Re: Single Channel AB763 no verb/vib

[samato]

Samato has a question about this post:

http://www.el34world.com/Forum/index.php?topic=5513.0

I just found and joined this forum today.  Wow, am I happy I did!  This is exactly what I want to build - a single channel, single input, no reverb/vibrato Deluxe Reverb.  I thought it was going to be much harder and very time consuming to get the design/schematic/layout thing but here it is, already done for me.  Thanks to all who participated and to this forum for making it available.

I am a beginner and have never built an amp before.  I'm an audio engineer and I did study electronics but never really "got it".  Recently I've started studying again and it's working out better this time.  I do have good soldering skills at least.

Questions:

1) Why was the extra pair of 6L6's added?  I don't think I'd want that as I want this thing to be as simple and small as possible.

2) What other changes do I need to make if I drop the "Mid" pot?

3) Would making the changes listed in the 3rd post of this thread make the circuit the same as the original Vibrato channel?  That's what I would want I think.  I'm not clear on the differences between the two channels on the original AB763 Deluxe Reverb but I know I always preferred plugging in to the Vibrato channel even without the effects on.

4) The Rectifier tube is a GZ34, right?

5) Shouldn't there be a 68K resistor on the input to the grid of V1 and a 1M resistor on the actual input jack?  I'm probably missing something here but I don't even see the input jack.  Is it just assumed that the builder would know what to do there?  Sorry, newbie here.

I would greatly appreciate any help/advice/etc. you guys may be able to offer on this project.  I know it is extremely ambitious on my part to think I can tackle this as my first amp build but it will be well worth it if I can pull it off.  If I can't it will be an excellent learning experience (as long as I don't electrocute myself!).  

I will gladly document my progress by posting diagrams, explanations, photos, and sound clips here (assuming that is acceptable on this forum).

Thanks

[tubenit]

1)  Some AB763 have four power tubes like Twin Reverb others have two like Deluxe or Super Reverb

2)  Look at a Princeton Reverb tone stack.  However, I would recommend the mid pot.

4)  This layout (below)  uses a solid state rectifier.  You can build one with a GZ34.  Look at a Deluxe Reverb

5)   Look in Hoffman's Library of Information about input jacks to answer this question

Welcome to the forum!

With respect, Tubenit

[samato]

Thanks Tubenit for moving/re-posting my questions.  

1) I knew the AB763 circuit was found in other amps but I didn't put 2 & 2 together, now I get it.  

2) I will consider the mid pot.  It's just that in the time I spent playing though a 70's Silverface Deluxe Reverb I don't remember ever thinking "Man, I wish I could adjust the mids".  From what I've been reading it seems like the key to getting the best sound out of an amp is simplicity and having the least amount of parts necessary to do the job.

4) Solid state rectifier, got it.

5) Aha, the "common hookups" page!  Thanks, that is very helpful.
http://www.el34world.com/charts/CommonHookups.htm

EDIT - Simplicity and using the least amount of parts is probably not the key to the best sound but at least a very important part.  I realize the quality, type, value, etc. of those parts is extremely important but that is a much more complex part of the equation I think.

[eleventeen]

My suggestions:

Give a load of thought to the "non-schematic" (primarily the physical form factor) aspects of this project.

A: what flavor of chassis you are going to build this on?

B: Are you going to move this around?

C: Would you like to end up with a one-piece amplifier/speaker/cabinet that you might be able to take to a jam or leave in your home without fear that someone might zap themselves on it?

I don't propose to interview you about these aspects, I'm just suggesting that you spend some time pondering them. An amp is not just a schematic manifested into an assemblage of parts.

I bring this up because I am kind of returning to tube amp repair and construction after about a 35 year hiatus. I have zero resistors lying around except for maybe two that I could cut out of a dead PC power supply and they are probably .17 ohm 5 watters. Useless. I have no drill press. I have no jars of 6-32 machine screws around. I certainly don't have a chassis punch set. I don't even have a proper workbench without having to sit on the fender (no pun intended) of a car when the car is garaged. I have a soldering iron, solder, some very high quality multiple colors of 18 ga wire which is irritatingly too big, most hand tools, and a Fluke 77 meter. My point is, that starting afresh here, I can't take anything for granted. There are no TVs in the garbage I can get a few parts out of. There aren't any terminal strips or fuseposts or pilot light holders lying around...unless I buy them. Not one, not one single part is just waiting around, eagerly waiting to be put into use.

