Mystery Muse Electronics Model One Preamp

8991XJ

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#23
The bay has a listing for the flyer for the unit giving some specs. Easy enough to copy the image and enlarge to read.
There is another one for sale there, too, maybe the owner knows something about it. Might be worth and ask for manuals or knowledge.
 
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#25
With the spacing of the serial numbers on a few Muse items on the web, maybe the first two digits are the year of manufacture. A guess on my part.
8991XJ, I looked over the high-res photos, and all of the individual component date codes I saw would support your theory that the first two digits of the serno ( "90" ) as the year of manufacture:

Pacific Transformer: "November 1989"

Big blue 10K ufd PS cap: "8914"

Motorola 2N2914 (dual low-noise NPN transistor package) "8904"

****

Given the parts used, quality of the printed circuit boards, and huge power supply (in separate enclosure) this was a max-effort preamp when it was made. Spence, I agree that fixing this preamp is a great opportunity to combine the sense of satisfaction from listening to something you fixed yourself + end up with a high end preamp for your troubles.

Nice!

3D
 

NeverSatisfied

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#26
Didn’t have time for any audio yesterday, had to do a brake job on the bosses Camaro. Frigging Brembo pads are expensive and only made it 45k, might have made it 50k but she drives like Lewis Hamilton.
Anyway, thanks for the info and I agree with the vintage 1990/91. When I checked the PS output voltage I was surprised at how loud the transformer was with the lid off. The chassis is steel and at least 2 times thicker than the PL stuff, presumably for noise isolation.
The power delivery plug system doesn’t make sense to me, it has obviously been replaced from original but also looks to be modified and not safely either.
I think sorting the power is my first objective and then finding a suitable volume control replacement will be next.
 

8991XJ

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#27
but she drives like Lewis Hamilton.
Doubt that. Lewis can drive.

I'm more of the thinking that she drives like a soccer mom late as usual, Gun the engine, Hit the brakes. Not that I know how she drives. Maybe she does track her car and laps better than most.

front brakes at 45k on a heavy car like that isn't unusual. If you had to do the rears, too, well then Chevy is putting low mileage pads on the rear to make em both wear out at the same time. Rears usually good for nearly 100k.
 

NeverSatisfied

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#29
Doubt that. Lewis can drive.
Lol, Lewis could learn a couple things from my gal. Her daddy was a racer and mechanic. Call her a soccer mom and after your vision returns she would tell you her first car was a V8 and every car she has owned since have been 2 door V8’s with most being standard transmissions.
 

Bob Boyer

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#30
Autocrossing it might explain that behavior as well. Fastest way to punch through the pylons with a big front-engined V8 car is to wail on it until about 20 feet further than you should coming into the turn, stand on the brakes to shift the weight off the rear and then turn the steering wheel in the desired direction and wait for the rotation before getting back on the gas again. No such thing as trail braking or carrying momentum through the apex with the big guns...

And yes, Lewis knows what he's doing, though I'd love to see him try Gurney's Eagle-Weslake V12 at Spa...
 

NeverSatisfied

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#31
Autocrossing it might explain that behavior as well. Fastest way to punch through the pylons with a big front-engined V8 car is to wail on it until about 20 feet further than you should coming into the turn, stand on the brakes to shift the weight off the rear and then turn the steering wheel in the desired direction and wait for the rotation before getting back on the gas again. No such thing as trail braking or carrying momentum through the apex with the big guns...

And yes, Lewis knows what he's doing, though I'd love to see him try Gurney's Eagle-Weslake V12 at Spa...
Pretty sure these new era F1 drivers don’t know how to use the third pedal.
 

8991XJ

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#32
Third pedal is an anachronism.

Reason the Europeans like their floppy paddle shifting two-pedal cars is they had to have three pedals until these new trannies came out cause their automatics sucked in their under powered little cars. They embraced the move away from 3-pedals. Americans seem stuck in the past with a demand for manual transmissions with a clutch. Sure they were the better choice but we always had decent automatics. Today the newer floppy paddle shifted stuff is faster.

Both my cars have manual transmissions and I like that.
 
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Bob Boyer

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#33
First time I tried the flappy paddles was test driving a then-new 3rd gen Miata on some country roads near the dealer. My autocross co-driver (who was always faster than me) could not extricate his rear bumper from my front bumper. I was not twisting the motor past 4000 rpm - the car had 25 miles on it - and he grew up running those roads. To say we were both seriously impressed with the quickness of the paddle shifter was an understatement.

We both, however, still preferred our manual Miatas.
 

8991XJ

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#34
Knowing the roads is major. I was visiting a college buddy back in the day driving to Tellico Plains and my in a Camaro and the local in front of me in a pickup truck and I couldn't keep up. My first time on the road and he has probably outrun the cops a few times on that same road.
 
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#36
Lee,

You are thinking of the MR2 -- super nimble car. It is the essence of a mid-engine design, putting as much of the weight inbetween the tires as possible, giving a low polar moment of inertia. (ie: You could change your mind even while in the middle of a corner...and the car would still do what you requested.) A true traveling companion, especially when driving on unfamiliar roads...

Edit: (Taken from Wikipedia) "The name MR2 stands for either "mid-ship run-about 2-seater"[1] or "mid-engine, rear-wheel-drive, 2-seater".[2] In French-speaking markets, the vehicle was renamed Toyota MR because the abbreviation "MR2" sounds like a profanity when spoken in French.[3]"
 
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NeverSatisfied

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#37
Since we are going down this rabbit hole. I have had many sports cars over the years, 3 Z cars, 4 Vette’s and all were standards. I now have a F type R and it is my first paddle shifter, honestly it stays in full auto 95% of the time. When I do use the paddles I have to concentrate on not moving my left foot and the overall experience is less fun for me but I have no doubt that if properly executed the paddles are much faster.
 

