Hum and no audio

[Paul Birkeland]

6-13mv takes a bit to get there starts at like 6 and slowly climbs
27 -12mv takes a bit to get there starts at like 6 and slowly climbs

Ignore what I said previously about 19.  What we see with 6 and 27 is the amplification after the first stage.  You have 13mV and 12mV of signal coming out.  This is way lower than what I would expect with 2.5mV of signal coming in, but it's consistent.

Can you carefully measure the AC voltage again at 10 and 23?  If you have 12-13mV at 6 and 27, you can expect far more than that at 10 and 23. 

 

[ryburdman]

10-230 mv
23- 140mv

I just want to mention as to make sure i am doing this correctly. When I am just holding the red probe in the air with the black connected i am reading around 260mv, if I unclip the ground and just hold both in the air I am reading 60mv. The readings I am giving you are when black is clipped to the ground and red its touching 10 or 23.

 

[Paul Birkeland]

Yes, the black probe needs to go to the ground lug on the chassis and the red probes to the terminals in question.

The reading on 23 indicates that your Reduction is passing some signal, but not a sufficient amount.

Can you post some fresh photos like the first set you posted?  In that set of images, I saw lots of issues and perhaps some of those are still present. 

If all else fails we can get you setup with a flat rate repair, but I would not at all be surprised to find that if I reflow all your solder joints, your Reduction will work fine. 

 

[ryburdman]

Here is a new set

https://photos.app.goo.gl/v5dcuCkjJgmHqJyB8

 

[Paul Birkeland]

The 0.47uF cap on the left channel looks like the leads are snapped coming out of one end.

 

[ryburdman]

I have checked both sides of both .47 uf caps it feels and looks solid not snapped but here are some close ups.

https://photos.app.goo.gl/uGH5pseHvAmEJkACA

 

[Paul Birkeland]

An optical illusion then. 

I'm not sure I have anything else to offer.  The signal tracing seemed to indicated that audio is making it through your Reduction, albeit with some channel imbalance, but your audio tests indicate just hum and no audio.  While we can do a flat rate repair for you, it seems equally likely that either your Reduction will work OK here or this will just be a matter of solder joints. 

Let us know how you would like to proceed.

-PB

 

[ryburdman]

What are we looking at for a repair fee?

 

[Paul Birkeland]

Since your kit is assembled with the stock parts and doesn't wildly deviate from the manual, you're good to go with the old $125 flat rate repair.  We can setup the order and UPS you a box and packing materials, then you are responsible for shipping the amp to us with those materials and paying for return shipping on the repaired kit back to you. 

 

[ryburdman]

Ok great, I am going to give it one more try to flow the joints, cross my fingers and see if that does it, if not I'll send it in.

 

[ryburdman]

One of the things I am trying is swapping the tubes to see if the problem follows them. As I do that I'm noticing the Left side (black) tube socket is really tight and tough to seat the tube. Could this be causing the issue?

 

[Paul Birkeland]

A tight socket is generally a very good thing.

 

[ryburdman]

Ok I give up, Ill send it in. What do I need to do to start that  process.

 

[Paul Birkeland]

You can call the office or e-mail queen@bottlehead.com.  Let Eileen know that we have chatted on the forum and I've sent you to her for the repair service and she'll get you taken care of.

-PB

 

[Paul Birkeland]

I got this kit on the bench today and it's impeccably built and perfectly functional right out of the box.