And...if I solved each and every one of those problems, then I could theoretically build a working 5-sided chassis with open bottom = shock hazard and be in a rough position as far as bringing it to a jam without trashing it. No cabinet, no speaker.

If that situation resembles yours, I'd strongly suggest buying either a kit for a whole amp and adding/subtracting the dozen parts that would constitute the difference. OR, buying a used amp and tearing its guts out and rebuilding it. Plenty of advice here in your new home.
 
Never mind the cost of sourcing every part from scratch, which is well known to be higher than buying an existing amp. It doesn't get you the cabinet and speaker (unless, of course, you buy those, and you can, and they are plenty expensive)

[samato]

Those are all valid points.  I have given thought to most of them.  I can't say I've got it all figured out but I don't see that as a reason not to go for it.  There are cost effective ways to obtain all the necessary parts, materials, tools, etc.

I just can't justify spending all the time, effort, and money that would be required to build an amp if there's not at least a chance it will be the one I want.  I know the kits are a much more logical approach for someone with my experience/knowledge but they don't offer what I'm looking for and they are, in my opinion, very expensive.  I'm estimating my costs for this project to be somewhere around $300:

$100 - transformers
$50   - speaker
$50   - tubes
$50   - components, wire, and hardware
$20   - chasis
$20   - wood to build cabinet
$10   - speaker grill cloth (or other suitable fabric)
---------
$300 - Total

Hopefully I can do better by being creative with certain things but others will probably cost more than I think so that will probably offset any savings.

The schematic/layout diagrams are my focus at the moment because I can't plan or start anything without them.  

[tubenit]

I have converted Bogen amps into excellent guitar amps for under $100.

Having said that, I typically think of $375-450 for a combo amp scratch build.

With respect, Tubenit

[samato]

$450 is a lot less than I can get a good Deluxe Reverb for, even a reissue.  Plus this one will be the size I want.  

One of the reasons I think I can save some money is the fact that this place is 15 minutes from where I live:

http://www.skycraftsurplus.com/electronics.aspx

They have a huge selection of capacitors, resistors, wire, hardware, and even transformers.  The prices are pretty low.

Speaking of transformers - looking at the section Skycraft has of them (see attached photo, this is a small part of that section), I've got to believe there are some in there I could use for my amp.  My question is assuming I can choose the right ones and test them (very big assumption at this point), would it make sense?  Maybe even just temporarily to get the thing working and replace them if it seems like they are making the amp sound bad?

[eleventeen]

My Gawd, an actual surplus store..? I didn't think those existed any more. When I started out I could take a bus to Radio Row, on Canal St, in NYC. For a 10 year old, that was heaven. After they tore that out & built the WTC, I moved to California, LA, and there were some great surp places around Burbank Airport in LA and Oakland Airport in northern CA for the next 25 years. Those are now all gone.

That store looks GREAT as far as tranny selection! You're probably not going to get anything resembling a decent audio output tranny there, but a PT certainly looks possible. If you find something that puts out enough for a tube amp, the chances of it having a dedicated bias tap are close to zero. All that means is that you derive bias from one of the HV legs.

In my career, the number of bad transformers I've encountered has been remarkably low, if we can agreee to discard ones that are obviously flamed out and dripping goop. You've got a nice selection there, you probably need to do a drive-by to see if there are any that put out more than 60 volts! 

Your task to be able to estimate current capacity from size; without buying a 45 pound beast!

[sluckey]

I prefer to just buy the right transformers and get it right rather than make a questionable transformer from a surplus store work.

Here's an AB763 Deluxe Lite that may interest you.
http://home.comcast.net/~seluckey/AB763_Deluxe_Lite.pdf

EDIT... fixed broken link.
http://home.comcast.net/~seluckey/amps/misc/AB763_Deluxe_Lite.pdf

[samato]

I prefer to just buy the right transformers and get it right rather than make a questionable transformer from a surplus store work.

