I now own an 8 Track player

So I just found an 8 Track Player.....

 A Prinzsound CRD8, Serial # 001429 (thanks man)

I spent a bit of time on it to get it going nicely and it does now. Information on it is very sparse to the point were the above post was the only reference I could find on it.

I want to do a fairly complete post on the fix so that web can preserve the info in case others need it:

I opened the case and the hardware was all quite good. Heads nice and not even very dirty. Only one drive belt in the whole unit and that still has good tension. The power plug was loose so I tidied that up and plugged it in. 

No smoke or bad smells. Plugged in a David Cassidy 8-Track (the tape I cared least for was picked for testing) and it thumped into life ( really does thump. Big fat solenoids ) and plugged my 70 Technics EAH-220 headphones in.

Right channel fine, left channel nothing.

Got to be the rec/play switch. Stripped and cleaned with iso. No difference. Made a quick and dirty audio probe with a guitar amp I had to hand and found the signal disappeared in the left pre-amp just before the volume. 

No service manual to be found anywhere on the web. 

Drew a circuit and overlay then put it back together and started checking voltages on the left channel against the right. Second transistor in the left channel sus; replaced the 2SC871 with a BC549 . Sound in both channels but the left starts quietly then fades to full volume after 10 or so seconds. Replaced various electro' caps to no affect until I looked at the what I had considered the least likely electro which was the cap to the playback head. 

Replacing that fixed it and it now runs just fine. It was quite obviously swollen on removal and had interfered with the bias of the first transistor until the cap in the emitter path had charged up. Finally I put RCA plugs on in place of the DIN plug.

I'll post the overlay and circuit diagram I worked out in as follow ups to this post.

The only real lasting damage is that I now quite like David Cassidy. 

 

PC board overlay: Solder side.

 

 

Circuit diagram of the left channel :

 

2016-07 Concrete Record Player.

The Dual turntable needs somewhere to live. I decided to make this a test of the process for my ideal record plinth.
The Concrete Record Player (plinth.)

The process: Make a mold and fill it with concrete

The mount points for the turntable are precise and too thin for concrete so I made a frame of plywood to be embedded in the plinth the the turntable will rest on and mount to. I made two and laminated them together for strength and the depth needed for the turntable spring support cups.

The frame mounted on the top of the mold with the turntable cutout under it. The frame protrudes and that will keep it embedded in the concrete. Here I am packing out the interior with packing foam and masking tape to keep the void in the middle empty.

The mold with the sides on and some dowels for the mains and audio cables. I didn't want to risk cracking the plinth by drilling these out after it had set. The first  concrete is in and you can see the wire squares I added into the concrete hoping it will strengthen the final block.

2016-06 Dual 1214 turntable restoration.

I want a better 78 player and found this turntable in a 3-N-1 stereo for $10. At that price it didn't matter if it was a no go. Looks like there had been some water damage and some missing bits but not too bad.
The motor did not spin freely which was a very bad sign so I worked on that first. The bottom of that armature was locked into the brass ball that acts as a bearing and guide. It was riveted into a support bracket that I destroyed before I realized I could possibly have disassembled it on account of one of the parts being so frozen I thought the two parts one.

(a bad first attempt that involved dental floss).

Hacked up a replacement bracket from a tip-top ice-cream lid and that worked really well .
Reassembled and the motor ran reliably and quietly but the speed selection, disk size and return were all faulty.

A good clean section by section, some small adjustments and I got all these working.
 
 Gave it a run (after using a magnifying glass and tweezers to straighten the stylus) and it sounded great. I had no suspicion that 78s could sound so good.
And I found the auto-change spindle lying inside the electronics in the case in the old 3 in 1 guts and that seems to work too.

2016-05 Speaker Stands

I've been keeping an eye out for something to use for speaker stands or a good design to build from scratch. I found these slightly odd stools.

They looked like this

Here they are stripped down

I reclaimed the wood from the seats, trimmed it to fit the width of the frames and added some stick n cable clips for the speaker wires.

These speakers have no internal cross overs and I have these that I use with them. Why not mount them on the back of the stands to keep them tidy too?

Like this

 ! For The finished !

(I really don't like blogger's lay-out tools / editor.)

