[MrMajestic2]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif You might have to dig into the troubleshooting pdf and do some voltage measurements.

I figured that much, I just don't know where the most logical place is to start.

 

[quattro98]

I started this a few years ago & then was too busy to finish it. Recently, I decided it was time to get it completed. This is my first true DIY project (although I have plenty of experience soldering & using a multimeter). I'm excited by how well it turned out.

The chassis is from ATI Research. I sent them files for the face plates & they did the machining & provided the knobs. Unfortunately, I understand they're no longer in business. The left-most knob is a headphone-preamp-out switch, the middle one is the volume control, & the right-most knob is for the input selector. Originally, the left-most knob was meant for a Tangent crossfeed circuit, but I decided to omit it, but I already had the faceplate machined for the 3rd control, so I added the switch. It comes in handy to disconnect the front panel jacks when changing headphones without powering off the amp.

I would like to thank Ti Kan (AMB), Jeff Rossel (Glassjar), Arthon (ATI), & all of the contributors at Headwize & Head-Fi. I was able to find answers to all of my questions in the various support threads which made this possible.

The amp sounds amazing & I'm sure it will make a great pre-amp if I want to use it to setup a 2 channel system.

 

[Lil' Knight]

Quote:

Originally Posted by Magsy /img/forum/go_quote.gif Finished my last board at four am last night...

I'm wondering what are the caps he used instead of the Wimas?
And what are the resistors in the R34,R35?

 

[Beefy]

Quote:

Originally Posted by quattro98 /img/forum/go_quote.gif I started this a few years ago & then was too busy to finish it. Recently, I decided it was time to get it completed. This is my first true DIY project (although I have plenty of experience soldering & using a multimeter). I'm excited by how well it turned out.

It's gorgeous. Really like it

Do the heatsinks stay cool enough? Doesn't look like there is a lot of room for airflow.

 

[quattro98]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif It's gorgeous. Really like it Do the heatsinks stay cool enough? Doesn't look like there is a lot of room for airflow.

Thanks. The amp seems OK (it's biased to 120 mA), but the power supply does run warmer than I'd like. The case for the amp has slots on both the base & the lid, while the power supply case only has slots on the lid. I might drill holes in the base of the power supply to allow for more ventilation.

 

[johnwmclean]

Quote:

Originally Posted by MrMajestic2 /img/forum/go_quote.gif I figured that much, I just don't know where the most logical place is to start.

A 1 volt discrepancy may be simply the tolerances of the CRD’s, does the rest of the board test ok?

 

[fishski13]

quattro98,
very sexy. where did you source the knobs?

 

[quattro98]

They're from ATI, who also supplied the chassis.

Quote:

Originally Posted by fishski13 /img/forum/go_quote.gif quattro98, very sexy. where did you source the knobs?

 

[amb]

Quote:

Originally Posted by MrMajestic2 /img/forum/go_quote.gif Ok guys, I need some pointers in the right direction. I have a B22 board that measures 4.5V on R9, but around 3.5V on R10, R11 and R12. Any ideas where I should start looking? Everything looks like its soldered into the right place.

A bad JFET in the Q1-Q4 quad? This should not have anything to do with the CRDs.

 

[fishski13]

Quote:

Originally Posted by quattro98 /img/forum/go_quote.gif They're from ATI, who also supplied the chassis.

damn.

 

[MrMajestic2]

Quote:

Originally Posted by amb /img/forum/go_quote.gif A bad JFET in the Q1-Q4 quad? This should not have anything to do with the CRDs.

Ok, thanks. I know where to start now.

 

[MrMajestic2]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif A 1 volt discrepancy may be simply the tolerances of the CRD’s, does the rest of the board test ok?

Actually it doesn't. R34 measures around 100mv at VR2s minimum position. So the only way that goes when adjusting is up, so something else must be wrong too.

 

[MrMajestic2]

Oh great, now I have problems with another board. R9 adjusting to around 4.5V at the maximum range of VR1 and then dropping past 4 volts and downwards. R34 is measuring zero

I have gone over both problem boards with a magnifying glass and finding no obvious mistakes.

 

[swt61]

Very nice quattro98!

Here are a few pics of my own β22. It's a four channel, with dual σ22s in a separate enclosure. There were many hands involved with this project...luvdunhill, N_Maher & fierce_freak. The Top unit is a fully balanced TPA Darwin source selector with six balanced inputs, two balanced outputs and a balanced loop out. The cases were built by me, and are figured Black Cherry w/a five coat, modified Tung Oil finish.

 

[quattro98]

Thanks! Those are amazing. I like how everything matches perfectly.

Quote:

Originally Posted by swt61 /img/forum/go_quote.gif Very nice quattro98! Here are a few pics of my own β22. It's a four channel, with dual σ22s in a separate enclosure. There were many hands involved with this project...luvdunhill, N_Maher & fierce_freak. The Top unit is a fully balanced TPA Darwin source selector with six balanced inputs, two balanced outputs and a balanced loop out. The cases were built by me, and are figured Black Cherry w/a five coat, modified Tung Oil finish.