Thanks for asking! Really well id say. Boards are stuffed, and heatsinks are isolated with that graphite stuff and nylon bolts (glad i thought to replace the metal bolts!). The case is all machined (drill press) and parts, knobs and such are installed for selectable gain and loading settings.. Soldering looks good to me, for a beginner... Wiring is almost complete.. Just waiting for some wire as I was short wiring.
As you know, My power supply was giving me trouble, so i got myself a new transformer (dual 22 instead of the split 24) and im glad i did. The dual secondaries and lower voltage have made things easier. The power supply at the moment appears to be putting out about 32v now instead of 40v so i wont need to adjust the voltage. But i still need to get it fully wired up before i can tell. ive simplified it by removing the crc filter and pared it down to a single 10,000uf cap per rail. Since id roasted one of my 6800uf caps i had an odd number of them so had to use what i have. the 10,000's are big kw fine golds so in interest of space im going to get it up and running with just the one per rail for now. Just neeed to finalize the wiring as i patched it up promptly to test it. If it works i might add another 10,000 per rail and a reisitor to make the crc again... But we'll see.. Its tight.
Should have the power supply up and tested tonight.. and Lastly hook up the power and test the board throught the bulb tester and set the voltage bias to zero.
Im really excited and its so cool to have what looks to be a nice piece of kit made by hand!
ahhhhhha the sweet sweet music!
The Pearl II sounds FAN-TASTIC!!!
I have it playing a Fidelity Research FR1 Mk3f MC cartridge my uncle and I just set up (what a nice gift! this cart is incredible!!) and its playing through though a pair of B&W 804's. it sounds incredible. Tone is wonderful, balanced, neutral. Upon my first test drive i had some imbalance in the channels, but my brilliant uncle chimed in "ill bet you 99% chance that one of your Right channel is out of phase with the other." Sure enough, the inputs where backwards on the right. Once that was fixed the stereo image improved and IM so pleased! Thanks for all your help with this project 6L6, bnorrish, omishra, and all others who chimed in with thoughts and guidance.
... one question though.. id love to hear input.... Mine has the usual solid state hiss one gets when turning the knob up... but the pearl seems to be producing a significant bit more than most components i've heard. Is there a way to reduce the hiss? does it improve with time? is the hissing noise normal? if there was anything id change id want for a darker, quieter background. ..thoughts?????
The Pearl II sounds FAN-TASTIC!!!
I have it playing a Fidelity Research FR1 Mk3f MC cartridge my uncle and I just set up (what a nice gift! this cart is incredible!!) and its playing through though a pair of B&W 804's. it sounds incredible. Tone is wonderful, balanced, neutral. Upon my first test drive i had some imbalance in the channels, but my brilliant uncle chimed in "ill bet you 99% chance that one of your Right channel is out of phase with the other." Sure enough, the inputs where backwards on the right. Once that was fixed the stereo image improved and IM so pleased! Thanks for all your help with this project 6L6, bnorrish, omishra, and all others who chimed in with thoughts and guidance.
... one question though.. id love to hear input.... Mine has the usual solid state hiss one gets when turning the knob up... but the pearl seems to be producing a significant bit more than most components i've heard. Is there a way to reduce the hiss? does it improve with time? is the hissing noise normal? if there was anything id change id want for a darker, quieter background. ..thoughts?????
Mine hisses too, al little bit more than ther MC input of my Sony amp. It is the only thing that I would like to see improved (though you need to hold you ear near to the speakers to hear it). Of course it hisses more than the other inputs of the amp, but that is because of the extra gain. If yours hisses a lot, maybe something is wrong. I had that with the first channel that I completed and that turned out to be a defective ZVP 3310 (mind you, it did put out music, only with too much hiss to be normal)
Great news!!! Congratulations on your project making music!
Hiss -
Did you verify that all the voltages are correct as compared to the schematic with the voltage notation? (Place the black lead of your DMM on power ground and probe around with the red lead set to DC volts.)
Did you adjust the pot to get zero volts at the test pad? Is that point stable?
Do you have any output offset?
Is C7 installed?
Please post well-lit, in-focus photos so we can take a look at it.
Lastly, do you have any hummm on the outputs?
Hiss -
Did you verify that all the voltages are correct as compared to the schematic with the voltage notation? (Place the black lead of your DMM on power ground and probe around with the red lead set to DC volts.)
Did you adjust the pot to get zero volts at the test pad? Is that point stable?
Do you have any output offset?
Is C7 installed?
Please post well-lit, in-focus photos so we can take a look at it.
Lastly, do you have any hummm on the outputs?
