William,
I have some positive progress to report, however it does puzzle me.
I switched the polarity on one of the input RCAs. So, board one is now tip to - input, and ring to + input and board two is unchanged at tip to + input, ring to - input. Then I hooked each pre output to it's own powered speaker, and have absolutely no grounds tied together between boards (the grounds on the PCB are still connected via the jumper on the board by the cap (C15?? I'm at work so I don't have it in front of me).
The distortion was gone completely, so I was very excited. I then unhooked the boards, and connected them to my regular stereo. No distortion, however, one side sounds perfect, the other is very weak with almost no bass content. I switch the boards around and the same thing happens on one side only, so it's not the stereo, and each board seems to work fine and is matched in volume when run individually.
Now..I will do more testing when I get home, because I'm pretty sure the levels in both powered speakers was fine, but when connected to my Anthem surround processor, one side goes quiet.
But, my first concern is, why should I have to reverse the polarity of one the inputs? It doesn't seem right. The polarity at the outputs are correct (tip to +, ring to ground on both boards).
Any new ideas? Could grounding help some of these issues now that the distortion is gone away?
Thanks,
Warren
I have some positive progress to report, however it does puzzle me.
I switched the polarity on one of the input RCAs. So, board one is now tip to - input, and ring to + input and board two is unchanged at tip to + input, ring to - input. Then I hooked each pre output to it's own powered speaker, and have absolutely no grounds tied together between boards (the grounds on the PCB are still connected via the jumper on the board by the cap (C15?? I'm at work so I don't have it in front of me).
The distortion was gone completely, so I was very excited. I then unhooked the boards, and connected them to my regular stereo. No distortion, however, one side sounds perfect, the other is very weak with almost no bass content. I switch the boards around and the same thing happens on one side only, so it's not the stereo, and each board seems to work fine and is matched in volume when run individually.
Now..I will do more testing when I get home, because I'm pretty sure the levels in both powered speakers was fine, but when connected to my Anthem surround processor, one side goes quiet.
But, my first concern is, why should I have to reverse the polarity of one the inputs? It doesn't seem right. The polarity at the outputs are correct (tip to +, ring to ground on both boards).
Any new ideas? Could grounding help some of these issues now that the distortion is gone away?
Thanks,
Warren
Hi,
does the bass come from the left now?
I think your tonearm is wired in a funny way (the earth that is).
Your cartridge has a +OUT and -OUT for left and right. Could you measure where the tonearm earth is run along? I think this somehow upsets everything. Maybe you could try a seperate earth wire for the tonearm/chassis?
William
does the bass come from the left now?
I think your tonearm is wired in a funny way (the earth that is).
Your cartridge has a +OUT and -OUT for left and right. Could you measure where the tonearm earth is run along? I think this somehow upsets everything. Maybe you could try a seperate earth wire for the tonearm/chassis?
William
Hi William,
The bass is strong out of the right side, which is the board that is hooked up backwards. More interesting notes, as soon as I disconnect the right output, the bass on the left becomes normal again. Connect up the right side, and the left gets quiet, losses all bass, and distorts slightly. I guess that makes sense, with the polarity thing. The odd thing is that it's still better than it was with the polarity correctly.
A rega planar 2 does not have an earthing post and searches around the rega site etc. seem to indicate that it doesn't need any external earthing. And it works great with 3 other pres (I tried another one) no problem.
So, I'm stuck, I'm going to try it with another turntable on the weekend hopefully, to see if it's exclusive to my table.
Frustration is really setting in...I really thought I had it last night...but alas...
Warren
The bass is strong out of the right side, which is the board that is hooked up backwards. More interesting notes, as soon as I disconnect the right output, the bass on the left becomes normal again. Connect up the right side, and the left gets quiet, losses all bass, and distorts slightly. I guess that makes sense, with the polarity thing. The odd thing is that it's still better than it was with the polarity correctly.
A rega planar 2 does not have an earthing post and searches around the rega site etc. seem to indicate that it doesn't need any external earthing. And it works great with 3 other pres (I tried another one) no problem.
So, I'm stuck, I'm going to try it with another turntable on the weekend hopefully, to see if it's exclusive to my table.
Frustration is really setting in...I really thought I had it last night...but alas...
