Starting a Deluxe Lite in a Stout Chassis (COMPLETE)

[Ambugaton]

Hi Everyone,

I have been contemplating starting the Deluxe Lite build by Sluckey. I had a couple questions while I compile my parts list... any help is appreciated!

I noticed a couple differences between the layout and the schematic. I don't have proper terminology for each component but I will try to explain.

- The .1uF cap going to pin 7 of V2 states that it is a .1uF/250v cap. I can only find a .1uF/630v, will this have any effect?

- The .1uF cap going from pin 1 on V3/V4 is labeled .047uF on the layout. Is that personal preference? I think I read in the other thread that this is will lower the bass response?

- The two 50uF caps in the bias circuit are not available in the store and the layout has 47uF/100v caps here. Is that what I should grab?

Thanks in advance!

[Ambugaton]

Also:

- The two 100k resistors going to pin 1 and pin 6 of V1 appear to be 3W resistors on the layout but the schematic doesn't specify. Only asking cause the other 3W resistors are labeled on the schematic.

[ToneJunkie]

For my build the plate resistors were 1W resistors.  You can use either 250V or 630V .1uf caps in that spot although with Slucky's layout cap space is a little tight, .047 so seem to be Slucky's preference but general blackface values are .1 (.1 is what I have in mine but I may experiment later) caps and lastly yes the 47uf 100V caps are perfect for the bias.

[sluckey]

If I were gonna build this I'd use all Xicon caps and all metal film resistors. 630v Xicons are very small and will fit nicely on that layout.

[Ambugaton]

If I were gonna build this I'd use all Xicon caps and all metal film resistors. 630v Xicons are very small and will fit nicely on that layout.

Cool. That's what I will do then. The thought that carbon film produces a warmer sound? Sales tactic or any truth to that?

[ToneJunkie]

Your probably thinking of carbon comp resistors... that debate can be found on many threads.  I have built amps with carbon comp, carbon film, and metal film... all of which turned into sweet sounding amps.  The only reason I use carbon film was when I was building Dumble style circuits I saw that he was using them so I bought large quantities and I'm still using the same stash after 8 years.  I think the metal film that Slucky suggested would be perfect :-)

[PRR]

> states that it is a .1uF/250v cap. I can only find a .1uF/630v, will this have any effect?

I don't have the plan memorized.

In general higher-volt replaces lower-volt, all the same. (Don't get a 10,000V cap the size of a beer-can for coupling in a guitar amp.)

And 250V seems shy to me. The running voltage may be 200V, but the cold-start voltage can often be over 400V for a few seconds. Film caps often stand some over-volt for many-many starts, true. But until proven otherwise, I'd prefer 400V, and 600V if size/cost are not problems.

A notable exception is the 0.68u cap Marshall puts on a cathode. Here it can never see over 4V. They don't make film caps that lo-volt; we usually end up with like a 200V part. 0.68u at 630V would be huge, enough to affect your layout and your budget.

50uFd, 40uFd, 47uFd are all the same to us. The original series ran 4-8-16uFd. A later series ran 10-20-40uFd. Still later the "rational spacing" 10-15-22-33-47 series became fashionable. Early e-caps were -50%/+100% tolerance, so you always picked high. Later ones are closer to the mark, but e-caps are always loose-spec so you only have to be "close".

[sluckey]

And 250V seems shy to me

This is the cap in the NFB circuit on Fender AB763s. Doug sells them.

[Ambugaton]

Thanks for all the input! I ended up going with metal film and Xicon caps as suggested. Everything is ordered and being shipped. Will update as I make progress and most likely ask several dumb questions. Thanks guys.

[Ambugaton]

First dumb question. Can anyone help me out with putting a SS rectifier in this build? Time to start researching! I'm sure there are plenty of posts that explain this.