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#38
Lee,

You are thinking of the MR2 -- super nimble car. It is the essence of a mid-engine design, putting as much of the weight inbetween the tires as possible, giving a low polar moment of inertia. (ie: You could change your mind even while in the middle of a corner...and the car would still do what you requested.) A true traveling companion, especially when driving on unfamiliar roads...

Edit: (Taken from Wikipedia) "The name MR2 stands for either "mid-ship run-about 2-seater"[1] or "mid-engine, rear-wheel-drive, 2-seater".[2] In French-speaking markets, the vehicle was renamed Toyota MR because the abbreviation "MR2" sounds like a profanity when spoken in French.[3]"
Thanks Davis. Only rode in it once but I was impressed. My youngest sons Mitsubishi 3000 GT is a corner eater too..
 

8991XJ

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#39
The Mr.2 with its center mass is an interesting car. I watched one in my rear view mirror spin a number of times on and off the highway as part of an accident. It spun within its wheelbase, not something a front or rear engined car would do. Late 80s, Rt 4 in Pittsburg/Antioch area, NorCal.
 
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#40
The Mr.2 with its center mass is an interesting car. I watched one in my rear view mirror spin a number of times on and off the highway as part of an accident. It spun within its wheelbase, not something a front or rear engined car would do.
(apologies in advance to Spence & his quest for Muse Model 1 preamp info... :0)

Agreed. It's true that where we position the weight in a chassis will have a direct effect on how fast it can rotate when external forces and/or driver input exceeds traction limits. Just like the ice skater modulating their spin speed via hand/arm placement:

ice skater rotational velocity.jpg


This all reminds me of when I used to tinker with 5-Liter Mustangs in the '80s. You would install the Ford Motorsports spring lowering kit (~3/4") and combine that with either Bilstein or adjustable Koni struts/shocks. Stickier tires than stock. Then a strut tower brace across the top and a K-frame brace across the bottom to better keep the suspension geometry from being all out of whack when maneuvering said flexible flyer.

And the result? The car was certainly more responsive/more of a driver's car, but ultimately at the limits the communication between car & driver boiled down to: (paraphased) "I'll never let go. I'll never let go. I'll never let go --- Yo! I just let go! :0)

Time passes, Mustang is swapped out for a pair of used Infinity speakers & a $250 '78 Fiesta commuter car. More cow bell, less tire squalling.
Life is hunky dory.

More time passes. My buddy Paul talks me into building/co-owning a FF Cobra replica. During the entire build, in the back of my mind was the unsettling thought that we were putting together an even faster car that would share that nonlinear behavior at the limits...

But as it turned out, thankfully the Cobra was very linear/communicative at/near the limits. I know that we reduced the overall weight significantly while maintaining pretty much the same size tire contact patches, but that didn't explain it all. Finally, this picture gave me a clue:

Bradley with driveshaft comparo.jpg
Stock length (aluminum Ford Motorsports) Mustang driveshaft on left. Custom-length driveshaft for FF Cobra on right.
[Driveshaft model is Paul's son Bradley.]

So, on the old 5-Liter Mustangs the engine is parked between the front tires. (The stock oil pan actually has 2 sumps/2 drain plugs in order to help the engine oil pan clear the K-member.) On the Cobra, not only is the wheelbase shorter, but the engine is completely behind the front crossmember -- I seem to remember the harmonic balancer is ~2" behind the Cobra's front crossmember:

Cobra engine setback.jpg
Engine setback photo. Note: Light blue upper radiator hose connects near front of Windsor 302.

Also, the powerplant's center of gravity is improved by aluminum heads & intake plus lightweight tubular exhaust. Aluminum-cased T-5 trans + aluminum bellhousing also helps:

Bradley w completed Cobra powertrain.jpg

With V2.0 of the powerplant we even lost 12 more lbs (24 lb cast iron stock) by adopting an aluminum flywheel:

24 to 12lb aluminum flywheel Cobra.jpg
(Best 12 lbs lost to date -- engine now brought more 'drama' to the driving experience...more immediacy, dynamics, inner detail, etc. :0)

****

I know, we changed a whole handful of variables between the lower polar moment of inertia, lighter engine/lower center of gravity, and over a 1,000 lbs total vehicle weight...but the net result was that the Cobra was very communicative & linear as I approached the grip limits. As a matter of fact the car's limits were > than my own. (As opposed to the Mustang, where on more than one occasion I nearly ripped the seat cushion from surprise extra-pucker-factor moments. :0)

Of course, even if I optimize the weight distribution I can still depart controlled flight if I decide to completely ignore the laws of physics. You can use a hammer to build a house, or destroy a Stradivarius. My plan is to never, ever find out just how fast that the Cobra can spin within it's wheelbase...
:0)

****

Spence, I think that I can salvage this posting. Obviously, for improved center of gravity with your Muse preamp, you are going to want to put that 40-lb power supply below the main box instead of above it. Keep the power/weight ratio as high as you can afford to go -- when it comes to audio, Speed Thrills! Horsepower numbers may move cars off of the showroom floor, but torque is really where it's at 100% of the time you are driving around town...the country...or the track. :0)

Cheers --

3D
 
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