Express fired up!!
Moderators: pompeiisneaks, Colossal
Express fired up!!
As I said in this thread:http://ampgarage.com/forum/viewtopic.php?t=3501 my Express build was ready to fire up. That thread shows the gut shots, etc. Just prior to the recent forum hiatus, I got a chance to do the initial power-up. More or less, I went by Paul Ruby’s power-up protocol: http://paulrubyamps.com/info.html#FirstPowerUp.
The Express uses a 120V indicator lamp rather than the 6.3V mentioned in Paul’s protocol. I did check the PT secondary HT and LT outputs and found 300V on each half of the HT and 600V across the full secondary. The LT was appropriate, also. I then soldered the secondary wires appropriately. With power on, B+ measured 417V. This was also seen at the OT primaries. B2-5+ all fell in appropriate ranges. Tubes (J/J 12AX7’s and EH EL34’s) were inserted and showed filament glow and no red-plating. There was no excess heat on the PT and the OT was cold. I set the voltage on pin 5 of the EL34's at -30V since I hadn't put in any external bias points.
There was a hum that increased with volume control increase. The preamp tube got warm and the power tubes got hot. Chop-sticking leads did not change the hum. Since there was no SMOKE, I put a NOS JAN Sylvania 12AX7 in V1, and that solved the hum. I replaced all the tubes with NOS and plugged in a guitar. Amazingly, it worked! I had spent a great deal of time reading this forum, drawing schematics and layouts, and asking questions. I had also tried to duplicate Francesca’s lead dress as closely as I could. I was still amazed that it came together without any significant problems– Beginner’s Luck, I think.
I spent the afternoon serenading the neighbors (whether they liked it or not). I live in a rural area, so there aren’t too many people to annoy, and the Sheriff doesn’t care unless it’s at night! What a tone!! There was obviously a little more noise with a Strat and SC’s than with the PRS single-cut and humbuckers. I was playing it through a 1 x 12 Ear Candy cab with a Celestion K12T200 speaker and it was still plenty bright. I’ll have too spend some more time on it before I try to gig with it.
All in all, it has been a very exciting experience. I do think that taking the time to understand the circuit, bugging the very accommodating people on this forum (e.g., Allynmey and UR12), and following the Francesca layout as closely as possible made it a success with very little frustration.
Now, I have to figure out a way to record some clips.
The Express uses a 120V indicator lamp rather than the 6.3V mentioned in Paul’s protocol. I did check the PT secondary HT and LT outputs and found 300V on each half of the HT and 600V across the full secondary. The LT was appropriate, also. I then soldered the secondary wires appropriately. With power on, B+ measured 417V. This was also seen at the OT primaries. B2-5+ all fell in appropriate ranges. Tubes (J/J 12AX7’s and EH EL34’s) were inserted and showed filament glow and no red-plating. There was no excess heat on the PT and the OT was cold. I set the voltage on pin 5 of the EL34's at -30V since I hadn't put in any external bias points.
There was a hum that increased with volume control increase. The preamp tube got warm and the power tubes got hot. Chop-sticking leads did not change the hum. Since there was no SMOKE, I put a NOS JAN Sylvania 12AX7 in V1, and that solved the hum. I replaced all the tubes with NOS and plugged in a guitar. Amazingly, it worked! I had spent a great deal of time reading this forum, drawing schematics and layouts, and asking questions. I had also tried to duplicate Francesca’s lead dress as closely as I could. I was still amazed that it came together without any significant problems– Beginner’s Luck, I think.
I spent the afternoon serenading the neighbors (whether they liked it or not). I live in a rural area, so there aren’t too many people to annoy, and the Sheriff doesn’t care unless it’s at night! What a tone!! There was obviously a little more noise with a Strat and SC’s than with the PRS single-cut and humbuckers. I was playing it through a 1 x 12 Ear Candy cab with a Celestion K12T200 speaker and it was still plenty bright. I’ll have too spend some more time on it before I try to gig with it.
All in all, it has been a very exciting experience. I do think that taking the time to understand the circuit, bugging the very accommodating people on this forum (e.g., Allynmey and UR12), and following the Francesca layout as closely as possible made it a success with very little frustration.
Now, I have to figure out a way to record some clips.
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Last edited by drhulsey on Wed Oct 24, 2007 5:14 pm, edited 1 time in total.
Tim
In case the NSA is listening, KMA!
In case the NSA is listening, KMA!
Re: Express fired up!!
This is a composite of the Francesca pic's which I patched together to have a photographic layout to go by. It was a GREAT help to me. I hope it will be helpful to others. I made a 36" x 18" copy to use on the bench.
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Tim
In case the NSA is listening, KMA!
In case the NSA is listening, KMA!
Re: Express fired up!!
Congratulations on the new amp. There is nothing like the virgin voltage application to a fresh project--especially when it works.
I've got blisters on my fingers!
Re: Express fired up!!
Great Job Tim!!!!



