Plexi 6v6 Sluckey/Huss

[HommeMarrBuckley]

Im trying to put together the Plexi6v6 done by Steve and Mark Huss and I am using Hammond A0-43 transformers.

http://sluckeyamps.com/6v6plexi/6v6plexi.htm
http://mhuss.com/Plexi6V6/
I hate posting these noob questions but it's best way to get moving.

I figure it is easy to describe better with pictures.  I am trying to see if I am on the right track here and I am trying to configure what tag strips and points I will need.
The speaker jack
Yellow/orangish is NFB wire.  Green and black are from OT.  Confused because on steve's site with picture, black looks like connected to tip but thought sleeve was ground.  I know it's something I don't understand or know.  I modeled my picture after what I thought I saw in his picture. 


Lamp 
Mark's had a diode, Should it be 220k in series here, is that correct in pic? 
Lamp has positive sign on one lug, it shouldn't matter which green from PT connects, right?  They go off to heaters, then. 


Bias pot
This bias pot is so tiny, supposed to use tiny flathead screwdriver to adjust it, maybe cut a chopstick head flat. I believe the bottom lug is ground but not sure if set correct. There's another pic of the biaspot with lugs up.

Lastly, presence pot is part of phase inverter section,  Is master volume part of PI or Tone Stack?
Many Thanks in Advance

[sluckey]

black looks like connected to tip but thought sleeve was ground

Black is connected to the tip and the sleeve is ground. Your NFB wire needs to connect to the tip lug, not the switch lug. I normally would connect the black lead to ground but I had to swap the green and black OT wires to fix NFB squeal. This was easier than swapping the plate leads on this amp.

Mark's had a diode, Should it be 220k in series here, is that correct in pic? 
Lamp has positive sign on one lug, it shouldn't matter which green from PT connects, right?  They go off to heaters, then.

Quit thinking about what Mark has. Per our pms last month you will be using a NE2 neon bulb connected to 120VAC. That's why you bought that lamp holder and NE2, remember. None of this will connect to the PT green wires. The idea was to not put a #47 lamp on the filament string. Connect one side of the lamp holder to one of the PT primary leads. Connect a 220K resistor to the other side of the lamp holder. Connect the free end of the 220K resistor to the other PT primary lead. (I would mount that resistor on a terminal strip rather than solder a wire to the dangling end.)

If you just must use a #47 lamp, then forget the 220K resistor and just connect the two sides of the lamp holder to the two green filament leads. That lamp holder can use either lamp bulb.

I would get a small screwdriver to fit that small bias pot. You can never have too many tools.

The MV goes between the TS and the PI. I would call it part of the preamp. Some people call it a pre-PI MV.

[HommeMarrBuckley]

Ok
Speaker
Green OT and NFB connect to tip
Ring and Sleeve lugs are connected
and Black OT connected at sleeve.


I am clear on Lamp.


Bias pot correct?

Quit thinking about what Mark has.

[sluckey]

Pot looks right. How will you mount it?

[HommeMarrBuckley]

Pot looks right. How will you mount it?

  my typical unrefined way, eyelets are pretty close.


Pretty bummed now because lamp clearance is a no go with the PT.  Tried spacers and nuts to lower PT height but just not enough to keep keps on.  My own fault for not thinking about clearance beforehand.  Have a #47 and NE2 and neither will clear without touching the PT.  Anyone point to me specific  LED/lamp, I'd appreciate it.  I have a 11/16" chassis hole and about 5/8" space before contact with PT.


Also need to get a 4 1/2" x 1 7/8" piece of sheet metal/aluminum to cover holes in back so I can mount the fuse.
Really thought I was going to like getting to re-use this Hammond chassis but clearly I am without the proper design abilities to make this easy.  Needless to say the chassis will have a lot of air flow.
Not going to show much else but here's the head cab.  Waiting for the right time to rout and round off the edges.  Stormy outside all day and want to take my time with a bunch of practice strokes on scrap.
The cab shell is glued up/needs cleats and baffles.  Eminence Legend 15" came yesterday.  But all that is meaningless right now.

