Another DIY SS Amplifier with NVA Boards

[Dr Bunsen Honeydew]

No problem with that layout and one transformer driving two bridge recs is fine

[SteveTheShadow]

I forgot to add that legally at anytime in the future these are disposed of or passed on they cannot be called NVA amplifiers legally. You have to give them your own name and not emphasise the nva connection. I do this for you two, not for future of the boxes.

I wouldn't dream of disposing of these Richard. I'm aware of the privileged position, me and Stu are in.

[scotty38]

Could call yours "The Shadow"... Fits your name and also fits with where it's come from.....

[karatestu]

Hi Steve,

I wish you well with the project and I am happy to help if needed (if you don't want to bother Doc with it). You probably have it all in hand though.

Get those output transistors mounted effectively and the rest is a breeze I like your case by the way.

Stu

[SteveTheShadow]

Cheers Stu,
Transformer, caps and rectifiers are mounted, boards have been prepared for mounting and for easy connection to the output devices.
Output transistors are glued down and the glue is currently curing. There are no shorts from the collector to the case on any of the four devices.

I can't do any more on the main chassis today as the glue will take overnight to go off properly.
I will probably get the rear panel fitted out with the fused mains inlet that was supplied with the chassis and will fit the speaker and input sockets tonight. Or maybe I won’t; no rush.

[karatestu]

How hard / easy was it to use the glue Steve ?

[SteveTheShadow]

How hard / easy was it to use the glue Steve ?

Just a matter of mixing up 3:1 ratio of adhesive and hardner.
I spread a small amount, with a clean instrument, on the back of each device, then gently pressed it down onto the metal until an even unbroken bead of glue oozed out around the edge of the device.
I had predetermined where each device needed to be in relation to the board, and had formed the pins into a simple right angle, so that they pointed straight up.
The board has been prepared with three, 1mm diameter tinned copper wires from each of the six holes. These wires are pre bent and point horizontally off the board edge, so that, when the board is mounted, each wire picks up the corresponding vertical pin on the device itself.
Soldering is then dead easy.

Needless to say, I wore latex gloves during all gluing operations. You don't want that bloody stuff on your skin.

[karatestu]

How hard / easy was it to use the glue Steve ?

Just a matter of mixing up 3:1 ratio of adhesive and hardner.
I spread a small amount, with a clean instrument, on the back of each device, then gently pressed said device down onto the metal.
I had predetermined where each device needed to be in relation to the board, and had formed the pins into a simple right angle, so that they pointed straight up.
The board has been prepared with three, 1mm diameter tinned copper wires from each of the six holes. These wires are pre bent and point horizontally off the board edge, so that, when the board is mounted, each wire picks up the corresponding vertical pin on the device itself.
Soldering is then dead easy.

Cheers, thanks for that.

I may give it a go at some point but i like to be able to remove things easily.The amount of times i have made something, a modification is embarked upon and things have to be moved around.

Anyway, your amp is definitely gonna look lots better than my Heath Robinson affair.

[Dr Bunsen Honeydew]

I presume you are using Loctite Output, if so you are using it wrongly. Spread the paste across the transistor and paint the hardener on the heatsink, just press down and it self shims.

[SteveTheShadow]

I presume you are using Loctite Output, if so you are using it wrongly. Spread the paste across the transistor and paint the hardener on the heatsink, just press down and it self shims.

It's not Loctite, it's Electrolube, thermal bonding system adhesive.

https://www.electrolube.com/products/th ... materials/