Pass Pearl PCBs and related parts

[luvdunhill]

local sheetmetal shop is what I'd recommend if going steel. I wouldn't want to mess with it. Otherwise, cover it in mu-metal shielding and ERS paper

[n_maher]

Any suggestions for a case?

Rather than fight with chassis choices looking for something to provide the shielding I'd just order a potted and shielded transformer. Other solutions have a way of appearing kludgey without a lot of careful planning.

[swt61]

sure. I need you to do 2 measurements for me. First, put your meter in DC volts mode. If you get one of those cheap Centex red ones from Harbor Freight, like this:

Harbor Freight Tools - Quality Tools at the Lowest Prices

then place the knob in the position that points to "20 DCV" and the black probe in the "Common" location and the red probe in the VOmA location in the lower right hand corner.

Then place the probes across the motor terminals inside the case. Just follow the wires going from the socket to the PC board and measure at the terminal block. I believe it's marked X3. It doesn't really matter which probe goes where, as we just need an absolute reading. Be careful not to slip and short things out, in other words, don't let the probes touch each other when you're measuring. This measurement needs to be done with the table running for a minute or two so the speed is able to stabilize. Repeat the same measurement for the 45rpm setting.

Just to give you an idea, mine measured around 7.5V for 45rpm and 6.0V for 33rpm.

OK, I have to go into Corpus and pick one up first.

[DigiPete]

Rather than fight with chassis choices looking for something to provide the shielding I'd just order a potted and shielded transformer. Other solutions have a way of appearing kludgey without a lot of careful planning.

Well I'm not that concerned about shielding, I just thought there must be lots of little steel project enclosures out there that DIYers are familiar with.

Guess not.

[n_maher]

Well I'm not that concerned about shielding, I just thought there must be lots of little steel project enclosures out there that DIYers are familiar with.

Guess not.

Hammond has a pretty extensive line. What size do you need? Hard to suggest a chassis without knowing if you need 2" x 2" or 24" x 24".

[swt61]

OK Marc I got the CEN-TECH multimeter tonight. Can we do this tomorrow maybe?

[DigiPete]

Hammond has a pretty extensive line. What size do you need? Hard to suggest a chassis without knowing if you need 2" x 2" or 24" x 24".

Nate,

The hammond line would be good! Looking for a small case to house the

2 pearl trafos, 2 diode bridges and 2 smoothing caps. Maybe 3"x5"x3"tall or anything similar in size.

Cheers,

Pete

[n_maher]

Pete,

Be very careful selecting a case with very tight dimensions, especially from Hammond's line of small steel enclosures. I used one of the 1415 series of steel project boxes to house a transformer once and had to do a lot of "customization" to get it to fit because of the rather large lip that these cases have. The 1415C at 6 x 5 x 4H might work for you.

That said, one of those with a little Mu Metal took care of all of the noise issues I was having with the first beta22 that I built so it does work.

Nate

Nate,

The hammond line would be good! Looking for a small case to house the

2 pearl trafos, 2 diode bridges and 2 smoothing caps. Maybe 3"x5"x3"tall or anything similar in size.

Cheers,

Pete

[swt61]

sure. I need you to do 2 measurements for me. First, put your meter in DC volts mode. If you get one of those cheap Centex red ones from Harbor Freight, like this:

Harbor Freight Tools - Quality Tools at the Lowest Prices

then place the knob in the position that points to "20 DCV" and the black probe in the "Common" location and the red probe in the VOmA location in the lower right hand corner.

Then place the probes across the motor terminals inside the case. Just follow the wires going from the socket to the PC board and measure at the terminal block. I believe it's marked X3. It doesn't really matter which probe goes where, as we just need an absolute reading. Be careful not to slip and short things out, in other words, don't let the probes touch each other when you're measuring. This measurement needs to be done with the table running for a minute or two so the speed is able to stabilize. Repeat the same measurement for the 45rpm setting.

Just to give you an idea, mine measured around 7.5V for 45rpm and 6.0V for 33rpm.

OK, 33 rpm measures 4.96 and 45 rpm measures 6.49.

I hope that tells you something meaningful, because it sure doesn't mean much to me.

[luvdunhill]

OK, 33 rpm measures 4.96 and 45 rpm measures 6.49.

I hope that tells you something meaningful, because it sure doesn't mean much to me.

First, center the 2 front knobs so they are in the middle of their adjustment range. Kinda like setting a balance on a old receiver so the left and right channel are the same. If you have a indicator on your knobs, I'd rotate the knob so it's in the "up position" at this point. . The following values are read left to right when looking at the front of the controller, where 1 is when the actuator is moved towards the "ON" label of the switch. If you choose the left bank of switches to be 33rpm, then this will correspond to 33rpm when the switch on the front is in the left position.

