Newb first amp build

[rakkassan34]

Hi all I think I've bitten off more than I can chew here and need some help. I don't know squat about electronics even though I've been repairing and putting computers together for 15 years. Don't ask because I don't know how I do it either I guess I just have a knack for them. I don't even know what inspired me to build this amp. I was just surfing eBay one day saw a Gomez "el sonido" board for sale and decided I'm going to build a Bassman 6g6-b.  I don't know how to play guitar but I love rockabilly music. I have been obsessed with this build and have spent numerous hours reading and researching but none of that can compare to experience so all of you experienced people please take a look at my build as I go and give me some advice. Just to fore warn you I am using a Fender Chorus chassis that had burnt up it ain't gonna look pretty I already know that. I just want to hear that Setzer sound come out of this one day soon I hope. 

[rakkassan34]

I used plexiglass for turret boards and Xbox360 heat sink pegs as turrets since I had a bunch of them laying around from numerous red ring of death fixes. I replaced the copper wire on the rectifier board with some that I ordered from hoffmanamps. The main cap board (what's the proper name?) isn't soldered up yet I was just doing a test fit. My main concern right now is the cap on the presence pot. Every other build I've seen the capacitor is huge compare to this one. Should I replace it?

[HotBluePlates]

... I'm going to build a Bassman 6g6-b.  ...

Cool! Good luck with the build!

I don't know if your boards came with a schematic, or if you're referencing one. So here's the Fender 6G6-B Bassman schematic.

Look at your rectifier/bias board (with all the 1N4007 diodes). You're missing a 27kΩ 1w resistor which goes in parallel with the cap on that board (reference the layout; this board is towards the upper-left corner).

On you main filter cap board, you have a green-insulated jumper wire and a pair of 220kΩ resistors connected to the first two 20uF caps. Get rid of those, they're not present in the 6G6-B. I think I know what you were trying to do, but as-is the jumper is shorting high voltage to ground and the 220kΩ's are not in the right places for what you were looking to copy. The main filter board is not shown on the Fender layout (because it was outside the chassis under a metal cover), but the schematic shows these first two 20uF caps connected in parallel. So you will remove the green jumper and replace the 220kΩ resistors with wire.

On that main cap board, you probably also want to connect the - ends of the first two caps to the - ends of the other caps. Or, if you wanted to keep those grounds separate, make sure you install a wire for each set of grounds so you don't have a hard troubleshooting problem by having a missing ground.

On your main fiberboard, I see the 100kΩ plate load resistors for V2, but there are two caps connected to them (with a lead hanging in the air for each?): a silver mica cap to the left in the picture and an orange drop on the right. In the Fender layout, it shows only a single cap (0.002uF or 2000pF) across the 100kΩ which connects to V2 pin 6.

Other than those items, everything looks okay as far as I can see (pics aren't close-up enough to see color codes on resistors to know all values are correct).

... My main concern right now is the cap on the presence pot. Every other build I've seen the capacitor is huge compare to this one. Should I replace it?

Nope.

The schematic and layout says 0.1uF 200v. You cap appears to say 0.1uF, and it really doesn't need a 200v rating. Your cap appears to be metallized polyester, which is a dielectric and construction style which results in more uF's per unit volume. Others might be hung up on using orange drop caps everywhere, and the most commonly-used variety of those is polypropylene film & foil. That dielectric and style of construction makes a cap which is much bigger for the same number of uF's. Often, guys wind up using a 630v cap they have because it's on-hand, even though the presence control circuit will never see more than 50vac under any circumstance. A higher voltage rating also makes the cap bigger for the same number of uF's.

[labb]

You probably already know this but if not: get a schematic and or a lay out and mark every wire and component you install and connect as you do it. It will save you a lot of heart ache. Double check and measure where you can every component. Don't assume they are correct.

[rakkassan34]

Thank you for the reply. I didn't get any layout or schematic I've been referencing some from the internet and other builds.