Here's an AB763 Deluxe Lite that may interest you.
http://home.comcast.net/~seluckey/AB763_Deluxe_Lite.pdf

That does indeed appear to be closer to what I'm looking for.  I'll be studying it for a while. 

Would anyone care to comment on how this AB763 Deluxe Lite compares to/differs from the original AB763 Deluxe Reverb design?  All I can see at first glance is that it's single channel, the addition of a mid pot, and the lack of reverb/vibrato.

I'm also still trying to figure out if there is much difference in the original AB763 Deluxe Reverb's two channels, aside from the reverb & tremolo on the Vibrato channel.

[sluckey]

Would anyone care to comment on how this AB763 Deluxe Lite compares to/differs from the original AB763 Deluxe Reverb design?  All I can see at first glance is that it's single channel, the addition of a mid pot, and the lack of reverb/vibrato.

In addition to your observations, it has a bright switch/cap and the .1µF coupling caps between the PI and PA have been replaced with .047µF caps. R14, 270K, replaces the missing 220K mix resistor and 50K INT pot. Other than that, it's exactly the same as an AB763 DR, but with the VIB channel, reverb, and trem circuits stripped out.

I'm also still trying to figure out if there is much difference in the original AB763 Deluxe Reverb's two channels, aside from the reverb & tremolo on the Vibrato channel.

Well, the VIB channel has an additional gain stage. V4B restores the gain lost due to the way the reverb circuit ties in. I've heard that the VIB channel is slightly hotter than the NOR channel, but my hearing is not good enough to detect a difference and I won't be putting a scope on it to see if there's a measurable difference. One other slight difference, the VIB channel has a permanent bright cap and the NOR channel has none.

[Fresh_Start]

OK, sluckey types more quickly and less than I do...  

I'm also still trying to figure out if there is much difference in the original AB763 Deluxe Reverb's two channels, aside from the reverb & tremolo on the Vibrato channel.

Yes, there is a significant difference.  Look at the shaded area in sluckey's schematic.  That's the "Normal" channel signal path.  Now look carefully at the Vibrato channel's signal path in the AB763 schematic (print it out from Doug's Library and use a highlighter).  Instead of what's shown on sluckey's schematic in the shaded area, you'll see a 3.3 meg resistor in parallel with a 10pf cap and an additional gain stage before the input to the phase inverter.  Actually, the attached preamp schematic (also from sluckey) shows it much more clearly.

The important thing to understand is that the 3.3 meg resistor forms a voltage divider with the 220K resistor going to ground at the right-hand end of the reverb circuit.  That results in about a 94% signal reduction before it goes into the "extra" triode.  

(technically, the bottom portion of that voltage divider actually is the 220K resistor in parallel with the combination of the 470K resistor attached to the Reverb pot and the lower "leg" of the Reverb pot - effectively only 150K with Reverb at "0", yielding a 95.5% signal reduction)

Sluckey's "Deluxe Lite" looks like a really neat, clean circuit.  However, that extra triode does add something to the circuit's tone IMHO.  One possibility would be to "steal" a triode from the reverb driver to get that extra gain stage add a 12AX7, use one triode for the additional gain stage and the other for Princeton Reverb type tremolo, but that would require some design experience and a fair amount of experimentation.  Or use two triodes of a lower gain tube like a 12AU7 in parallel where the added gain stage is.  Alternatively, you could add two 12AX7s and build sluckey's "Tweed" Deluxe Reverb using 3 triodes for the reverb and the 4th for the added gain stage.

Hope this helps,

Chip

[samato]

Thanks guys for all the input and thank you Sluckey for posting the diagrams.  It will take me a while to catch up to what you're saying and what the sonic results might be but when I do I'll have some more questions.

[samato]

On a different note, what do you guys think of one of these Rola 12", 8-ohm speakers for this amp?  I can get them pretty cheap.  I'm told they came out of a Hammond organ.  I can test them before buying, though maybe only through the organ.

[tubeswell]

On a different note, what do you guys think of one of these Rola 12", 8-ohm speakers for this amp?  I can get them pretty cheap.  I'm told they came out of a Hammond organ.  I can test them before buying, though maybe only through the organ.

