Build Options for Hammond AO43-1 Chassis with Transformers Update: 6V6 Plexi

[72Blazer]

I wanted to try something different and intrigued by some of the amps on Sluckey's website.

I have a Hammond AO-43-1 Chassis with:

AO24157-1 PT
AO24158-0 OT
Choke (no markings)

I am still trying to research the specs on the transformers.

Looking for some suitable build options here.   I really wanted to build Sluckey's Dual Lite-but I don't think this PT/OT will be suitable. 

Would this be a good start towards a 6V6 Plexi?

[sluckey]

I used the AO-43 PT, OT, and choke in my Plexi 6V6. Another forum member built several Deluxe Reverb size AB763 amps on the AO-43 chassis. Turned out nice.

The choke is 14H, no current rating. BTW, it was not part of the power supply. I've attached the schematic. Should give you a clue about the PT and OT.

The OT has an 8Ω secondary  and would work just fine in my Dual Lite. The PT puts out too much voltage though.

[AmberB]

Yeah, the choke is the reverb driver tube load.
Interesting that this popped up because I came here to ask if anyone knows what the specs are for the reverb tank for the AO-43 circuit.  I have a couple of different pans, but I don't know which one would be the proper input impedance for this reverb driver circuit.

[72Blazer]

Much appreciated Sluckey.  I think I will go with the 6V6 Plexi and I see it is very well documented on you website.

This should be fun

I know this is probably a subjective question.  Is there much tonal difference between this 6V6 plexi build and a Marshall 18 Watt TMB?  I have/built a the 18 Watt but have never owned a plexi or a 6V6 plexi.

The answer to AmberBs reverb question will this thread down the road for someone

Vr
J

[72Blazer]

On another note Sluckey-when you gonna build another amp?!

[sluckey]

On another note Sluckey-when you gonna build another amp?!

I'm done. The fever is finally gone! Wanna buy some amps?   

[72Blazer]

Pressing ahead with the 6V6 Plexi Build based on Mark Huss's Plexi 6V6 as modified by Sluckey using his design/drawings.  Have not decided on the chassis yet.  I'm just gonna rob the trannies from the AO-43.

Here is the turret board I just finished.  I'll post updates as this build progress.

Vr
J

[sluckey]

Did you run out of turrets?

[72Blazer]

I have more Sluckey-but are you hinting that I am missing some?  I did use your drill guide.

[sluckey]

Never mind. I should have looked at the last pic. I've never seen anyone start lacing turrets before they are all installed.

[dude]

I’ve built three plexi’s with that chassis, used the choke and PT but used an 18 watt PT, only because it has three secondaries. I followed Mark’s layout design, the board length but used Sluckey’s layout, slightly different than Marks.
That PT can handle 6L6’s with no issues, l even tried EL34’s, PT did not get very warm after a long jam session.
I have a hand written layout if you’re interested but looks like you have the bd about done. Replacing the EL84 sockets was the major issue. l cutout a rectangle and put a plate over the cutout, then used a step bit to drill the 6v6 holes, it’s tight. Another issue is putting the bd in the correct place, to get the pots out without taking he bd out,l use 3/8” standoffs and most important locate the bd as close to the tubes as possible or you won’t be able to get the pot out easily.
I have some pictures of the assembly and plate l put used, basically pictures before the bd. Let me know if you’re interested and l’ll post them. Also, l used two can caps, l drilled the second next to the original but if l did it again, l’d just use the hole on the other side.
 

[72Blazer]

Thanks for the info Dude.  Please post your build info.  It will help down the road and probably someone else.

Vr
J

[dude]

Here's some pics that might help with location in that narrow chassis. I use 1" standoffs to elevate the PT for room. If you like to see anymore pic's, let me know. I have some of the face plates I made, thick paper printed from a print shop, I used 1/16" plastic from Home Depot to cover the front, have some left over too. I have a drill patterns (16 x 2") to fit over chassis, front and back panel too, if you're interested let me know. Of course if you didn't already drill the holes, have a few left over thick face plates too, exact size to fit that chassis.   