[sluckey]

Here's one solution. Get four 1/2" x 3/4" x 3/4" L-brackets from Lowes and mount them on the PT so you can stand it up, rather than laid down like you have it now. Then it won't be in the way of anything. Like this...

[HommeMarrBuckley]

Standing up, doesn't clear hole, like in the pic, I would have to lay another sheet down.  Lowes/HD have sheet metal/alum?  Perhaps but they probably don't cut it. (tried several times and pic is right side up--dunno why it reverts to being upside down-but you get idea)


In 2nd, this is about the only way on it's side but I dunno for this configuration with orientation to choke and PT and just normal operation.

[sluckey]

There's nothing awkward about what I suggested. But if you can't make it work then you could always just not use a pilot light. Plenty of amps don't have one. Or you could get another chassis and this time measure twice, cut once. A blank chassis would look so much better than that chassis. Or, you could buy Doug's precut chassis. Or, I could sell you another AO-43 chassis. Lot's of options. I would stand the PT up.

[HommeMarrBuckley]

Is this just too close?  Lug and bulb shaft are pretty much touching.  I dunno doesn't seem that bad.  I added keps on the other side to give a few more mm of clearance.

[sluckey]

Use your needle nose pliers to rotate that rear lug so it is not pointing downward toward the PT. An/or bend it 90°. Then use your ohm meter to measure resistance between each lug and chassis. Should be infinity.

With it being that close, I'd not use the ne-2 connected to 120V, but I would not hesitate to using the #47 connected to the 6.3v filament winding. Just be sure neither lug is actually shorted to chassis.

EDIT... Another simple solution is to replace the four PT bolts with longer bolts. You can get longer bolts from a shop that repairs small electric motors.

[HommeMarrBuckley]

With ohm meter, got 0.L (does bulb need to be in?)

EDIT... Another simple solution is to replace the four PT bolts with longer bolts. You can get longer bolts from a shop that repairs small electric motors.

I thought of that but just didn't think you do it because those bolts are like super tight in there.

[mresistor]

Another idea to raise the PT that is in laying down position , is to find some threaded stand-offs of the same thread pitch as the pt bolts and thread them on each pt bolt and then using 4 small bolts thread them into the stand-offs from inside the chassis.  For instance, https://www.grainger.com/category/round-standoffs/spacers-and-standoffs/fasteners/ecatalog/N-8nm and there are many more places that sell these and the octagonal variety.



some others  https://www.zoro.com/value-brand-round-standoff-6-32-12-l-pk10-183519/i/G3691107/?gclid=CKqwvYPqr84CFUUdaQodygcJmQ&gclsrc=aw.ds

[drew]

Couldn't you just saw off the whole rear part of that lamp holder thing and figure out a way to use an LED as the light source?

[HommeMarrBuckley]

Appreciate everyone's help and ideas here.  Thank you.

Another idea to raise the PT that is in laying down position , is to find some threaded stand-offs of the same thread pitch as .......

There's a mom and pop hardware store that I frequent that's close to me but closed today.  I might look into this idea.  I will just have to see about possible strain on the bolts (seems 8-32, because that size keps fits snug on it) but this sounds possible.  To be cont.

[PRR]

> Lowes/HD have sheet metal/alum?  Perhaps but they probably don't cut it.

They do, but that's not it.

Hardware aisle, across from nails/screws, is hundreds of small drawers. Odd size nuts, washers, spacers, and also little pre-made L-brackets.

Sadly they usually have 3 when you need 4.....

[HommeMarrBuckley]

So, if I would use L brackets and stand it this way, the orientation with the choke and OT is ok?

[sluckey]

yes

[HommeMarrBuckley]

3/4 x 1/2 x 1/2 L Bracket.
Mount holes not exact but close.  I had to watch how much I tightened everything but it is snug and secure.  Excellent fit that suits this build.
Thanks Steve


I think the spacer idea would have worked too.