Depends what Rola speakers they are.  Some rola/'celestion' type speakers are pretty variable. Specs of their old line here:

http://www.retrovox.com.au/rola.html

[samato]

I went ahead and bought 3 of those speakers, would've been 4 but he accidentally ripped one of the cones while I was there.  I really don't know if they are Rola or what but they are very lightweight and don't look like anything special.  They sound pretty good though.  We put each one, one by one, into an empty home stereo speaker cabinet with the back off and connected them to my Fender Pro Jr.  I also checked DC resistance and all were around 8-ohms.  Nothing sounded blown so I figured I can't go wrong for $20.  I might have to make a cabinet for the big one and run my Pro Jr. through it at home when I have band rehearsals because it sounds pretty good and seems to have less volume than what I have in there now which is too loud.  

He also gave me some sort of 9-pin, 12ax7 type tube.  The letters have been rubbed off so I don't know exactly what it is.  I also took the opportunity to dig through one of his trash cans and picked out a few circuit boards populated with components.  I know I probably won't be able to use a lot of those, if any, but I figured it couldn't hurt.  One board has a bunch of carbon comp resistors and big orange drop type caps.

Question about extension speaker cabinets:  If I want as small as possible it would probably be best to make it open back or at least partially open, right?  It seems like most people go with closed but that probably doesn't work well for the small size I want to have, with not much room to move air behind the speaker.

[dude]

samato,

I think you got a great deal on the speakers, they're probably around 20 watts each. Too bad you lost the fourth but if you get an OT with 8 and 4 ohm secondary, two should handle 6V6's but I'm not sure about 6L6's.

Wish I could find a hit like you got, not too much in my area except Craigs List.

al 

I prefer to just buy the right transformers and get it right rather than make a questionable transformer from a surplus store work.

Here's an AB763 Deluxe Lite that may interest you.
http://home.comcast.net/~seluckey/AB763_Deluxe_Lite.pdf

Can I ask where the filtering is located in your Deluxe lite? I assume hanging under the chassis enclosed in a metal box like some Fenders? Could I put the filtering on the board if I'm careful with my grounding?   

al

[samato]

Hmm, so you think I would blow the speaker if I tried to go with two 6V6's, 8-ohm OT, and just one of those speakers?  You're probably right about them being rated at around 20 watts, I figured somewhere between 15-25 watts.  The Deluxe Lite puts out around 22 watts, right?  

I'm only planning on having one speaker in the amp, and maybe an extension cabinet sometimes.  I like to travel light.  I carry my current rig with guitar, amp, couple pedals, cables, etc. on my motorcycle.

[sluckey]

Can I ask where the filtering is located in your Deluxe lite? I assume hanging under the chassis enclosed in a metal box like some Fenders? Could I put the filtering on the board if I'm careful with my grounding?

I never built the Lite. Instead, I built the DR Vibrato channel with reverb but no trem. The filter caps are located on top of the chassis. That special layout uses a slim board that fits neatly inside a Hammond 3x4x17 chassis and the chassis is a perfect fit for a 5E3 Deluxe cab.

You can put the caps directly on the board if you have room. I prefer to do that. However, I was trying to stuff a lot of circuitry into a tiny space and did not have that option. My goal was to put a single channel DR with reverb into a 5E3 cab. Here's a link so you can see the challenge...

     http://home.comcast.net/~seluckey/amps/tdr/tdr.htm

BTW, printing that layout full scale produces an exact size board layout that can also be used as a drill template.

[dude]

Hmm, so you think I would blow the speaker if I tried to go with two 6V6's, 8-ohm OT, and just one of those speakers?  You're probably right about them being rated at around 20 watts, I figured somewhere between 15-25 watts.  The Deluxe Lite puts out around 22 watts, right?  

Yeah, you would blow a single speaker with 6V6's, you'd need about a 30 watt single from my experience. It's the distortion that will blow it, if you keep it clean you might be OK but that's impossible  

A Princeton Reverb has two 6v6s and runs 15 watts, I believe. I know the Deluxe Reverb is 22, I could never figure that out.

