[yellowjeep]

Sweet, thanks Nemo. I just ordered the PS I posted earlier, I sort of forgot about it. I wish I would have remembered as I will be stuck waiting for it now. 

 

[yellowjeep]

Something interesting. I just got my board today started going though my box of components. For C104 and C105 I ordered these. The data sheet states that they are 12.5mm dia. but I just measured about 5mm dia. they are labeled 220uf 16v so I am assuming they will work its just odd that they would be that far off in size. 
 
Edit. The data sheet says 6.3x11 so the product page is off. This should still work though correct? 

 

[Nemo de Monet]

They'll still work. You can (almost) always make physically-smaller parts work; the opposite is usually not the case.

 

[yellowjeep]

They are on the board!
 
Another snag, the trim pots I got are the ones listed on kansei's BOM. If I orient them the way he did in this picture using all three pins won't I be losing the adjust-ability and negating the point of the trim pot?  Do I need to clip the pin furthest from the adjustment screw? Sorry if this is a stupid question, I am way out of my element. These are the trim pots BTW
 

 

[Pseudonyms]

What kind of cans have you guys tested this headphone amp on, and at what impedance?
 
I just picked up a pair of DT 880's @ 250 ohms, and I am curious if this would be a good amp project to work on 

 

[yellowjeep]

Here is where I sit now. I did a lot of reading about pot and figured out how I needed to mount them.  I was expecting my heat sinks to be here today but no joy. The build has gone a lot smoother than I expected. I only misplaced one set of resistors but that got sorted quickly. Now I just need to figure out how to wire the input and output, time to do more reading. Here is  a link to an obnoxiously large version.
 

 
Pseudonyms, I won't be much help as I haven't finished yet but I plan on using it with HD555s (that I am modding), HD280s and my KCS75s (also modded). I built a small 75 ohm  impedance adapter and I will try all of the said cans out with that too. Eventually I am going to build my self some Thunderpants, I have heard those synergize really well with hybrid amps.  

 

[ludoo]

Quote:

What kind of cans have you guys tested this headphone amp on, and at what impedance?
 
I just picked up a pair of DT 880's @ 250 ohms, and I am curious if this would be a good amp project to work on 

I use it with old Yamaha orthodynamic phones (HP-50A and HP-3), 150ohm, and it works beautifully.

 

[kansei]

I used Sennheiser HD600 and they worked very well.

 

[Fred_fred2004]

I've used mine with K702's and 600ohm K240's and it seemed to drive them very well
 
cheers
FRED

 

[Nemo de Monet]

I've used mine extensively with ATH-M30s (65ohms), and to a much lesser extent with RP-HTX7s (40ohms), some severely ancient ATH-5s (??ohms) and even some cheap old Koss UR-19s (32ohms), and have encountered no problems. Sorry, just not cool enough for high-impedance 'phones, I guess.
 
They also drive 8ohm speakers really well, too.

 

[yellowjeep]

Delayed again. I finally got my heatsinks form HK yesterday only to find out that they are a way to small using the photos from this thread as a reference. I was going to just buy some from radio shack but their exceedingly crappy customer service made me leave before buying them. I went ahead and ordered the Wonderco heatsinks talked about early in this thread. I got an email form Wonderco about 10 min after I paid saying that they had already shipped, but it looks like I have another 2 weeks before I will finally get to listen to this amp. 

 

[Nemo de Monet]

Just remember, if it was easy, anyone could do it.

Don't worry, though - it's definitely worth the wait.

 
 
 
 

 

[yellowjeep]

Still waiting on the power supply, Wonderco heat sinks worked beautify. I should have got those in the first place. Does anybody have a couple of random tube they wouldn't mind parting with, maybe something that didn't suit your tastes or just sounded bad. I am mostly interested in experimenting rather than finding a perfect tube at the moment so cheap would be good.  

 

[yellowjeep]

MUSIC!
 
So it works about 95%. I have some weird hum issues that I don't really know where to start with. I have a feeling that a lot of it stems from not being cased yet. The hum is minimized when I touch the power jack, and sometimes when I touch the pot at the same time minimizes it more. I also have the issue that others have described with the "bzzzzthemp" sound when the amp it turned on with headphones plugged in. 
 
I also feel like there might be a channel imbalance but that could be that the soundstage is so much wider than the Fiio E5 I had been using. It could also be that everything has to work has to have some burn in time as well.  I haven't tried it out with anything other that my pair of Koss KCS75s but so far it sounds fantastic, just need to take care of the hum issues.
 
 
Edit Sounds good with HD555 too 

 

[Nemo de Monet]

The hum sounds like a grounding issue, but troubleshooting that can be "fun".  As to imbalance - this can often be due to the tube used, though djusting the trimpots may or may not help. This is where it helps to have multiple tubes to play with - the odds of two tubes being identically imbalanced are relatively slim.
 
What kind of power supply are you using, and what's the output voltage? I've had some horrible problems with noise and hum with non-isolated supplies. I eventually settled on one of those 24V Meanwell SMPSes that are like $15, crammed into a plastic enclosure. Dead silent, which surprised me greatly.
 
I'm not sure where you're at, but if you're really extremely desperate for cheap tubes to play around with in this, I've got and am happy to part with a new 6N23P that's only been used for an hour or so. Really very nice-sounding, just very very microphonic, which is subpar on a desk with two computers, in a house with four people and three cats.

I've also got a 1979-vintage Chinese military 6N11, that was "OEM" with one of those cheap Bravo Audio amps, which I'd be happy to get rid of. Don't really recall anything about it, to be honest. Probably not as good as the Electro-Harmonix 6922s, but probably better than the current-production 6N11s.
 
There are some probably-quite-decent 6DJ8s and subs on eBay right now, quite cheap - including some 6N23Ps at a bargain price that are probably worth pouncing on. Otherwise if you hunt around a bit, you can usually come across NOS JAN 6922s for reasonable amounts, and all the ones I've tried (Phillips/Sylvania) have been extremely good. Ditto the Electro-Harmonix 6922, at least in the cheaper, non-gold-plated version.