DIY Voyager power amp Build

[337alant]

Thanks Rich, I have high hopes for these mono blocks, if they are a success Ill bring them to the NEBO 5

Alan

[337alant]

Knocked up the Vellaman 4700 speaker protection modules total and I have decided that the layout below works for me and the final layout.
VBE and NCC200 module will be bolted directly to the side panel heat sink

voyager 3 by 337alant, on Flickr

I still don't have the NCC200 output driver heat sinks so In cant test the boards or fit the output transistors


Alan

[337alant]

Progress today
Well bit of a life saver today, thanks to Les, as he sent me 4 new output driver heat sinks as I couldn’t get any further with the NCC200 boards without them
So fitted them and the output 753/653 drivers, Its best to try your boards before actually fitting the output transistors as per MisterC6 sound advice this way if there is anything wrong you are less likely to fry the board and take out the Output transistors and a few other parts in the process
I temporarily connected up the front end of the boards with the Diode and 220r so I could try them in one of my old NCC200 amplifiers
So I hooked everything up and then got that switch on moment took a step back and rechecked everything again, and good job I did as I realised I hadn't fitted TR6 ?? WTF


Voyager 6 by alan.towell1, on Flickr

just goes to show check everything twice then check it again after that it all checked out OK so hit the big switch on, then off in a second Mmmm no blue smoke so ; left it on and checked between TP3-4 and got the required 1.6-7v which was adjustable via bias resistor so all looks OK Phew that’s a relief.


Voyager 5 by alan.towell1, on Flickr


On to fitting the output transistors but I realise I don’t have any Mica washers FFS, I only the blue PTFE type so will wait until I get the Mica type and not sure how good they are as I bought them from Ebay ?
Some good info here by the way
http://www.ti.com/lit/an/sboa020/sboa020.pdf

BTW feed back and input cap at present are Mil spec wet tant with 0.5% Sochin 10nf polystyrene film cap bi pass

Anyway under instruction from SWMBO we’re off to the caravan for the week end to chill out so no time to finish of even one amp
Present layout status


Voyager 4 by alan.towell1, on Flickr

BTW there is a group buy going on for an order of VBE boards on PFM at the moment, this will probably be the last time these board will be available

http://www.pinkfishmedia.net/forum/s...d.php?t=160891

Alan

[337alant]

Progress
I picked up 4 Mica insulators for T03 from Maplin and this allowed me to complete the installation of the output transistors and heatsinks on the Ncc 200 boards
I bolted the NCC200 and VBE boards directly onto the side heatsink

voyager 10 by 337alant, on Flickr

I made up some temporary leads to test the power supplies before connecting to the NCC200

voyager 6 by 337alant, on Flickr

For the front end supply after rectification I am getting 71 volts from the 44-0-44V transformer

voyager 9 by 337alant, on Flickr

This is before the VBE but that's a little high for me as the output from the VBE is still giving me 64-65V

voyager 5 by 337alant, on Flickr

This VBE doesn't have any Zenner diodes fitted so I could fit some 56V zenners but that would be a drop of 9V not sure if that is ok reading LesW warning on the schematic ?.
I don't have the correct Zenners anyway
I could fit higher value resistors in line on the Cap 6 boards ?

voyager 4 by 337alant, on Flickr

voyager 7 by 337alant, on Flickr

The output stage Power supply is giving out 53V as expected for my 250V house mains,

Tim, your right the Transformers are dead silent

Back to work tomorrow so will have to park this tread for a few weeks, I would have liked to have got both amps temporarily hooked up and been able to leave them soaking for a few weeks but I have run out of time I am afraid

Alan

[337alant]

Ok received some SMD 56v zeners so fitted them and a wire link back to ground, now getting a healthy +/- 54.5v from tthe VBE supply


VBE zener by alan.towell1, on Flickr

Done a temp wire up for one amp and switched on, no blue smoke so thats a relief.
DC offset 30mv and tried to set the bias but not getting what I expected?, now realise that we have 2 seperate supplies to the amp so a little confused TBH as to how the bias should be adjusted

I set the bias in the Hackernap fashion by adjusting the voltage accross the 0r22 resistor to 3.5mv

Will have another go at setting the bias in the Avondale method tomorrow by connecting 2 meter's to both the FE and OP +ve connectors, I guess I should add them both together. Any advice on this appreciated ?.

Alan

[337alant]

Ah that's more like it put a new battery in one of my meters

Connected a meter to the front end and one to the output supply.
The front end has a steady 12.67ma and the output has an adjustable supply via the bias pot which I have set to 22ma, this gives an overall total of 34-35ma which is what I normally set these amps too
Happy bunny now as the amp seems fine and stable
Excuse the wiring its just a temp lash up

voyager 12 by 337alant, on Flickr

Alan

[awkwardbydesign]

Ah that's more like it put a new battery in one of my meters

Alan

Confusing, ain't it?

[Puffin]

I hate it when that happens. Why can't DMM's have a beep facility when the battery is US!

[337alant]

Confusing, ain't it?

I hate it when that happens. Why can't DMM's have a beep facility when the battery is US!

It sure is, and I am glad I checked them both before starting to rip the amp apart

Been baby sitting the grand kids today so not much progress, did get a start on tidying up the wiring and hope to finish the case work and wiring on Amp No1 tomorrow


voyager 13 by 337alant, on Flickr

Alan

[337alant]

Well Amp No1 is complete and playing music

Plugged the amp into my old passive pre and a Hitachi Tuner and its playing music sounds great

voyager 17 by 337alant, on Flickr

Extended the LEDs from the Speaker protection device to show the yellow LED during the switch on delay and if there is any DC present the red LED display's
Also took a green LED from the OP Cap6 to show the on/off status

voyager 15 by 337alant, on Flickr

Just used a captive lead for the mains and also fitted a XLR and Phono input

voyager 16 by 337alant, on Flickr

voyager 14 by 337alant, on Flickr


Now all I have to do is do it all again for amp No2

Alan