Magnatone Vibrato/Reverb build Project

[sluckey]

DON'T TAKE IT OUT!

[wsscott]

Believe me I wasn't going to do that!  But I was curious about what the effect would be on the circuit.  Seems like the DCV at B would be much too high and it would need to be reduced somehow.

[sluckey]

Filter caps don't drop voltage. They just smooth it. Go read that power supply link again.

There is a good chance that you may have to juggle the resistor value between Node A and Node B. The missing load of the PA will cause all the voltages to rise. But that's assuming you will use the exact same PT as in the orig M10A. I seriously doubt that! It's unlikely but the PT you choose may already give you 'perfect' voltages. This is not something to worry about but plan to change a resistor (or two) in the PS rail. IOW, make sure your layout will provide easy access to the power supply resistors.

[shooter]

fwiw;
this is one of the better finds for WHY answers, It'll make studying for the boards seem easy 

http://www.aikenamps.com/index.php/white-papers

[wsscott]

Thanks again to both of you.  Stephen

[wsscott]

For those sections of the layout where there are several components in a row leading to ground, such as in the Vibrato speed/intensity section, is it ok to jumper them together as in a daisy-chain and then lead off to ground from the last one in the chain--as opposed to connecting each one to GND separately? 

[sluckey]

yes

[wsscott]

Sluckey, in your Reply #87 you attached this photo http://sluckeyamps.com/lil_maggie/m_big.jpg .  Do you have a photo of the underside of the board so I can see how the hookup wiring looks?  Or another build that you did?  My DIY Layout drawing has a lot of wires coming out of it and it just looks messy.  I'm trying to neaten it up, etc.  Thanks.

[shooter]

you have a lot of tubes, so more wires.

look at one of Dougs  turret boards for an AB763, something like twin reverb layout.

this is a simple 3 tube, the blue wires are jumpers, the layout keeps parts for each tube "close" to the tube.  When I build it, the jumpers will be on top, as a service guy, I hate the extra work of "looking" under the board 

[wsscott]

I notice that in the layouts that both of you have provided, in most instances you've got the components running vertical and parallel to each other, and that you connect them where needed with horizontal jumper wire.  But there are times when no jumper is used, and the components are connected at an angle to each other at the turret, sometimes like a V junction.  Is there any reason why you don't use the jumpers sometimes and just connect the components directly at the turret and lose the parallel scheme?  Is this just an appearance sort of thing?

[sluckey]

There are two pics on this link that deal with my underboard jumpers. I highly recommend doing them this way. Look closely at the way the jumper is inserted thru the bottom of the turret and hooked over the top of the turret. My jumpers will not accidentally fall out when soldering other components. Jumper wires are 24AWG solid tinned copper. I stripped insulation from 22AWG teflon wire to slip over the jumpers when they need to be insulated.

     http://sluckeyamps.com/VAC15/ac15.htm

[sluckey]

I notice that in the layouts that both of you have provided, in most instances you've got the components running vertical and parallel to each other, and that you connect them where needed with horizontal jumper wire.  But there are times when no jumper is used, and the components are connected at an angle to each other at the turret, sometimes like a V junction.  Is there any reason why you don't use the jumpers sometimes and just connect the components directly at the turret and lose the parallel scheme?  Is this just an appearance sort of thing?

It's just my style. I prefer parallel components but some times you just need a "V" or "birds foot" for neatness or to be compact.

[wsscott]

Great photos from your build.  Its really helpful to see how it was assembled in stages.

[wsscott]

Well I finished this layout, and am attaching 2 files and ask you to take a look. The main issue I'd like some input on is whether the layout looks like it will hold the components ok or if things are too close together.  I've attached the DIY layout and the Hoffman Turret analyzed layout for a turret board. I printed out the Turret board to scale and everything fits, I just don't know if the turrets are too close together.  The board is 15.125" x 3.125".  As far as the circuit is concerned, I'm going to go over it a couple more times to make sure its correct, and at this stage it would be appreciated if there's anything that jumps out at you that is a wiring problem--sort of like before.  I appreciate your time and help.  Thanks.  Stephen

[shooter]

can you post the schematic, and your .diy file ?

thanks

dave

[wsscott]

Sure.  Its attached.  Stephen

[shooter]

HA, I have an older version
suggestion, delete the power wires going back to the caps, they're called out at both ends. that cleans up the clutter some.  If you "need" them edit selection to dots, I use dashes for under board.   

