Jump to content

Firstwatt F5: Why some people should not DIY


spritzer

Recommended Posts

  • Replies 102
  • Created
  • Last Reply

Top Posters In This Topic

Yay, 1 channel running. Noticed some very funky instructions in the Pass guide to this amp - it says to start with both trimpots at minimum - that resulted in about 8V across R12, had to very quickly adjust it to get a more reasonable voltage, was scared I burned something.

Second channel is getting some funky bias settings (where I reversed PSU polarity), replaced R11/R12 and 450/550s and the input jfets, but can't get above 0.4V across R11/R12. Could the mosfets be fried? It sounds strange, as I'd expect to get 0 output then. This board was getting 0V across the resistors before I replaced 450/550s. No change after replacing the jfets. Any ideas? I'm a little lost, not really sure what to replace next, except the mosfets as all the resistors look fine (not burned).

i used the Vishay-Sfernice T93YA trimpots and "minimum" = fully clock-wise. also, i got very little V movement with rotation and then, bam, i was sitting at 1.5V.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.