[ivant]

Also the enclosure most of the time is the single most expensive component

 

[scytheavatar]

http://www.head-fi.org/forums/f113/b...-worth-324811/

 

[digger945]

Quote:

Originally Posted by ivant /img/forum/go_quote.gif 4 boards B22 build is unable to have active ground since the active ground board is configured differently from the other boards(No gain). Minimum boards needed is 5 if you want both balanced and 3 channel active ground.

You are correct. I'm not building the B22 so I'm not sure if it will work with my build.

Quote:

Originally Posted by juswyq /img/forum/go_quote.gif If that's possible I will just go straight for the balanced kit.

See above. I don't know if what I'm trying to do will work with my build, but I'm digging for info to find out.

Quote:

Originally Posted by ivant /img/forum/go_quote.gif Also the enclosure most of the time is the single most expensive component

I did most of the machining myself on my own Parmetal enclosures. It depends on what type of enclosure you use and if you have the panels done by a service like Front Panel Express.

 

[n_maher]

Quote:

Originally Posted by digger945 /img/forum/go_quote.gif I am efforting now to use just 4 boards to cover balanced and active ground SE. It will require a switch on the amp but nothing special.

[edit]sounds like you figured out it was not as easy as you thought it would be.

To the OP, if money is tight the beta22 is a bad project to undertake. Thinking that you only need the parts from Glass Jar or that what is left will be cheap is more than likely going to end up with you having a pile of parts and no amp. Generally I'd say the cost to populate the boards might represent half the total cost of the amplifier, it's even worse when building a balanced version.

 

[digger945]

Well I'm using the 4pdt switch that Ti describes here for the inputs, I wanted to research until I knew if I could use the two positive amp boards for the SE signals and connect the TRS ground to the output of the other two negative amp boards to sink/source the current, perhaps using another switch.
In order to share this amp with the others at the upcoming meet I will finish it as I originally intended and maybe do something else later.
I have also considered using one B22 board as active ground for the SE HP outputs later. Configuring a fifth Dynahi board to serve this purpose is also something to consider maybe.

 

[juswyq]

Quote:

Originally Posted by n_maher /img/forum/go_quote.gif [edit]sounds like you figured out it was not as easy as you thought it would be. To the OP, if money is tight the beta22 is a bad project to undertake. Thinking that you only need the parts from Glass Jar or that what is left will be cheap is more than likely going to end up with you having a pile of parts and no amp. Generally I'd say the cost to populate the boards might represent half the total cost of the amplifier, it's even worse when building a balanced version.

Besides the parts from glassjar I'd need the enclosure, the balanced potentiometer/stepped attenuator, and the input and output jacks, and switches.. I've sourced out the enclosure and attenuator and have factored it into the total cost; the jacks and switches shouldn't be too expensive.. Am I missing out anything here?

The enclosure and attenuator are expensive but surely they wouldn't constitute half the cost of the amp?

 

[sachu]

Quote:

Originally Posted by digger945 /img/forum/go_quote.gif I did most of the machining myself on my own Parmetal enclosures. It depends on what type of enclosure you use and if you have the panels done by a service like Front Panel Express.

Turns out my University has a CNC machine in the mechanical department..I can apparently use it..just need to get hold of some of my mechanical buddies to do some machine work for me when I get around to my next project...If the CNC is too much work to use, then I guess I will just use the machine shop they have...the lowly drill presses among others..

I have the toroids ready for my beta 22 amp..planning on going with a passive ground but each channel with its individual sigma 22 to be able to use it as a power amplifier with speakers...Don't underestimate the cost of a project though..DIY doesn't necessarily mean cheap...blowing just one capacitor or diode can destroy a bunch of other components down the line..in which case if you don't have spares on hand, shipping for these items can quickly add up

 

[digger945]

I have spent more on little things like jacks, thermal interface pads, wiring connectors, push button switch, dact attenuator etc. than the actual parts to populate the pcb's themselves. The whole time I was doing the machine work for the amp itself I carried a Mouser bag with about $600 in small parts(not a big bag either), attenuator parts, etc. just to do the layout and measuring for drilling and such. This is just the amp, now I start on the PS, which will be much easier to lay out and not quite as expensive but close.