Re: Express fired up!!
Looks Great, I'm sure it sounds great too. That's some beefy iron there, what did you use if I may ask?
John
John
Re: Express fired up!!
Congratulations! Watch out for that ringing in your ears...
Wife: How many amps do you need?
Me: Just one more...
Me: Just one more...
Re: Express fired up!!
I'm sorry. I can't hear you for the ringing in my earsmlp-mx6 wrote:Congratulations! ...

The transformers came from Moose (Toneslut) and are made by Heyboer. I try to bench press this amp 100 time a dayJohn_P_WI wrote: That's some beefy iron there...


Thanks for all the encouraging words


Tim
In case the NSA is listening, KMA!
In case the NSA is listening, KMA!
- skyboltone
- Posts: 2287
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- Location: Sparks, NV, where nowhere looks like home.
Re: Express fired up!!
Yeah man. And thanks for the composit. I was thinking of doing something similar but now I don't have to. If I can think of anything else I need you to do for me I'll PM you.
Great build!

Great build!
The Last of the World's Great Human Beings
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
Re: Express fired up!!
Fabulous, Great Job. Really heartening to hear your success.
Did you run the PT/OT wires out of 3 or 4 holes?
Did you run the PT/OT wires out of 3 or 4 holes?
Re: Express fired up!!
Not being as electronically gifted as many on this forum, I needed something to help me see the BIG PICTUREskyboltone wrote: And thanks for the composite.



2 holes for the OT and 1 hole for the PT. All the PT wires exit the bell in one hole on Moose's PT.gearhead wrote: Did you run the PT/OT wires out of 3 or 4 holes?
Tim
In case the NSA is listening, KMA!
In case the NSA is listening, KMA!
Re: Express fired up!!
Good job!
Can't wait to start on mine...
Can't wait to start on mine...

Re: Express fired up!!
delete
Last edited by Fredaxis on Wed Oct 24, 2007 8:37 pm, edited 1 time in total.
Re: Express fired up!!
Great job Dr !!!
Looking very good.
And thanks again for Francesca composite picture,very helpful.
I cannot wait to see Allynmey preparing a new series of chassis!!!!!!
I NEED ONE!!!!!
Looking very good.
And thanks again for Francesca composite picture,very helpful.
I cannot wait to see Allynmey preparing a new series of chassis!!!!!!
I NEED ONE!!!!!

Re: Express fired up!!
Looks great Tim!!
I can't wait to get my Express done...and get my Liverpool done right!
I can't wait to get my Express done...and get my Liverpool done right!
Eardrums!!! We don't need no stinkin' eardrums!
Re: Express fired up!!
Thanks for the good words, guys
Both of them 
Darin, with all your experience you don't get the benefit of beginner's luck like I did. I expect to be tearing my hair out with the next onedartanion wrote:...and get my Liverpool done right!


Tim
In case the NSA is listening, KMA!
In case the NSA is listening, KMA!