My Very First Ever Build AA764 Vibro Champ. (Cab is here)

[M Fowler]

tribi9

Don't hesitate to ask these fine people hear any questions no matter how dumb you may think the question is because it is so important to get the build started correctly and stay on that path. Aleast your taking it slow that is good and inventoring your components.

I'm surprized that company didn't just say keep the stuff and we will send you out the correct parts.

Mark

[tribi9]

Awesome! Thx Mark, I appreciate.

Well they are sending me the replacement and a UPS label to send this back. I guess they can still get some use out of it but I mean the UPS charge would probably be bigger than any money they can make on it... Oh well, as long as I get the right parts am good!

I decided to have a custom 1x12 cab made and that's why Im selling some stuff on the classifieds to, to raise funds for the new cab...

It also means I need a new speaker @ 4 ohms... Damn this little project turned expensive quick.

I couldn't bring myself to spend any money on an 8" speaker and I don't want to mod the buffle on my current cab so a new cab it is. It's cool cuz now I get to pick the color.. maybe a blonde? Don't know yet...

[Structo]

As far as what wires to twist.

Usually the AC power wires are twisted which can reduce the chance of hum.
Like the 5v rectifier wires, HT wires, heater wires.

Especially the heater wires. Take a length of two wires and insert them into a hand drill chuck.
It's best to use two different colors so you can keep the heater wires in phase for the tubes.

Have somebody hold the other end with pliers or you can do it yourself if you are coordinated.

Spin the drill, don't make the twist too tight or it can affect the insulation.
Just a nice even twist.

Then starting with your preamp tubes, make some 90 degree bends and cut the wires for each tube.
Retain the phase or polarity of the wires on the preamp tubes.

IOW, make sure the same wires go to pin 9 on down the line and the same for pins 4 & 5.

[Phil_S]

Hi,
May I suggest, instead of putting the lead into the top of the turret, that you bend it around the barrel in a semi circle. It is better not to close the lead into a full circle, for future service requirements. It is OK to use the hole, but it will give you a neater job (IMO) if you bend around the turret.

So far, you are doing well. I don't solder a board until I've got all the parts on it, including lead wires that will got to tube sockets, pots, etc. That way, you can back out when you see trouble or an error. Just some food for thought.

BTW, that hole in the turret is good to use if you need to run a wire on the bottom side of the board, but it won't work well if you've already filled it from the top.

Phil

[M Fowler]

I've populated the board many different ways but I like what Phil said about bending the leads around the barrel of the turret rather than using the hole. It makes for good solid mechanical connection and the solder will really bond it together. That is why I like the double turret so I can use buss wire to tie the turrets together down low if I need to do that and the resistors, caps and hook up wire on the top part. The important thing is good connection and good solder flow. There have been many times I had soldered something together to find out later that I should have waited to add another lead or component. In a hurray.

I have been thinking about getting the double turret with the fork top rather than holes.

Mark

[tribi9]

Thx for the tips guys.

I actually ran into that problem, had to unsolder one component to place another one that needed to go on the same hole. lol.


What I was thinking of doing is using the lead benders I got from hoffman and making the "angled leg" really short. I'm not sure how the semicircle will work. Do you have a pic of a populated board Phil?

Thx again guys for helping out a n00b amp builder.

Cheers

[Structo]

I just use a pair of high quality needle nose pliers to bend leads.

They work good to straighten the little kinks and make right angle bends.
You don't ever want to bend the lead right at the component.

For making hooks on the ends of the leads, there is a round nosed needle nose type pliers that works well.

I have seen a lot of turret boards like you are building.

Generally the components are stuffed in the holes and the flying leads are wrapped around the turrets.

Each to there own.

For tweaking I actually prefer an eyelet board.

A good solder sucker and it's no problem to change out parts.

[tribi9]

Question for you guys...

If a schematic calls for a cap rated @ 600V, can a cap rated @ 400V be used? (For values like 0.1uf, .047uf, .022uf)

Thx

[Phil_S]

tribi9:
Voltage rating on caps: You need the cap to be rated, at the very least, for the voltage that will be seen on that part of the circuit. For an AA764 VibroChamp, unless you've done something unusual, you won't be seeing more than 400V anywhere. So, I'd say, if that's what you have, you'll be OK using it.