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Photos to come. Ive taken them just need to get them on the computer.
So... I started checking the voltages for the left channel as per the diagram and recording them. Funny thing though. When i was done, that channel no longer is playing music or hissing.. Just a very very low output in the tweeter...! this hiss is rather Annoying when the record isn't playing.
With all other stereo equipment off here are the readings:
Pearl voltages (over one minute)
Left
+dc pad: 30.87 to 30.98
-dc pad: -32.15 to -32.29
+ Rail at R4: 24.02 to 24.03
- rail at R10: -23.65 unvaried
P1: +25mv to - 23mv fluctuating/drifting up and down. One sample saw fluctuations of +- 300mv
R6 1.606v
R9 20.05v
C15 (- side) 0 volts. (+side) -39mv to +35mv
Input: 0 mv and 0 mv
Output: sample one: -8.8 to +11mv 0mv at ground
Sample two: -20 to +13.9mv
( polar elna silmic)
Strangely, when the other equipment is on, the voltage at p1 fluctuates much much wilder... Around 1volt. Last night when i first powered it up p1 only fluctuated a couple of mvs and -may- have demonstrated less hiss than today.
Grrr! What might have happened to my left channel? I tried testing the output with a test record tone at 1khz with a multimeter set to Hz.. Which did nothing.. Produced zero. Did i make an oops?
So... I started checking the voltages for the left channel as per the diagram and recording them. Funny thing though. When i was done, that channel no longer is playing music or hissing.. Just a very very low output in the tweeter...! this hiss is rather Annoying when the record isn't playing.
With all other stereo equipment off here are the readings:
Pearl voltages (over one minute)
Left
+dc pad: 30.87 to 30.98
-dc pad: -32.15 to -32.29
+ Rail at R4: 24.02 to 24.03
- rail at R10: -23.65 unvaried
P1: +25mv to - 23mv fluctuating/drifting up and down. One sample saw fluctuations of +- 300mv
R6 1.606v
R9 20.05v
C15 (- side) 0 volts. (+side) -39mv to +35mv
Input: 0 mv and 0 mv
Output: sample one: -8.8 to +11mv 0mv at ground
Sample two: -20 to +13.9mv
( polar elna silmic)
Strangely, when the other equipment is on, the voltage at p1 fluctuates much much wilder... Around 1volt. Last night when i first powered it up p1 only fluctuated a couple of mvs and -may- have demonstrated less hiss than today.
Grrr! What might have happened to my left channel? I tried testing the output with a test record tone at 1khz with a multimeter set to Hz.. Which did nothing.. Produced zero. Did i make an oops?
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No hum, just hiss
No C7 installed
Test pad not so stable, especially this morning... yesterday was pretty stable +/- 10 mv maybe. ... today was plugged into power bar with the rest of the stereo components... now varies as noted above. +-25mv all othe equiment off, and +/- a volt with other equipment on..
What is output offset?
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If you can hear the hiss from your listening position when no record is playing, something is wrong (or you have very good ears). Maybe it is the same thing I had: a defective ZVP3310. You might try to swap that one. But if the cause of the problem lies elsewhere, you might blow just another. Voltage by setting P1 fluctuates in my channels as well. Mostly somewhere between +/- 40mV, sometimes it suddenly runs away to +/- 100mV or so, and then come back. I have set P1 after warming up the amp for some time, and now I just don't bother anymore. But a fluctuation of 1V is too much. Maybe some oscillation is going on.
What have you put in for C15? Wayne put it in the schematic for frequency compensation if needed, but the default is to leave it out. I don't think I've heard from anyone putting it in.
What have you put in for C15? Wayne put it in the schematic for frequency compensation if needed, but the default is to leave it out. I don't think I've heard from anyone putting it in.
Congratulations!
Yes, good well lit photo will help. Because I can hear hiss with 100% volume, and no record playing only while I put my ear next to tweeter ( within 1"). No more hiss or hum.
Care need to be taken - short possible component leads, wires routed away from amp stages. Specially output wires away from amp stages, input wires short.
Please see this, my build for example -
Link in post - http://www.diyaudio.com/forums/pass-labs/156397-pearl-two-215.html#post3480713
Thanks,
Yes, good well lit photo will help. Because I can hear hiss with 100% volume, and no record playing only while I put my ear next to tweeter ( within 1"). No more hiss or hum.
Care need to be taken - short possible component leads, wires routed away from amp stages. Specially output wires away from amp stages, input wires short.
Please see this, my build for example -
Link in post - http://www.diyaudio.com/forums/pass-labs/156397-pearl-two-215.html#post3480713
Thanks,
Photos: FormosaWest Gallery - My Photo Gallery
Ill add more shortly.
