Finally got time to build my first one. It's configured bone stock. Worked first try.
My first listen was using the headphone out jack from my laptop, into an old pair of
Senn. HD 497's. Sounded good, but not great.
Then I decided to see what it would do with good stuff, so used my Yggy DAC as
source, into a pair of mod'ed HD800's.
What I can say is without reservation is that this little hand warming wonder
definitely scales with better source and 'phones, because the second configuration
is sounding like a giant killer. Very dynamic and resolving, and it's not even broken
in yet.
If this is how good it sounds stock, I can't wait to hear it with upgraded components.
I'm going to build my second one stock also, but the two I have coming are going to
get the VIP treatment. I'm planning on building one optimized for low-impedance cans,
and the other for high-impedance.
xrk971, this design is proof positive that one doesn't have to spend mega bucks to get
excellent (trans)portable sound. Outstanding job my friend.
My first listen was using the headphone out jack from my laptop, into an old pair of
Senn. HD 497's. Sounded good, but not great.
Then I decided to see what it would do with good stuff, so used my Yggy DAC as
source, into a pair of mod'ed HD800's.
What I can say is without reservation is that this little hand warming wonder
definitely scales with better source and 'phones, because the second configuration
is sounding like a giant killer. Very dynamic and resolving, and it's not even broken
in yet.
If this is how good it sounds stock, I can't wait to hear it with upgraded components.
I'm going to build my second one stock also, but the two I have coming are going to
get the VIP treatment. I'm planning on building one optimized for low-impedance cans,
and the other for high-impedance.
xrk971, this design is proof positive that one doesn't have to spend mega bucks to get
excellent (trans)portable sound. Outstanding job my friend.
Hi Funch,
Thank you for the kind words. Did you put yours in a case yet or sitting bare? Photos? For your "stock" configuration, are you using the large 2200uF 16v rail caps? Those make a difference in soundstage and imaging vs the 100uF that I originally spec'd.
I have dozens of headphone amps, some very nice ones, but I keep finding myself using this simple ol' little amp again and again. I would love to get a different pair of headphones to see what the effect of phones might be.
So far, I know of people using it with the following, and all have loved the sound.
- HD600
- LCD-2 (70ohm)
- DT880-250
- DT770-250
- MDRV6
- HD800
- HD598-50
Did I miss any?
Thank you for the kind words. Did you put yours in a case yet or sitting bare? Photos? For your "stock" configuration, are you using the large 2200uF 16v rail caps? Those make a difference in soundstage and imaging vs the 100uF that I originally spec'd.
I have dozens of headphone amps, some very nice ones, but I keep finding myself using this simple ol' little amp again and again. I would love to get a different pair of headphones to see what the effect of phones might be.
So far, I know of people using it with the following, and all have loved the sound.
- HD600
- LCD-2 (70ohm)
- DT880-250
- DT770-250
- MDRV6
- HD800
- HD598-50
Did I miss any?
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I only have the stock parts on hand atm. I'll be ordering up some better parts for my
'boutique' builds soon. I'm also going to order some of those rechargeable batteries.
Just using alkies now. I do have some RFS 100uF/25V cap's that I can try on the
outputs. Maybe I'll do that. If I can turn this thing off long enough.
Not 'tinned up' yet. Just sitting on my desk. I'm still trying to find the post with the
panel template that was posted a while back.
'boutique' builds soon. I'm also going to order some of those rechargeable batteries.
Just using alkies now. I do have some RFS 100uF/25V cap's that I can try on the
outputs. Maybe I'll do that. If I can turn this thing off long enough.
Not 'tinned up' yet. Just sitting on my desk. I'm still trying to find the post with the
panel template that was posted a while back.
It's on Post #120. I should link it from Post #1.
http://www.diyaudio.com/forums/atta...ass-headamp-gb-pocket-class-hole-template.pdf
Edit: I just checked, it actually is linked from Post #1 at the very bottom.
Use a paper hole punch for cutting the holes. Enlarge the volume pot with a hand reamer. Don't use drills on the large holes - a total mess and hard to make look good. The LED one is ok to drill.
http://www.diyaudio.com/forums/atta...ass-headamp-gb-pocket-class-hole-template.pdf
Edit: I just checked, it actually is linked from Post #1 at the very bottom.
Use a paper hole punch for cutting the holes. Enlarge the volume pot with a hand reamer. Don't use drills on the large holes - a total mess and hard to make look good. The LED one is ok to drill.
