First Express Done

[David Root]

And checked out by the customer. Loves it. Other than the can caps power supply, if it looks a lot like Francesca that's no coincidence. I did also add bias check tipjacks, and the grounding is a bit different than KF's.

Thanx to RJ for most of the parts. Customer supplied a NOS Stancor A-3801 and all tubes. Thanx also to Ron Worley for his assembly tips, very useful.

It hummed and fed back a good bit until I cut the OT leads to right length once I had them phased right.

Never done one of these before, interesting experience...I have not taken quite as much care with lead dress before! Seems to have paid off.

Man it is wicked loud! With my Tele the guitar had to be cranked down so I could get the volume pot up above about 2. I think my pickups must be quite powerful ('60 Voodoos). And with customer's tubes a nice surprisingly fat tone into an older Tone Tubby red alnico.

[lpd]

A great time tube rolling and test driving the amp. Nice elastic fat sound. Look forward to bringing her home!

[lpd]

Double post

[lumox0013]

that is beautiful work ! congrats lpd . I would love to hear a clip if you get a chance .

[lpd]

that is beautiful work ! congrats lpd . I would love to hear a clip if you get a chance .

All credit goes to David Root. I just found the stancor opt and orange drop caps

We are going to put a volume pot with more forgiving taper to see if we can tame the on/off volume gain, otherwise is very good sounding to my humble ears. Clips will be up as soon as she's buttoned up.

[guitarmike2107]

nice looking build guys

To help the volume control look at the way komet put in the fast/slow gain switch, makes a big difference and well worth doing IMHO.

Is there much hum in the amp with the volume turned down, I have looked at the PT and OT so close together on so many builds and can't see how they are not causing some hum?

Cheers

[lpd]

nice looking build guys

To help the volume control look at the way komet put in the fast/slow gain switch, makes a big difference and well worth doing IMHO.

Is there much hum in the amp with the volume turned down, I have looked at the PT and OT so close together on so many builds and can't see how they are not causing some hum?

Cheers

Hum seemed low if detectable at all but we didn't open her up wide due to volume levels. Just the usual TW hiss.

[M Fowler]

I isolate the input jack on my Trainwrecks.

[David Root]

Thanx guys. All the pots in the amp are A-B RV4. The 1M are very old, I would guess '50s or very early '60s, as there is a thick patina on the cases and the part number does not show up on an internet search and is nothing like more recent ones.

So this means they are 30% taper, which is probably OK for all except the volume pot, which I should have thought of...duh!

We decided to change out the volume pot to a 1/2W early '80s Clarostat, which I have several of and they are 10% taper. Hopefully this will make the beast more manageable!

I will also be putting a .1 ohm 5W wirewound in the heater line as it is pulling 6.8V now. 4.1A draw vs. 4.8A winding.

[lpd]

Thanx guys. All the pots in the amp are A-B RV4. The 1M are very old, I would guess '50s or very early '60s, as there is a thick patina on the cases and the part number does not show up on an internet search and is nothing like more recent ones.

So this means they are 30% taper, which is probably OK for all except the volume pot, which I should have thought of...duh!

We decided to change out the volume pot to a 1/2W early '80s Clarostat, which I have several of and they are 10% taper. Hopefully this will make the beast more manageable!

I will also be putting a .1 ohm 5W wirewound in the heater line as it is pulling 6.8V now. 4.1A draw vs. 4.8A winding.

Aside from the onset of volume the amp sounds very good.

[RJ Guitars]

Congrats David,

Great looking work! What a great score to be able to pick up an original Stancor for an Express build. I appreciate all the photos, especially the gut shots.

Now is it up to lpd to put it in a hardwood cab and road test it?

Thanks for sharing. It's great to have documentation on another DIY Express build.

rj

[David Root]

Thanx Bob, it's going in one of your Mandatory Black headboxes. Maybe later into a nice hardwood box

[lpd]

Congrats David,

Great looking work! What a great score to be able to pick up an original Stancor for an Express build. I appreciate all the photos, especially the gut shots.

Now is it up to lpd to put it in a hardwood cab and road test it?

Thanks for sharing. It's great to have documentation on another DIY Express build.

rj

She's going into a tolexed head for now but after playing through the amp I can assure you a hardwood cab is in the future when I have a few extra shackles.

I will attempt to record some clips for reference once she's buttoned up and broken in.

[David Root]

I added Gutshot 2 to show the replaced volume pot and the .1 ohm 5W in the heater circuit, so currently as built. Shows the pots better.

[David Root]

Removed the Clarostat pot and put the old A-B RV4 back in. Customer greatly preferred the A-B pot as tone is noticeably better and he also preferred the feel--more 'elastic'.
Downside is the pot is back to being almost an off-on switch.

Removed the .1 ohm 5W from the heater circuit too. This did not seem to improve the slight residual hum, which I thought doing so might have done.