So after my suspected motherboard/psu woes (that have now been ruled out), I ended up finding myself in need of a sound system. I had this old hi fi unit my dad gave me years ago gathering dust and not being used because:
- It uses din plugs, 2 pin for speakers, 5 pin for audio interconnects. I've never owned anything else that uses din plugs, and this didn't come with any.
- Even when the speaker wires were jammed into the holes at the back with matchsticks (yes, this is how my dad used it for years), a cable would occasionally (read as "frequently" drop out resulting in loss of sound).
- When the cables stayed in place, you had to constantly fiddle with the volume control. it would crackle like crazy whenever you moved it even slightly, and one channel or the other would loose sound completely (even though the cables were in place).
So I bought a 3.5mm to 5 pin din lead when my dad first gave me the amp. But due to the other problems I never really gave the thing much use. When it was working though, the sound was superb. Even when we were moving house and throwing away a load of stuff, there was no way in hell I was letting this thing go
I spent a while hunting around for 2 pin din plugs, but the staff at most shops just gave me that blank look that says they don't have a clue (to be fair the staff were probably an average of ten years younger than me, and the stereo is almost another ten years older than me). A few days ago I finally tracked down some 2 pin din plugs with screw top bindings at the place that does maps for Lin (been in there loads of times, they've never had any in stock, known what they were, or where to find them, I got lucky this week)
So after creating some new speaker cables, and finding the jack to din lead (to connect my PC up to the thing obviously), I still had one more problem to tackle. The volume pot. Now this hi fi unit is so old, I spent three years looking for it online before I found any reference to it. Now there's quite a few but the first was this. My model isn't a Schneider, but then neither are the Schneider ones. The Sound Project TA series of hi fi equipment was actually built by Phillips (Japan), and sold under various brand names around the world in the early 70s. Mine is almost identical to the model on radio museum, apart from being badged as made by PYE. I've got the 8000 model, they also did a 4000, 6000, and 12000 as far as I'm aware...
Now the problem with the volume pot is a well known one. During use the volume pots build up carbon on the contact points which eventually causes friction and loss of connection (hence the crackling and sound dropping). During my time spent searching for an easy solution to fix this problem without replacing the whole pot I kept finding recommendations for a contact cleaner (wd40 is no good for this sort of application by the way), which costs around £35-£50 for a 3.5g tub which is apparently good enough for 10 uses... So far I'd spent a grand total of £7.80 on this project, and I've been skint recently with so many family birthdays, school events and the like, I didn't really want to spend more than a 5er or 10er...
I took the top off the amp, and started cleaning the dust out:
I only took this picture because I was expecting to have to completely strip the unit down to get it all clean and wanted a build log sort of thing (read "reference for where I need to put everything back"). However it turned out to be a lot easier than expected and this is the only picture I took, sorry about that... You can just about make out the volume pots in the top right of the image with two white wires... You can also just about see the two dark channels which are the openings leading inside the pots.
The volume pot is actually made of two separate dials, and they're both open. I could see the brushes moving as I turned the volume control, and I could see all the gunk that was caked into them as well... As mentioned previously I didn't want to spend a lot of money on the "proper" cleaning stuff. Seemed like a waste of money if I'm honest, and still does
I squirted a bit of alcohol (lynx lol) into the pots, and stuck a piece of paper in, then turned the volume control so the brushes had to go over the paper. Repeated the process a few times, and hey presto... I had clean (looking and smelling) volume pots, the brushes are spotless and the surface they travel across is now like a mirror.
So I hooked everything up to my Xonar DSX (192Khz, 24bit, Hi Fi mode on), and fired up an old favorite that I only have as a low bitrate (128) mp3 now... It sounded good for the first time in years, but I could still tell it was an mp3... So I went and tracked down a high bitrate (320) mp3. The sound was amazing... So crisp and clear, with smooth but bouncy bass...
Then I started playing some flac files...
The highs are crisp and sharp, the bass is clear and smooth... Then I remembered the awesome switch (labelled as "CONT") and flicked it into the on position
Throwing that switch makes a huge difference. It's like night/day. In the off position, the sound is nice and clean/clear, but it lacks depth, there's no punchiness to it. In the on position then I remember why I went to the trouble of fixing the thing
The sound became even sharper, clearer, and the bass started to roll around the room like warm waves on a sandy beach. At position 4 (of 20) on the volume dial, and with the awesome switch on I can listen to music and actually enjoy it for hours on end (something I haven't been able to do for years while I've been using the py old stereo system from that I've recently got rid of). My speakers actually sound like the pretty decent floor standing speakers they are now, the old amp had never been able to drive them properly.
Now I just have to make sure I don't annoy my neighbours too much