Bottlehead Forum
Bottlehead Kits => Moreplay => Topic started by: anthonynchandler on February 06, 2025, 12:31:24 PM
-
Greetings from the Great North!
I finished my wonderful soldering journey with the Moreplay only to find myself at the dreaded voltage problem on the final page. I thought I would post a cry for help based on my Resistance and Voltage Checks first before posting images, as the numbers may tell more than photos for now.
I passed the Power transformer test. I passed the glowing 6v6 test. I passed the Raw B+ voltage test. My numbers for those were spot on.
For the resistance Check the main incongruencies with expectations were:
Terminal 9 - OL
A5 1.94
A6 OL
B5 - 215
B6 - Ranges
Voltage Check DC
Terminal 1. -1.2V
Terminal 4 - 0.1
Terminal 6 - -1.2
Terminal 11 -1.1
Terminal 14 - 0.1
Terminal 16 - -1.1
I should note that I did try the Moreplay in my system (I was not sure if I was just messing up with the multimeter and was off by 1000 or something) and there is nothing. As per my reading of the "rules on p.58 I could proceed with the voltage check. I wore rubber boots and had a hand in my pocket [with Alanis Morissette playing on my phone].
Any thoughts before I go through the entire circuit tomorrow? I thought my solder points were good, and I think my capacitors are in the right directions.
So close...many thanks.
Anthony
-
On your resistance test, terminal 9 should read 10k ohm, and that it reads OL suggests your vol pot red lead isn't connected to terminal 9. Its not clear to me if that would cause all the other issues.
Actually the A6 resistance also should not read OL either, that implies it's not connected to anything. For the A&B 5&6 pins I recommend setting your ballence pot at about the middle of it's range. You should then read values like 40-60k ohms, and A5 & A6 should be almost the same and B5 & B6 should be almost the same. If yoou don't get that there's a wiring issue there too.
-
I should note that I did try the Moreplay in my system
Any thoughts before I go through the entire circuit tomorrow? I thought my solder points were good, and I think my capacitors are in the right directions.
Definitely don't try to use a piece of gear you know isn't working in your system, as that can cause lots of damage to other components and you aren't really learning anything by doing this.
Can you post some photos of your build?
-
I am attaching a selection of images which might help if I connected something in the wrong place. Everything seems attached properly, but I could be wrong. Absolutely my mistake to attempt a hook up without 100% measurements being proper. I thought that with the passed tests on the previous checks I may have simply been measuredly those points incorrectly. My mistake.
What I found strange was that the misreadings both seemed to be off of the tube sockets in the same spots for both A and B.
Anyway, any help offered is greatly appreciated.
Anthony
-
More
-
What DC resistance values do you get across the three lugs on the lower level of the volume pot?
-
Black lower - 0 with beep
Middle lower lug - 0.900
Red - OL
-
How about the other level of the pot?
-
Hi Paul,
Black Upper- 0 with beep
Middle Upper lug - 0.904
White Upper - OL
I went over the diagram and found that the C/D on the selector switch were in the wrong place (blame my eyesight on that one - so hard to see those letters). So I fixed that and then went back over any questionable solder joints. No changes on the readings on Resistance for 9 (still OL) and the A5/B5 and A4/B4 remain incorrect.
Now does the orientation of the larger film resistors affect anything. I have the print facing the opposite direction to the tube sockets.
Thanks,
Anthony
-
Can you send me a link to the meter you're using?
If it's not an autoranging meter, you may need to go up on the resistance scale to resolve the 10,000 Ohm reading.
-
Sure. It is a Klein Tools MM300.
https://www.kleintools.com/catalog/multimeters/digital-multimeter-manual-ranging-600v
It is manual ranging
-
Paul,
Okay...when you mentioned the multimeter I changed how I was measuring the circuit for resistance and was able to get the proper numbers except forB5/B6 which seemed to range a bit, but is definitely not clear like the A side.
When I now measure voltage, all of the numbers are perfectly within the ranges posted.
A.
-
If the voltages are OK and you swapped the wires on the selector switch, then you could attempt to use the preamp again.
-
Okay. Voltages are all okay. I also found the problem with the B tube socket: a tiny end of the resistor on the balance was touching the metal on the balance knob. So now I get the correct reading on that.
I have all readings correct for resistance and voltage.
But...no sound at all when plugged into a system. I get tube glow, I get no sound. I tried using different amps and sources in the different places, but nothing.
What fun - ha ha ha.
-
Are you confident that your cables are in the correct RCA jacks? If all the voltages are good, it'll be something pretty simple like this.
-
Yes. I am, BUT let's confirm in case I am not.
The inputs are the three sets of RCA jacks. I have tried using different jacks from the three with both a phono pre output and a connection from my iPhone.
