Radio Shack Accurian Receiver, quality of amp? (pics inside)

[sam9]

If I understand, the function is to distribute audio through the house AC mains? I read of these schemes before. It never seems to really take off.

Anyway, I suspect the quality of the send/receive function is the limiter. Very likely, any reasonable amplifier will offer audio performance far beyond those limits.

 

[pchw]

To me, the biggest improvement was from replacing the preamp section by a single 6GM8 tube!!

 

[Leolabs]

More current from the toroid,pls???

 

[Neil Davis]

The +/- 15VDC supply is for the preamp board (if you take a close
look there are two op-amps on that board; there are some zeners
in the power supply and since it is running op-amps, then I
would be quite certain that it is regulated. . .but not too much current.

Yep. I tried replacing the op amps with "higher quality" types and they drew too much current for the simple zener regulator scheme. I didn't feel like changing the resistors going to the zener and told the guy I was helping that it wasn't worth it. I replaced the audiophile op amps with the TL082 and called it a day.

 

[gychang]

My next step will be to bypass/remove the bass treble tone controls. Upgrade the volume pot to a better one. And maybe upgrade some of the critical parts with better ones.

-Ken

Ken: please put the pictures on if u can so us newbies can follow your mods.

gychang

 

[pchw]

FWIW, this is a picture of what I did:
http://www.polkaudio.com/forums/attachment.php?attachmentid=24838&d=1179091849

 

[Notagenius]

1. Buy up stock
2. Dump on auction site
3. ??
4. Profit

some of their stuff has horrible build quality, other stuff is great. their RJ-45 crimpers suck.

they've gone the tweako route, selling cables for $50.

 

[alvinlim]

240v AC

any chance of an easy mod to 240v AC?

 

[gychang]

mod?

anyone have a suggestion of a mod for a novice to follow to improve the sound? pictorial recommendation will be ideal.

gychang

 

[salesmonster]

I just bought 2 of these today.

I pulled the receiver board immediately. Powered it up and it is much better than $15 should be. Currently it is powering a pair of Paradigm Atom v.5.

I think I bought the last 2 in the Cleveland market, so act fast if you want one.

Also, the build quality is better than a lot of "nice" stuff out there. It is certainly built to a price point, but I would be hard pressed to manufacture something this cheap.

I'm sure the internals were designed in a modular fashion to keep engineering costs down, but what they created is a DIY playground!

Slightly off topic:

I was desperate for an amplifier, since we lost everything in a move-related fire a few months ago...I'm pulling together the parts for a chipamp now, but it is nice to buy something so cheap for utility amplification.

BTW: You don't wanna know what was lost in the fire!

Dave Rice
Rainmaker Consulting
rainmakerconsulting.biz
rainmakerconsulting.wordpress.com

 

[Stuart Easson]

6 available

Hi All,

Just wanted to let people know, there are 6 available at my local RadioShack, I bought one yesterday. I am willing to buy and ship them to people if they can't find one locally etc...but...

I am out of town until Thursday. If people are interested I will check the stock situation when I return, but the bottom line will be a little different depending on where your want them shipped. Mine was just less than $20, but I had no means to claim the student discount.

We will be using paypal if transactions occur.

HTH

Stuart

 

[gni]

Great offer by Stuart (a Brit living in Santa Cruz?)

Accurian Amplifier
All Resistors are gold = 5%
All Resistors are 1/8W unless otherwise stated

Remember to rotate the transformer until the hum goes away. .
mine was low to begin with; after mods, I put it back in a rotated
position. . .noise. . .slow rotated until all hum went away. . . about
three inches from speaker. . .

Main Audio Board

R18 (Y,V,R,Gl) 4/7k 1/8W LED Power Supply

R100,200 (Gr,Br,Br,Gl) 510 1/8W Input

R101,201 (Br,Bl,O,Gl) 10k 1/8W Input

R103,203 (Br,Bl,R,Gl) 1k 1/8W
R104,204 (Br,Bl,R,Gl) 1k 1/8W
R105,205 (Br,Bl,Br,Gl) 100 1/8W
R106,206 (Br,Bl,Br,Gl) 100 1/8W
R107,207 (Br,Bl,Br,Gl) 100 1/8W
R108,208 (Br,Bl,Br,Gl) 100 1/8W

R109,110,209,210 (Gy,R,R,Gl) 8.2k 1/4W Input

R111,211 (Y,V,Bl,Gl) 47 1/8W
R112,212 (Y,V,Bl,Gl) 47 1/8W
R113,213 (Gr,Bu,R,Gl) 5.6k
R114,214 (Br,Bl,R,Gl) 1k 1/8W
R115,215 (Y,V,Bl,Gl) 47 1/8W
R116,216 (Y,V,Bl,Gl) 47 1/8W
R117,217 (Y,V,R,Gl) 4.7k 1/8W
R118,218 (R,V,R,Gl) 2.7k

