First Amp Layout Design, Need Input and Advice

[rocket88]

hey guys, i'm hope someone could help me out a bit. after working off of pre-existing layouts for a few builds, i decided try my hand at making my own layout, obviously using the schematic to work off of. i'm a little unsure if the layout is correct, and was hoping with all the experience here i could get someone to look it over, and let me know if there are any errors. i should also say that i build and design effects pedals on vero all the time, and this is the first time i've done anything on turretboard. believe it or not i actually did this the old school way on graph paper, then transferred it into DIYLC to make it look nice and pretty. if anyone has good advice on designing layouts i'm all ears and would really appreciate it.

anyways, enough of my babbling. it's a first gen sunn model t

Schematic:


turretboard layout:


thanks in advance.

[Enzo]

Rocket, hi, and welcome.

But really, what I'd have to do is sit down with your layout, and trace a schematic from it, then compare that to the schematic you posted. That is a lot to ask, especially since your layout only lists connections rather than show them. I'd have to draw in lines to the tube sockets and other attachments to see. And all that is something you can do first. Look at any of the old Fender layouts.

I do see some errors, at least they appear so. Your hum pot has 100k parallel resistors, while the schematic uses 1k.

Your bridge looks funny. Do you intend it to be two parallel diodes on each wing of the HV winding? There are no transformer wirings shown, so I assume you have a center tapped HV winding. If that was intended to be a bridge across a non-center tapped winding, then it is wrong. If it uses a center tap, why bother to cross the middle ones?

[rocket88]

thanks enzo. i copied those resistors from somewhere else in the layout and must have forgotten to change them. can't believe i missed that.

no worries, i'll print it out and draw in the connections and check it. i tired to do that while working on the layout as i was going through it. it lead to so many changes along the way. it probably would have been a good idea to start with something a little simpler, but then again i always jump right in.

i know it's a lot to ask, but figured if i'm going to jump in and try to make my own layouts, getting as much direction as possible. i had asked awhile ago about creating a layout for the green amp and was just told i should follow what is in the original. at that time i didn't really understand how the amp is laid out, so for now i've give up on building that amp.

i tried to not show them on the board as I was trying to the layout easier to read since I don't know what chassis i'm going to put it in so i don't know the distance of the wires and tube position.

for the bridge in the schematic it shows there are 2 rectifier diodes that come off the red wires of the transformer and going to the standby switch. i was doing some searching on those diodes and they seem to be non-existant. i had also read in a post from chuck h talking about a replacement for them and he said

"As for the two "MR1-1600" diodes, those ARE the rectifier. I know there are some burly diodes out there, but I don't know the part numbers and a search with the numbers you provided wasn't very effective. I would just use 6 1N4007 diodes. Three in series on either side of the PT HV secondary."

i messing around with positioning them to get them in series by crossing them. i haven't chosen the transformer yet, so i don't know if it will be center or non-center, as i'm hoping to get something as close to the original as possible, which i think will be from mercury so i should check with them which it is.

seriously thanks for the help so far.

[Enzo]

Crossing them doesn't put them in series. You want to see three in series? Look at a fender Twin Reverb or something similar.

Follow what you did there, and you will find you have a diode from each red wire to one point, then two more diodes to their common point, except the to points are also wired together. SO in essence all you have is two diodes side by side from each red wire to the big common point.

I don't mind helping with direction, but it would take me an hour and a half to draw through all that.

[rocket88]

That makes sense actually. I was trying to keep everything close together and see how I messed that up. It looks like an easy fix. I'll go back and make all the connections as check it all. Thanks man.

[loudthud]

You really need to pay attention to how big the parts actually are. If you don't have some parts to measure, find them at and industrial supplier like Allied, Mouser etc. and download a data sheets.

Having the rectifiers close to the input jacks or preamp tubes is a bad idea. Should be at the other end of the chassis.

Heaters on the preamp tubes are wrong. Pins 4 and 5 are on one side, pin 9 is on the other.

[dchang0]

loudthud is right.

Use datasheets to determine sizes of components. Some capacitors can be surprisingly large.

I'm not sure you can really solidify a layout prior to building it. Yes, as loudthud pointed out, there are some placements of components that can be immediately identified as problematic on paper, but you may discover some unexpected sources of parasitic oscillation or noise/hum caused by the layout only after building it in real life. Conversely, some layouts could be dramatically compacted because some components could be placed closer together than originally envisioned on paper.