2016-04 Empty the LP Queue

I have about 4 to 5 hundred LPs waiting to be listened to or just to be shelved.
It's getting to me. This month I want to review and shelve them all.
I started a bit late and set 8/day as a goal. Had a cold and took a break then came back reinvigorated and decided on 10/day and 20/day in the weekend.
Then the Rotary Book fair happened and I added 25ish to the Queue. Now I've set myself 15/day and 30/day in the weekend. I might make it.
Here's my progress chart that I keep to enthuse myself:

It went well enough. I've kept on top of things too now that I have better organised shelves with some free space. Next to do are the 45s.

2015-12 Repair Solarvox speakers

This was to be an easy one. HA! Anyway... I have a number of HiFi speakers from the '60s - '80s and they take up space. Sorted them out and found this pair have a sound I like but a blown tweeter.

The label on the back is interesting...

I found an appropriately rated tweeter from JayCar and fitted it. It sounded very very bright. A series resister would be all that's needed to reduce the level of the modern more efficient driver but doing that by listening and changing the resistor seemed fraught.
I decided to try measure it :

• Make sweep and noise files and play them  on the left then right channels
• Use the Tascam recorder to grab a recording 
• Have a look at the spectrum of the recordings and adjust until they match.

Generate tone:  sox -n sweep1.wav synth 10 sine 10-20000
Generate noise:  sox -n wn1.wav synth 10 whitenoise

Then play it back and record it on the tascam.

Script:

while true ; do for F in *.wav ; do echo "Playing [ $F ]" ; play $F ; sleep 1 ; done ; done




Note the rug on the chair to create a special sound proof recording area.



After some trial and error the spectrogram of white noise seems the best way to see what's going on. Got these from
sox infile.wav -n spectrogram outfile.png
after trimming the tascam recordings down to just the white noise burst.

This is the new tweeter 

This is the original.













An 8 Ohm resister seemed to be about right:

I did both speakers as the high end is clearly better.

2015-09 Line out for the Yamaha CN-70

I got this for $30 or less. I have the room right now and it seemed in good nick and is. I removed an odd mixer that had been added but came without its power supply so was useless. I had been hoping to use it for a line out. (The organ is very well built for service).
That got me thinking about adding a line out. Found a circuit diagram. Found some room on the side panel. Had the parts.

Test Point 82 clearly indicated on the main board is just before the Expression peddle and the main Vol so that's about right. Drilled a hole and made a plate to hold a 6.5mm jack socket.

Mounted it, soldered it up and tried it out.

Noisy but good. I think the way to fix the noise would be to go back toward the tone banks, make a low noise amp and pick it up from there. There'd be no rhythm or auto play stuff that way though but I was toying with giving them their own outputs anyway. Maybe later.
Sounds AWESOME through last months PTOM (a spring line reverb tank reverb. must write it up). Very Marty Rev 

2015-02 Control surface for audio processing

I've been considering a sound processing language for a while. Looked at supercollider and liked it but never really did anything with it. Tried again recently and found chuck. I had a play and liked it. Not sure why I prefer it but it's something like: less elegant but faster to code.
The missing bit was an interface so effects and apps writen in chuck could be conveniently controlled during performance or production.
Found interface.js which can use OSC to send messages to any osc aware system/program (which chuck is) and has a constrained but easy to use way to build a panel of controls. These panels are accessed as web pages served by an included server so a tablet can access it.
Presto:  The knobs, sliders and buttons are all touch sensitive on the tablet and you have a versatile touch sensitive control surface that can talk to chuck.

Details follow:

Notes on installing chuck.
I use Fedora both 20 and 21 on two different machines with the CCRMA repo (CCRMA fed21 repo here) with:

       sudo dnf install chuck
       sudo dnf install miniaudicle

The standard packages seem OK.  ( I did build from source to try to fix the windows in miniAudicle not remembering their locations between sessions: got bogged down in QT, but the build was process was reasonable )
The way I use it is to start  jack (with qjackctl) then run miniAudicle.
You'll get an IDE, a console window (shows error, information and print type debug messages) and an execution control window (called Virtual Machine). Like this:

The doc's are a bit out of date for the osc stuff but  these examples are current and will set you right.
You start the virtual machine then use the IDE to edit and run code. Lots of good examples to play with in the link above. (you don't have to use jack: there's  miniAudicle-pulse and miniAudicle-alsa if it suits you better)
Update: Nearly there. A bit stuck on the OSC stuff and chuck keeps locking the osc message stream. Nuts.

