[kfh227]

OK, I want an inexpensive rig for work tht is above average. I got poked into looking at the Toshiba 3950/60 and a CMoy. And if I'm going to start soldering (which I havn't done much of) I might as well mod hte 3950 too.

So, two things. DIY amp and Toshiba mods.

----- 1
DIY AMP

Well, I was thinking. If I do a DIY amplifier, I figure I could do up to $50 for the parts of a DIY amplifer. I'd have to buy the gun, sodder and other little things I would need. Those are extras and not included in the $50 budget. I already have a multimeter(better one) but that's about it.

The actualy DIY amp:
I could do a CMoy with better op-amp(s) or I could simply do a totally different amplifier design than a CMoy. Truth be told, I want what would give the best sound quality. And I an be prodded to up the budget slgihtly.

How come I never see class D amplifier designs for headphones? Maybe I just missed them.

So, what design and what will the parts cost?

------- 2
Toshiba 3950/60
What mods can be done? I think there are two. Upgrade the power supply section. And Upgrade the output section (better op-amp and caps).

Let's keep the budget here at $50 for all the parts also.

So, now I'm looking at a total cost of about $160. Way over my origianl budget of $100, but if I end up with the sound quality of $450 worth of off-the-shelf equipment....why not spend $160

----------
This is still all in the research phase. If people point me in the right direction via links, I can do the research. First it was a 125 gallon fresh water aquarium and now this. My wife is going to kill me. Just make sure I don't spend to much money

 

[kfh227]

And my experience with soldering is VERY limited and I havn't done it for atleast 5 years. I think I know enough to get the job done, granted it might be sloppy.

Oh, is there an "official" cmoy web page. I found it at one time but never bookmarked it.

 

[JMT]

Tangent's Audiologica

I would recommend that you buy some perfboard at Radio Shack, some cheap wire, and practice your soldering skills. Then build the Cmoy and/or perhaps one of the other amp offerings on Tangent's site. You can do it, if you get stuck there are a bunch of people here willing to help.

Have fun.

 

[Earwax]

For the 3960/3950 there's the Swenson mods http://johnswenson1.home.comcast.net...3960_mods.html
and the Vinnie Rossie mods
http://home.nc.rr.com/keihin/toshiba3950/vinniemods.htm

I haven't done either yet, but I think my soldering skill is at the point now where I could do the Swenson mod fairly easily so I'm ordering up parts for it now. I'm getting some 1uf Solen capacitors from Parts express and some Xicon Polystyrene 330PF from Mouser. Just a few bucks, it'll be a big bang for the buck mod if I can actually hear any improvement at all.

 

[AndrewFischer]

Quote:

Originally Posted by kfh227 I'd have to buy the gun, sodder and other little things I would need. ... My wife is going to kill me. Just make sure I don't spend to much money

A few suggestions.

A pencil style soldering iron will work much better than a gun for small electronics work. The soldering irons sold at RadioShack are not very good. It will be harder to get a good joint with an RS iron.

Personally, I like the tried and true Weller WTCPT. A new one will run you about $140.00. eBay might find you one for a lot less. This would be a lifetime tool.

A good budget Solder Station would be a Tenma from MCM electronics. The 21-7950 looks good at $39.95. I've used a previous model. It was suprisingly good for the price. There is also the 21-7945 for $24.95

I wouldn't go overboard on exotic solder either. Kester '44' or Multicore. You can get a small pack for under $2.00 -- Tangent has a good write-up.

 

[kfh227]

Quote:

Originally Posted by Earwax For the 3960/3950 there's the Swenson mods http://johnswenson1.home.comcast.net...3960_mods.html and the Vinnie Rossie mods http://home.nc.rr.com/keihin/toshiba3950/vinniemods.htm

Thanks for the links.

And to others, thansk for hte advice, especially on picking a soldering iron

Karl

 

[Pars]

Yeah, the Rat Shack irons, tho somewhat workable, do make soldering a chore. I did several CMoys / A47s and a couple of MINTs with the 25W one. Tips are crap, even when new. I now have a Hakko 936ESD and love it.

Probably the best bang for the buck soldering iron would be the Hakko 936 clone from circuit specialists for $35. Read up about it on a recent thread, here.

hth

Chris

 

[AndrewFischer]

MCM has the real Hakko 936 on sale for $77.95.

 

[bubbagump]

Quote:

Originally Posted by Pars Yeah, the Rat Shack irons, tho somewhat workable, do make soldering a chore. I did several CMoys / A47s and a couple of MINTs with the 25W one. Tips are crap, even when new. I now have a Hakko 936ESD and love it.

i'll second that. the flaky heat distribution is the main thing that bothers me the most.

 

[bubbamc119]

class D amps are digital, only good for cheap subwoofers.
class A, A/B or B is what you want for headphones.

Bubba

 

[kfh227]

Quote:

Originally Posted by bubbamc119 class D amps are digital, only good for cheap subwoofers. class A, A/B or B is what you want for headphones. Bubba

Actually, class D's arn't digital. What they do is multiply the input signal with a 100,000 Hz sin wav (for example). In doing so, you can get very high power ratings. And on the output, you filter out the high frequencies, thus giving you a powerful output signal of the original signal.

It's a cheaper design to manufacture from what I understand.

And yes, very commonly used in subwoofers.

UPDATE: OK, the advantage is efficiency. But hte theory behind it makes them noisy, so for subs only.

http://www.ofsoundmind.com/OSM2/tech...ment/amp5.html

So, you are correct. not good for headhones at all. And I guess they use pulses, not a high frequency sin wave.