DIY Modules?

DIY Modules?

Remember the likes of Sage Audio?

High performance audio circuits encapsulated in potting boxes with connection pins so you could configure your "own" amp, preamp, mixing desk etc?

Well, do you? (remember)

There was also ILP and probably Crimson...

So if I did all the hard work by potting the modules you may require, like: tone controls (tone control potentiometers would be mounted on flying leads from the module - of course); mic-preamps; guitar preamps; tape-head preamps; phono preamps; balanced to single ended stages; single ended to balanced stages; even a headphone amp; a control or line preamp; a mixing amp; a pan control stage; mic-preamp with phantom power; power amp (range of); you name it, etc etc...

Would anybody at all be interested?

Originally posted by mrarroyo Interesting concept Graham, have never seen the likes of it. What would you start with and how would the end user use it? Sorry for the newbie questions.

Very valid questions!

Right now I don't know what I'd start with, but due to the (long awaited) readjustment of people's thoughts into savings rather than debt, I think it has to be the most in-demand item on the list (or even something I haven't thought of?), whatever that is - - so, suggestions please?

I realise that a kit can seem (or is) daunting - it was much the same way with me in my teens, very much the "fear of the unknown". My suggestion here (as I do the finishing touches to the Genera phono preamp kit) is a "half-way house" - a kind of nearly finished "kit", or indeed, an uncased and unterminated finished product.

It was a long time back, over thirty years, when I first came across these encapsulated DIY audio modules. Unfortunately, some of them were vastly over rated: power amps advertised at 150 WPC that were (inside) just 30 watt power op-amps bolted to a large piece of aluminium. I'm sure many were duped, and that's possibly why you don't see these modules on sale today.

If you can imagine a small slab of hard black plastic the size of a sardine can (hope they're the same size as in the UK) with stiff tinned copper wires protruding out the top (or bottom if held upside down), a bit like one of those square bridge rectifiers: that's the sort of thing I'm thinking of.

Inside is everything that can be "potted" - all the fiddly transistors, diodes, resistors, capacitors (especially those that could break easily), so that all you needed was a power supply (easily made by the DIYer); input and output connectors; volume, tone, balance potentiometers (depending on what module it is) - that sort of thing. And not forgetting a suitable enclosure - the user defines how it's cased. In fact, the user can make virtually anything he(she) likes from one or more modules, to serve whatever audio needs/desires he(she) has.

I guess such an audio module is like a large "chip" that "does it all".

We would specification pre-test each audio module on a production jig, just like we do with our existing products, to ensure each audio module performs to specification. We'd have to do this pre and post potting to ensure each audio module is perfect.

There is one audio module that's been on my mind: I feel I cannot make a DAC because I never followed DAC chip development, but people have asked me for years to do one. What I can offer instead of a full DAC, is the audio-out bit...

The audio outs on a DAC chip are either voltage or current or sometimes there are both options. My thought is to make the analogue stage in an audio module the DIYer can hook-up to his(her) DAC chip outputs. There would be pins to connect either the voltage out, or the current out, which enables it to fulfill either function, as well as the "input" for the DAC chip's reference voltage. Then all you'd need is to give it some power and connect its output pins to some output jacks.

The way of physically mounting these audio modules could be onto a piece of perforated paxolin board, or by clamping them down to a chassis (it would be easy for us to supply a simple aluminium clamp with each one - or even arrange a mounting through-hole depending...). Then the user would hard wire all the connections, maybe using some tag strip for neatness.

Things like tone controls could be easily incorporated into some existing gear by obtaining a tone control module and the necessary pots could be supplied with it, or then again, left to the user's choice.

A summing amp module would allow the construction of a mixer which could be as basic, or as complicated as one wishes through inclusion of preamp input modules, panning modules, tone control modules, even a second summing amp for a pre-fade listen "bus"; a monitoring section which could include a headphone amp...

Hopefully such a range of audio modules would revolutionize DIY audio onto a scale where many more people could build their own gear, and successful DIY audio gear at that.

What I do need however, is suggestions - the more the merrier.

And not forgetting questions, because questions provide the answers to what the user really wants.

A 500 series card frame is what I believe you mean.

Although this is not what I meant, it was an idea I did have some time ago and made the first edition of the Gram Amp Communicator with a universal card-frame front panel.

The problem in doing that, I found, was it was "way above the heads" of most, and didn't attract a single studio (or similar) sale.

Most of your example "wants" could easily be served by this module idea.

The paxolin board is basically veroboard without copper tracks and has 1.3mm holes, but having said that it looks like the big pieces installers used to use doesn't exist here anymore.

Instead, mounting of each module would therefore be by some form of clamp to the base of a chassis, the inside of a box, that sort of thing.

Lead outs to controls and connectors from the connection pins on the module... quite straightforward. Power connections probably requiring a bit of explanation and understanding: card frames never easily accommodate star earths from my experience and most pro-users (including aunty beeb I'm afraid) didn't care either.

I think I need to flesh things out a little further, but suffice it to say that the flexibility to allow the constructor to build and expand exactly what he(she) wants, will be the main consideration.

Yes, but we used to make things look much better...

The next time you see the insides of a BBC radio studio on a news program you may just be able to spot the occasional card frame housed in a polished wooden "top-box"...

Some housed cards without fronts and these have a smoked plexiglass front cover (so you can monitor the LED indicators). The others housed modules which are cards with fronts attached or enclosed modules like the earlier Gram Amp 2 Communicator phono preamp.

Hi Graham,

This is, in today's market, a real "out of the box" suggestion.  As I wasn't DIYing 30 years ago, I can't recall the potted modules.  I like the idea of tested products for the novice/short of time/jst let me build it now brigades.  The potting is my only initial baulk, and that's probably because it's an alien concept.  Not of potting per se - I wanted to look into potting some small circuit boards here for various reasons (thermal stability etc).  If the modules were offered as a full-pot solution AND as a kit, then that would be great for all camps.  I'd like to know what was in the module (components, circuit, layout) and then I wonder how I'd replace a failed resistor, for example.  I suppose that's the difference between a consumer and DIYer, but this novel concept might well bridge that gap in the same way that the DAK series has/will.

Interesting to see how this concept will develop...

Cheers

Jon