Left channel fading. [solved]

[Samsquatch]

Finished building my Seductor and Smash late Sunday. Building those kits was the most fun I've had to myself, with my pants on, in a long time. So much so I'm looking at the Reduction for my phone pre. Too bad the Canadian dollar has tanked.

Had my first listen yesterday and it was rewarding to say the least. I did notice though that the left channel sounded a little weak, but choked it up to the album, it being a first listen as well. Unfortunately after a little time today the left channel is almost gone. I swapped the tubes in both amps, swapped speakers and wired them up with some new cable but no change. Right channel is strong. All my joints look good. My voltage and resistance checks on the Smash were spot on. The Seductor resistances were good, but with a few anomalies outside of the 10%, but nothing WAY out. Here are the ones that are outside of the given ranges,

12.     27V

18.     71V

28.     69V

I'm only giving those because they fall out of the ranges specified on the voltage check sheets. The rest all fall within the 10% allowance.

Thoughts, questions or concerns?

Mike

[Doc B.]

Try reflowing the solder joints on the left channel terminals.

[Paul Birkeland]

Can you give all the voltages on the two 8 lug strips of the left channel.

27V on terminal 12 is a bit telling, but may reveal more with all the other voltages.

[Samsquatch]

Once work finishes getting in the way of my play time I'll sit down tonight and flow all the solder joints again and then measure the voltages and post them. Thanks guys.

[Samsquatch]

Okay, so I reflowed the solder joints and there was some changes in the voltages but the left channel is still week. Really no bottom end on it.

Here's all the voltages and I'll -> to any changes that took place.

1. 0V
4. 114V
5. 107V
6. 375V -> 347V
7. 111V
8. 0V
9. oV
10. 0V

11. 0V
12. 27V -> 38V
13. 109V
14. 108V
15. 349V -> 321
16. 0V
17. 0V
18. 71V ->38V
20. 108V

21. 95V
22. 375V ->351V
23. 105V
24. 0V
25. 0V
26. 0V
27. 0V
28. 69V ->39V
29. 106V
30. 106V

31. 347V -> 324V
32. 0V
33. 0V
34. 423V -> 389V
35. 211V -> 195V
36. 211V -> 195V
37. 0V
38. 0V
39. 382V -> 353V
40. 0V

41. 0V
42. 106V
43. 354V -> 333V
44. 109V -> 102V
45. 359V -> 334V
46. 0V
47. 371V -> 352V
48. 0V

Hope this helps.

Cheers

[Paul Birkeland]

Can you very carefully get a DC voltage measurement on pin 9 of each EL84 socket?

-PB

[Samsquatch]

I'm getting 330V at both sockets.

[Samsquatch]

As I was checking the voltages at the pin 9s yesterday I noticed that I had not trimmed the 1.07 Kohm that runs from 9L to C7 - C1 and it may have been grounded again near the nut at 1L. Too close to call. Anyways, I was needing some tunes and threw on an album tonight. Left channel is there and clear as a bell and strong. The microphony that I thought came from the sensitivity of the Smash tubes seems to have really calmed down as well. I'm seduced. Time to spin another fuzzy warble.

[Paul Birkeland]

Hello Mike,

This is good to hear! We will be here if you run into anything else.

-PB

[Samsquatch]

That's probably the main reason I went with you guys, support. And the product just looks so so good. And the reviews. And the price points. And now I know how good they sound. And honestly, after drooling over this site for so many years and waiting to make the first purchase, I would have felt like I was cheating if I strayed somewhere else.