenty o bass, but they get in the way of the sound sometimes. If you set them up ala Audio Physik methodology - they suck. Too much facial surface area. Too many reflections, Too much external coloration for one set of speakers. However they are great with "Metallica Weekends" and such where I really just want to kill the neighbors.

(Disclaimer: when I use "kill" here, I meant metaphoricly, with music)

CD Player/DAC: New Sony DVD560s with built in decoder
and 96/24 DAC and upgraded output op-amps (OPA2134).
Also new-ish Sony CD changer (mom's).
Turntable/Phono Stage: none yet
Other Source(s): WinAmp mp3 from my PC soundcard
going to design a high-end soundcard next year (maybe)
Other Accessories/Room/Misc.:
Speaker Cables/Interconnects: Working on bi-wire twisted pair from solid 16AWG magnet wire (hope its as pretty as TBR's)
(8/01 - on hold)
Other (Power Conditioner, Racks etc.): Surge supressor (does that count?)
Tweaks: It's all a big tweak!
in fact it all started as a tweak!
Room Size (LxWxH): long x short x tall
Room Comments/Treatments: Couch, love seat, TV, PC, lamp, magazine rack
Comment: sounds like crap but comfortable, I just turn it up louder so i cant hear the room as much.
Music Preferences and Comments:
Music Used (Genre/Selections): Anything gritty, dirty, packed with intense emotional/social problems, yet as devoid of politcal issues/agendas as possible.
System Goals/Comments: (1) To have 2 complete systems designed from scratch (source to speaker-cone)
(A) using CD/pre/pro-DAC/anl.amp/passive spkrs
(B) using DSD/PWM - powered spkrs.
(2) Convince my mother to buy a house so I can have my own dedicated listening room (and still annoy the hell out of her).
System Strengths: Gorgeous channel separation, stage, image
good FR from small spkrs; non-fatiguing sound - to listen is bliss, if you don't listen (like if your busy cooking or like me, building another component) it doesn't annoy or give headaches.
System Weaknesses: my current system is not really a "system"... it's a "franken-system"
Video/HT System: None
TV/Projector: dont like TV, but if i were to have one for myself, a 36" Sony would be my choice for the price... if price werent the obstacle, then a mitsubishi plazma with a 63kHz scan converter/interpolater (saw one at the 97? home theater show in newport beach). Next would be a mid-line Proxima dmd/arc lamp front projector with 1280x1024 res and S-video/XGA inputs. about $7k. thats about 3ft./$1k (diagonal)

currently the set we have is a basic 'watch the news' jobby

Processor/Receiver/Amplifiers: Sony pro-logic, was a 'decent' reviever in its day (5 years ago) the price was right and its soon to recieve some mod's: 6 channel pre-outs (ala Crystal Semi.), new low noise input selector (Maxim Semi.) and Blue volume-knob LED (yes, i'm deranged)
Speakers (Center, Surrounds, Sub): currently none... used to have a 6th order BP sub with 2 isobaric 10" pioneer woofers, it was pretty big but could produce bass that could cause vomiting and diarrhea, as well as rattle the dishes, knock pictures off the wall, and cause time-space distortions with material below 20Hz.
(ok, ok the picture wasn't hung very good!)
this was mostly an educational experiment in sub-building for me.

i have on the drawing board, a MUCH smaller 2nd order sub with 2 isobaric pioneer 8's.

Sources (DVD/VCR): Sony Hi-Fi 4 head (ol' reliable)
Sony DVD560s
Other HT Gear: have some currently-unused monster cable home-theater patch cables
Comments on HT System: HT, for me, has taken a backseat (actually just a pile behind the loveseat) to some serious stereo audio engineering projects such as my digital preamp. See some 3D cad work on my link below.
URL Link:
Other Interests/Hobbies/Occupation: Im a electronic 'Design Engineer' (official title) at ARMA Design in San Diego, where I work on hardware applications, embedded systems, firmaware, ect. I like to ride mnt. bike & travel. I also like to teach, & was an English teacher for grades 2/3 in Bangkok Thailand, last year. Other interests? Oh yeah.. and Audio gear.

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