Those unselected fets are noisy! Does it make a sonic difference? We'll find out in Season 2. To me, if you tend to go all out with your builds and sprung for burson v7v you might as well go for low noise CCSs.
Sad part is that US semiconductors companies are now like airlines (maybe have been for a while), if you want to get low noise parts, or to pick your seats on the plane, you have to pay extra. That, or you get 'boarding group 8' parts.
j112+Pearl 3 Matching -- Act II
After getting my spare P3 matched and doing some listening, decided that there was significant change and, so, matched my second P3 that is active here in my winter system. Here's some information meant to help prospective "matchers" along with the much-awaited listening details.
First, here are the matching tools. Got these in order to match the transistors in the BA2018 preamp and fashioned a simple jig that makes measuring many parts easier. You can use a simple MM with your own circuitry and bread board -- if you've got the parts and design. I have found that the soldering bread boards are the best for my needs. This JPeg shows the retail Peak components that make the process straightforward (but a little pricey -- about $200 for the analyzer and SOT23 -- the latter is required for SMD testing). This testing jig will work for all of the transistors in the Pearl 3 and will be reporting on the SMD matching down the line. This jig will not, unfortunately, measure power amp Mosfets -- they require more voltage/current than the Peak can generate.
Ordered 10 premium J112s from Mouser ($31.40 -- https://www.mouser.com/ProductDetail/106-J112) and the first two were almost perfectly matched -- which led me to conclude and state in my first posting above that these premium J112s were closely matched. This was incorrect; the next 8 checked had fairly severe differences and were able to produce only one more acceptably-matched set. Disappointing news here and I suggest that if you are matching a single P3 you order at least 5 of the 106-112s.
Also ordered 100 of the lower cost 512-j112s ($15.30 -- https://www.mouser.com/ProductDetail/512-J112). The first 10 checked did not match at all. Out of the second ten, got one close match and it is shown in the 512-J112sMatched JPeg below. So, if you want to save a few bucks you could order 10 or 20 of the 512-J112s and probably get at least one close-matched set.
Am also concerned with noise (as shown below in the listening info below) and, so, went with another set of two 106-J112s. The entire process of changing R27 and J112 is simple and only requires that you have some kind of desoldering tool. Have gotten addicted to the Hakko 301 through reccos above but should note that it is both pricey and requires significant maintenance.
So, FINALLY! Time for the listening analysis.
Let's start with the good news...
RING! RING!
Oh no, not the phone...
It's an auto message from Mia's FI dog collar (damn).
She's gotten out of the backyard and is heading east. Got to track that Siberian down before she gets out of the subdivision.
Will be back directly with your listening info...Honest!!!
After getting my spare P3 matched and doing some listening, decided that there was significant change and, so, matched my second P3 that is active here in my winter system. Here's some information meant to help prospective "matchers" along with the much-awaited listening details.
First, here are the matching tools. Got these in order to match the transistors in the BA2018 preamp and fashioned a simple jig that makes measuring many parts easier. You can use a simple MM with your own circuitry and bread board -- if you've got the parts and design. I have found that the soldering bread boards are the best for my needs. This JPeg shows the retail Peak components that make the process straightforward (but a little pricey -- about $200 for the analyzer and SOT23 -- the latter is required for SMD testing). This testing jig will work for all of the transistors in the Pearl 3 and will be reporting on the SMD matching down the line. This jig will not, unfortunately, measure power amp Mosfets -- they require more voltage/current than the Peak can generate.
Ordered 10 premium J112s from Mouser ($31.40 -- https://www.mouser.com/ProductDetail/106-J112) and the first two were almost perfectly matched -- which led me to conclude and state in my first posting above that these premium J112s were closely matched. This was incorrect; the next 8 checked had fairly severe differences and were able to produce only one more acceptably-matched set. Disappointing news here and I suggest that if you are matching a single P3 you order at least 5 of the 106-112s.
Also ordered 100 of the lower cost 512-j112s ($15.30 -- https://www.mouser.com/ProductDetail/512-J112). The first 10 checked did not match at all. Out of the second ten, got one close match and it is shown in the 512-J112sMatched JPeg below. So, if you want to save a few bucks you could order 10 or 20 of the 512-J112s and probably get at least one close-matched set.
Am also concerned with noise (as shown below in the listening info below) and, so, went with another set of two 106-J112s. The entire process of changing R27 and J112 is simple and only requires that you have some kind of desoldering tool. Have gotten addicted to the Hakko 301 through reccos above but should note that it is both pricey and requires significant maintenance.
So, FINALLY! Time for the listening analysis.
Let's start with the good news...
RING! RING!
Oh no, not the phone...
It's an auto message from Mia's FI dog collar (damn).
She's gotten out of the backyard and is heading east. Got to track that Siberian down before she gets out of the subdivision.
Will be back directly with your listening info...Honest!!!
Attachments
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I did match all parts in my PEARL 3 builds from left to right channel.
I matched all my JFets in the inputstage (Toshiba 2SK209GR).
All resistors and caps have been measured and matched.
The active devices have been matched with a PEAK ATLAS DCA75PRO and adapter.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html#SID=24
https://www.peakelec.co.uk/acatalog/pca23-peak-component-adapter-sot23.html#SID=27
The results soundwise are excellent. But the circuit itself does most. Some testing of OPAmps... let your ears decide.