[HommeMarrBuckley]

 More snags—learning.
With PT now up, the filter cap is awfully close, I might move it to the right.  Good idea or not worth it? (will probably have to drill another hole—note the power and standby switch* in the pic)
The choke is pretty close to the power tube socket but I think it should be ok.
With hardly any experience, I didn’t think of the opposite nature of this chassis compared to last one I did.  Not too big a deal but now have to be careful with not having any lugs or connections touching the bottom of the chassis.
Bums me out that my power/standby switch will be upside down.  I tried to turn it rightsize up and I bent the lugs to see but one was extremely close to the PT bolt and I could just see in time it getting loose and touching.  Will just have to accept that flipping down is “On” position.  Annoys me that little groove/channel* in them because really obvious to see.

[sluckey]

Just rotate the PT 180° to provide more clearance for the cap can. And put the screw head on the inside of the chassis to provide more clearance for the switch.

[Willabe]

The bell cover end of the PT is the cooler side of the PT. The lams will be warmer.

And that amp sits right side up, tubes up? Heat will rise up and away from the cap can.

[HommeMarrBuckley]

Bare with me Steve, but did you mean 180° like in your pic in post#5?
If so, it can't stand that way because the hole is too big.
Why did you delete the part about the screwhead?  That might work.
The switch lugs are really close to the chassis,
I was thinking of adhering some of the fiberboard onto the chassis there just in case the lugs might move or touch.
Wouldn't that help insulate from shorting?
I have been purposely procrastinating from the electronics because of the obstacles.
Plus, it has been nice outside after days of rain so I worked some more on the cabs (put in the cab section).

[sluckey]

Just do it. All 4 bolt holes will line up. Who cares about the big hole under the PT. It's supported by the L-brackets. If this doesn't work for you please take a pic with it rotated so I can understand why.

BTW, I recommend you cut a plate to go under the PT as shown in post #5.

[HommeMarrBuckley]

Who cares about the big hole under the PT. It's supported by the L-brackets............
BTW, I recommend you cut a plate to go under the PT as shown in post #5.

Like this?  I thought the orientation with OT and choke should be opposite this but I am probably wrong.


Here's how close the switch lugs are--yikes--my own fault.

[sluckey]

Like this?  I thought the orientation with OT and choke should be opposite this but I am probably wrong.

NO! I said rotate 180°. You only rotated 90°. Give it another quarter turn.

[sluckey]

There's an easy solution to your switch dilemma. Put those Carling switches aside for another project and buy some switches with solder lugs on the back, rather than the end. Like this...

     http://sluckeyamps.com/PeeWee/A_big_bottom.jpg

[HommeMarrBuckley]

This?
Ill work those L brackets.


Thanks--didn't even think of other different SPST switches.

[sluckey]

This?
Ill work those L brackets.

Arrgh! Put the L-brackets back on exactly like they were in reply #18. Then rotate the transformer 180° keeping the L-brackets on the chassis.

[HommeMarrBuckley]

Thanks for putting up with my ignorance.
Ill get the Ls on tomorrow and look for those switches.

[sluckey]

Now you're cooking! That should give you additional clearance for the cap and your L-bracket holes should line up just as before.

BTW, I struck the statement about screw head earlier because of a brain fart. I momentarily forgot you were using L-brackets and was thinking the screw was actually one of the long PT bolts. Since you are using short screws with the L-brackets, reversing the screw head would be easy and would provide more clearance for the switch.

There is some thin paper insulating material (usually gray colored) that is used in transformers, motors, and switch enclosures that is used for insulating purposes. It would work fine to insulate your switches. May have to drop by a motor repair shop. They would probably give you enough for your purpose. I would drill a 1/2" hole in it and put it between the switch body and front panel of the chassis. Then bend it to fit flat against the bottom of the chassis. The switch will hold it in place.

Here's a pic of what I'm talking about. I just used some hanging folder paper for illustration only because I don't have the correct electrical insulating paper. Please use the correct paper if you decide to do this.

