[Centinul]

Well I would like to build an A47 amp and I'm having trouble putting a parts list together. I'm probably going to order from www.digikey.com. Here are the parts that I THINK I NEED SO FAR, as mentioned in the following A47 Instruction set:
A47 Instruction and Layout

Code:

[left]Capacitors 2 565-1610-NDCAP 470UF 50V ELECT KY RAD $1.04 2 495-1086-NDCAP .47UF 50V METAL POLY $0.64 2 495-1087-NDCAP 1.0UF 50V METAL POLY $0.82 *In case I ever want to tweak the bass* Resistors 1 P2U4103-NDPOT 10K OHM 12MM HORZ MET BUSHIN$2.66 5 2.49KXBK-NDRES 2.49K OHM 1/4W 1% METAL FILM $0.54 *Gain to 5* 5 4.75KXBK-NDRES 4.75K OHM 1/4W 1% METAL FILM $0.54 *Gain to 3* 5 47.5XBK-NDRES 47.5 OHM 1/4W 1% METAL FILM $0.54 5 100KXBKRES 100K OHM 1/4W 1% METAL FILM $0.54 ICs\Transistors 2 1N5822DICT-NDDIODE SCHOTTKY 40V 3A DO-201AD $1.36 1 BUF634T-NDIC 250MA HS BUFFER TO-220-5 $8.10 1 296-1994-NDIC 1/2 RAIL VIRTUAL GND TO-92 $1.30 2 OPA2227PA-NDIC DUAL PRECISION OPAMP 8-DIP $7.92 2 AD823AN-ND IC OPAMP FET DUAL 16MHZ R-R 8DIP $10.00 1 HLMP1790-NDLED SS GRN DIFF LO CURR PCB 3MM $0.34 Misc 2 BH9V-W-ND HOLDER BATTERY 9V WIRE LEADS 0 0.88000 $1.76 3 CP-3535NG-ND CONN AUDIO JACK 3.5MM STEREO 0 1.01000 $3.03 1 360-1155 SWITCH TOGGLE SPDT 6A 0 4.20000 $4.20 2 AE7313 IC SOCKET .300 8 DIP GOLD 0 0.93000 $1.86[/left]

From the schematic of the A47 I still need 470 microF capacitors, a "D1 1N5822" and "P1a 10k". I don't know which type of capacitors I need. I tried looking through the Digikey.com website and there are so many different capacitors to choose from, and I don't know which kind I need. Also I don't know what a "D1 1n5822" is and I do don't recognize the symbol. The "P1a 10k" looks like a variable resistor but again I don't know which one I should choose so please let me know.

I would like to get started on this project and I just want to make sure I have the right parts. Please any help is appreciated.

 

[Kenny12]

u'll need a pot for the volume control

50k dual gang is the most commonly used

perhaps also switches and battery holders, headphone jacks and etc

 

[Centinul]

Since I'm new to all this stuff I don't know how to translate "50k dual gang" pot to a real part that I can find on the digikey.com website. I also don't know what kind of switches I need either. I've tried looking for some switches but they all seem to be really expensive so I must be searching for the wrongs ones. I know I need an on-off for the power as well as a DPDT switch to switch between speakers and headphones. I've added battery holders even though I think this is going to be a wall powered unit.

 

[Xakepa]

I'd rather get more res (10 each), they are so cheap, and that .1uF polyprop is too low IMO....why don't you by-pass it with 2.2 polyester

The powercaps you need are 470uF (or bigger) Panasonic FM series, 25V (for 2x9V battery). FM series caps are supposed to be the best from Digikey catalog. Bigger, 1000uF ones I use are pretty tall, 1" I guess and might not fit a small case - look for the dimentions on the catalog page. And you can order some fast powercaps as well, like...495-1090-ND to put next to the big guys.

Look for the pot on Tangent's page, you'll find digikey part no. there. Also, digikey are out of 634 DIP-8 buff (untill next year I was told); they have TO-220 version though. Dunno which schematics you'll use; I used one from a tread here named "Build a failure...", you can search for it - it uses RS protoboard, and is pretty simple.

Another thing...if you're not very cash strap...get a different dual OpAmp for IC1 just to see the difference....like AD823.

Good luck

 

[Centinul]

Xakepa -- I chose those 0.1uF cap's because that is what was specified on the layout. If you would like to see the layout please see the link in the original post. I also don't understand what you mean by "fast powercaps" either.

Also when you mentioned trying a different op-amp, were you talking about replacing the OPA2227P???



P.S.... I appreciate all this help and I would like to get started on this project ASAP.. am I almost done?

 

[Xakepa]

There's a better layout posted here, by user "Ruffy"...named "Build a failure"...search 4it

Fast powercaps are by-passing power caps which provide current fast as the large ones are relatively slow.

Yes, try smth else than for 2227 at IC1.

Gotta go now

 

[Centinul]

ok Xakepa I took your advice and searched for the thread that Ruffy posted. I took the parts list he had and I chose to use that instead and added a couple of other things I needed.

Is there anything else that I should add to the list or am I allset to go??? Thanks!

 

[Xakepa]

Checklist

-Power - plug->switch(LED)->spliter->caps
-Signal - plugs in->pot->input cap/res divider->opamp (feedback R1/R2)->opamp2 -> output res->plug out
-GND- buffer

Get a spare TLE2426 - they're easily fried if smth goes wrong. Get different res for different gain (mine is 3, 4.7K/10K feedback spliter, you might want more), get more res so you could mach them.

You need 10K res for the feedback, Ruffy missed 'em

Get a spare protoboard as well - if you're a clutz like me and your setup is not very good, could get pretty messy on solder side. Saves a trip to RS.

You're allset at that I guess

 

[Centinul]

Xakepa,

First I just wanted to say thanks for all the help. I'll add the extra TLE2426 and resistors. Judging by your post, it looks like once I make the additions I just mentioned I should be ready to go. Since Ruffy missed some of his stuff, where can I get a schematic for all this so I know where all the components go?

Also, please give me the ok on the parts...

P.S... where in NH are you from because I live in southern, ME.

 

[Xakepa]

UR welcome.

Ruffy missed 10K res from his digikey list, but the protoboard schematics on that post is OK, I saw you found it

Your list looks OK, just add 10K res, get Panasonic FM caps and you'll have everything for the basic setup.

I'm in Durham, UNH...but I'm not a student and not a professor, eighter

 

[Centinul]

I was about to order the parts for my A47 when I noticed that Digi-Key is out of the BUF634P. Mouser and Newark are also out of it and the estimated time that the product will be in stock is the middle of January. Where else could I order this part so it will be here in a reasonable time? Thanks!

 

[Xakepa]

For the Ruffy's schematics, you don't need P (DIP-8) version of the buffer, you need TO-200 version (634T)...but they don't have that one eighter....

You can build the amp w/o a buffer at first - it should work, but might be pretty bright, flat and not very loud.

 

[Centinul]

Is there any sort of replacement at all? I don't want to wait until mid january.
I searched ebay and the only one costs $20!

 

[dsavitsk]

You should be able to use the Intersil HA3-5002-5 buffers instead. You'll need to change the layout a bit, but you should be rewarded with better sound. The Newark part # is 06F5241.

 

[Centinul]

what's involved in changing the layout? Do you mean actual changing of components or just the physical layout?