"Look at your rectifier/bias board (with all the 1N4007 diodes). You're missing a 27kΩ 1w resistor which goes in parallel with the cap on that board (reference the layout; this board is towards the upper-left corner)"
I added a bias pot like I've seen from other builds and they've all removed the 27k resistor from the rectifier board. I'm using 5881 tubes which is why I added the bias pot. Should I put the resistor on the rectifier board?

I haven't soldered the main cap board yet. I'll rearrange some things on it and post again. I used the jumper wire because I have all the caps facing the same way. Most boards I've seen one cap on the end is inverted. I just thought it would look a little cleaner with them all facing the same way.

"On your main fiberboard, I see the 100kΩ plate load resistors for V2, but there are two caps connected to them (with a lead hanging in the air for each?): a silver mica cap to the left in the picture and an orange drop on the right. In the Fender layout, it shows only a single cap (0.002uF or 2000pF) across the 100kΩ which connects to V2 pin 6."
I was in the process of replacing the orange cap with a lower value silver mica. I've heard most remove that cap completely for that Setzer sound but these Gomez boards it lets all the high end of this channel through. I plan on using a switch to select straight thru or capped just to add my own little mod to it

So the presence pot cap is ok?

Thanks again for your help.

[rakkassan34]

A few more pics

[EL34]

Thanks for the order.
Hopefully you will need more stuff before you are done with your build. 

[HotBluePlates]

I added a bias pot like I've seen from other builds and they've all removed the 27k resistor from the rectifier board. I'm using 5881 tubes which is why I added the bias pot. Should I put the resistor on the rectifier board?

No, if you're adding a bias pot you won't put the resistor on the board. But now that you have the pot, you will need a resistor from the left lug (as seen in your picture; nothing is on this lug) to ground. If you have a 10kΩ pot, a resistor of ~18-22kΩ should be good.

Using that resistor insures you can't turn the bias down to 0v, which would cause your tubes to redplate. Not connecting that lug to ground through a resistor also will prevent the pot from doing anything; bias will always be at maximum negative voltage, keeping your tubes running cool.

So the presence pot cap is ok?

Yes, it's fine.

[rakkassan34]

Thanks for the order.
Hopefully you will need more stuff before you are done with your build. 

If this one turns out ok I'll be needing plenty more parts for my own version of a bassman with a reverb pan. I already told ya all my parts are coming from you from now on. Superfast shipping and it's just nice to see a box packaged by a human and stuffed with newspaper.

[rakkassan34]

No, if you're adding a bias pot you won't put the resistor on the board. But now that you have the pot, you will need a resistor from the left lug (as seen in your picture; nothing is on this lug) to ground. If you have a 10kΩ pot, a resistor of ~18-22kΩ should be good.

Good catch, thanks again

How about these input jacks. They're mono jacks from the local radio shack. I hope the connections are the same as I'm seeing on layouts I've been looking at. In one of the pics I'm using green/black wire to point to the face. Should I put a plastic washer there to insulate it from the chassis?

[HotBluePlates]

The jacks look fine.

On those Alpha pots, the solder joints to the case (to make a ground connection) look like colder solder joints. If you can push at them with a screwdriver and pop them off, they're cold joints.

First, unless you have a ground buss along the back of the pots, there's probably not much use in soldering to them to establish a ground. Many/most pots don't have reliable conductivity from the shell to the metal bushing that would contact the chassis. Second, Alpha pots in particular have a coating of some kind that inhibits soldering; you need to sand/grind the surface to get a silvery patch that exposes bare metal, then solder to that.

[g-man]

Deleted

[eleventeen]

I'll second the motion on getting shorter lengths of bare wire...either on your 68K's hanging off the input jacks or the various wires connecting to the tube sockets. The rule of thumb is, the insulation should be back from the terminal the outer diameter of the wire; however, in this case, and I'm not trying to set up the impossible challenge for you, I would be trying to get the insulation back from the terminal by about the diameter of the BLACK, internal insulation, not the white outer cloth insulation.


