I recall Wayne mentioning that it was really difficult to overload the input of the Pearl2. Try it in a stock configuration or maybe with a reduced gain and see if it's an issue. I bet it won't be.
I will show my wife - maybe she will OK a Dynavector 10x5.
You will love that cartridge. I had one for awhile, (well, a 10x4...) and kick myself for getting rid of it. The only reason why I don't have another is that I am saving for a Shelter 501, which is twice the price.
Having listened to the Shelter a lot and by owning a 10x4 among others I can attest to its being very good for its price but also that you do very well to go for a 501. Its very musical in tone, still having much resolution but in a mellow manner. Like a Lyra gone holidays to the Caribbean sorta.
Big Blue LEDs
The big blue LEDs are power indication for plus and minus power into the preamp chassis. I picked the biggest ones Radio Shack stocked so that I could see the glow through the ventilation slots. I "overachieved" so I had to bend them over to shine on the back wall of the chassis ! They DO look cool with the lights down low ! (Kinda like the spaceship set of "Alien", the classic sci-fi flick)
BTW, even with bleeder resistors across the caps, this thing holds charge for a long time. The LEDs are on for a couple minutes after I turn the AC off. Use caution when unplugging the umbilical !
The big blue LEDs are power indication for plus and minus power into the preamp chassis. I picked the biggest ones Radio Shack stocked so that I could see the glow through the ventilation slots. I "overachieved" so I had to bend them over to shine on the back wall of the chassis ! They DO look cool with the lights down low ! (Kinda like the spaceship set of "Alien", the classic sci-fi flick)
BTW, even with bleeder resistors across the caps, this thing holds charge for a long time. The LEDs are on for a couple minutes after I turn the AC off. Use caution when unplugging the umbilical !
If you're looking for a quick way to get started on the Pearl2, here's an easy way to 3/4 of the way there!
Pearl1.5
The power supply simplicity of the of the Pearl2 and the 2nd stage simplicity of the Pearl1 ! Ladies and gentlemen, a hybrid ... the Pearl1.5!
It lives! And sounds beautiful!
http://www.diyaudio.com/forums/anal...l2-pcb-but-havent-started-yet-pearl1-5-a.html
Cheers,
Jeff
Pearl1.5
The power supply simplicity of the of the Pearl2 and the 2nd stage simplicity of the Pearl1 ! Ladies and gentlemen, a hybrid ... the Pearl1.5!
It lives! And sounds beautiful!
http://www.diyaudio.com/forums/anal...l2-pcb-but-havent-started-yet-pearl1-5-a.html
Cheers,
Jeff
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Interesting! And a great use of the PCB. I honestly like to see things used in a way different than intended.
You kinda lost me on the description - you say the PSU is similar to the 2, but looking at it, there seems to be only one regulator, and it looks to be a single supply... How do you have it wired?
I would love to see a schematic of your circuit! Can you draw it out?
You kinda lost me on the description - you say the PSU is similar to the 2, but looking at it, there seems to be only one regulator, and it looks to be a single supply... How do you have it wired?
I would love to see a schematic of your circuit! Can you draw it out?
Pearl1.5
1st stage from the Pearl2
Positive Power supply from the Pearl2
2nd stage from the Pearl1
The 2nd stage from the Pearl1 uses the Positive Power supply on the Pearl2 PCB.
Instead of using the dual 389FET in the Pearl1, I used two 170s in parallel (like 1in the first stage of the Pearl2)
I'll try to draw up a schematic ...
Cheers,
Jeff
1st stage from the Pearl2
Positive Power supply from the Pearl2
2nd stage from the Pearl1
The 2nd stage from the Pearl1 uses the Positive Power supply on the Pearl2 PCB.
Instead of using the dual 389FET in the Pearl1, I used two 170s in parallel (like 1in the first stage of the Pearl2)
I'll try to draw up a schematic ...
Cheers,
Jeff
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Hi dcbingaman,
when you use 50R and 100R for the loading, they will be in parallel with the base 47K on the PCB, so the total loading for each switch position will be:
load 1: (50 x 47K)/(50 + 47K)
load 2: (100 x 47K)/(100 + 47K)
Is this correct?
Kop89, yes that is correct. In reality, the values you calculate will be so close to the desired load values that you just use them instead....the cartridge sees the 50 ohm resistor across the switch, and the voltage produced drives the much higher impedance of the input stage. In this way you can get three values from one 2PDT switch with a center off position - in your case: 50 ohms / 47K ohms / 100 ohms.
I picked values based on the two MC's and the MM I use most often - 50 ohms for an Ortofon Synergy SPU, 150 ohms for a Shelter 90X, and 47K ohms for a Clearaudio Maestro.
You can do the same with capacitance as well - shunt the input at the switch with those little polystyrene caps or silver mica caps to get XXX pf on either side, and use the center off position for MC's where you want to minimize input capacitance.
I picked values based on the two MC's and the MM I use most often - 50 ohms for an Ortofon Synergy SPU, 150 ohms for a Shelter 90X, and 47K ohms for a Clearaudio Maestro.
You can do the same with capacitance as well - shunt the input at the switch with those little polystyrene caps or silver mica caps to get XXX pf on either side, and use the center off position for MC's where you want to minimize input capacitance.
Thank you dcbingaman, your connection diagram has been very helpful.
I plan to use Ortofon 2M Blue, so maybe 45dB gain will work best. Recommended resistive loading is 47K, and capacitance loading is 150-300pF. Considering capacitance already in tonearm cable, what kind of capacitor value do you think I can try for the loading?
There is no proper answer to the ?Transformer or no Transformer? question... It's a matter of taste. Some combinations will sound better with it, some without, and in every case it will be your preference that matters.
Try the 103 with the transformer into the Pearl, you are not going to overload it. It will most likely be awesome!
Try the 103 with the transformer into the Pearl, you are not going to overload it. It will most likely be awesome!
Most tonearm cables are enough for 'normal' cartridges. If you want to try adding some capacity to the input, start small. Maybe 50-100pf. Add to taste.
Also, please report your findings back here, we will be curious as to how your tuning goes!