Edcore Recommendations?

[Jhyatt2012]

Going to start a #183 build and am wondering about Edcore transformers. Anyone using them and what OT, PT and Choke would be recommended for the 183? I may be putting in a reverb circuit as well.

[dreric]

Going to start a #183 build and am wondering about Edcore transformers. Anyone using them and what OT, PT and Choke would be recommended for the 183? I may be putting in a reverb circuit as well.

You may want t re-think the Edcors. Some of it depends on what chassis you use, I don't think the Edcors come in a lay down configuration.

Also, the 183 uses EL34's rather than 6L6 so you need a transformer that can handle the additional heater amps. Some have used Marshall style or had PT made up. 183 also uses a Marshall style OT.

There are numerous 183 build threads, I'd see what others have choose rather than trying to spec out another manufacture.

Rj has the most experience with Edcores

http://www.rjguitars.net/

Good luck and enjoy your build.

Eric

[ER]

I'm using XPWR127-120 for power, their 5H choke, and CWPP100-MS-1.7K on an amp with a #183 power section.

Like dreric said, they don't come in laydown style, but not a problem if you're drilling your own chassis.

I like the XPWR127-120 because it has 7.5 amps on the heaters and a 12v- 500 mA secondary for relays (B+ is 690v@400mA with a 60v bias and center tap). I haven't fired it up yet-still in the middle of the build so I don't have final voltages, may need to tweak the dropping string, I'll post results when I get there.

They sure look nice and I've been really happy with the sound and quality (and price) of the Edcor stuff I've used in the past. It did seem like it took a while for them to ship, but I wasn't in a huge hurry.

-ER

[David Root]

That CWPP100-MS-1.7K is a monster! I have one for my 150W SSS build, it's rated 100W 20-20KHz so it's plenty good for a 150W guitar amp.

[Jhyatt2012]

I'm learning and am not completely sure what all the designations on the transformers mean. The longer I stare at these things the more sense thay make, though. I have a couple of parts lists that have the Marshal transformers so I may end up going that route. The tranny is no problem as I am drilling my own. This is my first from scratch build and I was looking at other options and happened across these. Good to know about the higher power requirements for EL34's.

[Jhyatt2012]

So for the 100W #183 should I use lower than the CWPP100-MS-1.7K? Gonna start my build this weekend and would like to go ahead and place the order for the transformers

[ER]

No, it's perfect for 100 watts- More power will just limit the frequency response at the extremes, but since it's rated 20-20K at 100 watts and a low E sting is right around 82 Hertz it can handle even more power and be fine for guitar. I prefer a more "hi-fi-ish" OPT and would take a hiwatt partridge tranny over a stock marshall if they were readily available.

If you can find a more affordable marshall replacement go for it, also #183 I believe uses a twin style power tranny.

I went with the Edcor stuff because I was concerned about enough heater current for 6ca7's, didn't want a separate relay tranny inside the chassis, and was looking for a bit of hiwatt/dumbleland mojo in the output tranny with wide frequency response. My build isn't a straight 183, it's more of a hybrid amp based on my gut feelings and the sound I'm hoping to achieve, thought the power supply and output section are 99% #183.

It all depends on how close to the original you want to get. The fender laydown twin tranny, 4H choke, and marshall OPT are all readily available from a number of places.

[David Root]

ER is right. The 1.7K primary is good for 4xEL34 or 4x6550, and the heater current requirements are essentially the same. With that Edcor OT and 4xEL34 you have all kinds of headroom and extended frequency response which you won't get out of a Twin OT, given the #183 plate voltage with the standard PT. The Marshall OT will give you more beef than a Twin OT too, but not I think like the Edcor.

[Jhyatt2012]

Thanks guys that helps a lot. ER, I'm really looking forward to hearing how yours sounds when you're done. I'll keep you posted on how mine progresses.

[M Fowler]

I've used the Edcor 1k7, 2k1 and 3k3 four hole builds, great sounding iron.

Mark

[Jhyatt2012]

I'm wanting to add a reverb tank and internal dumbelator to a #183 and am a little confused as to how to power the reverb. I've found several posts about reverb circuits but can't find anything about voltages from the transformer - not that it's not there, I may not know where to look exactly. With the Edcore PT and OT, would I still need a separate small transformer, or would I step the voltages from the main power supply board? I have a couple of layouts I'm looking at:

http://www.el34world.com/Forum/index.php?topic=7957.0

and the attached file for the deluxe layout.

[M Fowler]

You need a Fender reverb transformer it is a very small unit and the red wire gets connected to your B+2.

http://www.mojotone.com/amp-parts/trans ... erb-Driver

Mark

[ER]

The reverb transformer is for impedance matching between the driver tube and the tank, A stock fender tank and transformer is the easiest way to go.

Different tanks have different input impedances;
AB type= 8-10 ohms input
BB type= 150-180 ohms input
EB type= 600-800 ohms input
FB type= 1475-1925 ohms input

All tanks will have an output impedance of 2250-2575 ohms.
They all vary a little by manufacturer hence the range.

Your regular Fender reverb transformer have an primary impedance of around 25K ohms (to load match the parallel plates of the 12at7 driver) and a secondary of 8 ohms to match an AB type tank. It has a power rating of 3.5 watts. The turns ratio is the square root of the impedance ratio (25000/8=3125, Sqrt 3125=~56) so a 56:1 stepdown.

If you use a different driver tube or tank type you just figure out the transformer you need for proper loading. For instance if you have an old Hammond organ Gibbs tank (FB type) that you like the sound of and still wanted a 12at7 like on a Fender or Dumble 3 tube reverb, 25000/1475=16.95, SQRT 16.95=4.11, so a 1:4.11 transformer would work in that case, which would be your typical 10K:600 line matching transformer with a power rating in the neighborhood of 3.5 watts.

The stock fender stuff is tried and true and inexpensive, but if you're like me and want to do something different or use junk box parts it's good to know how to do it.

Some guys think built in reverbs can kill an amps tone, possibly because of current draw from the extra tubes, I don't know but you should be fine with the higher current rating on the edcor.

P.S. I finished my build and posted the voltages with the edcor and the 183 style power section/supply on my build post.

peace- ER

[Jhyatt2012]

That's exactly what I needed to know - thanks!

ER, have you gotten a sound test yet?

[M Fowler]

Here is another layout to look at if you don't have this.