Thanks. Just after I posted, I found the link on page one.
Good advice for prep'ing the tin. This isn't my first mint tin dance, and I've made all the
mistakes already. Speedy drills and paper thin aluminum are not a good combo for sure. I use a pin vise to drill the pilot holes, then work my way up.
I also just installed the RFS output cap's, and am already liking what I hear. Smoother,
without loosing the detail. Tames the HD800's nicely.
Good advice for prep'ing the tin. This isn't my first mint tin dance, and I've made all the
mistakes already. Speedy drills and paper thin aluminum are not a good combo for sure. I use a pin vise to drill the pilot holes, then work my way up.
I also just installed the RFS output cap's, and am already liking what I hear. Smoother,
without loosing the detail. Tames the HD800's nicely.
I probably should have let it burn in more to give a proper impression of the OSCONs,
and I am using HD800s.
Already, I'm going to recommend using the Elna's for the output. As a bonus, it looks
like the 100uF/25V that I have will fit. They do come in 16V as well, and are shorter.
I just happened to have the 25V on hand.
and I am using HD800s.
Already, I'm going to recommend using the Elna's for the output. As a bonus, it looks
like the 100uF/25V that I have will fit. They do come in 16V as well, and are shorter.
I just happened to have the 25V on hand.
I did some battery life experiments with my pocket class a stock build. Here's the results:
9.3.2017 50 min of listening
13.3.2017 40 min of listening
14.3.2017 1 h 43 min of listening
15.3.2017 32 min of listening and the amp started switching on/off
In total 3 h 45 min listening time with fully charged EBL 600 mAh re-chargeable batteries. Voltage was 14 V when the amp started going on/off. My bias currents are 53,2 mA in left channel and 48,5 mA in right channel @ 16 VDC feed.
By the way, I'm planning to build a desktop version of this sweet little amp with 16 VDC power supply feed. I'm going to use matched FETs and heftier rail caps delivered by X. What would be a recommended bias current value for desktop use, so it would be good for lower impedance cans too? Do I need additional cooling for the fets (aluminum bar/connection to chassis?)?
9.3.2017 50 min of listening
13.3.2017 40 min of listening
14.3.2017 1 h 43 min of listening
15.3.2017 32 min of listening and the amp started switching on/off
In total 3 h 45 min listening time with fully charged EBL 600 mAh re-chargeable batteries. Voltage was 14 V when the amp started going on/off. My bias currents are 53,2 mA in left channel and 48,5 mA in right channel @ 16 VDC feed.
By the way, I'm planning to build a desktop version of this sweet little amp with 16 VDC power supply feed. I'm going to use matched FETs and heftier rail caps delivered by X. What would be a recommended bias current value for desktop use, so it would be good for lower impedance cans too? Do I need additional cooling for the fets (aluminum bar/connection to chassis?)?
I'm in the process of casing mine up, and discovered a potential problem. The front
circuit board lead for C2A on mine is contacting the tin. The same with the front LED
pin. I'm going to use a small washer (the stock one isn't thick enough) on the volume
pot to space the board back away from the tin more.
circuit board lead for C2A on mine is contacting the tin. The same with the front LED
pin. I'm going to use a small washer (the stock one isn't thick enough) on the volume
pot to space the board back away from the tin more.
It turns out that standard black vinyl electrical tape is the exact height of the tin wall. I run a strip of it around where the board is to prevent any potential accidents. But as you say those are GND leads anyway. The tape also acts as heat absorber on wall to help reduce internal temperature on the board.
My Silmic output cap's are tall enough that the leads in question actually touch
right at the roll at the top of the sides. These cap's are absolutely at the limit
of what will fit. They rest on the bottom of the tin. To be safe, I've covered the
bare tops with black tape.
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Funch,
Can you please show a photo? I don't understand how leads from the through hole side would touch the tin on the SMT side? There's 7mm clearance between the board and the lid. The output caps are not anywhere near the rolled top edges. Or are you taking about unit caps? Anyhow a photo would be great.
Thanks.
Can you please show a photo? I don't understand how leads from the through hole side would touch the tin on the SMT side? There's 7mm clearance between the board and the lid. The output caps are not anywhere near the rolled top edges. Or are you taking about unit caps? Anyhow a photo would be great.
Thanks.
Welcome on board the Pocket Class A train! Be prepared to be transported to great sound.
PM replied.