Theres some shots of my boards.. if it doesn't work for you let me know.
most of the time the drift is only a few mv as indicated above, but once or twice ive had wildly fluctuating several hundred mv and once around a volt up and down... no identifiable cause. when i first set the offset it fluctuated only a few mv.. when the left channel sorta went out this morning, i unplugged it from the power bar sharing the rest of the stereo and plugged it into a power conditioner in another room and its back to its +-20-30mv fluctuations.. put it pack in the stereo and the dead channel seems to have resolved itself... (?) weird.
It sounds really good, but I definatly hear substantial hiss from listening position. When music plays it shrouds the hiss significantly, but in low level passages at high volume its noticeable.. especially over the speakers. Through my bryston headphone amplifier the hiss is a lot less noticeable, but
I have the gain increased to 65db for the LO MC cartridge i'm using.
The gain resistors i have in it are 300ohm.
I have the user input resistor installed (by a rotary switch) to give 10ohm input impedance.
If you have to put your ear to the speaker to hear hiss you have WAY less hiss than I (and i'm envious). its kinda like tape hiss on an old tape..
Theres no hum unless i bring the power supply up close.
Should the output have fluctuations like the p1? ....
Ill add more shortly.
Theres some shots of my boards.. if it doesn't work for you let me know.
most of the time the drift is only a few mv as indicated above, but once or twice ive had wildly fluctuating several hundred mv and once around a volt up and down... no identifiable cause. when i first set the offset it fluctuated only a few mv.. when the left channel sorta went out this morning, i unplugged it from the power bar sharing the rest of the stereo and plugged it into a power conditioner in another room and its back to its +-20-30mv fluctuations.. put it pack in the stereo and the dead channel seems to have resolved itself... (?) weird.
It sounds really good, but I definatly hear substantial hiss from listening position. When music plays it shrouds the hiss significantly, but in low level passages at high volume its noticeable.. especially over the speakers. Through my bryston headphone amplifier the hiss is a lot less noticeable, but
I have the gain increased to 65db for the LO MC cartridge i'm using.
The gain resistors i have in it are 300ohm.
I have the user input resistor installed (by a rotary switch) to give 10ohm input impedance.
If you have to put your ear to the speaker to hear hiss you have WAY less hiss than I (and i'm envious). its kinda like tape hiss on an old tape..
Theres no hum unless i bring the power supply up close.
Should the output have fluctuations like the p1? ....
... maybe i'm over stating the hiss level.. i dont know!... at normal listening levels its audible. at high listening levels its very audible.
i wish i could demonstrate. maybe its normal...??? i dont know.
at high listening levels do you get hiss? anyone else playing with a higher gain setting?
maybe the hiss is not so bad... it seems that as i sit here its improving... perhaps the break-in process and warm up is improving things.
my only point of reference for low output MC carts in stereos is my uncles and a friend, and they both have Mitch Cotter step up transformers and control units... which are dead quiet.
can you gentlement give me a nice description of your experience of hiss so i can try and discern if what i'm experiencing is normal?
the pearl unquestionably sounds terrific. ---> fan-freaking-tastic! , absolutely. the equalization is perfect, really.
i wish i could demonstrate. maybe its normal...??? i dont know.
at high listening levels do you get hiss? anyone else playing with a higher gain setting?
maybe the hiss is not so bad... it seems that as i sit here its improving... perhaps the break-in process and warm up is improving things.
my only point of reference for low output MC carts in stereos is my uncles and a friend, and they both have Mitch Cotter step up transformers and control units... which are dead quiet.
can you gentlement give me a nice description of your experience of hiss so i can try and discern if what i'm experiencing is normal?
the pearl unquestionably sounds terrific. ---> fan-freaking-tastic! , absolutely. the equalization is perfect, really.
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Do you mean to say you hear hiss while record playing?
I feel you should test the hiss while stylus tip rested on stationary LP record. This would tell us about amount of hiss phono stage is really contributing.
IMO while playing record, empty passage may not be only pearl 2 hiss. This is very high gain, clear output and could reveal anything at the output which is supplied at input. It may be hidden by other phono stages. Also fluctuation seems okay as I can see its varying +/-7mV and sometime +/-12-14mV too. May be surrounding influencing something? Still it sounds great.
I feel you should test the hiss while stylus tip rested on stationary LP record. This would tell us about amount of hiss phono stage is really contributing.
