LDR DIY help?
Hi chaps
I run a Lightspeed attenuator, a pretty nifty passive pre which I rather like. It has recently developed a kind of intermittent fault of late (like hiccoughs) where is drops volume level for a second or two every hour and then returns to normal. George (Mr Lightspeed) himself has advised me of a part that probably needs replacing (we already swapped the wall-wart).
It is the front potentiometer, basically a volume control pot, but it isn't in the audio signal path at all; rather it controls how bright the LDRs (light dependant resistors) are, and therefore how much resistance they have. He kindly sent me a link to the appropriate part (I don't know if this is what he used) from Mouser, but the handling fee is £12 and with customs etc we are looking at silly money for a part that ought to cost £3 in the UK.
Can anyone point me at the appropriate part from a UK supplier? I am hoping it will be similar to what's there, so I can replace it easily (I can probably solder a like for like replacement).
Here is a quote from George's email to me:
On 21/08/2012 23:16, George Stantscheff wrote:
The last thing that can be done that end is to replace the front volume
(led) controller, but it needs someone who can solder as there are 3 wires
attached to it inside.
It's only 2 pounds for you to get the part from Mouser in the UK.
http://uk.mouser.com/ProductDetail/Alpha-Taiwan/RV24BF-10-15R1-A100K/?qs=sGAEpiMZZMtixQy3ohoCGB1pFF2cl67ieqv4p5h0%252bLs%3d
To open the Lightspeed remove the knob it is a small Alan Key that secures
it, then remove two top rear screws then all four front ones pull the
front panel and bezel forward slightly then slide out the top chassis
plate.
If this doesn't work unfortunately that means the quad matched ldr's have
been damaged, either by mains spikes or dc offset being fed into the input
or output, or even some abnormal signal. These are $150 to be replaced +
your shipping both ways which is about another $100
Cheers George
Thanks in advance, chaps!
I run a Lightspeed attenuator, a pretty nifty passive pre which I rather like. It has recently developed a kind of intermittent fault of late (like hiccoughs) where is drops volume level for a second or two every hour and then returns to normal. George (Mr Lightspeed) himself has advised me of a part that probably needs replacing (we already swapped the wall-wart).
It is the front potentiometer, basically a volume control pot, but it isn't in the audio signal path at all; rather it controls how bright the LDRs (light dependant resistors) are, and therefore how much resistance they have. He kindly sent me a link to the appropriate part (I don't know if this is what he used) from Mouser, but the handling fee is £12 and with customs etc we are looking at silly money for a part that ought to cost £3 in the UK.
Can anyone point me at the appropriate part from a UK supplier? I am hoping it will be similar to what's there, so I can replace it easily (I can probably solder a like for like replacement).
Here is a quote from George's email to me:
On 21/08/2012 23:16, George Stantscheff wrote:
The last thing that can be done that end is to replace the front volume
(led) controller, but it needs someone who can solder as there are 3 wires
attached to it inside.
It's only 2 pounds for you to get the part from Mouser in the UK.
http://uk.mouser.com/ProductDetail/Alpha-Taiwan/RV24BF-10-15R1-A100K/?qs=sGAEpiMZZMtixQy3ohoCGB1pFF2cl67ieqv4p5h0%252bLs%3d
To open the Lightspeed remove the knob it is a small Alan Key that secures
it, then remove two top rear screws then all four front ones pull the
front panel and bezel forward slightly then slide out the top chassis
plate.
If this doesn't work unfortunately that means the quad matched ldr's have
been damaged, either by mains spikes or dc offset being fed into the input
or output, or even some abnormal signal. These are $150 to be replaced +
your shipping both ways which is about another $100
Cheers George
Thanks in advance, chaps!
Comments
Even my last conventional passive (P90) had some kind of loose connection thing going on which caused occasional hum, which went away after a little re-soldering. So does my TSS on one of its inputs come to think of it. It just happens I guess, especially with second hand gear.
OK OK, I get it you meanies. I'll just have to cough up. One of the kids can go hungry this weekend, the middle one has put on weight recently. It'll be for his own good...
I was just wondering if an appropriate eBay item would fit the bill? Like this one - it seems to match the data sheet of the mouser part here.
I have felt a niggling irritation with my system for a while now, but have been pretty busy so haven't had much time to find out what 's going on. It seemed to me that the bass was boomy, lacked detail, and felt slow. It definitely didn't used to be like this.
I listen in a sort of nearfield position, my speakers are placed on the long wall of the lounge and I am sat closer to them than the distance between the speakers. One side, to my left, is adjacent to the dining area so is free of side walls, while the other side is a metre or so from the room boundary.
Last week I had a free afternoon and the family were out, so as the constellations were aligned I sat down for an afternoons music. Only to be annoyed at the system. So out came the SPL meter, on went the pink noise, and I found that the speaker at the open end of the room was 4dB louder than the other. Playing music at decent levels meant I was really overloading half the room with bass energy, but because it was the open end (and I am a deaf philistine) I never noticed a balance problem.
A few minutes later I had swapped everything around, trying different combinations to be sure it was the lightspeed playing up, and once I was sure it was I whisked it away to fit the new potentiometer. 20 minutes later it was back in - and the balance was all over the place! I left in with pink noise for 15 minutes, as George S wrote in the instructions to let it settle for quarter of an hour before any serious listening.
After that I checked both speakers individually with the SPL meter, and had perfect balance once again - result! I had an hour left to play some choons, and the system sounded better than I remembered it doing for ages. It just shows how issues can creep up on you, even to the point of being quit obvious before you notice anything is wrong!