Author Topic: Weak output from my WT300  (Read 579 times)

Offline thefretman

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Weak output from my WT300
« on: December 18, 2018, 09:04:17 PM »
Hi guys new to the forum. Just got hold of an older WT300 hybrid and am having trouble getting any wattage out of the unit. Cleaned the jacks and pots with contact cleaner still weak output. Need to crank the input to 2 o'clock and the master past 3 o'clock to get maybe 2 watts into my 8 ohm 15" cabinet. Cabinet is okay with another amp.
Can we get a hold of a schematic for this unit so I can track down the signal chain.
Thanks,
Motown and R&B guy
Eden WT300 w/ 15" cabinet
Musicman Sterling 4

Offline Rip Van Dan

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Re: Weak output from my WT300
« Reply #1 on: December 19, 2018, 01:01:20 PM »
Hi thefretman,

Wow, you got one of David's first hybrid amps.  I have a pdf file of the manual for you if you'd like to PM me your e-mail address.  I believe we have a minimum post rule that doesn't allow you to PM another member until you've posted a few things, but you can easily meet that requirement by posting a few things in the testing area. If you don't already have the manual, please let me know.  The manual has some very specific info that you need to follow to get the best out of your amp.

Most of the time the problem you describe is caused by corrosion on the various contacts and cleaning ALL the 1/4" input and output jacks, paying particular attention to ones that are rarely used clears it up.  The signal chain runs through virtually all of them on the back of the amp and if one of them has some corrosion on it, it will drastically reduce or stop the signal from getting through.

Looks like you've already done that so it's probably going to be a bigger problem.  Armin (Bassmann1968) will probably drop by shortly and ask you some more pointed questions.  He is an electronics wiz and knows the Eden amps and cabs inside and out.  He'll be able to help you with troubleshooting that.

Dan
Rip Van Dan
Dan Gracia
'82 US-made Fender Jazz Bass with maple neck
5-string Rogue LX405 Pro (Surprisingly good "no-name" bass)
WT500/800 Highwayman (signature model)
D.N.S 410-8, Eden EX112 x2
Line6 G10s wireless
==
spares:
Eden RS400, GK BK250, BPX115 cab, acoustic B410 cab, Sunn Beta 202 (2x12)

Offline Bassmann1968

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Re: Weak output from my WT300
« Reply #2 on: December 19, 2018, 02:34:52 PM »
Hi,
try to feed a signal to the FX return. Result?
Try a patch cable from FX send to return. Result?
Rock on!
Armin

PLEASE LIKE EDEN ON FACEBOOK!!!
No schematics available!!! Don't ask for it.
;)

WTP-Pre,1350,WTX260,WT300/400,WT1000,WTX1000N,NAV,WTDI
D112XLT,D210XST,D410XLT,D810RP,DNS410,DNS112

Offline thefretman

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Re: Weak output from my WT300
« Reply #3 on: December 19, 2018, 10:54:38 PM »
Hi Bassman1968.
With the feed into effects return I have the same levels as previously. I turn up the master and get it tooutput limit with the red led. With my scope I am sending about 2V pp to the power amp PM400. B+ is around  70V and B- is also  minus 70V. seems like the amp wants to go but gets trottled back when the output limt comes on. Not sure what normal levels out are from preamp to amp. Do have a preamp schematic but no luck with the power amp schematic. Amp was made in 1997.
Motown and R&B guy
Eden WT300 w/ 15" cabinet
Musicman Sterling 4

Offline Bassmann1968

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Re: Weak output from my WT300
« Reply #4 on: December 20, 2018, 12:40:53 AM »
Hi,
HV is ok.
2V is a bit high, but should work. Normal is 1.0-1.5V.
Schematic is a problem since Eden is not giving them away to the public.
Check Q1 and Q2 on the PM400 board. Those should be J112. They are for the Mute circuit and I bet they are broken.
Rock on!
Armin

PLEASE LIKE EDEN ON FACEBOOK!!!
No schematics available!!! Don't ask for it.
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WTP-Pre,1350,WTX260,WT300/400,WT1000,WTX1000N,NAV,WTDI
D112XLT,D210XST,D410XLT,D810RP,DNS410,DNS112

Offline thefretman

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Re: Weak output from my WT300
« Reply #5 on: December 20, 2018, 09:46:35 PM »
Found a PM400 schematic on the web. Seems like C4 is the culprit. It was pulling down the voltage to the current
transistors in the input section. Have all the amp power now. Did David make these at home cause it seems
pretty bare bones for soldering on the boards. No time to clean off the rosin from soldering in the components.
A lot of wires strung along the underside of preamp boards to the tubes, etc. Boutique I guess. Sound is good.
Is there a mod for getting the compressor in/out with a switch?
Cheers!
Motown and R&B guy
Eden WT300 w/ 15" cabinet
Musicman Sterling 4

Offline Bassmann1968

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Re: Weak output from my WT300
« Reply #6 on: December 21, 2018, 01:19:29 AM »
There was never such a mod offered.
I also never saw anyone doing it.
I had plans for my WT300, but never got the time for it.
Thanks for the feedback on C4.
Rock on!
Armin

PLEASE LIKE EDEN ON FACEBOOK!!!
No schematics available!!! Don't ask for it.
;)

WTP-Pre,1350,WTX260,WT300/400,WT1000,WTX1000N,NAV,WTDI
D112XLT,D210XST,D410XLT,D810RP,DNS410,DNS112