I never built the Lite. Instead, I built the DR Vibrato channel with reverb but no trem. The filter caps are located on top of the chassis. That special layout uses a slim board that fits neatly inside a Hammond 3x4x17 chassis and the chassis is a perfect fit for a 5E3 Deluxe cab.

Here's a link so you can see the challenge...

     http://home.comcast.net/~seluckey/amps/tdr/tdr.htm

BTW, printing that layout full scale produces an exact size board layout that can also be used as a drill template.

Thanks for the info, nice to know a Hammond chassis (3x4x17) fits a 5E3, I have one and you see Hammond chassis all the time on fleabay and Craig's List. Thanks for the link. I love the 15 to 20watts you get with 6V6s and the tone, EL84's are OK but you don't get that tight bass.

al

[Fresh_Start]

A Princeton Reverb has two 6v6s and runs 15 watts, I believe. I know the Deluxe Reverb is 22, I could never figure that out.

Different voltages, different phase inverters, and, probably most importantly, different output transformers.

Chip

[samato]

I guess I didn't need to buy those speakers then.  I only got them so I would have one to put in the amp I'm building, knowing that I might upgrade it at some point.  Oh well, maybe I'll make a 2 x 12 extention cabinet just to have around.  It would be 4 or 16 ohms though.

[samato]

Hey Sluckey - any chance you could send me your Deluxe Lite Jshem file, assuming that's what you used to make it?

[samato]

OK, sluckey types more quickly and less than I do...  

I'm also still trying to figure out if there is much difference in the original AB763 Deluxe Reverb's two channels, aside from the reverb & tremolo on the Vibrato channel.

Yes, there is a significant difference.  Look at the shaded area in sluckey's schematic.  That's the "Normal" channel signal path.  Now look carefully at the Vibrato channel's signal path in the AB763 schematic (print it out from Doug's Library and use a highlighter).  Instead of what's shown on sluckey's schematic in the shaded area, you'll see a 3.3 meg resistor in parallel with a 10pf cap and an additional gain stage before the input to the phase inverter.  Actually, the attached preamp schematic (also from sluckey) shows it much more clearly.

The important thing to understand is that the 3.3 meg resistor forms a voltage divider with the 220K resistor going to ground at the right-hand end of the reverb circuit.  That results in about a 94% signal reduction before it goes into the "extra" triode.  

(technically, the bottom portion of that voltage divider actually is the 220K resistor in parallel with the combination of the 470K resistor attached to the Reverb pot and the lower "leg" of the Reverb pot - effectively only 150K with Reverb at "0", yielding a 95.5% signal reduction)

Sluckey's "Deluxe Lite" looks like a really neat, clean circuit.  However, that extra triode does add something to the circuit's tone IMHO.  One possibility would be to "steal" a triode from the reverb driver to get that extra gain stage add a 12AX7, use one triode for the additional gain stage and the other for Princeton Reverb type tremolo, but that would require some design experience and a fair amount of experimentation.  Or use two triodes of a lower gain tube like a 12AU7 in parallel where the added gain stage is.  Alternatively, you could add two 12AX7s and build sluckey's "Tweed" Deluxe Reverb using 3 triodes for the reverb and the 4th for the added gain stage.

Hope this helps,

Chip

Okay, it took me a while but now I understand what the explanation above means and I have made a decision based on it.  Even though I can hear the difference between the Normal & Vibrato channels on a Deluxe Reverb and prefer the sound of the latter, for this build I will go with the Normal channel but maybe add the permanent bright cap.  Adding an additional gain stage complicates things, adds to the cost, and gets away from the idea of keeping things as simple as possible.  Besides, the Normal channel still sounds great on that amp.

[sluckey]

any chance you could send me your Deluxe Lite Jshem file, assuming that's what you used to make it?

It's a Visio file.

[samato]

any chance you could send me your Deluxe Lite Jshem file, assuming that's what you used to make it?

It's a Visio file.

Oh - and that probably can't be imported into Jshem, right?