[72Blazer]

Dude, I might take you up it.  I'll shoot you a message.

I made some progress this morning.  The caps that are missing on the board are on order.

[sluckey]

Here's a tip that will make life much simpler for you. Install all the interconnecting wires to the board ***BEFORE*** you permanently install the board in the chassis. I cut the wires longer than needed then trim to length once the board is installed. I usually have to temporarily set the board in place to get a close estimate of wire length so I don't waste so much wire. This may need to be done several times. When all the wires are connected to the board then the board is mounted in the chassis for the final time. Now the wires can be trimmed to final length and connected to the sockets, pots, etc. I usually have a couple inches wasted wire for every connection. Here's a pic of my AC-15 board ready to be installed in the chassis...

[dude]

I made some progress this morning.  The caps that are missing on the board are on order.

That board looks like Slucky's Stout chassis size, hope not, won't fit in the AO43. I had to cut a board I got from AES (or Doug can sell you a board but his width is wider, he has standard 3" something width only). My bd width is 2 1/4" and length around 7 or 8 inches to fix in the AO43, so I had to use a layout like Huss's, 2 1/4" x 8", forgot the length but around 8" long. 
I assembled the wiring just like Sluckey mentioned.  If you wan to be able to get the pots out if one goes bad, you need to install the bd like I did in the pictures. If you did use the stout bd, you can make the AO43 chassis wider by popping the rivets on the back and bending the chassis two inches longer. You'll have to do some sheet metal work and rivet 16 gauge sheet metal extending the width. Maybe your using the stout chassis, then my face plates are useless to you.       

[72Blazer]

Steve copy all and that was my plan once I figure out what chassis.  I may just build another board. 

So Sluckey did you in fact use one of Doug's Stout chassis?

Vr
J

[sluckey]

So Sluckey did you in fact use one of Doug's Stout chassis?

No. I used a 12.5 x 6.5 x 2.5 blank chassis from Watts Audio. That was before he went bananas and had to close shop. I don't like Hoffman's predrilled Stout chassis. It puts the tubes on the same side as the controls. My layout will not work well with that chassis layout.

Now if Doug still offered a blank Stout chassis I would use that. It's only a half inch shorter than my chassis. You know, Doug built a 6V6Plexi in his Stout chassis. It's well documented with plenty of pics on his website.

[72Blazer]

The remaining components arrived.  Have not had much time for this.  I have a massive water leak in the foundation of my house.  Copper pipes are failing after 30 years.  Got a plumber scheduled for a total re-pipe of the house up in the attic using PEX pipe.  No more leaks in the foundation for me.  arghh..

Here is a look at the board as of today.

Vr
J

[PRR]

....Copper pipes are failing... using PEX pipe.  ....

I paid for my PEX tools by salvaging the old copper. They don't care about leaks; they do markdown severely for iron (valve bonnets and handles) so use a magnet and pipe-cutter to segregate your scrap. (Copper with light solder, $3; mixed iron/copper $0.50.)

Assuming the plumber has not already figured this into the job.

Assuming this is not like my uncle's house, copper embedded forever in concrete slab. (WHO thot that was a good idea??)

[sluckey]

Assuming this is not like my uncle's house, copper embedded forever in concrete slab. (WHO thot that was a good idea??)

This is probably his situation since he lives on the coast in the Florida panhandle. Copper under or embedded in the slab was and still is a common building practice. However, PEX seems to be taking over in the newer homes.

[sluckey]

This is how I prepare wires to connect to the board. Easy to do before the board is installed. STRIP, TIN, HOOK, BEND.

1. Strip the wire. Sharp strippers needed for teflon wire.
2. Tin the wire. I do this before making any solder connection, not just for boards. Paste flux is your friend.
3. Hook the wire. I use small round nose pliers to get a smooth hook.
4. Bend the wire to 90°. I use the round nose pliers for this too.

Then drop the wire through the hole, twirl the hook to catch the turret, give a little crimp, and solder.

[72Blazer]

Yep copper entombed in a cement slab.

Thanks Sluckey.  That will be my plan.