[morsel]

Soldering an SO8 IC to a BrownDog adapter is easy and only takes a couple of minutes. This has been discussed in the DIY forums, but to summarize:

Optionally apply flux to the pads with a flux pen. Clamp the IC in place with a heatsink and position it precisely with the end of a paperclip. Solder one leg, check the alignment, then solder the rest of the legs. Remove the excess flux with 90% isopropyl alcohol and a cotton swap or old toothbrush.

 

[wilsonjm]

Beautiful amp! I really like your craftsmanship on it. I planned on building my future amps with those new Hammond cases, Neutrik long jacks and the large Kilo knobs...and now i'm convinced that it looks great!

Nice work!

BTW though - I would agree that the MKS2 are not the best choice for C1. Try a polyprop. cap, or just remove it as long as DC voltage isn't an issue.

 

[puppyslugg]

Hi zhtham,

How did you get the knob onto the 'fake' alps pot? Is the a knob 1/8"?

 

[Toe]

Quote:

Originally posted by erix One thing, however. The caps you have in the C1 position (MKS2?) are not the greatest for signal quality. You should find a good polypropelene (Wima MKP4 or MKP10 or Panasonic's from Digi-Key or Solen or other exotics from Welborne or somewhere) for that position. Or leave it out.

Something I've been wondering about: How do you figgure out what value to use for this cap, or if you even need one at all? Is there a general rule like X value cap for Y offset? Or does the size not matter, as long as there is one?

 

[wilsonjm]

Toe,

I think that C1 and R2 form a low pass filter. If i remember correctly the formula is 1/2piRC where R = R2 and C = C1. Then this is the minimum frequency that can pass through? Don't quote me on this though

Common values used by people on this forum are 0.47uF - 1uF for C1 and 100k-1M for R2

 

[thomas]

high pass filter...

the equation gives the corner frequency, the frequency where the response is down by 3dB

and you're an EE student?!?

 

[BDA_ABAT]

Just beautiful work!!! Hard to believe it's only your second DIY project... Good job!

Bruce

 

[lextek]

I want one!

 

[tangent]

Quote:

Is there a general rule like X value cap for Y offset? Or does the size not matter, as long as there is one?

DC does not pass through a capacitor at all, so any capacitor here will reduce a signal to pure AC. The formula people have given you has to do with finding out what this high-pass filter will do to the AC portion of the signal -- "the sound".

 

[Gariver]

Congratulations zhtham! You've done an excellent job in all the facets of this DIY project. Your META42 looks very, very professional, and it is very, very beautiful! It is, indeed, hard to believe that this only your 2nd DIY project. Amazing, really!

A few questions...
You say PRR helped you with R3~R6 to optimize the amp for low impedance headphones, such as your Sony MDR-CD3000. So your amp will work very well with Grados. That's a given. However, have you tried a high impedance headphones with your amp? I'm curious on how your amp will work with the Sennheiser HD580s and HD600s. It would be nice to have an amp that works with all sorts of headphones. Most likely this "ideal" is not possible. TIA for your comments!

 

[Toe]

Quote:

Originally posted by tangent DC does not pass through a capacitor at all, so any capacitor here will reduce a signal to pure AC. The formula people have given you has to do with finding out what this high-pass filter will do to the AC portion of the signal -- "the sound".

Thanks, that's exactly what I wanted to know.

 

[zhtham]

I am still updating my tips & tricks post, here are some of the replies. BTW, i've added some pictures of my CHA47 Penguin Amp to my gallery as well.

Quote:

Originally posted by HD-5000: What size Hammond case did you use and does the amp open from the sides too or does just the top come off?

It's the 1455K1201BK from alliedelectronics.com. The top can slide out from the main housing after you remove both front/back panels.


Quote:

Originally posted by erix: One thing, however. The caps you have in the C1 position (MKS2?) are not the greatest for signal quality. You should find a good polypropelene (Wima MKP4 or MKP10 or Panasonic's from Digi-Key or Solen or other exotics from Welborne or somewhere) for that position.

I bought some real nice Dayton polypropylene film caps from partsexpress.com, but they are too big, I can't seems to find a place that fits

. So, i got some .47 uF Panasonic polypropylene film caps from digikey.com (P3474-ND). They fit nicely.

I experimented with increasing values, i bought some 2.2uF (027-415) and 10uF (027-428) Dayton Caps. I found that with increasing C1 values, the sound stage seems to move away from me. Vocals in my head, between my ears were transported to somewhere in front of me.

I think this is consider some kind of coloration of the music right? But i think i like it, maybe it's an alternative to crossfeed circuit? I tried using some electrolitic caps too, but i settled with the Wima MKS2 for i think they are the least i can do

I will use the Dayton Caps if i can fit em though'. Don't they have anything smaller? 250V tolerence were the lowest value i can find in partsexpress.com. I tried to jumper C1, I don't like it because the noise (when PCDP is seeking tracks) got amplified.


Quote:

Originally posted by Gariver: You say PRR helped you with R3~R6 to optimize the amp for low impedance headphones, such as your Sony MDR-CD3000. So your amp will work very well with Grados. That's a given. However, have you tried a high impedance headphones with your amp? I'm curious on how your amp will work with the Sennheiser HD580s and HD600s.

Actually i got those values after i read a posting by PPR at Headwize DIY Forum. Look at the 11th post over here. I have only Sony CD3000, used to own some Grados, sold em' all. Never had a high impedence headphone before

I was thinkin' of getting a pair of HD580/HD600 though. I've listened to those with Headroom Home at the San Francisco Tour. I really like them too, but i just got rid of all the other phones, i hate to start the collection cycle again

Ciao,
Z.

 

[aos]

Excellent job to be sure. I started drilling the same case yesterday and managed to screw up a simple hole. It really takes more time prepping the case than soldering and it's much easier to screw up

. So you deserve accolades for your work

.

 

[Gariver]

Your Sony CD3000 are excellent headphones. So you don't need any other cans.

I would like to add that you are a very considerate person. In every post, you take the time to give us the part number and the source. I really appreciate your efforts in that respect. In the past, I've gone bananas looking for components. Sometimes, of course, I've ended empty handed. With your posts, I don't have these problems. You give us ALL the details.

Thank you very, very much!