[John]

SS rectifier is just 2 diodes -1N4007 is what most everyone uses. Where you'd normally hook the 2 red wires coming from your PT to the plates of the rectifier tube (pins 4 & 6)? Instead you hook each red wire to the ANODE side of the diode. The cathode side is the one with the little silver band on it. I usually make a little turret board to mount 'em on, or you can use terminal strips, whatever is easy. The 2 cathode ends of the diodes get joined together, and then go into your first filter cap.


You won't need the 5V filament winding to heat your rect. tube since you're not using that, so heat shrink the ends and tuck them out of the way. Somewhere where you won't bump 'em with your soldering iron. Not that I've ever. 

[Ambugaton]

Rgr that, looking at Doug's common hookup page I see there are a few different ways to wire the diodes. Should I use the full wave diode since my PT has a center tap?

[sluckey]

yes

[Ambugaton]

Thanks, looks like most of my stuff will be delivered today so I can start dry fitting everything and get an idea of how this thing is going to come together. Thanks for the patience and help. I think I have most of my questions answered and there are several Deluxe Lite threads that have great info as well.

[Ambugaton]

So I received most of my stuff the other day... how does Doug do it? I ordered on Thursday and its delivered to Alaska on Monday? From SC...? I am amazed. Anyhow...

I went through and installed all the components... Seems like it will work out nicely. I will have to alter the PT mounting quite a bit and I am having some trouble keeping the orientation 90° from the OT. Does anyone have any more info on this thought? Since the PT is side mounted, do I have to worry about its orientation with the OT? If not, I can simply rotate 90° and drill new mounting holes. If it is a problem... the existing holes would be just close enough to the size I need to prevent me from just drilling new holes (some overlap would occur). I don't know if that makes sense or not.

Also, cannot find a 25KA pot, would using a 50KA make much of a difference for a mid pot?

[sluckey]

Also, cannot find a 25KA pot, would using a 50KA make much of a difference for a mid pot?

Use a 10KA. That's what the schematic calls for. The 25KA shown on my layout is an error. Always use the schematic for a reference on my stuff.

[Ambugaton]

Gotcha, think I just overlooked that.

So now I understand how to properly hook up most of this circuit and I will follow the grounding scheme that you explained in another thread for this build. Should I install the two 68K input resistors as close to pin 2 of V1 as I can or install it like it is shown on the layout?

[Ambugaton]

I'm confused on the Full wave diode diagram below. It uses 6 diodes and it seems like it would provide the most DC voltage with the least amount of required filtering... My question is that I have seen countless schematics/layouts that DO have a CT on secondary but still use the Full wave bridge rectifier. Is there a reason for this?

[sluckey]

I'm confused on the Full wave diode diagram below. It uses 6 diodes and it seems like it would provide the most DC voltage with the least amount of required filtering...

6 diodes (3 per leg) increase the voltage rating of 2 diodes (1 per leg) For example, a 1N4004 can be used up to 400V peak. That's only 282V RMS and is not enough voltage rating for most guitar amps. But if you put 3 of those in series you now can operate that string of diodes up to 1200V peak. But this 6 diode configuration will not provide any more DC voltage than any other full wave circuit and it will require just as much filtering as any other full wave circuit.

My question is that I have seen countless schematics/layouts that DO have a CT on secondary but still use the Full wave bridge rectifier. Is there a reason for this?

Countless? Really? Show me just two of those schematics please. Solid state schematics don't count.

Off the top of my head I know of one or two schematics that use a full wave bridge AND a center tapped PT. These circuits also provide a very high B+ and use two filter caps in series to be able to handle that high B+. The center tap is connected to the junction of those series connected filter caps. The purpose is to ensure that exactly half of the B+ will appear across each cap.

[Ambugaton]

Dang, I was confused on what I was looking at on some layouts I was browsing. Initially i thought the layout below was full wave bridge but realize I was wrong. Poor choice of words on my part (countless). Gets me in trouble at home too!

Will I ever see anything close to 1200V from the PT? Maybe a surge?

[sluckey]

Will I ever see anything close to 1200V from the PT? Maybe a surge?

