• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Eden WT400 repair/mod

What Eden WT do you rock?

  • Total voters
    60
#101
6thplanet said:
Do the 300 and 400 watt output boards look different? Maybe take some pictures to compare?
Click to expand...
Yes they do, but I don't have pictures of the power section. Armin (@Bassmann1968) might have some if we're lucky. The only picture I have is of the inside of my WT500 that was upgraded from bridged at 500-watts to bridged at 800-watts. Mine has two more big, fat, black, capacitors than the original power section does (total of 6 instead of 4 capacitors). It was an easy upgrade for him to make because the power sections of the WT500, WT600, and WT800 are all the same and just the power supply is different. My 800-watt version has 6 big black caps whereas the original WT500 had four. It also has a larger toroidal transformer than the WT500 does.

So odds are the WT400 has at least one more capacitor than the WT300 and might have a larger transformer too, but I just don't know.

This is the inside of my WT500/800 while it was still sitting on David's test bed for cabs. This NOT the WT300 or 400, but it's easy to see the black capacitors and the toroidal transformer. Those are the parts I'd expect to be different. I'm not actually sure if the WT300 and 400 had the toroidal transformers. They might have had the square block-type transformer.:
Hwyman500HotRodInside.jpg
 
  • Like
Reactions: 6thplanet
#107
The original WT-300,400,500,600,800 all used the same PM400 power amp module. The difference was in the power supply... larger transformers and more capacitance, plus the WT-400 has a pull-pot to disable the compressor.

US manufactured WTs seem to have a bit of inconsistency in nomenclature over time as the amps were updated. When the WT-800B (mono bridge into 4Ω) came out, there were a few transition units with the old power modules that were only able to bridge into 8Ω, and some didn't have updated cooling either. There were also A,B,C,D revisions of the original WT-800(A), adding to the confusion. From what I gather, Chinese made WTs were more consistent, and also had less idle hiss. My 1994 WT-500 had a surprising amount of idle noise, so much that I modified the gain staging to lower it.
 
  • Like
Reactions: AudioTaper, Bassmann1968 and fruitlabor
#108
12bass said:
The original WT-300,400,500,600,800 all used the same PM400 power amp module. The difference was in the power supply... larger transformers and more capacitance, plus the WT-400 has a pull-pot to disable the compressor.

US manufactured WTs seem to have a bit of inconsistency in nomenclature over time as the amps were updated. When the WT-800B (mono bridge into 4Ω) came out, there were a few transition units with the old power modules that were only able to bridge into 8Ω, and some didn't have updated cooling either. There were also A,B,C,D revisions of the original WT-800(A), adding to the confusion. From what I gather, Chinese made WTs were more consistent, and also had less idle hiss. My 1994 WT-500 had a surprising amount of idle noise, so much that I modified the gain staging to lower it.
Click to expand...
Can you tell from the pictures what this is? It does have the pull pot on the compressor and it does have idle noise. The back says 1993. Inside it says 1997. You can see WT402 on the main board with the controllers
 
Last edited:
#109
fruitlabor said:
Can you tell from the pictures what this is? It does have the pull pot on the compressor and it does have idle noise. The back says 1993. Inside it says 1997. You can see WT402 on the main board with the controllers
Click to expand...
Looks like a WT-400 to me, though it may have started life as a WT-300 and was upgraded at some point, maybe even during manufacturing as an in-between WT-300/400 unit. Eden offered a 400W upgrade service for several years, so it may be one of those. Regardless of the markings, it looks to be functionally the same as a regular WT-400. It has the WT-400 preamp board. The transformer looks fairly beefy. Without a WT-300 and 400 to compare directly, I can't be 100% certain, however.
 
  • Like
Reactions: AudioTaper and fruitlabor
#110
12bass said:
Looks like a WT-400 to me, though it may have started life as a WT-300 and was upgraded at some point, maybe even during manufacturing as an in-between WT-300/400 unit. Eden offered a 400W upgrade service for several years, so it may be one of those. Regardless of the markings, it looks to be functionally the same as a regular WT-400. It has the WT-400 preamp board. The transformer looks fairly beefy. Without a WT-300 and 400 to compare directly, I can't be 100% certain, however.
Click to expand...
That’s what I figured. It’s strange that it has 260 watts marked on the back. Thank you for your response
 
#115
Hi All,

Well, finally got the right info for his amp for @fruitlabor. He sent me a bunch of pictures and I sent them to Armin (@Bassmann1968 ), who was a moderator on the old Eden forum and the electronics guru of the forum. He took a look at the pictures and wrote me back. I forwarded his comments to @fruitlabor.

So, here's the story:

• The housing and the preamp are both WT400.
• The power amp is a WT300/400 because they had the same power amp, just used different power supplies.
• His power supply is from the WT300, so 300-watts into 4Ω is that maximum the amp will do as-is.​

So he got the preamp upgrades that came with the WT400 but not the power supply.

The power supply upgrade would be an easy thing to do because that chassis is designed for it, but the cost of the larger toroidal transformer is likely to be as much or more than the $200 he paid for the amp. The amp was finished on May 14, 1993 and it might have been right as Eden was moving to its bigger shop. So it might have been put together from the parts they had on-hand at the first shop as they were moving? Doubt we'll ever know "why" for sure, but at least now we know the "what" .​

Was a tangled web, but once again, as he did at the Eden forum, @Bassmann1968 comes through with the answer.
 
  • Like
Reactions: 6thplanet, Bassmann1968, AudioTaper and 1 other person
#116
Bassmann1968 said:
Short version, it’s a WT400 with WT300 power supply and transformer.
Rock on!
Click to expand...
An Eden WT-Unicorn.

Now I'm wondering about its back story. Did someone install the WT-300 PS into a WT-400? Or is it a half-upgraded WT-300/400? Perhaps a customer requested the WT-400 preamp upgrade without the power upgrade? Or??? One of life's deep Eden mysteries!
 
  • Like
Reactions: fruitlabor

Latest posts

Top Bottom
Back