I have not tried Silent Switcher yet with Pearl 3. I have used it with the Pete Millett @pmillett LR phono, http://www.pmillett.com/LR_phono.html and it’s amazingly quiet, the SS is powered from a USB battery pack. Photo attached.
When I build Pearl 3 with Silent Switcher, the plan is to have it all in the same chassis.
If you used a USB brick to supply the SS I’m sure the normal admonition applies of keeping the power supply well away from the RIAA boards to minimize noise.
When I build Pearl 3 with Silent Switcher, the plan is to have it all in the same chassis.
If you used a USB brick to supply the SS I’m sure the normal admonition applies of keeping the power supply well away from the RIAA boards to minimize noise.
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but you have a single-ended output on the Pearl.
the balanced connection is there to feed a balanced input on a preamp, no?
the balanced connection is there to feed a balanced input on a preamp, no?
Sure. My question is, can the balanced output circuit be used behind any SE preamp (if I build it separately with the DRV135 and the caps). I meant it not in connection with or as part of the Pearl.
DRV134/135 and THAT1646 can certainly be used as a general purpose balanced line driver.
The biggest downside is the relatively low input impedance of these chips. It is generally a good idea to include a buffer before the line driver IC, especially if a volume control is desired.
The biggest downside is the relatively low input impedance of these chips. It is generally a good idea to include a buffer before the line driver IC, especially if a volume control is desired.
With respect to "Mains" interference (which is not noise, 50 or 60Hz) it's electromagnetic coupling AND all the harmonics of the line frequency. To a large extent you can mitigate this (somewhat) with a steel chassis, better yet, a Danish cookie tin inside a steel chassis. The steel chassis connected to the "Line Ground". I said mitigate, not eliminate!
ADI advises keeping the transformer 3 feet away from their low noise amplifier in this application note (with nice pictures):
https://www.analog.com/en/resources...rement-for-a-low-noise-voltage-reference.html
ADI advises keeping the transformer 3 feet away from their low noise amplifier in this application note (with nice pictures):
https://www.analog.com/en/resources...rement-for-a-low-noise-voltage-reference.html
Many thanks! Yes, I would use a (tube) buffer in front of the balanced line driver.
And now back to the Pearl 3 😁
If you are going for a vacuum tube preamp, a line output transformer may be a better way to go.
The input impedance of the DRV134/DRV135/THAT1646 is about 10k. Which is going to be too low for many vacuum tube preamp designs. Look for designs that use a cathode follower output stage, or add an opamp before the line driver IC.
The input impedance of the DRV134/DRV135/THAT1646 is about 10k. Which is going to be too low for many vacuum tube preamp designs. Look for designs that use a cathode follower output stage, or add an opamp before the line driver IC.
I bought the Pearl 3 kit when it was avail at the store, planning to build it this Fall.
I just remembered I have Six LSK389B that I got some years back from another guy who was bailing out of a Balanced MC phono project.
Is the Pearl 3 the time and the place to put these to use? They are in TO-71 packages and the leads are long enough to straddle the holes in the PCB.
What source resistance should I use, and are these a worthy upgrade over the 2SK209 that came with the kit?
I just remembered I have Six LSK389B that I got some years back from another guy who was bailing out of a Balanced MC phono project.
Is the Pearl 3 the time and the place to put these to use? They are in TO-71 packages and the leads are long enough to straddle the holes in the PCB.
What source resistance should I use, and are these a worthy upgrade over the 2SK209 that came with the kit?
I was reading the data sheet for THAT1646. Looks like there can be up to 250mV offset on the balanced out. Datasheet says that additional capacitors are needed between sense and output pins. Look at Page 7:
"Output DC offset: Because the 1646's outputs are connected directly to their respective sense inputs, this circuit may produce up to 250 mV of common-mode dc offset at its outputs."
THAT_1606-1646_Datasheet.pdf
It's helpful to read Texas Instruments "Noise Figures Confusing" on the Texas Instruments website -- an application note written by (I think) Bob Pease in 1974, AN-174. https://www.ti.com/lit/an/snva515c/snva515c.pdf
After reading the ApNote, you should be able to calculate Ein from NF using the following graph:
Attachments
Hi,
I mounted the new Audio Technica AT33Sa 😍
Wow, the sound is now amazing! It's really time for a chassis
I mounted the new Audio Technica AT33Sa 😍
Wow, the sound is now amazing! It's really time for a chassis
I see.... 2SK209 is actually a better part! I did some more research on LSK389
LSK389 Re-Release (2020 PR)
In 2020, Linear re-released this part following new testing steps in their process. The parts I have are from way before that era. I guess the only real advantage to use the LSK389 is the tightly matched pairs in one package.
How about a Canadian cookie tin and a 1/4" thick Canadian aluminum extrusion?
While I began this project thinking about using a cookie tin that I had on hand when I happened on the 5" x 5" extrusion I've been leaning to using just the extrusion. Would it be better to stick with the original plan?
As the photo shows I can be flexible.