Not likely, but a 350-0-350v PT has 700v across the red leads! And the diodes are routinely exposed to over 1000V. For example, many big tube amps use a PT that will provide 400V RMS. That's 566V peak. That means the AC voltage that is applied to the diode rectifier swings positive 566v and negative 566v. That happens 60 times per second. When the PT voltage swings positive, the diode conducts and the filter cap can charge to positive 566v if no current load is on the power supply. When the PT voltage swings negative, the diode is reverse biased and does not conduct. But now you have negative 566v on one side of the diode and you have positive 566v on the other side of the diode. That's 1132v across the diode!!! Obviously, a 400V diode would fail. Even a 1000v 1N4007 diode is at risk. So, the answer is to use a relatively costly diode rated for 2000V, or use two 1N4007 diodes that cost 4 cents each.

[Ambugaton]

Rgr that. Will follow that logic!

I am installing the heater wires now. I think I know the answer to this but want to make sure... Can I hook the heaters from the tubes and from the PT to a terminal strip, and from there into 2 100ohm resistors going to ground and feeding into the light? Actually... I am sure this is ok after looking at Doug's heater wire diagram.

[Willabe]

Dang, I was confused on what I was looking at on some layouts I was browsing.

Much easier to see/understand on a schematic.

Layouts are not for trying to figure out an amp/circuit.     

[Ambugaton]

Did the inputs today. Not pretty but I sure did try. Look alright?

[John]

Should work; I've never done dual inputs but it looks right to me. Now, *if it were me* I'd have run your input grid resistors straight to the socket since it looks like it's close enough to do that. In fact I generally arrange my layout just so I can do that. Your other resistor going between the 2 jacks doesn't really need that sleeving on it.


It's taken me 6 builds to get my wiring even semi-neat. I don't believe I have a well ordered mind.

[Ambugaton]

Now, *if it were me* I'd have run your input grid resistors straight to the socket since it looks like it's close enough to do that

You know I really thought running them straight to the socket would be ideal... I don't know why I chose otherwise. If I get interference I will rewire and see how much it helps.

[Ambugaton]

Does it matter if the heaters/artificial CT run straight to the lamp or can I do what is pictured below?

[Ambugaton]

This look alright? Seems too simple, but since the jack is grounded I dont have to make any other connections?

[Willabe]

No that's not correct. The way you have it will be a direct short of the OT secondary.

The 4 wires from the OT secondary, 1 is ground/common, the other 3 are the hot/signal wires of different Z's.

The ground wire does not get hooked up to the Z switch it goes to the speaker jacks ground lug. The 3 hot signal wires go 1 to each solder lug that the switch chooses, the 4th switch lug is the switches common (looks like the far right lug in the pic), that 4th lug gets the hot signal from what ever lug the switch is set at/chooses, it goes to the speaker jacks hot. No OT secondary wire gets hooked up to that 4th switch lug, just a wire going from that 4th switch lug to the speaker jacks hot lug.

Make sure you get the OT secondary wire colors correct.

[Willabe]

Does it matter if the heaters/artificial CT run straight to the lamp or can I do what is pictured below?

What's in your drawing will work fine.

[Ambugaton]

Thanks!

[Willabe]

That's it, IF the colors are right. 

(If it were my amp, I'd try and twist the ground/common wire with the hot wires for a little noise rejection and to keep the wires controlled in the way their placed in the chassis, lead dress.)
 

[Ambugaton]

I was unaware that it would help with noise rejection. Thanks. My PT has a white and a black primary. Does it matter which one is fed to the iec and on/off switch?

I'm assuming white to neutral on power. Black to switch?

[Ambugaton]

Just verifying before soldering. I've read a couple different preferred/safest methods to wiring up the power supply. Ground will be on a pt bolt itself.

Also, can I use a regular 10k alpha for bias?

[sluckey]

can I use a regular 10k alpha for bias?

