Strange problem with Pearl 2 and SAE Cartridge

[McQuaide]

I've had this problem on and off with a NOS SAE1000e for a while now. The cartridge produces incredibly loud white noise when on the tonearm rest, but only with the Pearl 2. It's quiet with other phono stages. When the stylus hits the groove the noise quiets down.

It also makes strange sounds and loud snaps when the TT muting kicks in and out. Pulling one RCA cable kills the noise, and touching one of the signal terminals quiets it.

It only happens with the combo of the Pearl 2 and this HOMC cart. The cart is fine on other phono stages, and other carts are fine on the Pearl 2.

Any ideas Wayne?

Mark

 

[Russellc]

Well Bugger. My current fav is the SAE 1000 Lt....

Russellc

 

[McQuaide]

Bump...

 

[McQuaide]

Here's an update on my troubleshooting -- The noise seems to be related to C22. I have these caps in sockets now, so I can vary the load on the cartridges.

When I pull C22 from the right channel but leave it in the left, the noise goes away from both channels. If I pull C22 from the left channel, the noise stays in both channels, regardless of whether C22 is in the right channel or not.

This noise existed on and off before I installed the sockets, and with different caps.

Any ideas?

 

[Wellerman]

So if you pull c22 from the right channel, the noise goes away in both channels, and if you then also pull C22 from the left channel, the noise returns in both channels? ( I might have misread)

I would try soldering C22 in both channels to see if that works. Or alternatively, try without C22 in both channels (cable capacitance ot the TT interlink mightbe enough). I have silver mica ones in my Pearl.

 

[bnorrish]

I left off C22 in mine as a few suggested most cartridges do not need. I would leave them both off.

 

[McQuaide]

Solved

Well, it was something simple. This cartridge wants the TT ground to be earthed. Without that, you get blasting white noise, or crackling, or wierd tones slowly rising and falling, or radio stations, or sometimes nothing. As soon as I connected the Pearl ground post to earth it went dead silent.

My ground scheme was identical to 6L6s.

I'm now enjoying my best cartridge through the Pearl 2-Mezmerize-F5, and it sounds like I died and went to heaven

 

[McQuaide]

The saga continues...

After listening for a while, the left channel slowly fades and the some of the noises come back. None of the extreme noise from before I grounded it, but some squealing sounds.

Unplugging and re-seating the RCAs from the turntable returns everything to normal.

Does this sound like a grounding problem? It seems to deteriorate over time.

 

[McQuaide]

The noise is back with a vengeance today no matter what's grounded or not grounded. I measured it and it's up to 3.7 VAC coming out of one channel and .5VAC from the other of pure static.

I took voltage readings and here they are:

R33: -24 -24
R4: 23.5 23.5
Across R6: 1.6 1.8
R6-Q4: 19.8 19.8
R9-R7: 19.5 19.5
R8-R10: 9.6 9.5
Q3-Q7: 8.9 8.9
R11-Q3: 14.4 14.5
R24-Q9: .27 .26
Q10-R28: 22.9 22.8
R28-C24: -24 -24
R25-R27: -22.2 -22.2
R29-Q11: -22.9 -22.9
R6-Q4: 19.8 19.8

Touching the bare signal connections inside the unit kills the noise temporarily.

 

[bnorrish]

Possibly a component on the ground plane is not properly soldered, especially one of the caps? Also check the input and output hookup soldering on the board. I had noise on one channel. I found I had a couple bad solder joints on a few caps on the ground plane, plus the input ground solder point on board was bad.

 

[McQuaide]

I'll check it over. The odd thing is it only happens with this particular cartridge. And this cartridge has no issues with my other phono pre.

 

[FormosaWest]

Did you find the culprit McQuade?

have you tried another turntable/source? (just to rule it out)

guesses...: is your C22 Polar or bipolar (don't know if it matters?) Perhaps one of your caps is bad (or backwards)? perhaps a cold solder in the ground circuit? ...hmmpppp.. that must be annoying. hope you figure it out!

 

[McQuaide]

It's so weird, I've had to stop using the cartridge. It happens with three different turntables, and the cartridge is fine with a different phono pre (an ART DJ). And the Pearl is fine with several other MM cartridges.

When the SAE is first connected, there is a continuous blast of white noise. Touching the stylus with a brush or dropping it on a record stops the noise, but it continues to make weird noises while playing.

 

[FormosaWest]

hmmm. maybe the cart has some peculiar capacitance/resistance loading incompatibility issue.. is the noise like a heavy resonance or something, or just white noise?
id imagine building up noise is the result of standing waves or some kind of feedback loop and might be a grounding or inductance problem.

i really don't know what i'm talking about but what a curious issue you have!

If i had this problem id check over all joints from needle to phono out on the pre. I'd Check all soldering and look for any dull joints, or air pockets in solder. They should all be like silvery volcanos... and make sure your power lines are all adequately connected and not arcing or shorting. also, id make sure my dc lines were not running parallel to any of my input lines, and that all insulators are in good shape. that lines and jackets are not nicked. id check that the grounding pad in the centre of each channel is connected to turntable ground, and id check the integrity of the turntable ground wire, and its soldering point in the turntable. Id check the pins for the cart leads.

has the cart ever been damaged, or is the needle in rough shape, id make sure the cantilever looks okay.

and keep asking around. There appears to be alot of very intelligent DIYers and electrical engineers here. Im a pharmacist so not exactly my wheel house (otherwise i might suggest your pearl is allergic to that cart. haha. im sure that theres an identifiable cause. Sometimes its something we'd never imagine causing the issue... don't let it drive you nuts though.. last thing youd want is a beautiful job to get spoiled by a little frustration. enjoy it with another cart if you can and when you feel up to it, tackle the issue then.

if all the conductors and joints are okay, it could possibly be a bad component, or a fried one.

 

[McQuaide]

Fixed

To update everyone on this, there is indeed an incompatibility between this cartridge and the Pearl 2.

I sent the SAE to 6L6 who confirmed the problem existed with his Pearl 2 as well. He contacted Wayne, who recommended a simple fix -- a "Zobel" network consisting of a 680r resistor and 1000pf cap in series across the inputs. Apparently the high inductance of the SAE put the JFETs into oscillation, and the Zobel prevents this.

Wayne mentioned that all Pass gear has the Zobel network installed.

So I can now enjoy this fine cartridge thanks to 6L6 and Wayne. 6L6 even provided the caps and resistors when he returned the cartridge!

 

[bnorrish]

Wow. Thanks for update. 6L6 always there to help.

 

[Russellc]

Well, Whew! I've sort of worried about this as I have one of those SAE carts hooked to my tonearm now! Can you provide a pic of this zobels attachment?

Thanks,

Russellc

 

[vinylkid58]

I sketch might be helpful. I have a 1000E that whistles a little when I first power up my Pearl I.

jeff

 

[vinylkid58]

Like this?

 

[McQuaide]

Yep.