Sorry, I didn't see your question from Apr 9. Like Structo, I just use different kinds of needle nose pliers. I don't see the need for a lead bender. If I was in a mass production environment, that would probably be a great jig to have to assure uniformity and quality control, but not for a one-off.

I've got one long nose smooth jaw pliers. The long nose is good for grabbing things that are hard to reach and the smooth jaw doesn't leave marks. Because it is tapered, it makes a good bender for forming hooks of various sizes. If you want bends on both ends to be in the same plane, just put the resistor or cap on the table and use the table as the plane guide. Otherwise, you are likely to get legs that look like they are taking a walk.

The other pliers is a short nose with a rough jaw. This one is good for grabbing and holding and closing a loop. Stuff will slide around in the smooth jaw.

I'm not the most meticulous builder. In this one, I wrapped most of the components and used the hole in the top for wires. I have an earlier build where I filled up the holes and realized after that is not the best way to do it. I think those holes call out to the rookie builder.
http://home.comcast.net/~psymonds/TMB18W.htm
Ignore any obvious gaffs. They've been fixed. The amp works great.

[M Fowler]

I have been trying to find those smooth needle nose pliers but no luck so far, any ideas?

Mark

[tribi9]

Thx for your input Phil S, greatly appreciated. Nice project BTW.

I'm doing a stock build so if you tell me I'm good with the caps rated @ 400V then that's what I'll get.

I also got a new cab for my AA764. This one fits a 10" speaker. I'll post some pics when I get it cuz it's in a somewhat unusual color. Everything for the build is either here or on it's way to me except for the speaker. I still haven't decided on one yet. I want something chimy, clear and with tight bass.

[Phil_S]

Well, you might find that 600V caps are easier to source than 400V caps. The price won't be a big factor. Look at both. I wouldn't go below 400V for anything on that circuit except for cathodes which don't see very much voltage and typically 25v or 50v caps are way more than enough.

[Phil_S]

I have been trying to find those smooth needle nose pliers but no luck so far, any ideas?
Mark

These are branded Craftsman, but came from the cheap tools bin at Sears. I suppose K-Mart, having gobbled up Sears. has them, too. The number on both tools is 45679. Made in China. Spring tension on the handles. Rubber grips. Not expensive and work well.

[M Fowler]

Phil,

Thanks I will check there for some, I haven't noted any when I out and about but just maybe my local sears/kmart has them.

Mark

[tribi9]

Today I got some stuff from Mojotone. Lots of hardware and goodies came in.

I've been studying the layout and I'm pretty pumped. Honestly the VC layout is one of the hardest ones to read. Most of the scans out there are really shitty. I've been going back between the Ceriatone, the AA764 and the AB764 to make sense of the original. I wish I could get a really clear one but what I got will do. (Or it should at least)

Mojo sent me a 50K pot for the intensity as opposed to the 25K, not sure if that will have a major effect but when they sent me the order to double check that everything was fine. I ok'd it, and missed that the one pot had the different value on the order..... Oh well. :-\

One thing Im not sure is how I'm going to secure the tagboard. The screw holes don't really clear the board, so I guess Ill have to drill through the board. (Maybe I can use only one screw on top and hold the other end with the screw for the tube socket..... ???


The fuse holder, can cap are going in last after I put the PT and OT. I got a call from the place I got them that they were in, when I got there they realized they had made a mistake. (Hammond said they would Fedex them a package came in and the lady that works there assumed it was from Hammond but it wasn't...) Oh well!

Here are some pics of the little progress I made since receiving the parts.


[IMG:800:600]http://i114.photobucket.com/albums/n271 ... C01927.jpg[/img]

[IMG:800:600]http://i114.photobucket.com/albums/n271 ... C01931.jpg[/img]

[IMG:800:600]http://i114.photobucket.com/albums/n271 ... C01932.jpg[/img]

[IMG:800:600]http://i114.photobucket.com/albums/n271 ... C01933.jpg[/img]

[IMG:800:600]http://i114.photobucket.com/albums/n271 ... C01929.jpg[/img]