Warren
The Rega has no earthing point, as the tonearm chassis is connected to cable screen in the plastic "thing" sitting in the bottom of the tonearm. Your earth hence is connected through your signal cables. You could, but this demands some labour, try to seperate the earth from the cable screen - if you screw the small pinol screw out that is embedded in the bolt threading of the tonearm, you can pull out the plastic "thing" or socket of the tonearm, where you will find a small metal clip that is forces between the inside of the tonearm, and a cable screen soldering point on the plastic "thing".
This way you can experiment more....
Or, a lot easier way would be to try the whole shebang on another turntable, WITH seperate earth.
Cheers!
Buhl
This way you can experiment more....
Or, a lot easier way would be to try the whole shebang on another turntable, WITH seperate earth.
Cheers!
Buhl
Great news!! I tried another table, and it worked immediately with both pre inputs wired normally. There is absolutely nothing wrong with my Pearl's, you guys were right about it being the Rega table and it's grounding scheme. Inverting one input, and then reversing the pins on one channel of the cartridge did the trick. It sounds very good now, although after a while I get the very occasional transient spike in the output, but I'm thinking that that will go away with proper mounting in cases, a star ground, etc.
Now...which scheme should I use longterm, I'm thinking modifying the ground on the arm rather than having the cartridge wired unusually and having one of the pres inputs inverted....your thoughts...
Buhr, William and Promethius, I can't thank you guys enough for all your patience and help. To diagnose something like that from across the ocean, this forum is one of those things that makes internet so useful and great.
THANKS AGAIN...I'll post pics after I mount them in chassis, probably won't be until January...
Warren
Now...which scheme should I use longterm, I'm thinking modifying the ground on the arm rather than having the cartridge wired unusually and having one of the pres inputs inverted....your thoughts...
Buhr, William and Promethius, I can't thank you guys enough for all your patience and help. To diagnose something like that from across the ocean, this forum is one of those things that makes internet so useful and great.
THANKS AGAIN...I'll post pics after I mount them in chassis, probably won't be until January...
Warren
Hi guys,
Perhaps I spoke a little too soon...I know the Pearl's are fine, but here's a weird one...
I hooked them up to my "regular" stereo, and put on a wonderful sounding copy of INXS The Swing. Sat back and enjoyed it, sounded great. Then I through on another album (Thriller-MJ) and the distortion was back big time. Switched back to INXS, sounds perfect. Then tried Thriller again, distortion. Tried a third album (Raising Hell-Run DMC) and it's also distorted.
Why would certain albums sound perfect, and most distort? It's obviously the grounding in the arm...but why only on certain albums?
I guess this means I should modify my arm as suggested in a previous post, to separate the ground.
Hmmmm, I'm learning lots, but this is weird.
Warren
Perhaps I spoke a little too soon...I know the Pearl's are fine, but here's a weird one...
I hooked them up to my "regular" stereo, and put on a wonderful sounding copy of INXS The Swing. Sat back and enjoyed it, sounded great. Then I through on another album (Thriller-MJ) and the distortion was back big time. Switched back to INXS, sounds perfect. Then tried Thriller again, distortion. Tried a third album (Raising Hell-Run DMC) and it's also distorted.
Why would certain albums sound perfect, and most distort? It's obviously the grounding in the arm...but why only on certain albums?
I guess this means I should modify my arm as suggested in a previous post, to separate the ground.
Hmmmm, I'm learning lots, but this is weird.
Warren
Hi Buhl,
My cartridge is a Benz Micro 20E2 MC, with an output of 2mV. It was professionally set up by my Rega dealer, and is about 1 year old.
I've done some more testing and I now find the following works best:
I reversed the blue and white wires on my cartridge, and reversed the input on the opposite Pearl to negate the polarity difference. It sounds very good...however, there is occasionally a strong bass thump on bass transients. The Pearls are still not in their chassis, and there is no grounding yet, could the thump be grounding?
Also, I took the arm off my P2 as per William's instructions to investigate the earthing...I am interested in separating the ground so I don't have to have the cartridge and one of the Pearl's inverted.
In the Rega arm, the earth cable is connected to the blue tonearm wire and then to the brass arm mounting bolt via a clip. If I were to separate the black earthing wire from the blue tonearm wire and drill a hole through the bottom plastic plug and then to the preamp earth, would this be a way to separate the ground properly? I'd imagine I also have to remove the clip that grounds the blue tonearm wire with the brass mount? Any more guidance you could provide, I'd appreciate.