The outputs have been tried going to either an AudioLab 6000A (as power amp) or two DIY Nelson Pass Amp Camp monoblocks out to Klipsch Heresy IV speakers.
The system works without the Moreplay.
Am I missing something obvious? I try different outputs, move the balance and the volume and the selector.
-
Can you check the resistance between the black (whichever you'd like) wire on the selector switch and the white wire? How about black and red?
Your meter won't support signal tracing, but finding a meter with a 2V AC scale isn't super tough, and that can be used to figure out where things are dropping out.
Based on both channels not working properly, I'd be suspicious of wiring issues around the selector switch and balance pot.
Come to think of it, I looked back at your photos and didn't see anything showing the balance pot wiring, so posting a couple of pictures of that could be helpful.
-
Certainly. Give me a moment and I will photograph the two sections. I tried different tubes to troubleshoot, and then just switched through all of the jacks with all of the combinations. I figured that if it was something like one sloppy solder point then I would get some signal somewhere.
Photos and results of metering will be incoming.
Thanks
-
The resistance between black and white is 77
Black and red is 66.
-
Something we have seen happen now and then is CAT5 getting overheated and the individual wires end up touching when the jacket melts away.
This would appear as 0 resistance on the upper or lower middle lugs on the volume pot with the volume pot turned all the way up, or 0 resistance across the outer pairs of lugs on each level of the balance pot.
-
Hmmm, not totally following you with where the cat 5 melting might be connecting, BUT:
On the Balance I get a 77 on the top and a 66 on the bottom outer pairs of lugs
On the Volume I get a 10 on the top and a10 on the bottom outer pairs of lugs
Not sure where to measure for the middle lugs of the volume pot, but from terminal 23 to middle lugs I get 0.
ACTUALLY in the 200 range I get a 2.0 on the middle lugs.
-
Are you confident that your cables are in the correct RCA jacks? If all the voltages are good, it'll be something pretty simple like this.
Your post #20000!!!
-
At this rate I may be Paul's #25000 and #30000.
I gave it a rest last night, but I am afraid we are still with no sound.
Any more ideas on what to do next?
Many thanks,
Anthony
-
The first thing to do is to get a meter that can measure low AC voltages. This one looks fine and isn't too expensive:
https://www.amazon.com/AstroAI-Multimeter-Resistance-Transistors-Temperature/dp/B071JL6LLL/ref=sr_1_1_sspa?crid=33V3Y6WMBFOUH&dib=eyJ2IjoiMSJ9.0igT1Raq2QuSN2cSijNtPcSoCFfxOvx2OVUSjP30cWAYY1Q3-oK75-p8bZRBjrAIlbsVzJ3Wpq1OLklw65bsG8GuWib9FLbjE_eflH3oul5IgOkxofdLMuDET5qwdd6iZ4hiog0QQdFkQOezw8tjrfekHiZSTwAiDotLuDkOzcqZr0SnjcKNZYs_t84ic62bI7Gix58thh8uKi2eSdzMeCmTdX38fsmL3G4x9UPwC2DPXiJa2imGHc_TE_afTSkS6XKNc8JE2iEErpSnqlJVOzSqCAqTXvos7iSVccjXJ1I.Li9MpJnkJmhtn6ukfUL0GTAEni6PNJ8Q5iOT2IPBLlo&dib_tag=se&keywords=digital%2Bvolt%2Bmeter&qid=1739068248&sprefix=digital%2Bvolt%2Bmet%2Caps%2C186&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1 (https://www.amazon.com/AstroAI-Multimeter-Resistance-Transistors-Temperature/dp/B071JL6LLL/ref=sr_1_1_sspa?crid=33V3Y6WMBFOUH&dib=eyJ2IjoiMSJ9.0igT1Raq2QuSN2cSijNtPcSoCFfxOvx2OVUSjP30cWAYY1Q3-oK75-p8bZRBjrAIlbsVzJ3Wpq1OLklw65bsG8GuWib9FLbjE_eflH3oul5IgOkxofdLMuDET5qwdd6iZ4hiog0QQdFkQOezw8tjrfekHiZSTwAiDotLuDkOzcqZr0SnjcKNZYs_t84ic62bI7Gix58thh8uKi2eSdzMeCmTdX38fsmL3G4x9UPwC2DPXiJa2imGHc_TE_afTSkS6XKNc8JE2iEErpSnqlJVOzSqCAqTXvos7iSVccjXJ1I.Li9MpJnkJmhtn6ukfUL0GTAEni6PNJ8Q5iOT2IPBLlo&dib_tag=se&keywords=digital%2Bvolt%2Bmeter&qid=1739068248&sprefix=digital%2Bvolt%2Bmet%2Caps%2C186&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1)
You'll need some device with a headphone jack and an 1/8" TRS to RCA cable. This can be a laptop, phone, or tablet, and you'll either use a signal generator app or just a web based 60Hz test tone on that device to shoot signal into your Moreplay.
