From Scratch Amp Building Chronicle - 6/13/10 UPDATED!!

[Anonymous]

So to build this I should go with a 1969 chassis and filtering because of the added gain? Where we have the 50/50 filters on the top of the chassis.
I was thinking of doing the 1968 12 series kit by metro and doing a couple things, like add the tube and install a push pull master along with a depth pot. I'm thinking the there just isn't going to be enough filtering for the gain on this kit to do it?

You just flat could not build this on a 12 series kit. The main board in my design is 16 inches long. No way you'd have room for that and the filter cap board. Plus you need room for the relay power board and the extra 6V PT. BTW - the only reason there is an extra tube in this design is for the the EFX loop, not for extra gain...

Steve

 

[Anonymous]

your not sah5150 anymore youre "cadmaster" I wish I had those skills. Not that I have the time but still.

In my case, doing a completely custom board and just proving to myself this was doable, it was worth it... and yeah, I've gotten pretty decent at the CAD stuff now!

Steve

 

[Anonymous]

Once again... Awesome.

I cant wait to see and hear the finished product!!!

Thanks man! Things should move faster now! Less theory and more soldering!

Steve

 

[MichaelG]

Aaaaah! Finally...... the soldering

Man, been waiting for that layout to appear and it took forever! j/k Steve, I know it was a necessary step for you, but for those of us on the sidelines.....

 

[Anonymous]

Aaaaah! Finally...... the soldering

Man, been waiting for that layout to appear and it took forever! j/k Steve, I know it was a necessary step for you, but for those of us on the sidelines.....

HA! It really did take a long time, but I learned so much it was worth it! I already started some soldering last night though - more to come!

Steve

 

[dstroud]

Aaaaah! Finally...... the soldering

Man, been waiting for that layout to appear and it took forever! j/k Steve, I know it was a necessary step for you, but for those of us on the sidelines.....

HA! It really did take a long time, but I learned so much it was worth it! I already started some soldering last night though - more to come!

Steve

mmmm... nothing like the smell of burnt solder on a Thanksgiving morning! Can't wait to hear this beast!

 

[rupe]

Anxiously awaiting the results...this undertaking is about as cool as it gets!

 

[Anonymous]

OK, so another update. Here's what I've been doing...

DC Heater circuit:

So, I drilled out my chassis for a 250 Ohm, 4W pot and another little pre-made board. I'm using a .1 uF cap that Olaf sent me that fits perfectly in this tight spot. Here;s a pic:

Will solder this up when I get some good bus wire for the heaters...

Relay power board construction:

I took some red swirl board material I ordered from Watts Tube Amps and measure what I needed. The boards I got were 2" wide and I needed 1 3/4", so I measured and then used a razor cutter to due the initial cut with a straight edge. I then used a really small mitre saw to cut the board. I then printed out a board template and taped it to my cut board. You can kinda see what I did here at the top right of the paper attached to the board. My flash took away most of the detail, but you can see a couple of screw and turret holes.:

I then used a center punch to carefully mark the hole spots on the template into the board and then drilled it out with my press. I then took some cool turrets that Olaf sent me (he sent me the correct bit as well) and hammered them in - believe me - they are not going anywhere. I then assembled the components and tested out the standoffs I'll be using. Here is what the relay power board looks like now:

I haven't soldered anything because first I ned to drill out my chassis for the board as well as the bridge rectifier and 7806 voltage rectifier that are part of the circuit. These will be screwed into the board and I just find it easier to get everything situated, all wires connected and then solder everything together. That'll be the next step...

Steve

 

[Anonymous]

Modded the grounding scheme for the loop after a nice e-chat with Olaf:

Steve

 

[tweed]

 

[jerrydyer]

Steve "Solen Fast" Henning ? them is good caps. I did have a tip though. I had to move a cathoded res and cap because I had two high gain cathodes near each other.. I saw on your borard you have a couple next to each other. depending on how hot you get it with bypass caps, you might have to shuffle stuff around to avoid the ring when they start to hear each other.

