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Chipamp with potential

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I was inspired to make a desktop amp that work well for an Ipod/ cpu. YOU can build it and be proud of it. It should happily work by your side for many years, like a 'faithful dog'. It should also impress you and others with the quality of sound. Finally, it will evolve to meet your future needs.

I designed this amp with a conglomeration of other circuits that I was impressed with. Many of these circuits are commonly known, but here they are all packaged onto a single board. So, build board as you need, then add an audio source and good speakers = Rock out ~:).

Key objectives:
Pre-amp/ amp that fits in a external CD rom case (tight!)
Use available low cost components, Apexjr parts
Full assembly on one easy board layout
Input flexibility (CD, mp3, phono, microphone, computer, alien waves, etc.)
Quality audio output,LM4766 chip amp (0.01% THD from 20hz to 20khz, 30watts/ch)
Fader option between 2 input sources (satisfy the DJ in you).
Bi-amp preamp stage
Idiot proof DIY construction (this is a stretch goal)

Are there interested person's here for this unit??

Duke
 
to add,
circuit board is 5.5in square
it has tone controls, if you want them
the biamp is 12db with separate opamps, so the bass can be driven by a bigger amp when needed.

don't think I could have fit much more in. See the attached
 

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I would be interested in some data and schematics on this chip... I'm currently working on building a "sub miniature" bass guitar amp that I can take to starbucks and play along with a friend on an acoustic guitar... Also, could you please include a link to where I could purchase this chip?
Thanks,
Clayton Langeneckert
 
I intend to offer the circuit board with the amp chip and a few op amps, Lm4766 and Lm833. Not many people would have these chips in their stock.

A kit is the intention as a option. I'll buy in bulk quality components (met-oxide resistors and pet caps) and set up packs to help the novice.. like legos! It should be build-able by my 12 year old.

Circuit diagram to come (I changed it while doing board artwork)...
Build procedures to come..

It is a very flexible design for inputs. You should be able to configure for almost any input.
 
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Would the group want just the amp chip and board?
or
A kit to include resistors, caps, opamps, pot.. etc
There are yet other options
Zen (volume pot only, 1-2 opamps)
Standard (tone controls)
DJ (mixer and phono stage)
and then there is the biamp stage.
 
Member
Joined 2002
Paid Member
I've been working with Dukep to find the right components and
have them in stock and offer killer pricing on this.

Depending on the final PC Board used I will be able to offer quite
a few of the items needed and once it finalized will also offer a kit
to finish the project. And have some choices depending on how
fancy each of you want to be.

Steve @ Apex Jr
 
updates on costing

To all,
The block diagram and schematic is attached. It has multiple gain stages at your disposal. The phono stage is a 2 part active and passive, mimics the one documented in AN-346 on the National website. This should replace my cambridge P60 with substantial improvement.

For those interested,
Board and Amplifier Chip, 25usd
- these boards are due in 20-Jan.

A kit (all op amps, ne5532a and Lm4766t, no parts for hi/lo pass filters). This also has a heatsink & transformer, input rca & 3.5mm jacks, dual bannana output jacks. Passives are 1% met oxide resistors and 5% PET capacitors. Bridge rectifier is std GBU, but a high speed dual in t0-220 case is possible on board.
excludes the box, pwr cord, and switches
totals around 70-75 usd.
 

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oops, left out something important in the BOM, the Transformer +10 for the Apexjr 42v
Still waiting on best pricing for resistors and capacitors from mouser, I need quantity...
Ball park is now 80-85usd

dukep,
You can count me in for one. I won't be able to until after the 1st of February, though. Otherwise, I'm in.
Thanks for all your effort in this venture. I'm looking forward to this build.
Mike
 
circuit boards arrived

The order of some 100 boards are in. Still have a few pre-amp parts outstanding yet to be received from mouser.

Amp works without a hitch. Even my 6yr old daughter helped build the 1st. She likes the tiny blue bypass caps.

If interested in board & chip.. 25usd

I have a few kits, these are hitting 85usd, more details later on this.
Build procedures in the works. Likely all this info will be on a web site this week.
 

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I was back ordered a few resistors/ caps for the phono stage (as if many really want that stage). These are due by weeks end.
I am also writing up a build procedure/ setting up a web site to put the info & paypal etc.

The builder will have to add the case and power plug (a gutted electronic box). I haven't found a reasonably price one yet. It will fit into a cd rom case, the the transformer with have to be external. There will be a picture of that soon.

Contact my personal e-mail if more info needed.
 
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Most all parts are in but,
I was back ordered a few resistors/ caps for the phono stage (as if many really want that stage). These are due by weeks end. I sized down to two offerings, a kit -or- a board and chip.

I am also writing up a build procedure/ setting up a web site to put the info & paypal etc. 1st buys may need a money order. I will be detailing advanced builds that include 317/337 pre-amp power, guitar amp setup, bridging/ parallel for 16ohm or 4 ohm applications (green back celestions are 16 ohm). and others yet to be done, but a web site is the proper dumping ground for all this information.

The builder will have to add the case and power plug (a gutted electronic box). I haven't found a reasonably price one yet, but several 5 1/4 external cases exist on newegg.com that should work. The amp will fit into a cd rom case, the transformer with have to be external. There will be a picture of that soon.

Contact my personal e-mail if more info needed.
 
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