When you have those devices, we can start tracing signal in your preamp.
-
Ha ha ha...I KNEW I would need a different multimeter sooner rather than later! I had that one to help with with some house electrical jobs. The AstroAI is definitely priced right. Alright, I will order one and then see what we can discover.
I should have the cable with appropriate signal maker.
Many thanks,
Anthony
-
Paul,
I have the signal 60hz, the connection from my phone to rca and the new multimeter arrived.
Where do I begin?
Thanks
Anthony
-
Start by playing a 60Hz tone from your source with the 1/8" to RCA cable plugged in. Be sure to turn the volume all the way up! Now take your new meter and set it to AC volts and use the probes to measure across one of the male RCA plugs, and let us know what that AC voltage is.
-PB
-
Paul,
If I plug in the 60hz source to input 1, turn all volumes up, turn on the Moreplay and then measure across any of the RCA inputs [if you mean red to red rca and black to black rca on the same input].
then the ranging numbers go immediately to 0.
If I just touch the red probe to a red rca, then I get between 0.998 and 1.2
A
-
Put the black probe on the rca ground and the red probe on the rca center pin/cup.
-
No, this is a test to measure your device, the Moreplay is not to be used for this first test. Just plug the cable into whatever source is making the 60Hz tone, then measure the voltage across the male end of the cable when it isn't plugged into anything. It's important to know this number first.
-
Okay...sorry for being slow on this procedure. Hmmm, so if I measure AC volts just on the end of the source RCA then the number ranges a lot. I definitely do not get a simple number.
Maybe it helps me if I know where to place the red and black probes for each measurement.
If I connect my red probe to the centre pin of the red rca on the signal cord and touch the black probe to the outer sleeve of the same rca, then I get .809
Thanks, Ken!
Even though these probably mean nothing as I have no reference, this is what I got.
RCA 1 - 0.685
RCA 2 - 0.808
RCA 3 - 0.807
RCA 4 - 0.804
RCA 5 - 0. when I go to ground, but 0.857 when just the red probe
-
OK, so now you can plug the RCA plugs into the Moreplay. I would put them in input #2. Start with the selector switch set to 1 or 3, then measure the AC voltage across each RCA jack on input 2. (Black probe on shell, red probe on the center pin for each jack).
If you still see about 0.8V, then put the selector switch on input 2 and recheck.
If you still see about 0.8V, then measure the AC volts between ground in the amp and the red wire leaving the selector switch, as well as ground in the amp and the white wire leaving the selector switch (ground in the amp is any black wire on either the balance pot or ground pot).
If you still see about 0.8V, then measure the AC voltage at each of the middle lugs of the balance pot with the balance pot about centered. It will be less than 0.8V.
None of these tests require the Moreplay to be powered up, and I'd suggest leaving the power cord unplugged for now since it just isn't necessary.
-PB
-
Paul,
With the input going into Input 2, here are my cacophony of readings. Not sure if this helps us at all :-\
Selector Switch to 1
Input 1
Red 85v
Black 73V
Input 2
Red 0.8V
Black 0.8V
Input 3
Red 0V
Black 0V
Selector Switch to 2
Input 1
Red 60V
Black 143V
Input 2
Red 0.8V
Black 0.8V
Input 3
Red 107V
Black 0.8V
Selector Switch to 3
Input 1
Red 0V
Black 0V
Input 2
Red 0.8
Black 0.8
Input 3
Red 115V
Black It builds to 125 and ranges a lot
• AC volts between ground in the amp and the red wire leaving the selector switch. 0V
• ground in the amp and the white wire leaving the selector switch 0V
• AC voltage at each of the middle lugs of the balance pot with the balance pot about centered. 0V
-
Input 2
Red 0.8V
Black 0.8V
This is what we want.
• AC volts between ground in the amp and the red wire leaving the selector switch. 0V
• ground in the amp and the white wire leaving the selector switch 0V
• AC voltage at each of the middle lugs of the balance pot with the balance pot about centered. 0V
Is this with the selector set on input #2?
-
I believe so, but I can confirm shortly.
-
No, the selector must not have been on 2
Here are the current readings
• AC volts between ground in the amp and the red wire leaving the selector switch. 0801V
• ground in the amp and the white wire leaving the selector switch 0.801V
• AC voltage at each of the middle lugs of the balance pot with the balance pot about centered.
Bottom Center 0.707V
Top Center 407V
-
You have 407V coming out of the selector switch? Hopefully that's 0.407 and 0.707, that's about 5dB off, but the bigger deal is that the signal is present at the output of the volume pot.