Those efforts on measuring and testing active devices and resistors, caps,... this is the last little step up. A small step, but...
Cheers
Dirk
I matched all my JFets in the inputstage (Toshiba 2SK209GR).
All resistors and caps have been measured and matched.
The active devices have been matched with a PEAK ATLAS DCA75PRO and adapter.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html#SID=24
https://www.peakelec.co.uk/acatalog/pca23-peak-component-adapter-sot23.html#SID=27
The results soundwise are excellent. But the circuit itself does most. Some testing of OPAmps... let your ears decide.
Those efforts on measuring and testing active devices and resistors, caps,... this is the last little step up. A small step, but...
Cheers
Dirk
Attachments
And it is well known, that J112 and J113 spread pretty wide in their values. Also from one batch.
Cheers
Dirk
Cheers
Dirk
Hello..
I have been absent for some time now, due to some life complications, life seems to do that every decade of so.
Here is my pearl, built in to an old prema 5000 multimeter chassis. Everything is matched left and right, i went another path, on psu side,
I used common mode indiuctors , to clean up any ac ripple, and 20000uf pr monoblock to ensure low impedance on Audio spectrum, it is fed by external psu, which is classic dual mono toroids, feeding into crcrcrc, then feeding a low noise series regulator.
I have been absent for some time now, due to some life complications, life seems to do that every decade of so.
Here is my pearl, built in to an old prema 5000 multimeter chassis. Everything is matched left and right, i went another path, on psu side,
I used common mode indiuctors , to clean up any ac ripple, and 20000uf pr monoblock to ensure low impedance on Audio spectrum, it is fed by external psu, which is classic dual mono toroids, feeding into crcrcrc, then feeding a low noise series regulator.
Hello amplidude,
nice work! I like the copper-shielding around each pcb of the phono pre-section. Dual mono construction and lots of
filtering in the PSU. I would say - a good recipe for silence out of the PSU and good sound out of the PEARL 3.
Cheers
Dirk
nice work! I like the copper-shielding around each pcb of the phono pre-section. Dual mono construction and lots of
filtering in the PSU. I would say - a good recipe for silence out of the PSU and good sound out of the PEARL 3.
Cheers
Dirk
Hi cubic.
Photo is not showing the lid on each pcb, but they are totally in closed boxes.
I hope so. Theese past days i have made a reverse riaa, and some nice sets of phono to bnc, i will do some testing, to see riaa curve, and gain, on my oscilloscpe, and test it further on quantasylum tester, it is rather difficult to test at theese high gains, noise is everywhere.
As to the jfets i notice many use dca tester, but it seems to be very limited in current, so i tested in the old fashioned way, on an 6.5 agilent, and at the expected currents,Hooked to my pc., as a ccs from a lab supply, let the det settle for a few minutes, the let software take ten thousand readings, and take the average reading as its final reading , matching is very tight, is it makes a difference who knows, but i sleep better.
I will post some pics later of the psu part.
Stay safe.
Ps while measuring i noticed the coupling caps picked up lots of noise with my hands moving around, so i made some grounded copper shields around them. After that much more silent
Photo is not showing the lid on each pcb, but they are totally in closed boxes.
I hope so. Theese past days i have made a reverse riaa, and some nice sets of phono to bnc, i will do some testing, to see riaa curve, and gain, on my oscilloscpe, and test it further on quantasylum tester, it is rather difficult to test at theese high gains, noise is everywhere.
As to the jfets i notice many use dca tester, but it seems to be very limited in current, so i tested in the old fashioned way, on an 6.5 agilent, and at the expected currents,Hooked to my pc., as a ccs from a lab supply, let the det settle for a few minutes, the let software take ten thousand readings, and take the average reading as its final reading , matching is very tight, is it makes a difference who knows, but i sleep better.
I will post some pics later of the psu part.
Stay safe.
Ps while measuring i noticed the coupling caps picked up lots of noise with my hands moving around, so i made some grounded copper shields around them. After that much more silent
A few shots of the chassis and my trusted helper.
If you wonder about the jack connector, it is the remote on/off, i had difficulty finding multicable that fitted connector.
If you wonder about the jack connector, it is the remote on/off, i had difficulty finding multicable that fitted connector.
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Well..... might be useful to some, but I went another way with this particular issue from the first build.
Plucked out 2 pins from a DIP.socket, and soldered them to the holes of R27. Much easier to replace R27 to
obtain correct value. When satisfied with the result, I just soldered the desired resistor to the socket pins.
Eager to hear your impression soundwise of the standard match of J112´s vs perfectly matched J112`s 😉
Thanks Mark...... or.....
I´m 71 now, so if you´re trying to introduce me to something "new"....... try again 😆😆
Since I´m obviously challenged to express myself further..........
I have 4-5 lifetimes worth of DIP-8/16/24 sockets floating around, so breaking one or two up for whatever purpose when necesary,
is juuuuuust a little bit cheaper (for me), than keep ordering more stuff..
My then old... and very cheap boss, back in the 70´s when i was an apprentice told me:
"If you don´t have, what you need, then use what you have" 😉
Also, 99.9% of the general population are happy to listen to spotify on ipods(?). We try to do things a little different around here.