[samato]

I'm thinking about buying a Super Champ XD to convert into this modified Deluxe Reverb I want to make.  I think I can get the SCXD pretty cheap, maybe around $150 or less.  Here are the specs:

http://www.fender.com/products/search.php?partno=2331100000

It seems like I could use the:

power and output transformers
3 tubes - 12AX7, (2) 6V6
jacks
chasis
cabinet

If so all that would be left to buy would be:

choke
2 tubes - 12AT7, GZ34
turret board, turrets, tool
components - capacitors, resistors
pots
wire

I don't know if I could fit a 12" speaker in the SCXD cabinet and I'm probably missing a few things but overall does this sound reasonable to you guys?

[sluckey]

That conversion would be a difficult challenge for a beginner. You will have to do a lot of circuit modification to use that PT. Forget using a tube rectifier with it. You'll have to use a bridge. And you'll have to figure out how to get your bias voltage too. It can be done, but will require some good electronics knowledge.

The tubes and OT could be used. Maybe the chassis can be used too. You'll need new jacks.

I think if you watch ebay, you can find a much better conversion candidate, especially for a first time project.

http://support.fender.com/schematics/guitar_amplifiers/Super_Champ_XD.pdf

[samato]

Thanks, I won't waste my money and time on that one then.

[samato]

Hey Sluckey - Question about your Deluxe Lite diagram:

R14 is 270K-ohm 20% tolerance.  The original Fender "Deluxe Reverb-Amp AB763" calls for 27K-ohm 10% in this position.  Is this an intentional change you made?  Am I reading something wrong here?  If intentional what is the reason?

Thanks

[Fresh_Start]

Hey Sluckey - Question about your Deluxe Lite diagram:

R14 is 270K-ohm 20% tolerance.  The original Fender "Deluxe Reverb-Amp AB763" calls for 27K-ohm 10% in this position.  Is this an intentional change you made?  Am I reading something wrong here?  If intentional what is the reason?

Thanks

Don't sweat the tolerance rating - 10% is better than 20% and 5% is better than both.

The "R14" 270K resistor replaces the combination of the 220K mixing resistor plus the 50K Intensity pot in the stock AB763 circuit.  I couldn't find a 27K resistor in the AB763 circuit, but there is a 22K close by in the phase inverter (R16 in sluckey's Deluxe Lite).  Perhaps I'm missing something though...

Chip

[samato]

The 27K-ohm resistor (at least that's what I think it says) is at the bottom right hand corner of the box I inserted in this cutout of the layout diagram of the Deluxe Reverb AB763.

[sluckey]

R14 is 270K-ohm 20% tolerance.  The original Fender "Deluxe Reverb-Amp AB763" calls for 27K-ohm 10% in this position.

No it doesn't. There is no such resistor in the original. Chip explained the purpose of my R14, 270K and I discussed it very early in this thread.

EDIT... I didn't spec any resistor tolerances. I only use 5% CC resistors. I didn't put a tolerance band (for convenience) on my layout resistors. I know that in the real world that the absence of the tolerance band indicates a 20% tolerance, but that doesn't apply for my Visio stencils. Sorry for the confusion.

[sluckey]

The 27K-ohm resistor (at least that's what I think it says) is at the bottom right hand corner of the box I inserted in this cutout of the layout diagram of the Deluxe Reverb AB763.

That's an error on the layout. The schematic correctly shows a 22K value for that resistor. That's the tail resistor for the LTP PI.

BTW, there are several similar discrepancies between schematics and layouts for several of the old Fender amps.

[samato]

Thanks guys, makes sense.  I've been drawing it up, referring to the Deluxe Lite layout and the original layout mostly, but now I realize I need to check the schematics all the time too.

Would you mind taking a look at what I have so far and letting me know about any problems you see?  I've only gotten up to PI/driver stage so far.  I'm still a little confused about the part with the coupling cap C6 and R9, R10 - does that look right?

Also, I should remove the .047-600 cap on the ground switch right?

[Fresh_Start]

Also, I should remove the .047-600 cap on the ground switch right?

Please remove the ground switch and that "death cap".  Use a 3-prong cord.  Wire the fuse & switch as shown in sluckey's documents.

Chip

[sluckey]

I'm still a little confused about the part with the coupling cap C6 and R9, R10 - does that look right?

yes

[topbrent]

Here are a couple layouts for you. 
Single channel, ab763, no reverb, no vibrato.