This may seem difficult, but frankly your solder joints look pretty good in the sense that they are "stingy", you don't have a big honking glob of solder on them. That must mean you are not overheating or overfeeding them. One could say that this will never be a problem, but at some point, it *can* be should you ever need to stick a probe in there to troubleshoot something. Besides, you'll never get better at it unless you have a visual ideal to shoot for.


You don't want the insulation to actually touch the terminal, you want that "golden" distance. In terms of older Fender amps, this was of course never a problem because they used that wire with the "pushback" insulation so if the bare wire was a little bit too much, the insul could be easily shoved closer to the terminal and nobody would ever know.


My advice would be to grab something with a bunch of terminals on it like an extra tube socket or a multi-pin connector and practice trying to get that distance down. You seem to have good control over your soldering, so this would not destroy the socket for later re-use. It's only a matter of knowing how  you want the finished product to look and practicing a couple dozen times.

[rakkassan34]

I'll work on shortening the ends today, thanks all. I also have an idea for grounding the pots that I've seen somewhere. Take a long grounded stripped wire run behind the pots and ground them to that. Good idea or bad? I've read that it's best to have one ground to avoid ground loops but don't ground AC with DC is that right? if so I have no idea what's AC and what's DC in there. 

[EL34]

Thanks for the order.
Hopefully you will need more stuff before you are done with your build. 

If this one turns out ok I'll be needing plenty more parts for my own version of a bassman with a reverb pan. I already told ya all my parts are coming from you from now on. Superfast shipping and it's just nice to see a box packaged by a human and stuffed with newspaper.

Thanks, that's awesome!

[eleventeen]

"I'll work on shortening the ends today, thanks all. I also have an idea for grounding the pots that I've seen somewhere. Take a long grounded stripped wire run behind the pots and ground them to that. Good idea or bad? "


Yes, it's a good idea but rarely do-or-die. To do this, it's generally necessary to file off or sand off an area on the back of every pot to expose clean metal (it's steel--not copper--we don't ordinarily think of steel being very solder-friendly but it can be if it is freshly filed off and given a little more oomph than a normal solder joint) and to have a soldering iron of perhaps larger size/temp than normal. And get to it soon after you do your filing, whether the pots are already mounted or before they are installed into position. All you need is maybe a 3/8" x 3/8" patch of clean metal. DO NOT use any kind of acid flux if you have soldering trouble!! If you can't get it done with your current iron, forget about it or get a bigger iron/tip. 

"I've read that it's best to have one ground to avoid ground loops but don't ground AC with DC is that right? if so I have no idea what's AC and what's DC in there.

It's a little more complicated than that, but not much. Fender amps only partially obeyed "best practices" in this area but they DID make power supply grounds and filament grounds---when the filaments were a CT---close to the power trans, all together on one bolt. But when Fenders used the dual-100 ohm synthetic center tap scheme, that was grounded to the pilot lamp frame. Do a little more reading on "ground loops" and "star grounding". This can get to be a whole religion, but in general, we want NOT to use 15 different points on the chassis for gnd points and intermingle power and signal grounds any old place where we might grab them and particularly in the case of a steel chassis, we don't want ground currents running all over the place.

The other thing I wanted to suggest about your wiring is, I like to try to get the wires to a tube socket to approach the pins perpendicular to the circumference of the socket. Not tangent. This is a style thing, I suppose, but is kind of in the category as the "less exposed wire" reco I made earlier. You can readily see, that if your wires come into the tube socket at the tight angle AND have lots of bare wire exposed at the tube-pin solder joint, this is asking for trouble. This makes your wiring lots easier to look at should you need to, later. It is no more work to do when it's being built...so it's good insurance. Another one of those visual things that you'll easily adapt to once you get the picture. 

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[HotBluePlates]

... I've read that it's best to have one ground to avoid ground loops but don't ground AC with DC is that right? if so I have no idea what's AC and what's DC in there.

