The bulb goes in series with the live mains feed to the transformer (so primary side). The manual shows no user accessible fuse on the primary side so you can either tag the bulb across the switch (leaving the switch off at all times) and use the wall socket to power the amp on and off, or tag the bulb into the lead or mains plug somewhere. Where ever is easiest.
Attachments
Yes.Ok, if I'm understanding this correctly, I can wire it up like this?
Best way is to to mount a lamp holder to a base of some sort, take an extension lead, open the sheath, pull out the active wire and cut it, and terminate the two ends to the terminals of the lamp holder.
You can also wire a switch to short across the lamp holder, for normal powering.
(You can also solder the active cable ends directly to the lamp.)
60W is a better lamp power to start with.
You can also reduce the output stage bias current whilst fault finding (advisable).
Dan.
Next thing, the compatible transistors appear to be made by Sanyo, Wingshing & Mospec, according to datasheetcatalog.com. I looked up the 2SB817, just to try & get a feel for this. Should i prefer one manufacturer over another?
I would tend to go for more easily available devices such as the types I used in the Marantz thread.
I had a quick look at the package type, the outputs being flat packs.
So MJL21194 and MJL21193 for the output pairs.
MJE340 and MJE350 for the drivers and 2N5551 and 2N5401 for the pre drivers. Those last two are out of production I think but there are lots of others that can be used if its a problem.
What Max mentioned about reducing bias is good advice, you've probably seen similar in the Marantz thread. For your amp that means turning the preset to maximum resistance (so it is like a 1k in circuit rather than a short circuit). Max resistance equals minimum current for this circuit. I would turn the bias down on the good channel to as it allows more current to be available when using the bulb tester.
You are well on your way .I just finished reading both the Kenwood & Marantz posts. Those helped a lot & will be used as reference. Fuses should be here in a couple days. I should have a bulb tester set up by then. It's a busy work week, so progress will likely be slow.
Dan.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Solid State
- Need help with a Rotel RA-970BX