STK chips

[rick57]

Great technical ideas here.
. . . great bang for buck/ euro/ - how many?

Reason to ask:
To build about 6-7 speakers (sure it’s too much ) over the next year or two (+/- 10%) – *all active* : inc.
- a PHL/ Neo3 bookshelf,
- two three-ways (one a PHL/ ribbon version of SL Phoenix),
- an Usher bookshelf,
- a couple of active subs,

Need a lot of (not too costly) amps!

Will start with one each, based on:
ST 4048-X1
LM 3886
TDA 7293/4
Before I dream too much , would costs have yours run to?

**Complete * cost* (+/- 10%) 2 channels,
including power supply??

[sayang001]

Or try here for a huge collection of STK datasheets (some are only application GIFs, though so you'll have to lump it in those cases.

ftp://garlic.netsource.ch

look under 'pub', 'datasheet', 'transistor chip datasheet alphabetically ordered', and then 's'. Username is "zanco" and password is 'dial'

I get password not accepted ...

[rick57]

ok they're a bargain, but can we *quantify* this -
can we please have some posts

cost (excluding aesthetic eg case, without adding eg the solder - within 10%) for the 2 channels,
Complete with everything thing in the sonic chain, including power supply??


rljones - are you still in this thread?

[rljones]

Yeah, I'm still here. I was trying to avoid this thread.

If you read a few pages back, you'll see how I opened a few of these guys (4048XI) up and found that they're not all created equal. I would NOT use them in a design because of this. If someone wants to purchase my remaining stock (I think I have about 8 pieces of the 4044XI (all good stuff as I recall) and 8 or so pieces of the 4048XI (mixed), then email me.

Prices. Good question. Break it down into 3 parts: chassis, power supply and main boards. Under chassis, you also have your heat sinks. These heat sinks may or may not be part of the chassis. Are you going to design your own or buy one off the shelf? Figure on at least $100 for a chassis, more if you want it well built. Heat sinks will add to the cost. The size will depend upn how large your boards are (include the power supply section), the size of the transformer, how large the heat sinks are (which are affected by the power rating of the amp; how much power; class A or B, etc). Also, monoblock or stereo; monoblock means two chassis, and that means double the costs for the power supply and chassis. In this section, I'd also include my input jacks and binding posts. How much here do you wish to spend? You can spend as little as $10 or as much as $150 or so with WBTs.

The power supply will run you about $75 for a toroidal transformer (Avel), more or less depending upon the VA rating. The power supply will probably cost you at least $50: most caps run about $15 for a 12,000 uF at 63V; so that's $30 with only one stage of filtering, plus rectifier bridge (dual or single?).

Next, the audio section. Are you going to point to point wire, or build up a pcb? The various parts will probably cost you $30 per channel. But even here, if you start adding exotic bypass caps or DC blocking caps made of voodoo oils, etc, you can drive this section up into the hundreds of dollars.

The audio section is typically the least expensive part. The power supply and chassis parts cost the most and take the most time to put together. Drilling holes and wiring also take time, especially if you don't have the right tools.

You could skip much of the above costs if you gut an old amp or receiver, and utilize it's power supply and some of the parts.

Regards, Robert

[rick57]

Robert
Thanks for the info, I had read about the dodgy chips.

Not trying other GC projects with other chips?

Richard

[Da5id4Vz]

I'm not sure that this amp has been discussed before in the forum or not, but I'm pretty sure that it uses an STK chip.

I think it gives a nice reference to what can be achieved with these chips and what the value of the finished product is.

http://www.ird-thailand.com/products/mb100/mb100.htm

Can anyone verify my assumption about the STK chip?

I was two things have given me a new level of respect for these things in the last few years.

The first was dissecting a Genelec 1031a, STK XXXX (cant remember) an amazing sounding near field monitor.

The second came after I friend my fancy discrete component receiver in an act of late night stupidity. Needing a replacement amp, I dusted off my old Techniques receiver, that uses a pair of STKxxx (again my memory fails). I should have A-B compared the two before plunking down the money on the fancy stuff, the STK chips with a nice beefy PS blow it out of the water.

[Dj BASS AMP]

i dont thinks it is a amp base on STK chip...

[tbla]

TDA7294

[rick57]

Slightly OT:
I'm considering buying a quantity of TDA7293s, to drive some harder loads.
Did anyone ever get the 7293 working successfully in slave mode?


Regards

Richard

[bubu]

Hi Guys. I'll post here the pcb I used to build the STK4050 amplifier during my vacation. It works very fine. I'm in the DJ business and I use this amplifier to drive a pair of 8ohm Smart series Proel satellites. I plan to build one of the aussie amplifers - the 400W one (A.Holton - www.aussieamplifiers.com) to drive two HD15 subwoofers (www.speakerplans.com) but I'll do it in my next vacation in may. Yo'll need ExpressPcb to view/print the circuit . Print it as it is. It will mirror itself when you transfer it to the pcb. I use Mactac transfer foil (~2$/sheet - www.mactac.com). I will post the protection circuit as soon as I find the schematic (my wife's cleaning habit). Take care.