BLUF (bottom-line up-front): You already have your first two filter caps with separate ground lugs from the rest of the filter caps; solder a long wire per set of grounds (1st two caps, all other caps) to the turrets, feed them inside the chassis, attach a ring terminal, bolt them to the chassis on separate bolts. Put the power transformer center tap on the same bolt as the 1st two filter caps; consider the possibility of having a wire for the grounds for the output tube cathodes going to the same bolt.

Every other ground can be placed where convenient in the chassis.

"I've read ... don't ground AC with DC is that right?"

If the original author for that statement knew electronics, they never would have said it. There's no such thing as separate a.c. and d.c. grounds in the average guitar amp (maybe even the non-average guitar amp). I can give a technically-accurate explanation how a.c. essentially rides on d.c. throughout the amp, but that discussion won't help you get your amp built today.

[rakkassan34]

I can't thank y'all enough for the advice keep it coming. I didn't get much done on the amp today was busy cleaning up a flooded carpet fun fun. I did shorten up the exposed wiring on all my tubes, upon closer inspection there were a couple that were dangerously close to another pin. I bet once I put a tube in that would've moved that lead just enough to touch another, WHEW that would've put a hamper on things. I also wired up my treble bleed mod switch.

"while Gomez was trying to stay true to the Bass channel's .002uf "treble bleed cap" (sends the highs to ground) per Leo fender's idea for a bass guitar, it
is a horrible thing to have on a guitar amp so that needed to be clipped out. While this is all that is needed on an original 63' Blonde 6G6-B bass channel to open it up nicely for guitar, for some reason on the gomez it lets ALL the high end of this channel through and it needed to be tamed with a 250pf silver mica"

To hear for myself I decided to give me an option to switch between no cap and the 250pf so I threw a switch in and tested the continuity a dozen times to make sure I got it right.

I made up a ground bar for my pots also, I just have tape holding it in there as a mock up. I will file the back of the pots before I solder it to them and I'll ground the resistors to it rather than the pot.

[rakkassan34]

I just realized I made a mistake with my treble cap switch. I see both of the leads going into the same socket on the board. 

[eleventeen]

Any residue from that tape isn't going to help you; either with filing OR eventually soldering to the pot-cans. Remove it, I say. You can also scrape the back of the pots (where you intend to solder them) with a razor blade or a little patch of sandpaper under your thumb or even a sharp screwdriver blade. All you are trying to do is to expose some bright, fresh, unoxidized metal so that when you solder, your flux has to do the least work and you're giving yourself the best chance at success. You don't need to make a 200 Amp connection. Personally, I like to heat up the can of the pot with NO ground wire involved, and get a pea-size area of solder adhered to the pot. Then you come back later, reheat the solder "pad" and embed your bus bar into it. The bus bar is generally tinned, which means it will drop right into your bead and you're done. With a big soldering gun/iron, you don't have to worry about this, but a soldering implement big enough to make those pot-pads is arguably too hot for making your 12AX7 tube-pin connections.

[rakkassan34]

I got a little more done today. That ground bar across the pots was a bigger challenge than I thought. I filed the backside of them, put a small pool of solder on them then pressing the bar against them I heated the solder, pot, and bar. Looked good but a couple of them failed the screwdriver pry test. So I repeated the steps and it's good to go. I also hooked up the pilot light and a bunch of ground wires.

[HotBluePlates]

... the screwdriver pry test. ...

That was the thing that taught me the difference between a good solder joint and a cold joint. A good joint cannot be dislodged by that test.

[eleventeen]

Appears that you have created the world-famous "synthetic center tap" comprised of two 100 ohm resistors connected to the 6.3 volt heater wires and  junctioned to ground at the pilot lamp ass'y *AND* you have a REAL 6.3 volt center tap: the green-yellow wire coming out of the power transformer. Normally, one grounds the CT *OR*, if not present, creates the synthetic center tap. One or the other, not both. I don't think it will cause any problems should you do both; probably the wired real CT is slightly preferable...but only one of these efforts is needed.