R119,120,219,220 (R,R,Gl,Gl) 2.2 1/4W to base

R121,221 (O,O,Br,Gl) 330 1W

R122,222 (Y,V,Gl,Gl) 4.7 1W Zobel

R123,124,223,224 (R,R,S,Gl) 0.22 2W Output

R125,225 (O,O,R,Gl) 3.3k 1/8W

R126,226 (Br,Bl,O,Gl) 10k 1/8W


C101,201 10microF,25V Electro
C102,202 2n7J 100 Yellow Rectangle
C103,203 470J 50V Silver
C104,204 220microF,25V Electro
C105,205 47 Disc
C106.206 47 Disc
C107,207 blue
C108,208 blue
C109,209 473J 1H-P Silver Rectangle
C110,210 100nJ 100 Yellow Rectangle
C111,211 1microF,50V Electro

D101,201

Q101,201 C3198
Q102,202 C1266
Q103,203 C3198
Q104,204 A1266
Q105,205 C3198
Q106,206 A1266
Q107,207 C1027
Q108,208 A1023
Q109,209 TIP41C Power Heatsink
Q110,210 TIP42C Power Heatsink
Q111,211 Heatsink
Q112,212 C1815

PreBoard

C501,502 4.7microF,50V Electro
C502,504 blue
C505,506 1microF,50V Electro
C507,508 47 Disc
C509,510 4.7microF,50V Electro
C511,512 152J Silver Rectangle, Treble
C513,514 330J Silver Rectangle, Bass
C515,516 330J Silver Rectangle, Bass
C517,518 47 Disc
C519,520 103J Silver Rectangle
C521,522 682K Disc
C523,524 4.7microF,50V Electro

R501,502 (R,R,O,G) 22k input
R503,504 (Br,R,O,G) 12k input
R505,506 (W,Br,O,G) 91k opamp
R507,508 (Br,Gy,R,G) 1.8k Treble
R509,510 (Br,Gy,R,G) 1.8k
R511,512 (Br,Gy,O,G) 18k
R513,514 (Br,Gy,O,G) 18k
R515,516 (O,W,R,G) 3.9k
R517,518 (Br,Bl,R,G) 1.0k
R519,520 (Y,V,O,G) 47k
R521,522 (Br,Gr,Y,G) 150k
R523,524 (R,Bl,O,G) 20k


U501 4558D JRC 3265G
U502

VR1 100k Volume Stereo
VR2 100k Balance Mono
VR3 50k Bass Stereo
VR4 50k Treble Stereo

 

[gni]

My Mods:

Reroute the input through right side and directly soldered to preamp
board. I like the RCA cables directly connected to my amp. . .I hate
looking for cables. . . one less connection also. . . routed as far away
from the AC.

Brown board over power supply:
Old RCA outputs are still outputs, but now preamp outputs. Amp
is a little noisy for preamp, but nice to have that reduced level. . .
I hooked it up to my little powered sub. . .worked great and was
right level (330ohm/47ohm).


Bypassed the power switch. . . plugged in = ON.
Removed power switch.

Rotated transformer until hum was very minimal.

Routed secondary wires under mount (Blue and White wires)
Near front of transformer.

Need to wire nut the primary AC (Blue /White to brown/black).

 

[dbwinger]

Thanks for posting all of the info you have found out. Are you going to alter the zobel filter?

 

[damianl]

im in australia....cant get one...care to ship one out here i'll pay whatever it takes just as long as its worth it for my money. let me know on a price...

 

[Stuart Easson]

Shipping to Australia...

...no problem, but you'll have to decide if it's worth the price.

Perhaps someone here can tell you the weight, then we can use the USPS website to find the shipping costs. The RS price is likely to be the same, ~$20. I'll know for sure Thursday, so your final price is just the sum of the two.

Someone here needs to let you know if this critter can be made to work from 220v too. I haven't even had time to crack the box on mine, so I have no idea.

Stuart

 

[gni]

I don't think it will work at 220VAC. . . will double the
secondary taps. . . and halve the current. . .need one of those
stepdown transformers. . . .

 

[damianl]

i was hoping the transformer had 220v taps? Either way I do have an old step down "powerboard" here so I can use that. Can someone please advise on weight I can look up the shipping myself.

 

[gni]

I'll look in the manual. . .I think it listed the weight.

 

[DC Dave]

The amp alone without box or power cable weighs 7lb 3oz.