So, I get:

33rpm 10011001

45prm 00110110

this will hopefully dial it in where the knob is in the center and things are pretty close then you can fine tune the exact speed using the knob. If for some reason things just arn't working, then try inverting the 1's and 0's (i.e. move each switch to the other position) as your switches might have been installed backwards.

Also, I'm going to send you all the banding for the toroids from the group buy. If anyone needs any, please contact swt61.

[luvdunhill]

after the above is completed, here are the next steps. With the motor off, examine JP2, it's near the 6 black capacitors on the right. Place the jumper so it's connected to pins 1-2 (so, in the right hand position). Then place the meter in the ohms position and measure resistance across the motor terminals (X3). This is done just like you measured the voltage above, but with the motor off and the meter on the ohms setting. Let's call this resistance R1. I got around 70 ohms for my setup. Then, carefully disconnect one of the motor leads and make sure it doesn't touch anything and then switch the controller on and place it in the 45rpm mode and let the platter get up to speed (a few minutes is good). Then measure the voltage (remember to switch your meter to the voltage setting) yet again at X3 (this time with one lead of the motor disconnected). Hopefully, this will be above 5V, if not let me know (and double check that you're on the 45rpm setting). Let's call this voltage V1. Turn the controller off.

Now, with these 2 numbers in hand, do the following. Set that little trim pot thingy I gave you to the same resistance you measured in the first step (R1). Just measure from one wire to the other and turn the trimmer and get as close as you can (accuracy is key here). Now, plug the end of the "resistance thingy" into X3 where you removed the motor wire from and then connect the alligator clip to the other end of the motor. Thus, this resistance is now in series with the motor. Make sure things don't get shorted out and double check that things are setup as above. No, really double check

Now, turn the controller on and measure the voltage across X3 yet again. Then adjust the yellow trimmer on the board that is labeled VR1 until you get the same voltage across X3 as you measured above (V1). Once you've done this, turn the controller off, remove the series resistance and plug the motor in as it was before. Then turn the table back on and verify your speed settings for 33rpm and 45rpm.

Let me know how things go. You may have speed stability issues when it's all said and done that we can address in a less scientific manner. You can always move the jumper at JP2 back to the other setting (left position) and things should then be as they were before. In theory, the right setting of JP2 (current compensation turned on) should be better...

Have fun!

[swt61]

First, center the 2 front knobs so they are in the middle of their adjustment range. Kinda like setting a balance on a old receiver so the left and right channel are the same. If you have a indicator on your knobs, I'd rotate the knob so it's in the "up position" at this point. . The following values are read left to right when looking at the front of the controller, where 1 is when the actuator is moved towards the "ON" label of the switch. If you choose the left bank of switches to be 33rpm, then this will correspond to 33rpm when the switch on the front is in the left position.

So, I get:

33rpm 10011001

45prm 00110110

this will hopefully dial it in where the knob is in the center and things are pretty close then you can fine tune the exact speed using the knob. If for some reason things just arn't working, then try inverting the 1's and 0's (i.e. move each switch to the other position) as your switches might have been installed backwards.

Also, I'm going to send you all the banding for the toroids from the group buy. If anyone needs any, please contact swt61.

OK, These switch settings work beautifully. I can dial the 33 & 45 RPMs in perfectly, and still have plenty of adjustment room at the knobs.

[swt61]

after the above is completed, here are the next steps. With the motor off, examine JP2, it's near the 6 black capacitors on the right. Place the jumper so it's connected to pins 1-2 (so, in the right hand position). Then place the meter in the ohms position and measure resistance across the motor terminals (X3). This is done just like you measured the voltage above, but with the motor off and the meter on the ohms setting. Let's call this resistance R1. I got around 70 ohms for my setup.

With the meter in the Ohms position at the 200 mark I got a reading of 65.6 Ohms.

Then, carefully disconnect one of the motor leads and make sure it doesn't touch anything and then switch the controller on and place it in the 45rpm mode and let the platter get up to speed (a few minutes is good). Then measure the voltage (remember to switch your meter to the voltage setting) yet again at X3 (this time with one lead of the motor disconnected). Hopefully, this will be above 5V, if not let me know (and double check that you're on the 45rpm setting). Let's call this voltage V1. Turn the controller off.

I guess I'm not understanding you correctly here, because if I remove one of the motor leads at terminal X3 I don't have any power to run the platter at 45 RPM. What am I missing here?

Oh and BTW My jumper at JP2 was already connected to pins 1-2 (in the right hand position). Not sure if this significant.

[luvdunhill]

I guess I'm not understanding you correctly here, because if I remove one of the motor leads at terminal X3 I don't have any power to run the platter at 45 RPM. What am I missing here?