[rakkassan34]

Appears that you have created the world-famous "synthetic center tap" comprised of two 100 ohm resistors connected to the 6.3 volt heater wires and  junctioned to ground at the pilot lamp ass'y *AND* you have a REAL 6.3 volt center tap: the green-yellow wire coming out of the power transformer. Normally, one grounds the CT *OR*, if not present, creates the synthetic center tap. One or the other, not both. I don't think it will cause any problems should you do both; probably the wired real CT is slightly preferable...but only one of these efforts is needed.
I do have a center tap. Should I remove the resistors on the pilot light? Or is not grounding the pilot light not necessary?

[sluckey]

I do have a center tap. Should I remove the resistors on the pilot light?

That's what I would do. Then just connect the green/yellow stripe wire to chassis.

I only use the two 100Ω resistors when the PT has no center tap. However, there is a safety argument for using 100Ω 1/2W resistors instead of a real wired centertap. It's not unheard of for the output tube pin 3 (plate) to short to pin 2 (filament). This can happen while playing loud with no speaker connected, ie, OT secondary is open circuit. A high voltage will be reflected back to the OT primary and to the tube plate. This high voltage will often arc to the nearest ground which would be pin 2 (since the filament is referenced to ground via a center tap or the 100Ω resistors). That arc will likely require a socket replacement, but it can be even more damaging. If you are using the real wire center tap (remember the filament winding is big wire and has almost zero ohms resistance to dc voltage) there is a strong chance that the tiny wire for the OT primary winding AND/OR the tiny wire of the PT high voltage winding will burn open, making the transformer(s) useless. But, if you are using 100Ω 1/2W resistors instead of a real wire center tap, the small resistors will act as a fuse and burn open. Once that happens, there is no longer a path to ground for the arced socket. So, the 10 cent resistor saved the $$$ transformers in this scenario.

[eleventeen]

Excellent point by Sluckey. Although it may seem "unnatural" to use the synthetic center tap (made with the 2 resistors) versus the "real" CT, I have never found there to be any performance difference between the two schemas. One or other other is almost always necessary or serious hum will result. I was curious if anyone else had any contrary or confirming experience. I've never used the synthetic mode when a real CT was present, but he makes a good point about the piece of "insurance" the synthetic mode offers.



"Or is not grounding the pilot light not necessary?"


It's not about grounding the pilot ass'y---it is done to lower hum. Most tube amps will hum badly without one or the other heater-center-tap schemes. 

[HotBluePlates]

... there is a safety argument for using 100Ω 1/2W resistors instead of a real wired centertap. It's not unheard of for the output tube pin 3 (plate) to short to pin 2 (filament). ...

The only time I've had a tube fail was an internal pin 2 to pin 3 short. On a blackplate RCA 6L6GC. I think the amp used a heater center-tap, and it popped the fuse (because I use the correct fuse, every time). Had I been a knucklehead and used a too-big fuse, I'd have been buying a new PT.

[rakkassan34]

BLUF (bottom-line up-front): You already have your first two filter caps with separate ground lugs from the rest of the filter caps; solder a long wire per set of grounds (1st two caps, all other caps) to the turrets, feed them inside the chassis, attach a ring terminal, bolt them to the chassis on separate bolts. Put the power transformer center tap on the same bolt as the 1st two filter caps; consider the possibility of having a wire for the grounds for the output tube cathodes going to the same bolt.

Every other ground can be placed where convenient in the chassis.

Ok so Put a ring ring terminal on each of the 1st two caps and bolt them to where I have my power transformer grounded. I have my center tap, power transformer grounded to where my pot ground bar is bolted to the chassis. Then bolt the output tube grounds to this spot also. Sound ok?

[rakkassan34]

I love working on this amp head. I find it almost therapeutic, it puts me in such a calm focused state. Every morning I start off double checking my work from the day before. I was checking resistor values and connections yesterday and found out that I can't read as quite a few resistors had wrong values  for example my main tubes call for 470k 1W resistors my meter (I double checked with a diff meter also) says they are 47k. I don't get it the color codes look right but the meters don't lie. A couple of my pot resistors were wrong also. I'm still second guessing myself on the resistor on my rectifier board now. Any ideas on what it should be on this setup? I've got a bias pot and using 5881 power tubes the rest are 12ax7-c5's.