[samato]

Thanks for those layouts.  I'm actually learning a lot by drawing it out myself but it really helps me to be able to refer to diagrams that are known to be correct.

I'll have a lot more questions soon.  I'm anxious to start the build but I have more to learn before I'll feel comfortable, besides I still need to get the money together to fund the project. 

[samato]

Hey topbrent - That's some pretty good editing work to make those diagrams.  They look exactly like the originals but without the other stuff, which is all I want obviously.

I noticed the plates on your V1 are running at 170V and on the PI it's 180V.  The original has V1 at 180V, the first triode of the PI at 170V, and the second triode at 180V.  I guess this is from a different version than I'm looking at.  What is the cause of this change, something different with the power supply?

[Fresh_Start]

Don't worry about 10 volts DC on the power rail.

[samato]

Just wanted to post what I have so far of this diagram.  If anybody sees any errors please let me know.  Thanks.

[sluckey]

Your R18 should be 82K. Look at the Fender schematic rather than the layout.
http://www.schematicheaven.com/fenderamps/deluxe_reverb_ab763_schem.pdf

This layout has it correct...
http://www.schematicheaven.com/fenderamps/deluxe_ab763_schem.pdf

[samato]

Thanks Sluckey.  Once again I'm guilty of looking at just the layout and not the schematic even though I know better!  If that's all I messed up so far that's pretty good for me though.

[sluckey]

Redrawing the layout is the perfect way to become intimate with that circuit. And that's a good thing. Keep it up.

[PRR]

170V, 180V, 100K, 82K, 20%, 5%......

Bah. This isn't a moon rocket, where 10km means you miss the moon completely. It will play well at 150V or 200V. It will play well with 100K+100K in PI plates, though theory suggests a slight unbalance roughly correctable if the near-side load is ~~20% low.

Resistors used to be made like bricks: a pot of clay with a handful of sand for bricks or coal-dust for resistors. One brick may be 20% softer than another, do you really care as long as the house stays up? Old radios used the cheapest 20% tolerances, most guitar amps are from days when 10% was most available, today 5% are cheap and 2% is cheep-enuff.

But 2% is not "better". The designer will assume some tube values (which really vary +/-20% or more) then do his math. If he had that specific assumed tube, the perfect resistor might be 113,456 ohms. However anything from 75k to 150K works too, and so close you may be unable to tell a difference.

Where Sluckey had a missing band, he meant "use your your cheapest or favorite color". When Silver (10%) was cheapest, that's what we had. Gold is prettier and today you can't find Silver as a commodity resistor, so use Gold. Or if 2% are being dumped cheap, use 'em; but don't think that 98K-102K is "better" when the amp will work a treat with 95K-105K, 90K-110K, even 75K-150K.

And a different designer might have favored 200K. 270K and 470K were favored in radio audio amps: you lose a hair of treble but get a bit more gain below 4KHz and use less power (cheaper filtering). Fender did that, then moved to 100K. He may be right; this is the most-copied value on the planet. But Gibson and Ampeg sold a bunch of amps with other values, and using other values is a popular tweek.

[samato]

Yeah, I don't plan to be that anal about choosing my parts but I figure I should at least draw (or copy) the circuit accurately - going by the original or if I'm making changes they should be for a good reason.

I realize there is a "+ or -" tolerance for all parts & values, it says so on the schematics & layout diagrams.

[samato]

I'm driving myself crazy trying to figure out how the power supply, OT, and choke sections of this circuit work.  My brain hurts too much to formulate any specific questions right now but I figured I should post it here and see if I can get any input before I do too much damage.

[samato]

Would you guys be so kind as to have a look at my "completed" diagram and let me know if I have it right?  I guess this is a combination of a schematic and a layout diagram.  I wanted to have something easier for me to follow, with everything very obvious.  I hope it's not too hard to read.  I can try to post a higher resolution file if necessary.

I'm mostly concerned about the AC, power supply, and heater wiring but I'm not 100% sure about any of it so any help would be greatly appreciated. 

[sluckey]

AC cord needs 2 more wires.