Oh and BTW My jumper at JP2 was already connected to pins 1-2 (in the right hand position). Not sure if this significant.

right, so when you do that part of the setup procedure, the motor won't be running, but the circuit will be trying to run it. that's fine.

and on the latter, no it's not that important really, but know if things don't get dialed in 100% with this setup procedure, you can revert back to the working state by moving the jumper over.

[swt61]

right, so when you do that part of the setup procedure, the motor won't be running, but the circuit will be trying to run it. that's fine.

and on the latter, no it's not that important really, but know if things don't get dialed in 100% with this setup procedure, you can revert back to the working state by moving the jumper over.

OK I got the VR1 dialed in at the 5.75 V I had measured for V1.

The speeds changed for sure. I'm still able to dial in 33 RPM with some adjustment left at the knob. 45 RPM won't quite get dialed in at this setting though. However knowing that I can revert back to moving the jumper if needed, I'm going to leave it as is. I'll be playing 33 RPM records 99.99 percent of the time.

That was fun BTW! Am I an official begginer DIYer now?

[swt61]

The knob detent for 33 RPM is right smack in the center at correct speed.

:dance:

[luvdunhill]

OK I got the VR1 dialed in at the 5.75 V I had measured for V1.

The speeds changed for sure. I'm still able to dial in 33 RPM with some adjustment left at the knob. 45 RPM won't quite get dialed in at this setting though. However knowing that I can revert back to moving the jumper if needed, I'm going to leave it as is. I'll be playing 33 RPM records 99.99 percent of the time.

That was fun BTW! Am I an official begginer DIYer now?

ok, so can you give me the new voltages for 33 and 45, just like you did in the very, very first step? It will just take a sec.

Also, you have a massive package in the mail. When changing the resistors on the Pearl, I'd recommend taking one side off, then changing one channel, putting that side back on, and then removing the other side to access the other channel. It will make more sense when you see where the adjustment resistors are.

[luvdunhill]

The knob detent for 33 RPM is right smack in the center at correct speed.

:dance:

sweet! math does work once in a while. Then, just give me the voltage for the 45rpm setting, when the voltage is as close to the correct speed as you can get it and I'll calculate the new DIP settings.

edit: just for the hell of it, invert the DIP switches for the 33rpm setting and see if there is finer adjustment... I realized that for the 33rpm, both settings will "work" but one will give you better fine control. If the second setting gives you more control, then invert the settings for 45rpm and this may fix your issue... or either way invert for 45rpm and see what happens

[swt61]

ok, so can you give me the new voltages for 33 and 45, just like you did in the very, very first step? It will just take a sec.

Also, you have a massive package in the mail. When changing the resistors on the Pearl, I'd recommend taking one side off, then changing one channel, putting that side back on, and then removing the other side to access the other channel. It will make more sense when you see where the adjustment resistors are.

With one lead removed from X3 I'm now measuring 5.21 V for 45 RPM and 4.55 V for 33 RPM.

I'm sure that removing one side at a time for the Pearl will be easier to deal with anyway.

[swt61]

sweet! math does work once in a while. Then, just give me the voltage for the 45rpm setting, when the voltage is as close to the correct speed as you can get it and I'll calculate the new DIP settings.

edit: just for the hell of it, invert the DIP switches for the 33rpm setting and see if there is finer adjustment... I realized that for the 33rpm, both settings will "work" but one will give you better fine control. If the second setting gives you more control, then invert the settings for 45rpm and this may fix your issue... or either way invert for 45rpm and see what happens

I'm on my way to dinner, but will try inverting them when I get back.

[luvdunhill]

With one lead removed from X3 I'm now measuring 5.21 V for 45 RPM and 4.55 V for 33 RPM.

I'm sure that removing one side at a time for the Pearl will be easier to deal with anyway.

no, sorry, I meant the voltages with the motor connected.

[swt61]

OK, 45 RPM is at 5.70V and 33 RPM is at 5.02V.

[swt61]

Inverting the switch settings for 45 RPM is way too slow. The motor barely starts spinning the platter at first, and it's closer to 33 RPM than 45.

[swt61]

Also, you have a massive package in the mail. When changing the resistors on the Pearl, I'd recommend taking one side off, then changing one channel, putting that side back on, and then removing the other side to access the other channel. It will make more sense when you see where the adjustment resistors are.

Massive huh, that can only mean one thing...you added the T-50 to the package! You're a great guy Marc! Most people wouldn't give up such a nice headphone so generously.

[luvdunhill]

OK, 45 RPM is at 5.70V and 33 RPM is at 5.02V.

for 45, try 00011011

edit: should be 10001101