Anyways, I'm now waiting for my chassis to arrive, so I can mount the Pearls and implement a proper grounding scheme.
Thanks guys, I'd appreciate your comments...
Warren
My cartridge is a Benz Micro 20E2 MC, with an output of 2mV. It was professionally set up by my Rega dealer, and is about 1 year old.
I've done some more testing and I now find the following works best:
I reversed the blue and white wires on my cartridge, and reversed the input on the opposite Pearl to negate the polarity difference. It sounds very good...however, there is occasionally a strong bass thump on bass transients. The Pearls are still not in their chassis, and there is no grounding yet, could the thump be grounding?
Also, I took the arm off my P2 as per William's instructions to investigate the earthing...I am interested in separating the ground so I don't have to have the cartridge and one of the Pearl's inverted.
In the Rega arm, the earth cable is connected to the blue tonearm wire and then to the brass arm mounting bolt via a clip. If I were to separate the black earthing wire from the blue tonearm wire and drill a hole through the bottom plastic plug and then to the preamp earth, would this be a way to separate the ground properly? I'd imagine I also have to remove the clip that grounds the blue tonearm wire with the brass mount? Any more guidance you could provide, I'd appreciate.
Anyways, I'm now waiting for my chassis to arrive, so I can mount the Pearls and implement a proper grounding scheme.
Thanks guys, I'd appreciate your comments...
Warren
Hi William and gang,
Well, it's been quite awhile, but now the holiday season is over, I'm back to work on my Pearls. I now have them mounted in chassis, I will post pictures eventually. I bought myself a gently used Rega P5 turntable for Christmas, so now I have a P2 and a P5 to experiment with. Unfortunately, I'm still having the distortion issues.
I modified the P5 grounding to remove the blue signal earth from chassis earth, so now I have a "conventional" grounding scheme, with the an earthing cable that is not connected to the Rega signal earths in the tonearm, as per suggestions from you guys.
No difference whatsoever. I still get the distortion. Also, when I plug in the P5 to the preamp, on one stereo I have, I hear a high frequency tone coming out of the speakers . Removing the earth, moving it, connecting it, doesn't seem to make a difference. In my main stereo, I never hear that.
The P2 with the non-modified earthing distorts as it always did.
So, I'm back to the drawing board on these babies, I'm hoping someone has some new brilliant ideas. Name any test or crazy thing to try, and I'll try it, 'cause I really want this pre to work, especially with the spectacular sounding P5. Now I'm back to thinking it's not the turntable but the Pearl, but again, each of them work perfectly in isolation, it's just when both channels are used together that it turns ugly.
Thanks guys, and Happy New Year!
Warren
Well, it's been quite awhile, but now the holiday season is over, I'm back to work on my Pearls. I now have them mounted in chassis, I will post pictures eventually. I bought myself a gently used Rega P5 turntable for Christmas, so now I have a P2 and a P5 to experiment with. Unfortunately, I'm still having the distortion issues.
I modified the P5 grounding to remove the blue signal earth from chassis earth, so now I have a "conventional" grounding scheme, with the an earthing cable that is not connected to the Rega signal earths in the tonearm, as per suggestions from you guys.
No difference whatsoever. I still get the distortion. Also, when I plug in the P5 to the preamp, on one stereo I have, I hear a high frequency tone coming out of the speakers . Removing the earth, moving it, connecting it, doesn't seem to make a difference. In my main stereo, I never hear that.
The P2 with the non-modified earthing distorts as it always did.
So, I'm back to the drawing board on these babies, I'm hoping someone has some new brilliant ideas. Name any test or crazy thing to try, and I'll try it, 'cause I really want this pre to work, especially with the spectacular sounding P5. Now I'm back to thinking it's not the turntable but the Pearl, but again, each of them work perfectly in isolation, it's just when both channels are used together that it turns ugly.
Thanks guys, and Happy New Year!
Warren
Hi
According to my Rega Planar 3 Owners Manual, the ground is made by the original cable ground to the pre via the RCA connectors.
I have seriously modified my Rega Planar P3.
70mm MDF (high density board). Then drilled a lot of holes inside it, and poored melted lead into the holes.
afterwards i screewed it under the P3.
