How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

[tyger23]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

I saw an earlier comment of yours bringing up use of LDRs in another thread. Would it be worth the added complication to remove the pots from the signal path and instead use the pots to control diode protected NPNs to control cap bypassed LEDs optically close coupled to LDRs to attenuate input? Bad idea?

Not a bad idea, just not worth it in this particular implementation. The work you'll go through to hand-match the LDRs and so on wouldn't be worth it on this class of amplifier. Now, if you wanted to take aim at replacing them with an Alps Blue Velvet or something like that, then I'd say go for it. The distortion introduced by the pots is far below the distortion introduced by the chip amps in this product.

My issue with the Alps Blue Velvet (why I didn't do it) had to do with the available knobs. Changing to a blue velvet means having to buy new knobs because the factory ones are not compatible. The factory ones are knurled as versus flat. Also, the Blue Velvet's are huge, and I'm not 100% sure they'd fit without cutting away some of the PCB.

My mods above basically turn an $80 amp into something that competes in the $300-$500 weight class. Personally, I'd reserve the LDR's for an amp that's starting off in the $300-500 weight class.

[greywarden]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

+6,7,8

I have 3 of them I'd like to mod... maybe when I'm a poor college kid and all I can afford to do is $35 a month haha.

[Mark65]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

I'm with John A on this one, looks like even a ham fist like me could actually get through those mods. Methinks an AMP100 is in my future....:D

Well done, Sir! (bows)


Mark

[WernerM]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Tyger,
Do these conversions change the allowed impedance? The factory is 60W into 4 ohms, are they still 4 ohm stable?

[[email protected]]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

tiger, I would be happy to send you mine (the one that used to johnny's) so you can compare. I would also like it if you would perform the changes. would that be a possibility?

[tc]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

That is so awesome Ty! I am glad that, in death, that amp served a higher purpose than me throwing it in the trash can. Even though I am inching towards building my own (and I still indeed thank you for your suggestions), I might have to buy another one of those to play with your updates. Simply amazing.

Now, the real question.....is this going to your niece to run those uber-cool irridescent speakers?

Thanks for taking the time to do something useful with it. I appreciate it.

[tyger23]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Tyger,
Do these conversions change the allowed impedance? The factory is 60W into 4 ohms, are they still 4 ohm stable?

No changes in that manner. Still good for 4 ohms.

[tyger23]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

tiger, I would be happy to send you mine (the one that used to johnny's) so you can compare. I would also like it if you would perform the changes. would that be a possibility?

I can probably arrange that. PM me to discuss the details.

[tyger23]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Now, the real question.....is this going to your niece to run those uber-cool irridescent speakers?

No, I think I'm sending her a NAD 7220PE for that duty. It's based on the old NAD3020. Try as I might, I couldn't make any overall sonic improvements to that design while I was repairing it. She's getting the NAD over the AudioSource simply because the NAD has an FM radio built in.

[Æ]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

You'll note that I didn't make any changes to the rectifier circuit, mostly because I don't think it would net any real performance increase. The current design uses 6A4 rectifiers. Changing to FREDs or something similar just isn't necessary on a linear power supply.

How about some snubbers on the rectifier?

[tyger23]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

How about some snubbers on the rectifier?

There are caps across the diodes included in the factory design. Is this what you were looking for?

[foxfire3]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Tyger, do you feel the Nichicon caps are better than the Panasonic FC-series caps?

Thanks...

[tyger23]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

I've never done a direct comparison with the FC stuff. However, I've compared the Nichicon vs Elna Silmic II and the Nichicon's come across a tad warmer. I guess I'd pick which cap I use based on how I want the amp to turn out.

However, I do try and stick with one brand across the design. In this case, Mouser had more Nichicon stuff in stock as versus the Elna stuff, so I chose the Nichicon.

[mpotoka]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

When you say "a good soldering iron", how good do you mean?

I have two of these amps sitting on the shelf, but I've never soldered anything beyond a speaker crossover.

Is this project something a newbie could handle? Or should I look for someone in the Chicago area to teach me a few things first.

Thanks!

[radhaz]

Re: How to turn your AudioSource AMP 100 into a real amp. (Paying it forward)

Buy some solder wick and a desoldering pump, and have at that dead clock radio in your closet for practice. Personally, I have a Hakko station, as well as an 808 desoldering tool. A bit much for hobby work, but I like my circuit traces to stay on the board.