[HommeMarrBuckley]

After a couple engine shops and boat motor places with nothing, it looks like internet yields possible solution but of where to buy.
DuPont trademarked Nomex flame retardant insulation paper.  Wonder if there's a generic.  Made progress on the circuit board, will have questions with PT wiring later.
Learning on this one.  Pots are upside down too and backwards too, it's fine, I'm either going to check clearance to turn them upside down or just leave it the way it is (0 at 1o'clock, max at 11).

[PRR]

> couple engine shops and boat motor places....
> DuPont trademarked Nomex flame retardant insulation paper.

??  Ah- Sluckey's "drop by a motor repair shop" means Electric Motor shop. Around here the sign says "starter and alternator rebuilding", because nobody repairs vacuum cleaners and we don't have big industrial motors (and the few who do know to go there).

Heck, it is electrical fishpaper. If you still had a local Radio/TV Repair shop they would whack off a foot for you.

Newark.com GC fish paper $4 for lifetime supply

Castech fish paper, $4 sheets to $90 rolls

ESPE Fishpaper & Vulcanized Fibre, mass quantities slit to your spec

You could also go to auto-parts store and ask for a sheet of "gasket material". "Grey cardboard, not cork". The "grey cardboard gasket sheet" is nearly the same (maybe THE same) stuff as electric fishpaper, except instead of electrical test it is checked for heat and oil resistance. It is very unlikely to conduct electricity, and you only got 130V there. This will be $7 to $9 but local avoids shipping.

[HommeMarrBuckley]

Thanks for the fish paper tip.


Without a scientific brain, I am prone to copy/paste until I learn actually what I am doing.  This should be really easy for everyone here.
Here's my PT.
The black hot of my power cord connects to power switch lug then to 220k resistor then to Ne-51 lamp lug
The white of power cord connects to other NE-51 lug


The top three right are my fliaments--dark green to ground and other two go to heaters


Using solid state, so my red HiVoltage secondary (in middle) each one goes to each set of diodes on rec. board, striped to ground

The two left over (top left) they get twisted with the red secondary and goto rec board, as well?

One Black primary goes to remaining power switch lug, where does other go?-to fuse
Missing with what goes to fuse tip and side of fuse?

Do I need a .47uf cap and 220k resistor after A cap and between standby? Will I need that?

Steve, you recommended a sheet under the PT, does it need to be heavy gauge, could it be 22ga Aluminum.  Is this sheet for structure or for better operation/noise/wave cutoff
I need to add a piece, as well, to the back to hold the fuse but I will go with a stronger gauge there.
Pardon my ignorance everyone and sorry If I am way off with what I wrote above.

[sluckey]

Just follow my schematic to wire the PT.

[HommeMarrBuckley]

What if I am not using a GZ34, no diff?

[sluckey]

What if I am not using a GZ34, no diff?

Then tape the ends of the two yellow wires and connect the two red wires to your rectifier board.

[HommeMarrBuckley]

Ok, so tape off and tuck away the yellows.
Power cord, fuse, lamp and 2 primary?


Im Lost
guessing---power cord (white/neutral and one primary meet at one end of 220k resistor and on to lamp
power cord (black/line to end of fuse) side of fuse onto power switch lug.


Leaves one lamp lug and one power switch lug.


Initially, I planned on using the GZ34 but my 6v6s were too close together so I used the far rectifier socket for the 2nd 6v6.  That's why Im looking at his schematic as well.  I have a standby and I think I need to add that .47cap and 220k resistor  because I can't trace that or find it on yours.

[sluckey]

Let's put a pin in the mains and transformer wiring until you are actually ready to do the wiring. Right now you still have mechanical issues to deal with that will prevent you from actually doing any wiring. Get your fuse holder mounted. Put that plate under your PT if you like (I don't think it's necessary if the PT seems sturdy to you). Do what you intend to do with those switches. They are not safe as they are. Either rotate, get different style switch, or do the fish paper insulation. BTW, that fish paper electrical insulation is readily and cheaply available on eBay. Click on this link...

http://www.ebay.com/itm/2-Pcs-Fish-Paper-Adhesive-0-010-x-4-5-x-10-Battery-Electric-Fishpaper-Buy-USA-/121728054331?hash=item1c578eb43b:g:bpoAAOSwBLlVTXLs

[HommeMarrBuckley]

 
Yeah, that's the direction I needed.  A lot of compulsion today, dunno. 
Will look at a decent sheet of 16-18 ga aluminum to cut for fuse and that insulation paper or other switch.  Thanks for the link.
Back when they're mounted.