I remowed the original tonearm and attached an Moerch UP4 Tonearm. (A prototype made with 1/1000mm accuracy, according to Hans Henrik Moerch, who build it. I emailed him for tech help and alignment.
He told me to raise the platter for correct tracking, and to make an grounding wire from the bottom of the arm to the gnd of the pre, and disregard rega's original wiring.
Here's a link to the OM. In the "pink background" text, you can see that they originally uses the RCA ground to connect to the pre's ground.
I'm building the Pearl too, sure hope i'm not going to have the same problems.
I have read this tread, and i'm almost sure that you must have the problem in the Pearl itself.
What kind of power supply are you using ?
Are you sure that your wiring is correct (gnd's) ?
As i'm aware of, the Pearl boards only uses about 4W each. You could try and run them both from same supply, just to check if that will give you a hint.
Perhaps it's your mains supply, that needs filtering ?
Best of luck.
PS: I will keep my eyes on this tread and i will surely return with my experience when done with the Pearl.
http://www.zx10r.dk/RegaPlanar3.pdf
According to my Rega Planar 3 Owners Manual, the ground is made by the original cable ground to the pre via the RCA connectors.
I have seriously modified my Rega Planar P3.
70mm MDF (high density board). Then drilled a lot of holes inside it, and poored melted lead into the holes.
afterwards i screewed it under the P3.
I remowed the original tonearm and attached an Moerch UP4 Tonearm. (A prototype made with 1/1000mm accuracy, according to Hans Henrik Moerch, who build it. I emailed him for tech help and alignment.
He told me to raise the platter for correct tracking, and to make an grounding wire from the bottom of the arm to the gnd of the pre, and disregard rega's original wiring.
Here's a link to the OM. In the "pink background" text, you can see that they originally uses the RCA ground to connect to the pre's ground.
I'm building the Pearl too, sure hope i'm not going to have the same problems.
I have read this tread, and i'm almost sure that you must have the problem in the Pearl itself.
What kind of power supply are you using ?
Are you sure that your wiring is correct (gnd's) ?
As i'm aware of, the Pearl boards only uses about 4W each. You could try and run them both from same supply, just to check if that will give you a hint.
Perhaps it's your mains supply, that needs filtering ?
Best of luck.
PS: I will keep my eyes on this tread and i will surely return with my experience when done with the Pearl.
http://www.zx10r.dk/RegaPlanar3.pdf
OK, here's a thought....could it possibly be my cartridge??? To recap from a previous post, my cartridge is a Benz Micro 20E2 MC, with an output of 2mV.
Here's a test I just did:
Table #1: Rega P5 with Benz MC cartridge
Table #2: Rega P2 with Sumiko Pearl MM cartridge
Acoustic Research A-03 integrated amp (that has a built-in phono pre)
I tried both tables first with the A-03's built in phono pre. As expected, fine so far.
Then I hooked up Table#2 to my Pearl pre's, then from the pre into the CD direct input of the A-03. Sounded great, no distortion whatsoever, perfect!!!!
Tried the same with Table #1, hooked up to the Pearl pre's, then to the CD direct of the A-03. Here comes the distortion big time....AWFUL!!!
Keep in mind that in all my previous posts (prior to Christmas), I didn't have my P5 yet, so the Benz cartridge was mounted to my P2 and I had nothing but trouble. Now, with my old Sumiko MM cart on the P2, it works fine.
The Benz sounds great and has for a year and a bit with my NAD phono preamp, a Hagerman, and the integrated A-03, but will not work with the Pearl.
Am I nuts, or what could be happening here with the Benz? Is there anything I can do other than get a different cartridge?
Thanks,
Warren
Here's a test I just did:
Table #1: Rega P5 with Benz MC cartridge
Table #2: Rega P2 with Sumiko Pearl MM cartridge
Acoustic Research A-03 integrated amp (that has a built-in phono pre)
I tried both tables first with the A-03's built in phono pre. As expected, fine so far.
Then I hooked up Table#2 to my Pearl pre's, then from the pre into the CD direct input of the A-03. Sounded great, no distortion whatsoever, perfect!!!!
Tried the same with Table #1, hooked up to the Pearl pre's, then to the CD direct of the A-03. Here comes the distortion big time....AWFUL!!!
Keep in mind that in all my previous posts (prior to Christmas), I didn't have my P5 yet, so the Benz cartridge was mounted to my P2 and I had nothing but trouble. Now, with my old Sumiko MM cart on the P2, it works fine.
