I'd be inclined to just try randum stuff to see what, if anything, makes a difference. There's not much at stake here, no risk of damage.
1. Remove the extra capacitance from the power supply. Return the VSPS to stock.
2. Try with or without the phono input attached to the turntable. Try with or without the op amp in the socket.
3. Try the VSPS in a different system, away from the tube amp. Personally, I'd plug the VSPS output into a computer line/mic in and record the signal during shutdown. Use Audacity, so you can inspect the waveform in detail. If you have a laptop you can do this "in situ", recording the tube amp input signal (VSPS output) while the noise is happening.
/R
Changing topic slightly.
Has anyone been tracking the component prices at Mouser recently? I try to plug in the BOM list into their web site every once in a while, just to make sure the part numbers are still valid.
Now, when I first was putting together kits for the Phonoclone 3, I remember pretty clearly that the single-quantity BOM came to about $80. So if I bought in quantities of ten, I could offer the kits for $125 including boards, Paypal fees, and shipping, and still work in the black.
Well, I just checked and the single-quantity BOM stacks up to ~$150! $140 for the VSPS300. OPA27s are over $4 each, and many more components have doubled in price since I last remember. While I still save in volume purchases, and I've managed to supply some parts (C1-3) with surplus stock from other sources, the fact of the matter is even after the price increases I made last summer to the VSPS300 and Phonoclone kits I'm still barely breaking even... or that will be the situation once I get through my current stock of parts, at any rate.
I need your opinion, or at least your thoughts: the price of the Phonoclone 3 kits is going to start pushing towards $200. That seems like a lot to me, but according to Mouser the parts alone are worth $150. What should I do?
Has anyone been tracking the component prices at Mouser recently? I try to plug in the BOM list into their web site every once in a while, just to make sure the part numbers are still valid.
Now, when I first was putting together kits for the Phonoclone 3, I remember pretty clearly that the single-quantity BOM came to about $80. So if I bought in quantities of ten, I could offer the kits for $125 including boards, Paypal fees, and shipping, and still work in the black.
Well, I just checked and the single-quantity BOM stacks up to ~$150! $140 for the VSPS300. OPA27s are over $4 each, and many more components have doubled in price since I last remember. While I still save in volume purchases, and I've managed to supply some parts (C1-3) with surplus stock from other sources, the fact of the matter is even after the price increases I made last summer to the VSPS300 and Phonoclone kits I'm still barely breaking even... or that will be the situation once I get through my current stock of parts, at any rate.
I need your opinion, or at least your thoughts: the price of the Phonoclone 3 kits is going to start pushing towards $200. That seems like a lot to me, but according to Mouser the parts alone are worth $150. What should I do?
+1 It's simple. If the price of the parts go up, the price of the kit goes up too.
For what you get the kits will still be great VFM. The PC3 is a cracking phonostage, especially if you over spec the power supply like I did (it totally wiped the floor with the Dynavector P75 II I had previously)
Richard,
you cant do anything about the price of parts and your not ripping people off by charging a surcharge so even if people were to only buy the boards they would still have to pay the same for the components. to save your wallet you could start selling board only but the kits are more convenient. here in the UK we get ripped off and your kits are actually cheaper or around the same price than what i can source parts myself so it's easier just to buy the kit.
if the kits are $200 then thats the price.
dont put yourself out of pocket. your a very very kind man but kind wont pay bills.
bibs
you cant do anything about the price of parts and your not ripping people off by charging a surcharge so even if people were to only buy the boards they would still have to pay the same for the components. to save your wallet you could start selling board only but the kits are more convenient. here in the UK we get ripped off and your kits are actually cheaper or around the same price than what i can source parts myself so it's easier just to buy the kit.
if the kits are $200 then thats the price.
dont put yourself out of pocket. your a very very kind man but kind wont pay bills.
bibs
I agree about kit prices. Truth is, if what you're seeing is real (I mean not just limited to Mouser), then other gear are likely to increase in price by similar margins, so I'd expect your kits will retain their appeal for a decent sized market. You might see an initial sticker shock, but I wouldn't expect much of a change once that settles down.
Thanks for the kind words of support.
Shopping around, it seems components at Digikey and RS are priced about the same. The depreciating value of the Yen is part of the story, but I think also that Mouser in particular offered very attractive pricing 4-5 years ago when they made a big push to enter the Japanese market, and now they are moving to reclaim their profit margins.
I still have parts in stock from when I made placed some big orders at Mouser two years ago. Prices will stay as they are until probably the summer, but regrettably the kits are going to get quite a lot more expensive after that.
/R
Shopping around, it seems components at Digikey and RS are priced about the same. The depreciating value of the Yen is part of the story, but I think also that Mouser in particular offered very attractive pricing 4-5 years ago when they made a big push to enter the Japanese market, and now they are moving to reclaim their profit margins.
I still have parts in stock from when I made placed some big orders at Mouser two years ago. Prices will stay as they are until probably the summer, but regrettably the kits are going to get quite a lot more expensive after that.
/R
It was just a suggestion, rather than something I'd actually done ... but the procedure itself is trivial. Looking for a strange turn off buzzing doesn't require high sensitivity or a low measurement noise floor, so its just a matter of getting a 3.5mm stereo <-> RCA adapter cable, and connecting the VSPS output to the line input of a laptop. I'd use the free software Audacity to record the sounds of turnoff, and (assuming the turn off spike was not so dire as to saturate the input) just throw up the data on screen to take a peek.
One further step up in complexity would be to make your own probe with a 3.5 mm jack on one end and alligator clips or something similar on the other end. You could even make a "10x" style probe with a voltage divider and AC coupling, so that 1) protect the laptop for DC voltage and 2) lower the input signal to allow larger voltages to be measured with the line level input.
Hello all,
this is a really great place! I've already build 3 VSPS preamps for me and a couple of friends and everything seem to always work great!
Anyway, and since I'm no electronic guru, my question is; what components should I bypass in the RIAA section to remove the RIAA equalization? I was trying to use the VSPS with old filter types (using software..), but I'm not shure if removing C1, C2, R4 and R5 will do it right?
Cheers all,
Isaac Daniel
this is a really great place! I've already build 3 VSPS preamps for me and a couple of friends and everything seem to always work great!
Anyway, and since I'm no electronic guru, my question is; what components should I bypass in the RIAA section to remove the RIAA equalization? I was trying to use the VSPS with old filter types (using software..), but I'm not shure if removing C1, C2, R4 and R5 will do it right?
Cheers all,
Isaac Daniel
I can only speak to the VSPS300 and it's value. You would have to compare it to something to make a judgement. It is logical to compare it to another similar item except there is nothing that truly compares. There are certainly other phono stages but none with 1)split rail power supply, 2)one single stage of gain, 3)world class non current limiting power supply built in.
I think it would be the input capacitance of the used op amp + hookup cable + rca chassis
Yes, and my understanding is that the cable capacitance (100 pF/m typically) will dominate.
My advice is to just follow the manufacturers advice. If they suggest 100 pF, put 100 pF across the inputs...