02-02-2015, 10:39 PM
Murf
If you have another 90 (with an SE Output) or better yet a 70, you could use its speaker to see if it is the problem.
One more way (used it myself):
1. Make sure the field coil is good (3.2kOhm or so...)
2. unsolder the output transformer secondary and connect it to any PM 4 Ohm or so speaker, and
3. See if your sound improved.
4. While at it, measure acrss the unsoldered voice coil, should be about 0.7 Ohm.
If no help, see if the output transformer is good, replace if necessary.
Have you checked the tubes?
If you have another 90 (with an SE Output) or better yet a 70, you could use its speaker to see if it is the problem.
One more way (used it myself):
1. Make sure the field coil is good (3.2kOhm or so...)
2. unsolder the output transformer secondary and connect it to any PM 4 Ohm or so speaker, and
3. See if your sound improved.
4. While at it, measure acrss the unsoldered voice coil, should be about 0.7 Ohm.
If no help, see if the output transformer is good, replace if necessary.
Have you checked the tubes?
