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Eden WT-800
- Thread starter Dilfis
- Start date
Welcome to TB!
The schematic shows a single 12ax7 tube in the preamp section, possibly a Ruby.
This older thread indicates that changing the preamp tube didn't render much change.
https://www.talkbass.com/threads/new-tubes-for-my-eden-wt800.188135/
Others think there is some influence, but that the stock tube is fine.
https://www.talkbass.com/threads/preamp-tubes-for-eden-head.147852/
Most sources I've seen state that while the 7025 is claimed to be low noise, is is essentially the same as a 12ax7.
The schematic shows a single 12ax7 tube in the preamp section, possibly a Ruby.
This older thread indicates that changing the preamp tube didn't render much change.
https://www.talkbass.com/threads/new-tubes-for-my-eden-wt800.188135/
Others think there is some influence, but that the stock tube is fine.
https://www.talkbass.com/threads/preamp-tubes-for-eden-head.147852/
Most sources I've seen state that while the 7025 is claimed to be low noise, is is essentially the same as a 12ax7.
The 7025 will certainly work just fine. Eden uses a Ruby 12ax7 tube, but any good 12ax7 works fine. The 7025 tube was the low-noise version of the 12ax7 and used to be a more expensive tube. With modern 12ax7 tubes though, they are just as quiet as the 7025's and the 12ax7 was the OEM tube used. But if you have an extra one of those 7025's and want to use it, it will be fine. Be aware that rolling different tubes through the Eden WT amps won't really give you any discernible difference between them. The tube is in the impedance matching section and is operating within some pretty narrow parameters to add the tube warmth. You cannot get any overdrive, let alone distortion like you can get out of a tube in a Gain circuit.
When Marshall bought Eden they came out with a new WTP series which had the 12ax7 in the impedance section as normal for that warmth of sound, but also had a 12ax7 in the Gain circuitry and you could control just how much overdrive or absolute dirt you got out of the amp by just adjusting the "Tube Mix" control on it. You can get different sounds out of that amp by rolling tubes in the gain section, but not in the impedance section.
So now the question is, "which WT800 do you have?" There were a bunch of different ones - the WT800A model plus its updated versions which were b, c, and d. So you could have an A model or an A model with a b, c, or d version - confusing! Those would put out 400-watts rms per channel into 4Ω and bridge at 800-watts rms into 8Ω. My WT500/800 has the A model power section.Then there was the WT800B, which came out in July of 2005. It would go down to 2Ω per channel and deliver 550-watts rms into 2Ω. It would bridge at 880-watts into 8Ω or 1100-watts into a 4Ω load.
Finally, the WT800C model came out before the end of 2005 and it is very easy to identify because the Eden logo on the front of the amp lights up and it's the only one of the WT amps that does. It has the same features as the B model with a few extras and an addendum was included with the WT800C amps.
A sneaky thing that Marshall did right before they released their new WTP series was changed the text on the back of the amp at the bridged output from saying, "Bridged Ouput Only, 4Ω minimum" to "Bridged Ouput Only, 8Ω minimum". I personally think they did that because their new WTP900 amp couldn't handle a 2Ω load per channel or a 4Ω load bridged. So the new amp with all its bells and whistles wasn't as powerful as the older WT800C. When those amps started showing up with the 8Ω minimum on the bridged output, we thought it was just a misprint. When we got in touch with our Eden Forum contact with HQ, we were told they changed it because they didn't feel comfortable with running it bridged at 4Ω. Of course running bridged at 4Ω put out 1100-watts rms and the new WTP could only produce 900-watts.
Armin, who was the other active moderator of the Eden Forum back then and also the Electronics guru for the forum, popped one open and sure enough, it was exactly the same as every other WT800C. Marshall admitted they hadn't made any design changes and only changed the text on it. They claimed they weren't "comfortable" saying it could operate at 2Ω per channel and 4Ω bridged, even though the WT800C had been in use for 11-years at that point and never had a problem running at 2Ω per channel or producing 1100-watts bridged into 4Ω.
Anyhow, if yours is the WT800C that Eden logo will light up. We used to call it the "porch light". That porch light is also used on the Eden Terra Nova (TN models) class D amps, but you won't mistake one of those for a WT800. I have one of those TN amps and that light is just bright enough to be noticeable without being glaringly bright. Outside of that, if you don't have the porch light on yours, take a picture of the back of your WT800 and post it here. Then I can check it out and send you a pdf copy of the Manual for the one you have.
Thanks Rip, mine is a "C" model. It's about pretty old but has had low hours up till about a year ago. It's been a "daily driver" ever since.
I'm opening it up to spray clean the pots and do some housecleaning and wanted to make a decision as to what tube to order for
replacement; just for GP. I'll do an AX-7. My question concerning the 7025 came from having had one the first SWR 200 heads, it contained
a 7025 for the preamp. It was a lovely circuit, but a little under-powered for my tone shaping. I'm running two Aguilar 12's in 'stereo' at 350w per
cab @8ohms ea. Everything nicely responsive to my ear and out in front. Sad that Eden hasn't left the 'US' with any product support.
Thanks again
Thank you abarson, your info and links correspond with stuff that I've dug up recently. Just checking here for additional thoughts. I'll be using a Ruby 12AX7. Any other 12AX7 designations that you'd care to share? I forget what they may be; 12AO7, 12L7...etc...I don't need a change for any reason as I've come to
think that the circuitry is designed and tested with a specific tube in place. Amp sounds wunnerful and gives me all the parameters I want.