Most any style pot will function electronically. But if you drill a hole in the chassis so the shaft is accessible from the outside, IT WILL GET TURNED. And that could cost you a set of tubes, maybe even an OT. I would not do it with a 'regular' Alpha pot. I suggest using a Fender style pot that is accessible  from both sides of the chassis with a screwdriver, or put a trim pot on the board, or even use some expensive mil-spec locking pots.

[Ambugaton]

Thanks Sluckey, I knew that it was a bad idea and expected that same answer.

Got the lugs installed and ties done today. Hopefully tomorrow I'll get the board done and shouldn't be long for tests after that

[sluckey]

I strongly suggest you remove that paper from the board ***BEFORE*** you put anything else on it. Gonna be quite a job even now.

[Ambugaton]

Wow... words can't explain how dumb I feel right now. Didn't even realize there was removable paper.

[sluckey]

Where did you get that board?

[Ambugaton]

From Doug

[sluckey]

Did you put the paper on the board, drill it, and stake the turrets?

How is the paper attached? If glued or double sided tape you can just submerge the board in lacquer thinner or mineral spirits to dissolve the glue. The paper may even dissolve too. A couple acid brushes will help remove stubborn paper.

[Ambugaton]

It came with the paper attached. I will either try your method or just take my time with an x-acto knife. I would want to be careful with solvents, I don't know what would/would not damage the epoxy.

[sluckey]

I use double sided tape to attach my paper drill guide to a board. Then I use mineral spirits to remove the paper and tape from the board. It will not cause any damage.

[Ambugaton]

Couple more questions/areas I am unfamiliar with:

1. The 38 VAC wire that gets tied into the bias circuit... I assume that this is labeled as "bias supply" on my PT's diagram? Stupid question I know.

2. I still need to figure out what exactly a choke does and where it is placed in the circuit.

3. I have a floating preamp ground bus. Will this be as effective vs a bus wire that is soldered to the back of each pot?

4. Need to figure out how to apply the 10K resistors into the filter caps since I am using a cap can. This should be fairly easy as long as I just hook it up the same way its shown in the schematic/layout.

5. Also confused on how the SS rectifier is tied into B+, does that just mean it goes to the 40uF on the cap can? Then it looks like maybe the choke is placed between the 40uF "A" and the "B" cap?

[Ambugaton]

I use double sided tape to attach my paper drill guide to a board. Then I use mineral spirits to remove the paper and tape from the board. It will not cause any damage.

Great. I will give it a try.

[Ambugaton]

SS rectifier is just 2 diodes -1N4007 is what most everyone uses. Where you'd normally hook the 2 red wires coming from your PT to the plates of the rectifier tube (pins 4 & 6)? Instead you hook each red wire to the ANODE side of the diode. The cathode side is the one with the little silver band on it. I usually make a little turret board to mount 'em on, or you can use terminal strips, whatever is easy. The 2 cathode ends of the diodes get joined together, and then go into your first filter cap.

I see John answered one of my questions already. Thanks!

[Ambugaton]

This is the layout with information I gathered from other threads on this build. Seem ok?

[sluckey]

Yes, that's OK. I don't remember who did the additions to that drawing. Something to keep in mind... My layout drawing is meant to be able to build a board and make all connections between the board and chassis mounted components. IT IS NOT A COMPLETE WIRING DIAGRAM. Was never meant to be. It will get 90-95% of the wiring done but you will need to refer to the schematic in order to build a complete working amp.

[Ambugaton]

Understood. Being unfamiliar with all of this, it helps me to trace through the schematic and make a visual on the layout to help me understand.

[sluckey]

That's a very good idea. Relating the layout to the schematic may seem overwhelming at first but the more you do it, the better your understanding of "how it works". Eventually, you'll use the schematic whenever trying to understand a circuit operation and for troubleshooting. The layout is great for building a circuit or identifying components while troubleshooting, but contributes very little toward understanding the circuit. All of my projects start with a schematic. The layout is developed from that schematic.