[rakkassan34]

I slept in and missed my morning workout so y'all please forgive me for not putting this all in one post. Here's the work I completed yesterday.
Today I hope to find out where the black and red wire coming from the main board go, I think the standby switch, I don't know but I'll figure it out.
The colorful wires from the output transformer go to the main cap board don't they? 
One that has me confused is the brown wire going to the bass pot, original schematics show it connecting to the treble pot casing then to the bass pot. Is this grounded to the treble pot before it goes to the bass pot? My treble pot has 4 connections at the top not 3. I've looked at other builds with the same treble pot and it looks like they connected the brown to the far left tab on the treble pot and a wire from there to the far right tab on the bass pot. Is that the way to go?

[sluckey]

example my main tubes call for 470k 1W resistors my meter (I double checked with a diff meter also) says they are 47k. I don't get it the color codes look right but the meters don't lie.

I'm assuming that what you call your main tubes are the 5881 output tubes? If so, you still don't have it right. Those resistors should be 470Ω. That's yellow, violet, brown.

[rakkassan34]

Yes main tubes 5871's the correct name power tubes?
You're right again about them needing to be 470ohms I think I out 470k ones in there. All I know is I gotta change em out and I don't have any on hand. Hoffmanamps here comes another order

[EL34]

Ok, I am sitting at the computer waiting 

[rakkassan34]

I got busy at work today and didn't get time to put an order in. I gotta make sure resistors is all I need. I didn't have time to take progress pics today either. I'm down to wiring the output transformer, the choke, and the main cap board. I've been scratching my head for a couple days trying to figure out how to wire them all in especially the choke. Anyone know where those two black wires from the choke go?

[rakkassan34]

On you main filter cap board, you have a green-insulated jumper wire and a pair of 220kΩ resistors connected to the first two 20uF caps. Get rid of those, they're not present in the 6G6-B. I think I know what you were trying to do, but as-is the jumper is shorting high voltage to ground and the 220kΩ's are not in the right places for what you were looking to copy. The main filter board is not shown on the Fender layout (because it was outside the chassis under a metal cover), but the schematic shows these first two 20uF caps connected in parallel. So you will remove the green jumper and replace the 220kΩ resistors with wire.

On that main cap board, you probably also want to connect the - ends of the first two caps to the - ends of the other caps. Or, if you wanted to keep those grounds separate, make sure you install a wire for each set of grounds so you don't have a hard troubleshooting problem by having a missing ground.

Is this layout minus the 220K resistors on the first two caps correct?

[g-man]

Deleted

[sluckey]

The original used two 20µF/600V caps in parallel. The only 20µF/600V caps that I'm familiar with today are Sprague Atoms. They're $22 each and are probably too big to fit under the doghouse.

I recommend that you use your original plexiglass board but replace the two caps on the left with 100µF/350V caps. Much cheaper and Doug has them. See pic...

[HommeMarrBuckley]

Steve is right.


Click this link and print it out.  It is what I believe an accurate layout of the filter cap board (very first pic).  You can see a pic of the mounted filter cap board on page 6 of the post.
Dub's build is super nice.


Match your resistors and layout to the printout and orient the wires accordingly. 


http://www.mosriteforum.com/forum/viewtopic.php?f=30&t=5096

[rakkassan34]

How's this

[sluckey]

That's fine ***IF*** your unloaded B+ will be less than 500VDC.

[rakkassan34]

I took a few days off from working on the amp. My wife got rear ended by a minivan doing 60mph. Thank God my wife was in a minivan also and only suffered minor injuries. I gotta give it to Chrysler, I was able to drive it home, the other minivan that his us (Toyota) is a complete loss but no injuries in there either. I know crumple zones had a lot to do with the other van's damage and safety of the driver. I'm just glad no one was seriously injured.

Now back to the amp!