[wsscott]

Thanks, I've attached a pdf with the power wires removed.  Do you have any thoughts on whether the turret spacing will work or if they are too close together and would cause difficulty in mounting the caps and resistors, etc.? 

[sluckey]

Turrets look too close to me, but without a scale reference I can't really say. Ask Doug. He'll know.

I use a 5/16" grid to space turrets on my boards. The only deviation was the AC-15 board which uses a 1/4" grid.

[shooter]

turret spacing

did you use Doug's turrets from this common parts file?

[wsscott]

Yes, I used the larger one that has a .1" hole and .2" size specification.  Since I've not done or actually seen any turrets before, I don't know what to consider.  Do you know if he builds boards using either size? You know I just realized that the larger one is an "eyelet", and the smaller one is a "turret".  That would make a difference!  Do you know if there's a way to do a global replace in the DIY software so I don't have to go to each turret and change it?  Thanks again.

[wsscott]

Sluckey, so are you saying that if the turret fits within the boundaries of the 5/16" or 1/4" grid outline, then they will work okay for mounting components being right next to each other without needing any additional space between?

[shooter]

I just realized

yep, did that for a couple, then switched to turrets that Doug made.

I haven't been able to figure out how to "put a box around" (select) a group of components so I can move them as one.  can't "select all" turrets either.
gonna upgrade to latest version n play some today, it's artic freeze coming here!!!

EDIT:
fwiw
played with shift n ctrl keys, figured out if you click a turret, component, etc, then hold ctrl and click a second object, they both "highlight", then you can delete, move as a group.  looks like you can do it with as many objects as you want, didn't figure out how to "replace with"

[wsscott]

What I just tried and worked a few minutes ago is to go into Connectivity section on the left, click on Turret, then right click, Select All.  That then highlights all the turrets, then right click on one of the highlighted turrets, click Edit Selection, and then make the changes, and save.  Seems to work.

[shooter]

AH, thanks

click on Turret

was that "Doug's" or the Diy one?, I think there's a size difference, but haven't double-checked.

[wsscott]

I think it was Doug's.  There is one for turrets and another one for eyelets.  I think maybe the turret is one of his that got added to DIY. 

[sluckey]

Sluckey, so are you saying that if the turret fits within the boundaries of the 5/16" or 1/4" grid outline, then they will work okay for mounting components being right next to each other without needing any additional space between?

That's not what I'm saying. I set up a 1/4" grid. Then place my turrets centered on the cross-hairs of the grid, not inside the grid squares. My turrets have cross-hairs on them too and this makes it easy to "snap" the turrets to the grid cross-hairs.

[wsscott]

Gotcha!  I'm trying to re-do my layout in DIYLC but can't figure out how to make a global change.  Would like to avoid having to re-do each one of them.  But I'll keep working on it-there ought to be a way.

[wsscott]

I was watching one of Doug Hoffman's videos on the DIYLC software and he was talking about the turrets and connecting components to them.  He said that the hole on the top of the turret is very small and its hard to get more than 1 wire in them from the top.  He talked about attaching them by hooking to the sides, but was stressing the point of using turrets to connect jumpers.  My concern is that I've got quite a few connection points with 3-4 wires meeting and wanted to ask if that's going to be a problem for me when I hopefully get to the point of wiring the board. 

[shooter]

3-4 wires meeting

everyone has "their" flavor, mine, more than 3, I add a 2nd turret n jumper

[wsscott]

Thanks. 

[wsscott]

I've gone through the Layout and fixed a couple of my misses, and think everything is now right.  I wanted to ask though if you would mind taking a look at the attached schematic which is the Vibrato control section, and see if my corresponding section on the attached DIY file is correct.  It starts in my Layout in the area to the left of the C cap lead to the board.

I also had a question about the type of Pot for the Vibrato Speed.  I've seen RA type pots used on some circuits and didn't know if there's a reason Sluckey why I don't need that type for this build.  I think you said earlier in this saga that all of the pots are Audio Log.  Thanks.  Stephen

[shooter]

I'm not allowed to operate heavy equipment, so......
there's a red-ish wire exiting lower left, the other end doesn't go where you have it.

