I'm starting to get interested in these two projects as well. I've been thinking of them for a while.
-Chris
-Chris
You've got enough experience to build the Pearl 2, and it's a fantastic phono preamp, so go for it!!
Also, buy a couple extra ZVP3310, they are incredibly static sensitive and about 75% of builders blow one during construction. Have them on hand right away. 😀
Either I have been extraordinarily lucky, or I have some mystical protection against electrostatic charge, but I’ve soldered several tens of ZVP3310 and ZVN 3310 parts without a single blown FET. My favorite FET for DAC IV Stage, not to mention my Pearl II. I just touch the metal leg of my workbench before soldering each FET leg.
Hi guys, where can i buy pcb, or where can i find the gerber files?
Thank you so much for who can help me.
Thank you so much for who can help me.
Some news of my faulty Pearl2 channel (intermittent left channel failure):
It seems that now, when the problem appears, it's here to stay: The sound never come back alone.
I've noticed some things:
-P1 is trickier to set on the faulty board. On the good board, I set it to zero once and never had to touch it for months. On the faulty board, there's a slight drift.
-turning the Pearl OFF then ON makes the sound coming back.
-when the board is deffective, I can hear a sound in the speaker (some kinf of hiss) when I approach my hand from the cartridge.
-Once, I managed to make the sound coming back when trying to measure voltage between ground and R31.
-Another time, I only touched R31 lead with an unplugged probe of the DMM (a mistake, I thought it was plugged) just after setting P1 and the sound came back.
What do you think of that?
It seems that now, when the problem appears, it's here to stay: The sound never come back alone.
I've noticed some things:
-P1 is trickier to set on the faulty board. On the good board, I set it to zero once and never had to touch it for months. On the faulty board, there's a slight drift.
-turning the Pearl OFF then ON makes the sound coming back.
-when the board is deffective, I can hear a sound in the speaker (some kinf of hiss) when I approach my hand from the cartridge.
-Once, I managed to make the sound coming back when trying to measure voltage between ground and R31.
-Another time, I only touched R31 lead with an unplugged probe of the DMM (a mistake, I thought it was plugged) just after setting P1 and the sound came back.
What do you think of that?
Check connections of R13 (to Q4 gate and GND) And value of R13
Thanks. I'll do it tonight.
Questions - maybe stupid ones, but please help
I can't get this project out of my head.
Unfortunately VAT and customs are quite heavy in Denmark, where I live so I have wondered if there is a way to obtain the parts in Europe?
Specifically the PCB's and the transistors.
If I were to buy some LSK170 - which grade should I be looking for?
How close should they be matched?
Which grade if it was 2SK170?
Are there any other alternatives to the original parts ?
How many e.g. LSK170 should I expect to buy before I could be reasonable sure to have the adequate number of matched sets?
Is it only the 4 parallel ones that should be matched or is it all the transistors?
Are there any Gerber Files or something that could be used to make my own PCBs?
I will be very thankful for all you kind help 🙂
PS: was it not for the extra VAT and customs charge - I Think I would just order the PCBs from PassDIY
I can't get this project out of my head.
Unfortunately VAT and customs are quite heavy in Denmark, where I live so I have wondered if there is a way to obtain the parts in Europe?
Specifically the PCB's and the transistors.
If I were to buy some LSK170 - which grade should I be looking for?
How close should they be matched?
Which grade if it was 2SK170?
Are there any other alternatives to the original parts ?
How many e.g. LSK170 should I expect to buy before I could be reasonable sure to have the adequate number of matched sets?
Is it only the 4 parallel ones that should be matched or is it all the transistors?
Are there any Gerber Files or something that could be used to make my own PCBs?
I will be very thankful for all you kind help 🙂
PS: was it not for the extra VAT and customs charge - I Think I would just order the PCBs from PassDIY
2SK170BL or LSK170 B
Only the 4 in parallel at the input need to be reasonably matched.
I know the Gerber info is out there somewhere, I'll try to find it.
Only the 4 in parallel at the input need to be reasonably matched.
I know the Gerber info is out there somewhere, I'll try to find it.
Check connections of R13 (to Q4 gate and GND) And value of R13
Being ridiculously superstitious, I don't dare to thank you too quickly for your advice, but since it seems to work for the time being since I re-soldered R13.
Crossing my fingers....😀
A question converning gain: reducing R14 from 1kohms to 300ohms increase the gain from 55dB to 65dB.
Is it possible to go higher by reducing R14 again, or will it cause problems to the circuit?
Is it possible to go higher by reducing R14 again, or will it cause problems to the circuit?
Bet you haven't seen this before:
Output impedance of the first gain stage -- about 416 ohms. I would have though it was lower. (I used two different coupling capacitors -- that's why the curves vary at low frequency.)
This will (should) affect the values of the passive RIAA compensation network.
Output impedance of the first gain stage -- about 416 ohms. I would have though it was lower. (I used two different coupling capacitors -- that's why the curves vary at low frequency.)
This will (should) affect the values of the passive RIAA compensation network.
Attachments
folkdeath, at really high amounts of gain you would be better served by a Pre-Preamplifier (head amp) or transformer.
What cartridge are you using?
What cartridge are you using?
It was a theorical question. 😉
I use a modified DL103. 65dB is OK for me (the pot of my amp is at 12 o'clock for normal listening level).
I use a modified DL103. 65dB is OK for me (the pot of my amp is at 12 o'clock for normal listening level).
Dip switch for selection of load (MC)
Would it have (significant) bad impact on sound quality if the optional load resistor at input was made up of at list of resistors connected to a dip switch in order to have the opportunity to change the load?
My idea would be to have a small board with the switch - either at some stands glued to the PCB or right behind the input RCAs...
Another thing : what about having more inputs - and a rotary switch like ELMA in order to be able to have more turntables connected at the same time?
Finally : those of you that are using low output MCs - are you using the Pearl 2 without SUT or prepre?
I have been so lucky that I have bought a set of unfinished Pearls from a fellow member of our community - and now I am Loki g forward to finish the build.🙂
Would it have (significant) bad impact on sound quality if the optional load resistor at input was made up of at list of resistors connected to a dip switch in order to have the opportunity to change the load?
My idea would be to have a small board with the switch - either at some stands glued to the PCB or right behind the input RCAs...
Another thing : what about having more inputs - and a rotary switch like ELMA in order to be able to have more turntables connected at the same time?
Finally : those of you that are using low output MCs - are you using the Pearl 2 without SUT or prepre?
I have been so lucky that I have bought a set of unfinished Pearls from a fellow member of our community - and now I am Loki g forward to finish the build.🙂
DIP switch for input loading would work well, it's been done before.
The selector switch idea is good, I don't think it would be a problem.
The selector switch idea is good, I don't think it would be a problem.
Pass Labs use dip switches on the XP-15 for adjusting load, so they must be ok.
I use a cartridge with .4mV output and no SUT setup with Pearl II.
I use a cartridge with .4mV output and no SUT setup with Pearl II.
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