I recommend that you use your original plexiglass board but replace the two caps on the left with 100µF/350V caps. Much cheaper and Doug has them. See pic...[/quote]

Sluckey, Would the 100uf/350V caps give a better tone? I'm hesitant to replace what I already have only because I already have them and I'm soooo close to finishing that waiting another few days for an order would... well actually it would make me slow down, take my time, and focus more.
Oh the resistors on the first two capacitors. Should I use those or not? I've seen 3 diff setups, 1 without the resistors, another had them running from + to - on each cap. I'm confused.

[rakkassan34]

My output transformer has red, brown, blue out of one side and the other side has yellow 4ohm, purple 8ohm, green 16ohm, black
I just wanted to confirm where all these go
Red to +430v on main board
Brown to pin #3 of power tube (5881) 1
Blue to pin #3 of power tube (5881) 2

From the other side of the OT
Black to ext speaker
Yellow to speaker

What would I do with the purple and green? make more speaker outputs?

[rakkassan34]

I had a few more connections I'm just unsure of. The wires from the main cap board mounted under the chassis and wanted to verify the Brown, black, red, blue from the OT. I've attached what I think should happen. Damn I wish I'd have known to highlight a layout wire by wire as I connected it before I started. It's not as overwhelming as it was when I started because a lot of it is making sense. Has anyone got a 6g6-b layout for Jschem ?

[sluckey]

Would the 100uf/350V caps give a better tone?    ...Oh the resistors on the first two capacitors. Should I use those or not?

The series caps will not give better tone. But they will give you a 700V rating. You only need the resistors if you use series caps.

Brown to pin #3 of power tube (5881) 1
Blue to pin #3 of power tube (5881) 2

DON'T TRIM THESE WIRES TO LENGTH JUST YET! You may need to swap them when you power up.

What would I do with the purple and green? make more speaker outputs?

You could do that, one jack for each wire. Or you could use Doug's rotary speaker impedance selector switch. Or you could just tape the ends of the unused wires.

[sluckey]

wanted to verify the Brown, black, red, blue from the OT. I've attached what I think should happen.

The black wire you highlighted on the layout drawing IS NOT FROM THE OT. Only the RED, BROWN, and BLUE wires coming thru that chassis hole are from the OT. Both of the black wires coming thru that same hole are the choke wires. Look down near the SPKR jacks and you will see the BLK and YEL wires coming from the OT and connecting directly to the speaker jacks.

[rakkassan34]

Appreciate the help Sluckey, I caught another mistake today; got the blue and second yellow wire from the cap board mistaken. It's coming along slower than I wanted but I'm enjoying every minute of it especially with the help from y'all on this forum.   

[rakkassan34]

Well I should be done today. All I have left is to wire and install two input jacks for the norm channel. I had a hell of a time yesterday wiring the input jacks for the Bass channel because I bought input jacks from radioshack and the pin out on them is different than a switchcraft. I kept confusing myself and still second guessing myself so keep your fingers crossed. I used a light dimmer switch to build a way of slowly powering up the amp. I don't know if it's necessary just something I read somewhere to be safe. I'm going to surf some first start up tips and biasing instructions in a min. If any of y'all have any please let me know.
Hold on to your butt!! I'm gonna fire up this thing today!!! I'm sooooo excited and more nervous.

[labb]

give this a read      http://www.paulrubyamps.com/info.html

Also google "Lightbulb limiter"  for first power up.

[Willabe]

Light bulb limiter from Sluckey's web site.


http://home.comcast.net/~seluckey/amps/misc/Amp_Scrapbook.pdf



              Brad     

[rakkassan34]

It's done!!! Now I'm second guessing myself. I checked all connections more than a few times. Running over everything with a continuity tester I noticed that I have continuity all over my output jacks; from lead to lead to tip to chassis, just everywhere. The lead on the right doesn't have anything connected to it either, should this be grounded, should they have a plastic spacer so the body don't ground out on the chassis?
I soooo want to plug it up but scared to do so.