2015-01 7" record boxes

I have kept my LPs well sorted and it pays; You can find things and duplicates show up so you can keep the best LP.
But 45's have lived in stacks unsorted except of a fav's pile.
No more.
The mid shelf of LP store was always put aside for 45s but getting boxes ? I could not do this. Nothing was the right size, so I must make some.
Got some thin and strong cardboard boxes from the recycling at work, some cutting and hot glue and here they are:

I made them the same depth as the shelves and just wide enough so that 5 fit on each shelf. Much denser and more accessible too.
Freed up a bit of much needed space so now I get to move the LPs around to make room and then sort the 45's into categories I guess.

• Cut the box into sections.  1 for the front, 1 for the back and one for the bottom and sides.

• 
  

  I use a cutting mat and box cutter to make the parts. To score the bends I used the end of a median paint brush. Be careful to crush but not cut the cardboard.
• Hot glue the parts together.

Box cut into sections for parts

 

 

 

2012-04 Music and Video

I really need to finish a piece of music.

I had a general idea and planned to keep it simple; Some autoharp mic'd up close so all the key bridge noises and fingers on the strings and creaks etc. would be picked up then add some short wave radio noise and some tabla.

Setup the mic's. Do a sound check with the electric guitar first. Like the sound. Try some delay effects. Like that. Add some more. Sounding quite good and a sequence of notes comes together quite well. Do a take. Sounds good. Add effects. Yum.

Now the video.

I wanted this to be about Autumn. Dig out photos of Autumn of Daniel's farm and some dead tree and park photos. Get the TV23 image scripts out and generate some scenes with them. Fire up a video editor and mix the stylistically best fitting ones together to the right length and add the sound.

Quite nice really.

Upload to Youtube. http://www.youtube.com/watch?feature=player_embedded&v=A6Fl3EMZd2U

2012-01 Low Noise Phono System

I've always had a little hum on the record player. So low though that even quiet music obscures it.
However it is there and I recently got a copy of Tibetan Bells. TB is very quiet indeed, with long passages where a single bell note fades completely before the next is struck.

[1] Check the amp.
[2] Check the cables.
[3] Check the record player.

Amp:
Found the Tuner input on the amp, which I had been using had some hum. Checked them all: The Tape input is quietest by far.

Cables:
OK.

Record player:
Both check out fine.



OK, the pre-amp in the amp is noisy so I got a general preamp kit from jcar (http://www.jaycar.co.nz/productView.asp?ID=KC5159) to try. Cheap enough to discard if not good enough.
It sounds great. Housed it in an old power supply case and it goes directly to a spare input on the PC sound card.
I can easily hear the original tape noise kick in as the cutting engineer switches it in when mastering the LP on Tibetan Bells so the total noise in the system here is less then in the original studio (1970's analog) and there's no discernible hum at all. An added advantage here is there is no need to use any mechanical switches any more. I just use alsa mixer to directly control the sound-card input level and switch between inputs on the sound card.

Here's a photo of the finished pre-amp disguised as a pedestal.

2010-09 Stereo patch bus

Tired of plugging in various new devices for recording or playback. It's a chore and messy to the point where I'm deferring audio projects on account of it.
Some simple patch panels to allow selecting / routing inputs and out puts are needed.

2010-08 Theremin

A Theremin from a kit but then re-cased to look less ugly and more in keeping with it's ethereal quality.
The case is a wooden box of mystery I found in a junk shop. The kit is the revised one from Jay Car. I did Not add the mods' for more linear tone control or timbre controls. Save that for version II I think.

It's just about what I thought it would be like to play. The volume panel is counter-intuitive in that it's quieter the closer you place you han. I'd like it to be silent until your hand is near.

You adjust the length of the antenna until the tone drops to nothing when your hand is away from it then you're set.

2009-03 Record Player Arm Lifter

A small automaton with an optical sensor to lift the arm of a record player. I'd like to use junk sources for this and targeted a 3" floppy drive to provide the parts.

2008-11 Concrete Record Player

So its to be a record-player then: The Op-shop had some mint diamond styli for a few bucks so I bought them.
My Trusty Luxman skates a little and is too wide for the lundia. I felt like an audio project after all the PC based stuff so the Concrete Record Player Plinth is the POTM.
At last a home for my SME arm. Here you see all the parts I've been putting aside: The bearing, light weight patter and motor from a turntable with a crap arm but completely noiseless and stable - can't recall the brand. All sorts of cartridges and styli collected over the years and of course the pice of tone army resistance: a SME tone arm. Cost me $100(ish) in the 80's from a greedy eccentric who only prized it's resale value.

2008-03 Mic pre-amps

I've been using an old cassette recorder for a mic preamp and it fulls up a slot in my shelfs, isn't portable and has a bit too much noise.