IMO while playing record, empty passage may not be only pearl 2 hiss. This is very high gain, clear output and could reveal anything at the output which is supplied at input. It may be hidden by other phono stages. Also fluctuation seems okay as I can see its varying +/-7mV and sometime +/-12-14mV too. May be surrounding influencing something? Still it sounds great.
Have you ever tried it without all the extra wires and switches? Occam's razor and all that...
The switchwork and leads do look very nice indeed, however it might be worth a go just wired up in the most likely setup for your current cartridge.
It's a win-win for diagnostics, because if it makes no change you know your adjustability is not to blame and the boards are suspect, and if it does change than the boards are fine and the wires need attention.
The switchwork and leads do look very nice indeed, however it might be worth a go just wired up in the most likely setup for your current cartridge.
It's a win-win for diagnostics, because if it makes no change you know your adjustability is not to blame and the boards are suspect, and if it does change than the boards are fine and the wires need attention.
Your 65dB gain is some 8-9dB more than I have in my Pearl (768 en 820 Ohm gain resistors to equalize output level between the channels). So I would expect it to hiss more. Try 1k and 600 Ohm in stead of 300 Ohm and see if hiss decreases.
I can hear hiss with my ear close to the speaker, but I do not have to turn the volume up all the way to hear it. With the volume knob set to produce normal listening levels I can also hear the hiss. The same is true for the built in phono stage. From my listening position no hiss is audible, and the noise of a silent groove is higher than the noise produced by the Pearl.
So while I am curious if my Pearl is noisier than other Pearls, I just don't bother anymore. The noise is low enough not to influence the music.
I can hear hiss with my ear close to the speaker, but I do not have to turn the volume up all the way to hear it. With the volume knob set to produce normal listening levels I can also hear the hiss. The same is true for the built in phono stage. From my listening position no hiss is audible, and the noise of a silent groove is higher than the noise produced by the Pearl.
So while I am curious if my Pearl is noisier than other Pearls, I just don't bother anymore. The noise is low enough not to influence the music.
Formosa
The Fidelity Research cart you are using is a very low .14 output and very old school. I have one of these also and temporarily used it to set my gain at first. You will get better sound out almost anything with slightly more output and certainly less hiss overall than this one.
Regards
David
The Fidelity Research cart you are using is a very low .14 output and very old school. I have one of these also and temporarily used it to set my gain at first. You will get better sound out almost anything with slightly more output and certainly less hiss overall than this one.
Regards
David
Thanks omishra. I tested hiss with the record needle down, and plugged into a power conditioner. The voltage ofset is stablized and back to what seems to be normal minimal fluctuations. Thie hiss really seems to be decreaseing significantly. Others have noted this as well and asked what i did to reduce the hiss and all i could say is "nothing!" ... Its really decreased alot. Thanks for telling. Me about your fluctuations. Today im around +_ 14mv and yesterday evening was good too.
Haven't tried it without all the wires or switches, but i did experimentally isolate them with grounded aluminum foil to see if it was noise radiating from the regulators and there was no perceivable difference. I did move the wires up away from the transistors And regulators as much as possible. I may experiment by wiring in the values directly to see if it improves things further. things seem to be improving with time and its possible that a significant portion of this hiss is from the preamp, which i examined with an empty input, which demonstrated about 30-40% of the hiss, which has me think that my pearl may be only adding some. I don't hear hiss in the music at all anymore. Tonight i a/b'ed it with the rotel's phono section and at roughly equivalent volume levels the hiss was comparable and of better quality in the pearl! On top of that, the sound quality difference was wayyyy nicer on the pearl. The Rotel sounded tinnier and thin, the pearl more robust, warm, natural and full-bodied.
Perhaps it was just growing pains or something in the environment! Today its just singing! If i manage to reduce it further with any sort of intervention i will be sure to report back. But for the record, shielding all the internal switch wires didn't seem to improve anything. The switches are high quality silver contacts.
As mentioned above, my drift at p1 is much better today. Im still curious about the drift on the output though. If you hear or learn anything of interest about that id love to hear about it.
I really want to thank you for all the support you've given me and the rest of us daring to challenge ourselves and build our own hifi! You were joking. The pearl really does sound special!
Im leaning toward this very same conclusion! Thanks for the advise on the gain influence. I think you may be right there. If the gain was lower im sure it would attenuate the hiss even more... If i move on to a higher output cart in the future i might up the resistance to 600 or 1000k. ... Once my make-before-break switch arrives ill be able to hot swap them, so im looking forward to experimenting with that and some other higher output carts to achieve even better signal to noise.
Does your pearl sound as great as mine is starting to? If not before im definitely convinced of the "burn-in" concept.