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Old 1st December 2005, 03:40 PM   #1
Buhl is offline Buhl  Denmark
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Default Top ten ways to better a Pearl ?

In the spirit of the earlier post: "Top ten ways to better an aleph" - I will try and launch this subject, something I think will be of interest for the many people that have build the excellent Pearl Riaa.

Here are my ideas - although they dont count to ten....

1. Using a battery for voltage ref. instead of Zener diode

2. oversizing the external PSU, using CLC og CRC filter, and bypassing all caps (also the onboard) with small polyprops. External PSU located far from the RIAA it self.

3. More BIAS to the 2SK170, by lowering the source rsistor from 22 to 18 ohms ?

4. Bigger/better caps for output coupling ?

5. Copper shielding of the whole circuit

Thats only five - any other ideas / suggestions ?


Cheers !
Buhl
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Old 1st December 2005, 04:24 PM   #2
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Default More ideas

1. Match up the current for the 2SK170 and the 389. All mine were all over the place straight from the Q pack.
2. I used mumetal shielding for the box.
3. Blackgate NX work great on the output
4. Better signal wiring. First used DNM wire, replaced with XLO with very positive results.
5. After feeding it with a CLC, try raising the input voltage. The energy stored in those three 10K caps can juice up the circuit a little.
6. If using a LO MC, make a copy of the first gain stage to amplify. Tried a transformer, and it was not very good. Too much input capacitance with the four 2SK170's.

George
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Old 1st December 2005, 06:08 PM   #3
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Skip the 22 Ohm resistors
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Old 1st December 2005, 06:40 PM   #4
Stefano is offline Stefano  Italy
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Use LC filtering!
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Old 2nd December 2005, 11:54 PM   #5
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Hi !

Here is an idea I got from an article by Jean Hiraga:
Try lowering the voltage over the FETs ( and increase it over the bipolar ). You can go as low as around 3 volts. This reduces Igx , excesive gate current. It worked well for me in a Monster. Gave a more natural sound with more wood in wood instruments , more brass in the brass etc.

Thorsten ( another one )
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Old 3rd December 2005, 12:10 AM   #6
steenoe is offline steenoe  Denmark
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Hans, I dont even get the idea of bettering the Pearl!! I have nothing to complain about The sound of the Pearl is just marvellous About better supply filtering: there is no supply noise whatsoever! So what would you make better?? CRC CLC whatever, if there is no noise at all, what difference would it make? If you have trouble with the Pearl, its probably in your grounding scheme I dont think you can easily better this one Its about the most silent RIAA I have ever heard The soundstage is just outragous No humm, no hiss, no noise, if its connected in the right way I just love the sound of the Pearl!

Steen
Edit: You cant just drop the source resistor!! Your J-fets wont have the right working point!!
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Old 3rd December 2005, 12:23 AM   #7
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Hi Steen ,
can you please share a little bit about the other Single-Stage
Phono -Amp in the other Thread ?

Jürgen
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Old 3rd December 2005, 12:25 AM   #8
steenoe is offline steenoe  Denmark
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Hi Jurgen Its you again I will post some more in the RIAA for BoZ thread Ok with you?

Steen
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Old 3rd December 2005, 12:28 AM   #9
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Yes , shure !

Jürgen
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Old 3rd December 2005, 12:37 AM   #10
steenoe is offline steenoe  Denmark
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Hi Jurgen Its you again I will post some more in the RIAA for BoZ thread Ok with you?

Steen
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