Eden WT400 Problem

flat5 · #1 11-13-2011, 02:42 PM

Hello! I hope someone can help. My WT400 is over 12 years old - never a problem until about a month ago. It powers an Acme Low B-2, 4 ohm.

The power simply stops and the amp shuts down mid song. The on/off switch looses illumination. I toggle the switch and it used to come back on - the pre-amp warm up takes a few seconds. This power stoppage became more and more frequent and started taking more toggles of the switch to turn back on. Then I had to wiggle the power cord jack. Now it just won't come on. There may be a flash of illumination in the on/off switch but no power at all. I tried another power cord, a different outlet, a different power strip, I checked the fuse. Nothing now as it is on my desk in another room. Out of maybe 20 tries, it did go on once . But it cuts out soon after.

I don't do much electronic work but usually know what the problem is. Here ... ??? The switch, the pre, tubes, the main, the power jack - I haven't a clue and would appreciate any comments.

Thanks,

**B-string** · #2 11-13-2011, 02:47 PM

Could be a bad power switch, could be a fault in the protect circuit. You could jumper (with great care of course) the power switch to eliminate or verify that is the trouble. If the trouble is in the protect circuit it's tech time.

flat5 · #3 11-13-2011, 05:20 PM

Thanks B! I was think switch too, but I can't jump it. No experience. Is it hard/dangerous? Any links to jumping for dummies? Or, off to tech I go. Thanks again,

RickenBoogie · #4 11-13-2011, 06:02 PM

Yes, off to the tech you go. Good luck with it.

timmy1953 · #5 11-14-2011, 04:00 PM

I've had my wt400 since 1996. The only problem I've had is that when it gets dirty it starts doing weard things like making strange noises, and or loss of power. You might try having your head professionaly cleaned. Good luck.

Corporate Boy · #6 11-14-2011, 04:31 PM

mmmm.... i just started getting weird noises in my WT-400. I have never cleaned it. It has been around the block several times. I'll need to look into cleaning mine.

Bean639 · #7 11-14-2011, 04:39 PM

I have had this problem with my WT800. The amp has a built in shutoff circuit when it starts to overheat. In my case I was not pushing the amp any harder than normal. I took it to a tech and it was very dirty and had a few loose joints at the amp output jacks. (all of witch causes extra heat) A year later, the amp seems to perform very well now.

Hope this helps!

andertone · #8 11-14-2011, 07:37 PM

I had a similar problem with my WT400, in the middle of a song when I was pushing it and with a bit of bass boost (not excessive, but enough to move air), my amp would shut off for several seconds (seemed like much longer) then come back on.

Sent it to tech support and it's been working well ever since,
but I don't push it (this with a 4 ohm Bergie HT112/EX112 mini stack). At 8 ohms (one cabinet) this never was a problem.

Play a Streamliner 600 now with the Eden as backup, I like what the low end magic Andy (Agedhorse) has designed into that amp

JES · #9 01-18-2012, 07:48 PM

Hey Folks,

Reanimating this thread.

I seem to have lost all the power and low end from my WT-400. It's an issue both out the speaker and through the headphone outs. And it doesn't matter what the input is--bass or synth. Is this likely to be a tube issue or do I need to get it serviced? If so, is there any reason to send it to Eden or can a local tech fix it?

Thanks!

Interceptor · #10 01-18-2012, 08:24 PM

The schematics are published, and the parts used aren't anything odd so a local tech has a good shot at fixing it.

The config of the power amp section is really familiar to those who have gored on a AMP, Gibson or even SWR. The preamp isn't at all weird.

Most failures will be in the power amp section. The way the circuit works, the devices that will get hammered are the output transistors, the series resistors and the driver transistors. The Zeners get whacked as well. What I like about the design is that all the parts are easy to obtain, and the parts that get sacrificed are cheap. The way it fails saves one from frying the expensive stuff.

Great little amp. Worth fixing. Take it to a decent local tech.

Jim

vin*tone · #11 01-18-2012, 08:33 PM

Where can you get schems for an Eden?

**B-string** · #12 01-18-2012, 08:35 PM

Yes it could be a tube also could be the effects loop. Try an instrument cable from effects send to effects return and try it again.

MuthaFunk · #13 01-18-2012, 08:50 PM

Quote:

Originally Posted by vin*tone

Where can you get schems for an Eden?

I'd like to know this as well. WT-400 Schematics anyone???

Interceptor · #14 01-18-2012, 09:08 PM

Here's the preamp: Modifying Preamp Frequency Response - Eden WT-800 to WT-400

Go hunting for a AMP 420 and you're in the neighborhood of the Eden 400. Pretty much the same thing. Once you've grasped the 420 circuit, all of the children are easy.

The 400 schematics are out there. I just can't find 'em fast.

The amp section in the Eden 400 is close to an AMP 420. The Eden has a few differences, but the concepts are the same. As a tech, once I get the concept of a design, I'm happy. I figure most techs are wired the same way. MI gear tends to follow design patterns. Once one identifies the pattern, things becomes easier to troubleshoot. MI gear is built in such small quantities that a bit of pattern recognition and creativeness is needed by a repair tech.

js1 · #15 01-18-2012, 09:13 PM

Do a google search, then select images. A bunch there.

There's a number of different issues that old WT400s have. I know, because miine has had them all:

Voltage dropping power resistors failing
JFET going noisy
Fan failing, causng overheating

The small signal diodes also sometimes fail, which I replaced while I was at it.

Even though I have an electronics background, I was lucky to have a chat with a gent who did factory warranty work for Eden. He gave me the list above.

js