[sluckey]

As a sidebar, let's check out your lamp holder. Some of this style bayonet lamp holder have a built in resistor and are made specifically for use with an NE-51 bayonet style neon lamp. They can not be used with any other lamp bulb. A simple resistance test will tell if you have this type holder. And if you do, you will not need an external resistor and that will really simplify your wiring.

Here's the test...

You need your lamp holder, an ohm meter, and a gator clip test lead. Set your meter to measure actual ohms, not just a continuity check. Connect one end of the gator clip lead to one of your meter probes. Connect the other end of that gator clip lead to one of the lugs on the lamp holder. Unscrew the bezel lens from the lamp holder. Use your other meter probe to measure resistance to the center post inside the lamp holder. If you measure infinity (open circuit) swap the gator clip to the other lamp holder lug and repeat. Now you will measure either zero ohms or some resistance value that's probably in the range of 47K to 220K. Write it down.

Now put the gator clip lead on the other lamp holder lug and measure resistance to the SIDE shell contact. You should measure either zero ohms or some resistance value that's probably in the range of 47K to 220K. Write it down.

If both numbers that you wrote down are zero, then you will need the external resistor. BUT, if either of those two numbers is an ohm value between approx. 47K and 220K, you are lucky and will not need the external resistor.

Let me know the outcome. Also, if I'm being overly simplistic with the test instructions, please let me know and I'll take it up a couple notches.
 

[HommeMarrBuckley]

Fail!
Didn't get anything above 1ohm if that.  It's ok.  I put one (of the zillion holes) for a tag strip up in that area.
Looks like fish paper route, too.  Couldn't find where you got the toggle with lugs in the middle.  Checked mouser and ebay.

[sluckey]

AES has some. eBay has thousands...

http://www.ebay.com/sch/i.html?_odkw=spst+toggle&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xcarling+spst+toggle.TRS0&_nkw=carling+spst+toggle&_sacat=0


http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=spst%20toggle%20-%28mini%29&rt=nc&LH_PrefLoc=1&_trksid=p2045573.m1684

[dude]

Are those ebay carling switches the real McCoy or copied in China?

[HommeMarrBuckley]

Not very pretty but should work.  The Fuse is in snug and tight.  The fish paper adhesive didn't stick as well as I thought it would, I might redo the bottom layer (where lugs are) and put a drop or 2 of loctite or crazy glue underneath.  The screwhead creates the bump. The mounting hole piece is fine.

[Willabe]

If you were to make the fish paper 1 piece with an L shape 90 deg. bend, then the bottom part of the fish paper that's under the switches, if it did lift up off the chassis it would still stay in place under the switch connects.

You might have to make a cut in the bottom short L section in between the 2 switches because of that screw/bolt and then put a full length patch piece over the cut that will stick the patch to the cut bottom section and hold the bottom together and in place better. 

 

[HommeMarrBuckley]

Yes, it should be fine.  Just needing the assistance here with the wiring.  I plan to keep the wiring on these two long, in case I don't like it, I will just reverse them.

[HommeMarrBuckley]

Sorry for crudeness.  Is this accurate??
Had to do blend of Huss and Sluckey's schematic because I am not using tube rectifier.

[sluckey]

This is the correct way to wire your mains. I didn't include the secondary wiring because it was correct.

[HommeMarrBuckley]

Much Appreciated,Thank you Steve.

[HommeMarrBuckley]

Just finished with last point on bus bar, lots of thoughts but pretty late now, one that comes to mind is if 820Ω, 100k resistor and .68uf cap are they part of tone stack or pre-amp?---I have it wired as part of pre-amp section (with that section ground).
Just hoping that this thing won't be a firestarter