voltage check reduction new reduction build [resolved]

[lesouthern]

Hi-

Just did voltage check- seems I have an issue with terminal 2- what terminals should I be checking, and what should I be checking for?

thanks

Larry

Terminal Voltage Expected
1 0 0
2 151 70-90
3 0 0
4 151 145-155
5 0 0
6 0 0
7 74 70-90
7 74 70-90
8 0 0
9 0 0
10 0 0
11 0 0
12 0 0
13 72 70-90
14 72 70-90
15 71 70-90
16 0 0
17 0 0
18 67 70-90
19 67 70-90
20 67 70-90
21 0 0
22 0 0
23 1-2 0
24 0 0
25 0 0
26 67 70-90
27 0 0
28 0 0
29 151 145-155
30 0 0
31 85 70-90
32 0 0
33 5.9 6
34 0 0
35 0 0
36 0 0
37 5.9 6
38 10.4 10-11
39 4.1 4-5
40 0 0
41 4 4-5
42 10 10-11
43 0 0
44 77 0
45 77 0
46 0 0
47 177 180
48 0 0
49 0 0
50 164 165
51 164 165
52 177 180
53 177 180
54 0 0
55 0 0
56 151 145-155
57 151 145-155
58 0 0
59 164 165
60 164 165
61 0 0
62 0 0

 

[Paul Birkeland]

I would post some photos of your build.  I'm guessing you have one LED that isn't lighting.  Typically what I find when I get Reductions in for repair with this issue is a loose ground connection.  You can poke at the circuit with a wooden chopstick while it's running (not hooked up to anything though!) and I would bet that when you poke the loose connection, the LED that isn't lit up will light up. 

 

[lesouthern]

Hi Paul,

The light connected to A3 was flashing. I resoldered 11L, and now voltagef on terminal 2 is normal at 70

Now that the voltage was normal, I plugged it in and am getting humming.

Attached are pictures of my build. This is my first project, and electrical in general. Tried to follow suggestions but am sure my soldering will not win any awards.. be kind

thanks

Larry

 

[Paul Birkeland]

Now that the voltage was normal, I plugged it in and am getting humming.

What do you have hooked up to the inputs?  Do you have the tonearm ground wire hooked up to the ground post? Is it humming from both channels?

 

[lesouthern]

The humming is only coming from the B, black, left side.

I'm plugging this into a Rega Planar 2, the ground is supposed to be in the black side cable- there is no ground.

Also I notice the issue is only when I plug in the turntable

 

[Paul Birkeland]

Are you 100% certain you have the RCA jack hardware in the proper order?  I've seen this kind of situation pop up when the hardware on the RCA jacks is left in the same order it comes in from the factory, which isn't correct.

 

[lesouthern]

I've been using the P2 on the phono stage of my 1976 JVC JA-S31 for about a year, no hum with the cables in the correct sided RCA connections on the amp side.

I hear the hum on this amp if I don't have the black side connected.

For grins I tried switching the turntable cables on the Reduction, red to black, black to red, still have a hum

For all this I think the turntable is setup correctly. I would have to open the tone arm to do this? See picture.

Tried connecting Reduction to my Schiit Magni, still have hum

Pictures of my setup...

 

[lesouthern]

I've also tried connecting the Reduction to my audio technica, with the phono stage switched on. that has a ground connection that I connected. Still getting hum

 

[Jameson]

He’s suggesting the RCA Jack hardware is improperly installed on the amp, I think. Maybe review the RCA jacks and make sure they have the washers and nuts installed as the manual says, which is different than how they come out of the package.

 

[lesouthern]

I connected Reduction straight to my Schiit Magni, with the P2 also getting hum...

Think I have a build issue, but not sure where to start looking

 

[Paul Birkeland]

He’s suggesting the RCA Jack hardware is improperly installed on the amp

Yes, this.  The correct order is shown on page 13.

 

[lesouthern]

I see exactly what you mean.

Printing out the manual lowers the resolution of these images. I totally missed that until I looked at the digital version

thanks much

 

[lesouthern]

Paul-

I'm looking at the front page of the manual, at the RCA tabs. The washers next to the body are all white.

Are these supposed to be the black and red colored washers that come in the kit?

If so could you please send me a closeup picture of the topside of these RCA connectors?

I want to triple check I'm doing this right

thanks

Larry

 

[Paul Birkeland]

I would suggest reading the text in the manual, as it calls this all out very specifically.  The color of the washers isn't important (the photo is of the jack we used to use).  The order is very clearly laid out and the photo on the top right of the screen grab I posted shows the jacks we provide currently.

 

[lesouthern]

Thanks much for the support and patience with this newbie! Corrected the connections and that fixed the issue.

Have a successful Reduction build now. On to the Crack.

 

[Paul Birkeland]

You fixed that pretty quickly!