Next you will want to do this same testing but measure on pins 5 and 6 on each 8 pin socket. Assuming you still see about the same readings there, then you'd power up the Moreplay and measure the AC voltages at terminals 9 and 19 with the signal playing into the preamp.
-
Paul,
No sorry. That was my fault with trying to type the numbers when I cannot see the screen with the questions -sigh.
I have 0.807 V on both the red and white wires off of the selector.
-
Paul,
5/6 on the A channel is 0.632V, but on the B channel I am getting that same 535V on the 5/6 [and it is 535V versus 0.535V]
On terminal 9 it is 3.746V. and on terminal 19 it is 2.964V
-
Still no resolution on getting sound of my Moreplay, but it certainly looks nice next to my Crack build.
Any more ideas on what I might check next to see why sound does not appear?
Many thanks!
Anthony
-
Paul,
5/6 on the A channel is 0.632V, but on the B channel I am getting that same 535V on the 5/6 [and it is 535V versus 0.535V]
On terminal 9 it is 3.746V. and on terminal 19 it is 2.964V
When you see something like 535V in a kit with a lot less voltage than that present, that tends to indicate a bad solder joint on a ground wire in the amp.
Terminals 9 and 19 show about 3V of AC signal, and this is the output of the preamp. Can you turn the volume up all the way on the preamp and run this signal through it again, then report the AC voltages available at 9, 19, and the left and right output jacks?
-
Good afternoon Paul,
I went over all of the black wire and ground lug solder points with a resolder, to no avail.
With the signal at full and the preamp volume at full I get
Terminal 9 reads. 3.482V
Terminal 19 reads 2.958V
On the output lugs (All 4) I get a 0.0V
I should also mention that if I hook my signal up to the Moreplay and then feed that to my Crack, I can hear the signal in the Crack (both when the Moreplay is on or off; the balance and volume will affect the signal going to the Crack). It will not send a signal to my amps though. Sooo I am assuming the signal is just passing through the Moreplay without being amplified? I had a similar moment when I ran the signal through one output jack and out of the other only to realize it was just a U loop through one to the other! Bah ha ha.
Sorry...I know this seems strange.
Thanks,
Anthony
When you see something like 535V in a kit with a lot less voltage than that present, that tends to indicate a bad solder joint on a ground wire in the amp.
Terminals 9 and 19 show about 3V of AC signal, and this is the output of the preamp. Can you turn the volume up all the way on the preamp and run this signal through it again, then report the AC voltages available at 9, 19, and the left and right output jacks?
-
Can I see what the wiring looks like at the volume pot?
I would suspect that the CAT5 leaving the volume pot may have gotten overheated and melted together, which will short out the signal trying to get out of the preamp.
Your preamp is accepting line level signals and amplifying it properly, but it's not getting from the coupling caps to the output jacks.
-
Interesting. Okay, I will send a few images at different angles. If the cat 5 is melted, then is it at the pot or midstream? Would you suggest stripping those and reatttaching? I guess what surprises me then would be that both channels are shorting, but then maybe a short anywhere does the same thing to the whole system - ha ha ha.
Thanks,
Anthony
-
If you put the volume pot about in the middle, what are the DC resistances from ground to all of the lugs?
-
That upper center terminal on the pot is really crusty with flux and needs to be reheated.
-
I will redo the volume pot now, specifically the one you suggested.
Resistence measurements before resolder with black on terminal 23, volume at mid and power on Moreplay [but they measure the same resitence with power off)
Left Top (white wire) 9.76
Middle Top 0.945
Right Top 0.2
Left Bottom 9.95
Middle Bottom 0.881
Right Bottom 0.2
-
Now with the pot turned most of the way up, play your 60Hz tone into the amp and check for signal on the middle lug of the volume pot on each level.
-
Paul,
Not sure what to use to measure signal, but if it is resistance then on middle lug it is
Top 0.915
Bottom 0.853
If it is AC voltage, then it is
Top. 149V
Bottom 307.8V
I retouched solder on all of the lugs on the volume before this measurement
-
I never knew how easy it was to make your own signal generator. Can’t tell you how many times I wished I had one. Now I feel embarrassed for not knowing how simple and easy it is. Thank you for the simple, clear description of how to do so!
Dave
-
EUREKA!
WE HAVE SOUND! I believe that it must have been the "crusty" solder on the volume pot which Paul spotted. I would like to give thanks to Paul for all of the support with learning to follow the signal and taking time to get back to me when things did not make sense due to my lack of technical expertise.
I think that it will take some time to run the circuit and figure out how make it sound best within my system. The Moreplay does not sound like I would expect, so my ears will also need to adjust and figure out volumes and balance for my room. Regardless, I will write something and post it in a week or so.
Thanks again. It was not an easy process when it seemed easier than my Crack build, but then seemed to stall just before the finish line.
Be well.
Anthony Chandler