Back in the day I had an 8ohm Acme 410, which I paired with a bridged WT-800A... Only then did I experience thermal shutdown, at moderate levels no less. While the Acme cab is rated at 800w, it really likes a lot more juice and severely taxed my Eden. I sadly parted ways with the Acme and moved on to more efficient cabs, such as SVT 810s and Schroeder. The head will run hot under heavy use, but it has never shutdown on me since.
I recently took my Eden in for a DI repair and had my tech add a switch on the back that gives me the option to continually run the fan. The theory is that it maintains a cooler temperature, avoiding spikes in heat. Although, anyone who owns an early Eden knows how loud the fans are, so it's really only an issue in the recording studio. Speaking of, there's been mention that reversing the fan reduces the temperature by 10%, but I don't think anyone mentioned that it's also supposed to significantly reduce the fan noise too, is this true?
For those who have reversed the fan, is it as easy as just unbolting the fan and reversing it? Is there any soldering or other trickery that has to be done?
Thats cool...Our LOUD azz guitar player asked ..."why would you want to do that"? I said....Because I can! Ha! I am playing as a fill in for a jazz & blues group...they love deep, well rounded bass..one of the few bands(not that much exposure to date) that actually ask me to turn up...the trio...not so much...yet the guitar player/lead singer is loud as heck...and he loves it. Thanks for following along with your input..I'm a breath away from buying a 5 string deluxe Fender jazz..2 18's and a 4 10 will provide an awesome sound...IMO...Peace!
I just unbolted the fan and put it in reversed..there were small washers glued on the fan mounts in mine..One came off and ended up in the fan some how...I thought it was rubbing on the chassis...it was the washer...took it apart and it simply bolts right up..I'm going to cut the vent slots out as per Eden's instructions.. I also drilled a bunch of holes in the black amp cover to enhance airflow as described above. My fan wire was wrapped up pretty tight with a tyrap.. go easy with it allowing slack to move the fan about so ya don't break it of where it's attached to the board.
Very cool! I could certainly email Ivan myself, but was wondering if you could forward on that detailed instruction sheet on how to build that mod?
Here is what IR sent back to me...
Authored by Ivan Richrads,,,the heatsink was simply an offcut of
right angle aluminium extrusion
the dimensions are not critical
is more about what will fit in the
narrow space within the WT800
I drilled out eight mounting holes for
the four aluminium clad resistors
get your service tech to check out
the photos, he can probably work out
some suitable dimensions
it is highly likely you have some "dry"
solder joints on one or more boards
in your amp, judging by your description
of the fault conditions, which should be
desoldered, cleaned up, and resoldered
by someone with good soldering skills
and a temperature controlled soldering
I just did my WT400 + Pre-Amp Power Dropping Resisters mod. Here's pics showing it before and after:
You can see the little Ziener diodes took some serious heat just by proximity to the dropping resisters:
You can see the soldier connections we're really heated up in the area. I wouldn't be surprised if the amp was at one point running on a gig with molten soldier connections and not have any problems due to the way the secured the resisters with glue. Poor design but expertly executed to correct for the issue.
The WT400 has plenty of room to mount the resisters right to the chassis making this job somewhat easier. I left the amp on for hours without playing it and the resisters only got moderately warm. The little bit of heat generated seemed to transfer nicely to the chassis as I hoped.
The original resisters were rated for 5 watts and did not look discolored at all so I believe they are properly rated for the application. Just their location wasn't ideal. That said, I still doubled the power handling of the resisters and choose 10 watts each. With this mounting scheme they are also situated directly in line with the cooling fan.
I'm going to take this amp on my next couple gigs and give er a good run and monitor the heat dissipation. I highly recommend anyone with a WT series amp consider this mod for the longevity of the amp. If the preamp board is continually heated up the traces could eventually become damaged and repair is extremely difficult to keep it reliable after that.
Was thinking about this thread and though I'm sure this must have been tried... Reseating the tube on my old WT800A solved a distortion and hissy thing that I encountered...
Biamping... If you want a revelation... Biamping a 12 or 15 /6 design is freakin' amazing with a WT800. I mean like seriously cool tonal possibilities there. Miss my old WT head but I just don't need that kind of HP on stage anymore. If i did, I'd still own it. Mine was just a workhorse.
I think I'd know normal if I saw it ... 'Calvin
Nice looking work! I just came from my tech shop. For 200 bucks they will do the resistor mod along with other mods to enhance airflow and support the circuit boards. The owner is an Eden freak..loves the stuff. Just bought a new bass so I have to wait. Was going to b uy this bass used here but the seller took it of the market...then called the day after I bought a new one to offer it up again. Oh well..the cookie crumbles no matter what.
Quick update...Worked the ole WT800 pretty hard tonight for about 2.5 hours..2 sets about 1hr 15 min each. I placed a small computer fan in front of my amp, blowing thru the road case. I dont think the internal fan ever came on. The few times I checked it..it wasnt running. Matsr at about 12 oclock...gain about 2 oclock..Passive jazz.. Rocked the joint..The issue was heat build up IMO,,in my case......perhaps the tight case added to the problem. Hopes this helps others. Peace!