[SteveRB]

hey,
I've been trying to rewire the Hammond 1645 transformers on my Maple tree Audio stealth 60 from 8 ohm (stock wiring) to 4 ohm...

i followed the wiring directions on the manufacturer's specs but when the amp is hooked up to speakers, all i hear is a soft, line level crackle...   HELP!?!


I have attached the green and green/yellow leads to the positive speaker terminal and left the two black leads attached as they were.

Im not a total dummy, but i m also not an electrician. Is there anything i'm missing?


I will try putting it back the way it was as a control test, but please can someone walk me through this ... Lloyd?

[SteveRB]

ok,

wired it back to 8 ohm as it was, but now, no sound.    Damn it! 

I hope i haven't wrecked anything...  please any guidance?

The most i can say is that the crackle sound seems to only be coming from the left side. Other than that, the unit seems to power up normally (light, fuse, heat).

my process for the rewire is as follows:
1. cut the yellow lead that from transformer to speaker a/b switch
2. cut solder joint linking green green/yellow lead from transformer
3. taped off yellow lead from transformer (not needed for 4 ohm hook up)
4. spliced green green/yellow leads to positive terminal on speaker selection switch using yellow wire previously attached to transformer.
5. Repeated these steps on the other side...

[scottnixon]

When I looked at the manual, the yellow wire is the positive 8 ohm tap (see the arrow on the tip). The green+green yellow are tied together but don't attach to the positive post, only the all yellow wire is.

[scottnixon]

If you want a switch 4 and 8, then binding post to common on a bigass SPDT and yellow wire to one side and green/green yellow to the other.  That said.. if in your trials, you accidently ran the output trans unloaded, you could have damaged them.  Hopefully not though. 

[SteveRB]

Scott, thanks for the reply,

When I looked at the manual, the yellow wire is the positive 8 ohm tap (see the arrow on the tip). The green+green yellow are tied together but don't attach to the positive post, only the all yellow wire is.

yes, the situation you describe is the stock wiring for the unit: in the 8 ohm configuration. It is not my intension to have a 4 to 8 ohm switch, but to simple wire the amp for a 4 ohm speaker load. It is my understanding that to do so the yellow wire is no longer used and the combined green green/yellow now become the positive 4 ohm tap.  that is how i wired the amp which caused the problem...

Below is the link to the transformer wiring diagram.

http://www.hammondmfg.com/1608.htm

Is there a procedure i can do to test the transformers? Did i also possible damage my speakers and/or preamp?

I hope we can figure this out...

i really hope we can figure this out.

[scottnixon]

The yellow would still be used for feedback purposes in all likely hood, so I wouldn't tape it off completely. 

[SteveRB]

well, there was is problem. i  understood from the diagram that the yellow is not used in the 4 ohm configuration. can you please outline how the wiring should be set up?

I have it as follows:

white - not used
yellow - not used
green/yellow - positive terminal on a/b selector switch
black/yellow - negative terminal on speaker post

green - positive terminal on a/b selector switch
black - negative terminal on speaker post

(black and black/yellow are jumpered together at the speaker posts)

again, thanks for your help.

[SteveRB]

Thanks to all that replied.

Lloyd at Mapletree was able to help in solving the problem.

I am listen to music as i type...  awesome.