[shooter]

giving up in the circle, going to paint 

[wsscott]

You're right.  I guess I was tired and missed it.  I think I've got it wired correctly now for the B cap power supply source going to plate 6 of the 12DW7.  I also moved the secondary power source supply going from the C cap, and now it runs from the C cap connection at the 10K on the layout to the other C supply on the 270K.

[shooter]

look inside the circled area AND the schematic, there are 2 330K resistors that come together, ONE .0047uF connects there and goes to ground.

[wsscott]

Got it.  I moved the jumper that connects at the bottom on the 330K on the left and goes to the top of the 330K on the right, down to the bottom side of the 330K on the right, where it meets with the .0047uf.

[SoundmasterG]

I was going to build myself a Revibe, but with the Magnatone vibrato instead of the Fender trem, just like what you are doing. I have enough genuine Magnatone varistors to do it, and enough knowledge to work through what needs to change in the circuit to do it, but I haven't had the time to do it. :) So you might end up getting yours done first. It is an interesting project and I'm eager to see how it turns out wsscott!

Greg

[wsscott]

Yes, I'm excited to hopefully get to the assembly part of this project soon.  I still keep going back over my Layout.  I've never done a Layout before and its really tedious for me with this circuit.  I don't have much experience overalll.  The only amp I built was the Weber 5F1 kit, but it did work the first time I plugged it in--and its still working.  So I feel if I can get the circuit correctly laid out, then I can build it.  I was going to do the same thing as you by modifying one of the Weber Revibe versions with the Magnatone vibrato, but I was convinced by this forum that it would be better to take the Magnatone M10a circuit, and simplify it by eliminating the second channel, and I also decided to eliminate the tone boost circuit since it already has bass and treble controls, plus its not being built as a stand alone amp.  I want to use the Weber cabinet for the 5H15 Revibe, so that limits my chassis size to 15.5".  But by simplyfying the circuit it looks like it will fit on a 15.125" turret board.  However the Weber chassis won't work because of the cutouts, and CJ at Weber says they don't make custom chassis'. But I have found a company that does one off's with aluminum for about $50, so that should work fine.  I'm going to get a blank chassis and drill the holes.  The Hammond PT that I'm going to use doesn't need a cutout.  So stay tuned.

[wsscott]

Am I correct that the plates, grids and cathodes on the V6 12AU7 tube are bridged with each other, ie. the 2 plates are bridged with each other, the 2 grids are bridged with each other, and the 2 cathodes are bridged with each other?  If so, can I ask why?

[sluckey]

That's correct. It takes a lot of current to drive the reverb tank, more current than that single triode can deliver, so two triodes are paralleled to provide adequate current drive.

[wsscott]

Thanks.

[wsscott]

Does anyone know if there's a way that DIY Layout Creator can "test" a layout that's been created for shorts or open circuits?  I'm just trying to find a way to double check what I've created in my layout.  I'm a little gun-shy because I've missed shorts in my previous layouts about 3 times, something I should have caught, and was hoping the software can assist.

[wsscott]

I'm asking now because I'm about ready to send my layout to Hoffman to create my turret board with turrets installed, and I want to make sure what I've done is correct.  I guess if I discover an error in the board due to my mistake, I can just install myself some extra turrets where needed.

[sluckey]

Your eyes are the only proofreaders you have. I suggest to print the schematic and layout. Then use a highlighter to trace through small portions of the schematic and also trace through the corresponding portions of the layout. Resolve any differences you find. Rinse and repeat until you are confident that the layout agrees with the schematic.

Getting the layout to agree with the schematic is the most time consuming part of a project, especially with a complicated project such as you have. I suspect you'll even dream about layouts before you are done. 

[wsscott]

Sluckey-You're right about this being the most difficult part--at least I hope it is.  And yes, I've been dreaming about layouts now for about 4 weeks.  Not every night, but too frequent for my liking!  Thanks.  I'm glad its not just me.

[sluckey]

Just wait 'til you start troubleshooting in your dreams! 

[shooter]

+1
 

I've been thanked a couple times by operators that called at 4AM n I "fixed something" in my sleep!! 

[wsscott]

I've done that before too.  Its like you had an "epiphany"!

[wsscott]

I'm probably going to be ordering my custom turret board from Hoffman today or tomorrow with the turrets installed.  I figure I'll purchase some extra turrets in case I need them.  As to the turret boards, he sells 2 colors, but the black one he says is "non-conductive FR4-G10".  What's the difference in the 2 boards?

Anything I should think of/plan for when ordering the board?