Express with New Pacific Transformers - Modernized Approach

[fishy]

RJ,
Very cool looking build. The white is quite special....
You're enthusiasm never fails to impress.

[M Fowler]

Great looking build rj, very clean.

[RJ Guitars]

Thanks for the kind words guys... it's a really good amp. It's entirely stable with the 6V6's and maybe a bit over the edge with the Svetlana EL-34's. I expect that a set of vintage EL-34's or any other change in the power tubes is going to have a big impact on the stability behavior. I still haven't tried a set of premium preamp tubes mostly because this is so far a very low hum amp and for the first time a high gain Wreck build with relatively low hiss factor.

That little switch on the OT secondary started to melt down when I really cranked the EL-34's... I heard the amp start to fart out and then the switch started to send out smoke signals. Proof of my previously mentioned suspicion that this is not a good idea... I managed to get a full sized switch in there but only to run some more comparison testing.

I'm still trying to decide what kind of faceplate and cabinet to use so I could get this unit ready to play out.

This is my first build with a set of Pacific transformers and for now it's just sorta fun to have another flavor of Express around. Once all the Holiday guests and visiting is done then I can stack them all up and listen to them side by side... should be fun.

[njwrecks]

looks great RJ - keep us posted - all the best to you!

[bkvance]

RJ,
Looks really nice and clean, let us know how it sounds with the Pacific Trannies. Maybe a small sound clip if possible.

BKV

[bcmatt]

That little switch on the OT secondary started to melt down when I really cranked the EL-34's... I heard the amp start to fart out and then the switch started to send out smoke signals. Proof of my previously mentioned suspicion that this is not a good idea... I managed to get a full sized switch in there but only to run some more comparison testing.

What was your switch rated at? I'm curious myself about adding a switch to my Liverpool to try the 6k6 primary from time to time. I only tried the 6k6 once a couple years ago and decided I preferred the 5K3... but having the option once in a while would be nice...

I have one of these DPDT sliders kicking around:
http://www.tubesandmore.com/products/P-H35-242

They seem rated to handle more power than most typical toggles (at 11A 125VAC / 5A 125VDC). I already use one on my Tweed Deluxe as the OT secondary impedance selector... but really I don't know what kind of rating would be appropriate specifically. I probably don't know my stuff, but I would think that 11 Amps 125VAC is tough enough to handle anything anywhere in any possible guitar amp. I would like to know though.

[RJ Guitars]

That little switch on the OT secondary started to melt down when I really cranked the EL-34's...

What was your switch rated at? ...

This was a low end mini toggle rated at 250V-3A. I think there are a couple issues here:
1) While it failed in a stationary state, I had previously switched it a couple times when the amp was on. Just at idle and not cranking but there is a huge inductive load and I think the contacts couldn't handle it.
2) The voltage passing through the switch was well above the 250V rating.

I really want to get a direct sonic comparison between the two impedance's but I think for the amp to be totally reliable I'll need to remove that switch before I try to gig with it.

rj

[RJ Guitars]

WooHoo! It's finally finished. I've been trying to take the last little bit of effort and put all my test builds into cabinets. I've had this really nice Red Tolex cabinet around for a couple years. I also had some prototype faceplates made a few years back using a metalized plastic template. I didn't pursue any quantity of them because I didn't find them to be as robust as the anodized aluminum ones I have. However, I did have a few of them here and this one looked good and matched up with the red cabinet nicely.

After I got the faceplate on it and mounted it into the cabinet I took some photos and then moved it in from the shop to my office. The shop has a bit of equipment noise and fluorescent lights and I had not yet sat down and really listened to it. The first thing I found was that it was ridiculously loud... no surprise there but it's always a bit stunning just the same. Next thing I did was change the EL-34's with a pair of 6V6GT's. Slightly less loud and incredibly good tone... I'll try to get some clips because this one really has a nice clean tone and then cranked it sweetly sears the paint off the walls. This is through an open back cabinet with a pair of 10's... No specific name for her but just plan to call her the "Red Head"... and plenty of attitude!

[M Fowler]

Screaming Eagle

Very sweet looking amp rj, now sell a bunch.