Tubelab Simple SE with big honkin' Edcors?

[rknize]

Sorry I am flooding the forum with Tubelab builds. I guess this would be YATSSE?

OK, so even though I knew the rough dimensions of these Edcors, I didn't quite come to terms with their size until they arrived. Man, these things are huge...and heavy. You definately get your money's worth with these guys. There is no way I am going to fit these on the 12x10 chassis I have on hand, so I am going to have to rethink that. I knew they were overkill for this amp, but did I take it a bit too far? They are:

XPWR035
CXSE25-8-5K x 2

After testing with cheap Chinese tubes, I ran this amp for several hours on two evenings with the JJ 6L6GCs. The power transformer barely got warm. So nice have properly-implemented iron again in that respect.



I read a lot about going with oversize output iron to get better low-end frequency response, but there is the other extreme as well. Seems like most builders are going with the smaller Edcors. Has anyone build Simple SE with these guys?

I listened to this amp with the new speakers and was happy with the results (triode, no feedback), but I decided to tear it down and bring the Tubelab SE back to life instead. Guess 2W is enough after all. Never thought I would utter those words....

[Evenharmonics]

I'm not familiar with XPWR035. What are the voltages and are you going to use it on Tubelab SE?

[Richard Ellis]

Isn't it sweet to have everything come together so well?
No there is no overkill there as long as you stay within your output Z parameters. Did you notice the One-Electron high end OPTs??? They have a dimensionally different looking core? Recall that core size vs. winding turns vs. wire diameter vs. power they are all balanced together..change one and the other three must be changed.... a percarious balancing act.
I think the use of the "basic" Edcors is driven by the cost differences.
Its a great thing that your mains TX got "barely warm"....that way you will not have any heat related problems.
Now that your project 'Won't fit' you are free to explore your artistic side. Tube amps are a real artform I believe, both electrically and visually.....let your mind create a real work-of-art........
________________________________________Rick...... ....

[rknize]

Originally posted by Evenharmonics
I'm not familiar with XPWR035. What are the voltages and are you going to use it on Tubelab SE?

It's one of their designs from the PDF posted in their forums.

370-0-370 @ 200mA
6.3 VCT @ 5A
5V @ 2A

[rknize]

Originally posted by Richard Ellis
Isn't it sweet to have everything come together so well?
No there is no overkill there as long as you stay within your output Z parameters. Did you notice the One-Electron high end OPTs??? They have a dimensionally different looking core? Recall that core size vs. winding turns vs. wire diameter vs. power they are all balanced together..change one and the other three must be changed.... a percarious balancing act.

Yes...I have noticed lots of different combinations. I assume it's up to the designers to make use of what bobbins and laminations they have on-hand. I do have the UBT-2s and they are smaller...but have a LOT more laminations than I was expecting. Very nice transformers, but they lack an UL tap so I used them for the Tubelab SE amp

Now that your project 'Won't fit' you are free to explore your artistic side. Tube amps are a real artform I believe, both electrically and visually.....let your mind create a real work-of-art........[/B]

Yeah, I will probably do something interesting with this amp...probably out of some hardware store metal stock or something. Maybe time to try my hand at welding aluminum with the MIG...been looking for a paintable project to try that on.

[rknize]

Originally posted by Evenharmonics
...and are you going to use it on Tubelab SE?

Sorry...didn't see the other half of your question. This transformer is not the best for Tubelab SE. Even 300Bs aren't going to like 460V on the plates. Instead I am likely going to have Edcor make a special transformer for me that will allow both 400V and 300V operation for 300Bs and 45s. The specs are:

330-260-0-260-330 @ 175mA
6.3V CT @ 3A
5V @ 3A

I'll use the 520VCT taps for 45s, since I now have a few decent pairs of these on hand. I haven't bitten the bullet on 300Bs yet, but I probably will at some point to get a bit more oomph. This way I can switch over to the 660VCT taps when I switch the heater config and run the tubes closer to where they like it.

[Evenharmonics]

Originally posted by rknize

330-260-0-260-330 @ 175mA
6.3V CT @ 3A
5V @ 3A

300B needs 6.3V @ 4A min per Tubelab description.

[tubelab.com]

Has anyone build Simple SE with these guys?

YES, I did. It ROCKED!

but I decided to tear it down and bring the Tubelab SE back to life instead.

That's where my big Edcors are now, but my amp still looks like yours. I never had the time to finish the chassis.

300B needs 6.3V @ 4A min per Tubelab description.

If it is not too late 4 amps or more would be a good idea. Generic 300B's draw 1.2 amps, the 5842's draw .3 amps. That adds up to 3 amps of DC out of the regulator so you need more than 3 amps of AC out of the transformer. Some of the "super 300B" variants draw 2+ amps each. They cost far too much for me to even think about them.

Have you ordered one of these universal transformers yet?

[kuroguy]

Originally posted by rknize
Yeah, I will probably do something interesting with this amp...probably out of some hardware store metal stock or something. Maybe time to try my hand at welding aluminum with the MIG...been looking for a paintable project to try that on.

Try some nice wood for the frame and a piece of aluminum plate for the top panel, or at least a nice wood front panel. Glowing tubes and nicely figured wood belong together.

[rknize]

Originally posted by tubelab.com
That's where my big Edcors are now, but my amp still looks like yours. I never had the time to finish the chassis.

My ears really like the Tubelab SE with the KLF-10s, but I am hopeful that I stay motivated enough to finish both amps before summer really gets here and the itch to be out in the garage returns. Tubes are my winter hobby.

If it is not too late 4 amps or more would be a good idea. Generic 300B's draw 1.2 amps, the 5842's draw .3 amps. That adds up to 3 amps of DC out of the regulator so you need more than 3 amps of AC out of the transformer. Some of the "super 300B" variants draw 2+ amps each. They cost far too much for me to even think about them.

Have you ordered one of these universal transformers yet?

No, but I was about to. I should be able to add another amp to the 6.3 winding. I'll have to see how much this affects the cost. Going up to 5A for mega 300Bs are not the cards for me. If/when I do get a set of them, they'll be Shaugang or some other cheap variant. No mesh plate globe tubes for me unless I run into someone very generous.

Thanks Even and George for the heads-up.