I want to convert a 1970s belt drive turntable to a wirelessly streamed source so I can site it remotely from the amplifier. I intend to mount the RIAA preamp within a screened box inside the turntable base and then convert the signal to some sort of RF (maybe Texas PurePath?) and then restore it at the amplifier end at line level for standard RCA inputs. I don't want to use an acoustically inferior protocol like Bluetooth for obvious reasons. If it can be made to work there are nice advantages; no ground loops; turntable can be sited for best acoustic isolation.
The analog bit I am quite comfortable with, I have 40+ years analog design experience on all sorts of tricky amps. What I would like advice on is the best way to implement the wireless link without any software (not my strength).
Any ideas gratefully received. (I am UK based for component sourcing issues.)
Ian
The analog bit I am quite comfortable with, I have 40+ years analog design experience on all sorts of tricky amps. What I would like advice on is the best way to implement the wireless link without any software (not my strength).
Any ideas gratefully received. (I am UK based for component sourcing issues.)
Ian
Dan, if you think Bluetooth would be OK what hardware would you recommend for my application?
There are plenty of articles on the web suggesting that the compression in Bluetooth is audible even with aptX. The receiving end for this project is hi-end hi-fi amp and speakers. Bluetooth certainly makes a good job of connecting a boombox and smartphone I have, but I am not talking about that quality level.
There are plenty of articles on the web suggesting that the compression in Bluetooth is audible even with aptX. The receiving end for this project is hi-end hi-fi amp and speakers. Bluetooth certainly makes a good job of connecting a boombox and smartphone I have, but I am not talking about that quality level.
This project does not make sense in my view. You have to go to the turntable every 20-25 minutes, so it is logical to place it within walking distance to the speakers. What's wrong with cables?
You will note I quoted technical advantages (if I can get it to work) of acoustic isolation and ground loops, both of which are traditional bugbears of turntables. It DOES make a lot of sense in terms of my room layout. If you want to stand a turntable on a large mass to avoid acoustic coupling this isnt necessarily convenient to place close to amplifier.
It also makes sense for the additional application of transcribing vinyl to digital as the computer is another set of ground loops and potentially noisy switching power supplies.
Could I please have comments that are constructive about how to implement my idea rather than subjective comments about my room layout of which you know nothing.
An easier to implement method that fixes your ground loop problem would be to have the preamp in the turntable as you propose (always a good idea to amplify at source rather than remote), then add a balanced line driver also in the turntable. Then have a balanced line receiver at your amp.
There appeared "USB turntables" on the market recently. Perhaps the internals could be re-used, connected to an USB wireless extender, and received by an USB DAC. Just thinking.
I found this on a quick search, the mode you need is peer-to-peer communication:
http://www.newegg.com/Product/Product.aspx?Item=9SIA4P02ES8793
I found this on a quick search, the mode you need is peer-to-peer communication:
http://www.newegg.com/Product/Product.aspx?Item=9SIA4P02ES8793
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It was a question of your comment that Bluetooth is inferior.
What do you mean by this ?.
I have recently tried using an internal battery powered Bluetooth speaker feeding (via line out) into my 'B' shelf type system in my sunroom.
For casual listening/background music this wireless link seems fine enough.
On eBay there are numerous Bluetooth link systems and pcbs available at low cost.
I have not researched the depths of Bluetooth system operation to understand any limitations it may have, but IME on first inspection it seems 'good enough'.
Dan.
The balanced line idea you suggest richie00boy is a good one and I will probably incorporate it as additional hardware for comparison. No reason not to have both! Even though I still want to pursue the wireless solution. The noise floor for a balanced input is higher than unbalanced of course (all other things being equal) but whether this will matter in the real world depends on which noise source dominates.
Douglas Self gives an extensive analysis of this in his book "Small Signal Audio Design" and also shows how to mitigate the effects.
The Bluetooth idea has set me thinking that I might try out a proof-of-concept using it and then upgrade to a lossless method of transmission as stage 2 of the design. Could use a cheap module like this to do that:
JUSTOP BTT005 Bluetooth Wireless Stereo Audio Transmitter With 3.5MM Jack, Universal Adapter For Mobiles/Computers/MP3,MP4 Players, New Module with Bluetooth V2.1 A2DP profile: Amazon.co.uk: Electronics
Douglas Self gives an extensive analysis of this in his book "Small Signal Audio Design" and also shows how to mitigate the effects.
The Bluetooth idea has set me thinking that I might try out a proof-of-concept using it and then upgrade to a lossless method of transmission as stage 2 of the design. Could use a cheap module like this to do that:
JUSTOP BTT005 Bluetooth Wireless Stereo Audio Transmitter With 3.5MM Jack, Universal Adapter For Mobiles/Computers/MP3,MP4 Players, New Module with Bluetooth V2.1 A2DP profile: Amazon.co.uk: Electronics
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