Yes I did and it worked great. Dont know if it is still available, but if it is it worked well!. There are pics somewhere in this thread...never mind the power supply box, I think it was at least runner up in the ugliest power supply contest. An old Dynaco Pat 5 box with no face plate. But it hides away...
Russellc
I have the Chipamp as we purchased them around the same time sooo many years ago.
I am out in my shop looking everything over and it appears to me I will only be using the small power PCB and not the other 2 boards that came with the kit. It also appears I may need to install a few more parts on it.
I am going to grab a few pictures in a second and get them attached so you folks can see what I am referring to.
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That's OK, you will still appreciate this unit. I finished it, the BA3 FE and BA3 power amp around same time. I remember noting that the combination elevated my system WAY beyond the previous set up. The Phono preamp has lots of gain. With it B1, Pearl 2, and F5 drove my bedroom system at the time with 85 dB speakers louder than I needed by some margin.
What phono Cartridge will be used?
Russellc
What phono Cartridge will be used?
Russellc
Looks like 5 mV output. May be a little high for Pearl 2's input in Standard format. Several here have made the adjustments. Some have used little sockets for different resistors. My current cartridge is a high output moving coil, but only 2.3 or do output and works fine. Previous to this was a Shure with about 4 or 5 mV output and I thought was fine. Others have found the front end a touch over loaded. Not difficult to remedy.
Russellc
Great, thank you very much.
I will need to find one of those little devices so I can swap out the resistor for the cart.
I am also going to get two cases ordered here soon. One for the Pearl, B1 and motor controller. Than the second one for the transformer, PS and a little transformer for the motor controller.
I also have to investigate how to get a three position switch working, for off, TT and CD. And figure out the wiring so when I go to the CD it bypasses the Pearl.
Lots of stuff to do.
Leave the snubbers out of the power supply. I’ve tried with and without...sounds better without.
Does anyone know what resistor value I need to get 72db of gain? I am going to use an Audio Technica Art 7 that has a .12v output, which is quite low, so any suggestions of what is a good amount of gain would be appreciated as well.
The recommended load is 100ohm minimum by the way. Thanks
The recommended load is 100ohm minimum by the way. Thanks
Gain of the second stage is 40dB, first stage (net of the RIAA network) of 15dB = 55dB -- you need to get the second stage gain up to 52dB. You can try 270R and 220R for R14.
I would short the input of the phono preamp, and look at the output to make sure that it isn't oscillating with the second stage gain so high. I would be happier if you used a step up transformer. (I can look at it with my Pearl next week with the network analyzer to check for stability.)
Depends upon the leakage inductance of the transformer you're using, the judgment isn't generic.
Jack the diyAudio Universal Power Supply Board has two different ckts in two different places, and calls them both "snubbers".
In my opinion it's wise to install the red ones and omit the blue ones.
edit- I suspect the blue ones are there because one or more diyAudio members requested them ... and the board isn't universal unless it does everything that anybody ever proposed. So they're on the board, which gives you the builder the choice to populate them or not, at your discretion.
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In my opinion it's wise to install the red ones and omit the blue ones.
edit- I suspect the blue ones are there because one or more diyAudio members requested them ... and the board isn't universal unless it does everything that anybody ever proposed. So they're on the board, which gives you the builder the choice to populate them or not, at your discretion.
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I'd go with 300R on R14 and see if it's enough gain. Depends on your preamp/amp combo. I run .2mV and don't lack for gain.