Deoxit is the only recommended pots cleaner, and even that must be with as little as possible applied.
Again, don't fix what isn't broken.
- Feb 12, 2006
- 60,963
- 5
- 220,655
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
The changes are likely needed to comply with modern safety standards. Bridged into 4 ohms probably increased the power transformer’s operating temperature beyond safe limits during the normal or abnormal test cycles. This is not uncommon.
That's a valid concert @agedhorse, but I don't think it bears out. That amp came out in 2005 and it wasn't until Marshall's release of its new Eden WT600 and WT900 amps that they changed that 4Ω minimum load off the bridged output and put on 8Ω minimum load . The WTP amps were actually on the web site in 2015 along with the WT800C and in 2015 is when they made that change in the text. Then in 2016 the new WTP series replaced the WT series in the catalog as I expected they would. That's 11 years of history of it working fine bridged at 4Ω or running down to 2Ω on either channel. And a lot of folks ran them bridged at 4Ω over that 11-years of time. Again, this was not a new design. Virtually all of Eden's Endorsing Artists used it and plenty of them were running it bridged into two 8Ω cabs.
Were there any big changes that you recall were made in 2015 as far as safety standards that would have given them cause to do that?
Also, the new WTP900 could only bridge into 8Ω and that was an embarrassing limitation for them because that new amp couldn't deliver 900 watts to Eden's own hallmark D810XT 810-cabinet, which was a 4Ω cab and it really wanted all 900-watts (power handling is 1700-wattsrms). But the best you could get that amp to deliver was 450 watts rms into that 810 cab whereas the WT800C would deliver 1100-watts into it - more than twice the power. You could run two 4Ω cabs bridged into it though because if you plugged two 4Ω plugs into the amp, it automatically ran them in a series connection instead of a parallel connection if you selected bridged mode. So the amp saw an 8Ω load and would deliver all l900-watts to be split between them. That was actually a pretty cool solution! But if you plugged two 8Ω cabs into it, then it would see a 16Ω load and could only send out 450-watts to split between them. No such problems with the WT800C.
Yeah it sucks! If yours has the porch light, then you're good. I really wouldn't spray anything into the pots yet. Let's see if we can get Armin @Bassmann1968 to offer his opinion on this. I believe he was the one who told me not to do it. And, besides being the electronic guru moderator on the Eden Forum, he was an Eden authorized repair tech before Marshall sold them to Gear4Music.
For a temporary fix on crackling pots, turn them quickly all the way up and down multiple times. That will at least temporarily get rid of the dust from that contacts that usually causes that. But I believe there is a spray that will work on cleaning up the Eden pots but it's not DeOxit5 which is what you use for all the jacks.
- Feb 12, 2006
- 60,963
- 5
- 220,655
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Were the amps safety certified to 60065 before the change? My educated hunch is that the change went hand in hand with safety certification. Much the same happened with SWR after Fender acquired the company.
It doesn’t necessarily mean that it doesn’t work, but that it won’t comply with the requirements of the safety standard.
Well Nuts Andy, I don't know when the 60065 safety certification first came out. If it came out in 2005 or earlier than yes, I would presume so. If it came out afterwards, I would be skeptical of it getting that certification. The B model and C model both came out in 2005 and the C model had an addendum noting the cosmetic and internal differences between the WT800B and WT800C. I've attached the Addendum to the manual for the C model and they do mention some additional safety measures the B model didn't have, but I have no idea if those changes might be ones that were made to meet that certification. It's a one-page addendum and the internal changes are in the bottom half of the page.
Would there be a stamp, label, or icon on the back of the amp that would verify one way or the other? Here's the back of the amp if that helps:
- Feb 12, 2006
- 60,963
- 5
- 220,655
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
There's no indication that it meets IEC 60065 and CE is a self-declaration that is (or can be) more or less meaningless. It's also missing some of the essential labeling elements, specifically that the durability of Sharpie labeling won't pass the rub and solvent test. It's impossible to know for sure without the documentation. The newer (IEC 62368) standard is even more restrictive, which is likely what the newer models comply with and there is MUCH more scrutiny regarding the testing for faults and component temperature limits. It doesn't necessarily mean that the product is unsafe, but that it can't pass the testing to prove that it is safe.
Because of the ridiculous (IMO) costs associated with testing, it was pretty common in the older days to get it close enough and simply accept the risk. These days it's more difficult to go around these requirements because the bigger companies, dealers and distributors are wary of getting dragged into a safety related lawsuit and/or penalties. Each country or region is different, and that adds even more confusion.
I believe their early amps used Ruby tubes rebranded to Eden. They were 7025s. Later, I think they just used regular Ruby tubes.
Thanks @agedhorse. Maybe I'll give Marshall the benefit of the doubt then. The changing of the text on the amp and the release of their newer, lower performing amp sure seemed awfully coincidental. According to that serial number, which is indeed put on by a Sharpie, that amp was made in 2008. I think my 1999 Eden amp had all of those boxes entered with a Sharpie and not just the serial number. Later ones, like that 2008 amp, had only the serial number entered by a Sharpie.
I always appreciate your insight @agedhorse even though some of it is Greek to me!
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