 

[Anonymous]

Steve "Solen Fast" Henning ? them is good caps. I did have a tip though. I had to move a cathoded res and cap because I had two high gain cathodes near each other.. I saw on your borard you have a couple next to each other. depending on how hot you get it with bypass caps, you might have to shuffle stuff around to avoid the ring when they start to hear each other.

Hey Jerry - I assume you are talking about the 2.7K/.68uF stages that are real close. I've seen the inside of several old Jose mods that had the stages that close and they were fine, but I see what you are saying. I could stagger them a bit and I also have some room to separate them...

Thanks,

Steve

 

[jerrydyer]

Your distance might be fine. Cant really tell until its done. I have a switch that adds a bypass cap and as soon as that switch was thrown, squeeel, ring...moved the cap, noise gone . it may be more where the wire from the tube comes over, those two post were closer than the caps themselves. you know what, actually it was only when the additional gain stage was on. not just a cascaded superlead setup. Youll be fine

 

[kasperjensen]

This looks really friggin awesome.

I can't wait to see the finished product, and hear what it sounds like.

I take you will be building custom amps in the near future?

 

[Anonymous]

This looks really friggin awesome.

I can't wait to see the finished product, and hear what it sounds like.

I take you will be building custom amps in the near future?

Thanks and yes, I plan to be offering these as soon as I have the amp tweaked to my liking and ready to go.

Steve

 

[Death by Uberschall]

Late to the party, but all I got to say is DAMN!!!

On the knobs, that's easily fixable by offering different types to the buyer. Personally, I like knobs that I can see from a distance and tell where they are set (chicken head, Davies, etc.). White chicken head knobs would look great against that black panel and white lettering.

 

[Anonymous]

Late to the party, but all I got to say is DAMN!!!

On the knobs, that's easily fixable by offering different types to the buyer. Personally, I like knobs that I can see from a distance and tell where they are set (chicken head, Davies, etc.). White chicken head knobs would look great against that black panel and white lettering.

Cool - yeah, when ordering, you'll be able to specify the cosmetics of the amp (cab style, tolex, plexi panel colors, knobs, etc.) to your liking.

Steve

 

[Anonymous]

New layout that incorporates different relays and some updates for correct size components. I realized I could not use the relays I originally chose because I could not mount them on the board the way I wanted due to the fact that the legs of the relays were too close together. I've now gone with 6V Panasonic relays that have a 16 pin pitch instead of the Omrons I had planned to use, which only have a 12 pin pitch...

Steve

 

[jasonP]

This is just so awesome!!

 

[Anonymous]

Drilling and Staking my custom board

So... today I needed to build my custom board. I have a nice piece of red swirl board material that is 3.125" x 16" - exactly what I need for my board. The first thing I did was print out a life size template of my board showing where the eyelets needed to be placed. I'm using two sizes of eyelets for this board - 1/8" and 3/32" for the relay sockets and the LDR. I needed to cut 3 size holes - 1/8", 3/32" and 9/64" for the posts to hold the board in the amp. I assembled the bits I needed, taped the template to the board the best I could, clamped the board into my drill press and started drilling:

Here is the fully drilled board. It is not perfect by any means, but for the prototype it will work fine. The production amps I'll have a template made so everything is absolutely perfect:

Now it is time to start staking the eyelets. I chose to use eyelets rather than turrets because I just think it looks cleaner, especially since the relays really required eyelets. First, you stake the 3/32 eyelets since they are smaller and you need to have them flat to the board when staking. First, I put in all the 3/32 eyelets:

Just a quick test to make sure the relay sockets fit. And they do!:

Now, tape the eyelets in using electrical tape so they don't fall out when you turn the board over to stake it. Make sure they are flat to the top of the board!:

Now use the pointy end of the staking tool in the drill press to stake the eyelets. You're not turning on the press, just using a bit of force the spread the bottom of the eyelets so they stay in nice and tight. You don't need to press hard at all:

And now do the same thing for the 1/8" eyelets. Here is a picture of the finished board ready for components. We're humming along now!:

BTW - from start to finish, this process takes about 3-4 hours. Crazy how long this stuff takes!

Steve