The Benz sounds great and has for a year and a bit with my NAD phono preamp, a Hagerman, and the integrated A-03, but will not work with the Pearl.
Am I nuts, or what could be happening here with the Benz? Is there anything I can do other than get a different cartridge?
Thanks,
Warren
Benz Micro 20E2 MC
I think it might be the way your cartridge is loaded.
According to this link:
http://www.dreamaudio.kiev.ua/benzmicro.htm
Your cartridge should be ok ?
So perhaps it's the capacitance in your cable that messes things up ?
The Pearl's input load resistance is determined by the first resistor at the input (47Kohm).
(Do not change this resistor to a bigger value, which surely will give some problems, so max 47Kohm).
The cartridge can be loaded with lower impedances by means of resistors and/or capacitors across the 47Kohm resistor.
I would try different values across the resistor to make a perfect match for your Benz Micro 20E2 MC (High Output Moving Coil).
You could start out with a 100pF across the 47Kohm resistor at first.
Hope this will be of some help.
I think it might be the way your cartridge is loaded.
According to this link:
http://www.dreamaudio.kiev.ua/benzmicro.htm
Your cartridge should be ok ?
So perhaps it's the capacitance in your cable that messes things up ?
The Pearl's input load resistance is determined by the first resistor at the input (47Kohm).
(Do not change this resistor to a bigger value, which surely will give some problems, so max 47Kohm).
The cartridge can be loaded with lower impedances by means of resistors and/or capacitors across the 47Kohm resistor.
I would try different values across the resistor to make a perfect match for your Benz Micro 20E2 MC (High Output Moving Coil).
You could start out with a 100pF across the 47Kohm resistor at first.
Hope this will be of some help.
The Pearl design has no problem that we know.
The built Pearl from you should be OK because it works in some cases.
It should be then the loading of the MC.
47K is to high so you should find out what kind of load it needs and put that across the 47Kohm.
Normaly MC need a low resistance and a small cap.
The built Pearl from you should be OK because it works in some cases.
It should be then the loading of the MC.
47K is to high so you should find out what kind of load it needs and put that across the 47Kohm.
Normaly MC need a low resistance and a small cap.
Hi,
sorry to disagree but a Benz MC is perfectly happy at 47kOhm (had a L04 for quite a long time) and is almost not affected by capacitance at the input (that is for MM cartridges with a much higher output impedance).
Have you measured your input dc-values with and without the cartridge connected? Maybe some current is going through the Benz wich would also cause distortion if it gets too much (with two channels connected) Just a thought......
William
sorry to disagree but a Benz MC is perfectly happy at 47kOhm (had a L04 for quite a long time) and is almost not affected by capacitance at the input (that is for MM cartridges with a much higher output impedance).
Have you measured your input dc-values with and without the cartridge connected? Maybe some current is going through the Benz wich would also cause distortion if it gets too much (with two channels connected) Just a thought......
William
Thanks guys. I swapped the cartridges, so now the Sumiko Pearl is on the p5 and the Benz is on the P2, and I get the same results, so it is not the table grounding, it's not the Pearl pre, it's the Benz cartridge.
It's a high output MC, and it's recommended input resistance is 47 k, so that can't be it.
I'm now thinking of going with a Rega Elys 2 or something like that, which are MM type, but have very high output (7mV). Is this going to cause problems with the Pearl? I'd like to use a Rega cartridge because then I don't have to use expensive spacers to get the right VTA on my P5.
Any suggestions of a good $250-500 cartridge that people have used successfully with the Pearl, preferably with a Rega table? I want a high output MC or an MM.
William, I will check the DC voltages on the input to see if that could be the culprit.
Thanks!
Warren
It's a high output MC, and it's recommended input resistance is 47 k, so that can't be it.
I'm now thinking of going with a Rega Elys 2 or something like that, which are MM type, but have very high output (7mV). Is this going to cause problems with the Pearl? I'd like to use a Rega cartridge because then I don't have to use expensive spacers to get the right VTA on my P5.
Any suggestions of a good $250-500 cartridge that people have used successfully with the Pearl, preferably with a Rega table? I want a high output MC or an MM.
William, I will check the DC voltages on the input to see if that could be the culprit.
Thanks!
Warren
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