CAE 3+SE Transformer mod?

LeftyStrat · Post by **LeftyStrat** » Sat May 11, 2013 7:56 pm

So my quest for a three channel preamp is now leaning towards the CAE 3+SE. Clean channel is very Fender-ish. Crunch is very Marshall-like.

But supposedly there is a transformer mod that makes these sound much better.

Anyone have any ideas what this mod is? Perhaps just higher voltages?

Leo_Gnardo · Post by **Leo_Gnardo** » Sat May 11, 2013 9:59 pm

LeftyStrat wrote:So my quest for a three channel preamp is now leaning towards the CAE 3+SE.

Now there's an excellent choice! I'd recommend tracking down Bob Bradshaw & ask him.

LeftyStrat · Post by **LeftyStrat** » Sat May 11, 2013 10:09 pm

I actually just found a post on the old ampage archive of someone that built one with several good suggestions:

http://archive.ampage.org/threads/6/gag ... tml#347796

Leo_Gnardo · Post by **Leo_Gnardo** » Sun May 12, 2013 12:49 am

LeftyStrat wrote:I actually just found a post on the old ampage archive of someone that built one with several good suggestions.

Good hunting Lefty. The usual conditions hold, keep supply voltage high for a snappy tone. After that it's modify to suit your ear. Can't say I've heard of swapping out power transformers on the CAE for what, a dab more B+?

It's been a while since I had a look inside one, but as I recall there's xtra heavy PC board with nice fat traces that would only separate with heavy-handed soldering. Bob B. used to mod them to taste for his customers, maybe John Suhr did as well.

The only preamp I saw that had even heavier-duty innards was the Soldano 3 channel. Meanwhile the 2-channel Soldano was a made-in-Taiwan POS, but even that responded well to modification. Just have to have a light touch on the cheezy PC board.

LeftyStrat · Post by **LeftyStrat** » Sun May 12, 2013 1:19 am

Yeah, I was contemplating building a clone of the Soldano X88R, but from clips found the 3+ to have better cleans.

Looking at the schematic, it's pretty much the AB763 preamp. The crunch channel is very similar to a plexi with the one wire mod. I may actually put a relay around the extra gain stage.

I plan on programming an Arduino to handle switching and MIDI, so I can use my modded FCB1010 to control it.

I haven't studied many high gain designs, so I'm not sure what the inspiration for the lead channel was; four gain stages with a CF into the tone stack.

I also love that there is a switchable James-style tone stack at the end. Overall just a great design.

Leo_Gnardo · Post by **Leo_Gnardo** » Sun May 12, 2013 1:32 am

LeftyStrat wrote:Yeah, I was contemplating building a clone of the Soldano X88R, but from clips found the 3+ to have better cleans.

Looking at the schematic, it's pretty much the AB763 preamp. The crunch channel is very similar to a plexi with the one wire mod. Overall just a great design.

When in doubt, steal from the greats. Heh, heh...

Of course you can swap different tubes in there too. 12AY7, 5751, like that. You know what you're doin', I'll leave you to it.

Reeltarded · Post by **Reeltarded** » Sun May 12, 2013 1:47 am

Enola is 4 stages into a CF. Stunningly unusable! lol

LeftyStrat · Post by **LeftyStrat** » Sun May 12, 2013 1:51 am

Reeltarded wrote:Enola is 4 stages into a CF. Stunningly unusable! lol

What is Enola? Only one I'm familiar with is the one OMD sang about.

Reeltarded · Post by **Reeltarded** » Sun May 12, 2013 1:59 am

Enola is what I made out of my BB combo. A drity whore of a thing.

I had to put a mix switch on it to even kind of get a clean sound with three stages.

LeftyStrat · Post by **LeftyStrat** » Sun May 12, 2013 2:15 am

Leo_Gnardo wrote:
When in doubt, steal from the greats. Heh, heh...

Of course you can swap different tubes in there too. 12AY7, 5751, like that. You know what you're doin', I'll leave you to it.

As Picasso said, "Good artists borrow, great artists steal."

I originally planned a Fender clean channel, a Marshall crunch channel, and some lead channel, either Dumble or Soldano.

But the fact someone has done it and been successful makes me want to use it as starting point.

I find build errors are much easier to debug than design errors.

Leo_Gnardo · Post by **Leo_Gnardo** » Sun May 12, 2013 3:38 am

Reeltarded wrote:Enola is what I made out of my BB combo. A drity whore of a thing.

I had to put a mix switch on it to even kind of get a clean sound with three stages.

Aw, I thought it was Paul Prudhomme's sister Enola, who has a terrific restaurant (Enola's, of course) just north of highway 12 in Looziana.

Yeh, too many stages won't get you much of a clean sound. As demonstrated by many a Mesa Boogie.

Remember our slogan, simplicity yields clarity. Well, usually.

Lefty, one 3+ owner I know had the crunch channel modded by BB into another OD channel. In any case, yes 'it's deafinitely' best to modify a winning design.

Now I gotta go melt a watch for Dr. Dali...

roberto · Post by **roberto** » Sun May 12, 2013 8:31 am

You can find all the information here directly from John Suhr: http://www.hugeracksinc.com/forum/viewt ... =1&t=79066

I can see it with spectrum analysis but it has been a while so I forget which harmonics are different.
It is a subject of debate in the hi fi world as well and may have to do with the shape of the AC before it is rectified. Yeah I know, DC is DC and I am Mr anti Voodo. But.... after listening to two identical circuits returning in to the same amp it was making me crazy for a long time. I had rebuilt my personal OD100 to have the SE+ lead channel and it kicked the preamps ass. With this transformer it sounds much more like the built in to the amp circuit (warm 3D low end and a different touch to the notes, sweeter less brash) still not exact but 75% closer. Why? I'm sure there is a reason, maybe impedance of the supply or something but this non toroid sounds better to my ears and correct it was what EVH used on F.U.C.K The Dream is over and like 3 or 4 other tunes. In fact I have that old preamp in my shop right now, numero uno

Otherwise there was a facebook group on facebook:
http://www.facebook.com/group.php?gid=1 ... 852&ref=mf

It could be helpful to write them here, as long as they were available for everyone, and now they are only for facebook registered users.

Leo_Gnardo · Post by **Leo_Gnardo** » Sun May 12, 2013 3:57 pm

Thanks Roberto for the hugeracks link. After reading the whole HRI thread, it looks like the white toroid PT is suitable for the trash bin, the original style toroid is a step better and an "ordinary" non toroid PT is the thing to have, all have the same specs. Hm, I never much liked toroids anyway. So there ya go Lefty. If you're going to mod one or build from scratch you know what to do. I'd trust John Suhr's ears any day.

LeftyStrat · Post by **LeftyStrat** » Sun May 12, 2013 5:33 pm

Thanks Roberto, that was very useful. This is why I love working with tube amps. Like John, I too am very anti-mojo, but sometimes our 'engineering equivalents' aren't. In the end we just have to use our ears.

The link John provided to the differences in EI and toroids was also eye-opening. I didn't know they reacted differently to DC offsets.

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CAE 3+SE Transformer mod?

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