Banned
Joined 2002
http://www.atiresearch-anodized.com/ATI-679M.html
These guys rock. I have one other there other style cases and they are beautiful.
J'
These guys rock. I have one other there other style cases and they are beautiful.
J'
Power Transformer Help
Hi,
I'm from Genoa (Italy).
I've buy the wonderful BrianGT's board .
I've seen in a Italian Audio Forum, an used Bartolucci Power Transformer (2 secondary X 0-15V@3.5A).
Anyone help me if that transformer is suitable for mini-A ?
If no, what are the rigth choice ?
Another Q: I've seen that in the mini-A schematic there are a diode near any mosfet (in parallel). What diode is rigth ?
Any suggestion is welcome.
Ciao.
Luca
Hi,
I'm from Genoa (Italy).
I've buy the wonderful BrianGT's board .
I've seen in a Italian Audio Forum, an used Bartolucci Power Transformer (2 secondary X 0-15V@3.5A).
Anyone help me if that transformer is suitable for mini-A ?
If no, what are the rigth choice ?
Another Q: I've seen that in the mini-A schematic there are a diode near any mosfet (in parallel). What diode is rigth ?
Any suggestion is welcome.
Ciao.
Luca
woho, i built a mini-a
My first diy-audio project
Ill try to answer your questions luca. The transformer should work, i run my mini-a at +-15V rails, it draws 0.9A per rail.
The schematic here should be the one you're looking at http://surl.se/azog in this one all the zener diodes should be 9.1V, i think the ones i used were rated up to 1A, pretty standard non SMD units (unfortunately, but they fit and they work so...)
regards,
Pontus
An externally hosted image should be here but it was not working when we last tested it.
My first diy-audio project
Ill try to answer your questions luca. The transformer should work, i run my mini-a at +-15V rails, it draws 0.9A per rail.
The schematic here should be the one you're looking at http://surl.se/azog in this one all the zener diodes should be 9.1V, i think the ones i used were rated up to 1A, pretty standard non SMD units (unfortunately, but they fit and they work so...)
regards,
Pontus
Banned
Joined 2002
It's a bit soon to say much about the sound since I've only finished one box to make it easily portable from the lab to my apartment. Once I've fitted some proper connectors on both channels I'll give it a go with proper speakers (amphion argon2) and compare it to my audion silvernight.
But as a first impression it is quite nice, very silent and good dynamics considering the boxless speaker.
But as a first impression it is quite nice, very silent and good dynamics considering the boxless speaker.
Banned
Joined 2002
Hi Pontus,
I apologize for the delay in replay but I'm back in Genoa today from season holydays.
Thank you very much for your post.
Have you used the BrianGT Mains Board ?
I've seen in the photo of your mini-A that you use filter choke (Mundorf ?). Any suggestion (value, type etc.)
Ciao.
Luca
I apologize for the delay in replay but I'm back in Genoa today from season holydays.
Thank you very much for your post.
Have you used the BrianGT Mains Board ?
I've seen in the photo of your mini-A that you use filter choke (Mundorf ?). Any suggestion (value, type etc.)
Ciao.
Luca
No worries,
I haven't used the brianGT mains board, but tbh it does seem alot more compact and thought through, it may be a good idea to keep some space around the rectifiers for heatsinks.
the choke filter is basically C-L-C with a 2.2 mH air coil. I don't see any reason why another type wouldn't be applicable, just keep DC resistance low to not burn too much power on it. I believe mine are around 1ohm and they do get warm but not too hot.
I've acctually nearly finished one of the monoblocks, soldered terminals and tried it together with my audion silver night 300b SET amp, wasn't bad at all
Will try to get some pictures up soon, with the plexi front cover, hopefully both channels next to each other.
I haven't used the brianGT mains board, but tbh it does seem alot more compact and thought through, it may be a good idea to keep some space around the rectifiers for heatsinks.
the choke filter is basically C-L-C with a 2.2 mH air coil. I don't see any reason why another type wouldn't be applicable, just keep DC resistance low to not burn too much power on it. I believe mine are around 1ohm and they do get warm but not too hot.
I've acctually nearly finished one of the monoblocks, soldered terminals and tried it together with my audion silver night 300b SET amp, wasn't bad at all
Will try to get some pictures up soon, with the plexi front cover, hopefully both channels next to each other.
An externally hosted image should be here but it was not working when we last tested it.
It's alive in stereo! Been playing for the last 8 hours, I figure ill leave it on for a good while. And yesterday, once i got it working again after sandblasting the sidepanels and mounting connectors etc, despite me beeing really wound up on redbull (and it beeing 3-4 in the morning) by god Ane Brun's voice sounded so sweet! *insert random clichés about hifistuff here*. It will be alot of fun comparing it to the other amp, i've just got to come up with a good way of testing it, perhaps building that preamplifier with RIAA for MM, MC and 2 other inputs + 2 pre outs... As for now i have now way off adjusting volume for the "mini A" other than my soundcard, and its not really fair to the rest of the equipment.
Banned
Joined 2002
Fyhr said:
I am so amazed these days how many things get turned on for the first time at 2-5 am
my first set of mini a's were alive at 3:15 am and played all night, however i went to bed at 4 and let them run. You will find that they sound alot better after 1 week of burn in and when turned off then on again waiting at least 45 min to 1 hour they are perfect temperature and sound their best.Jase
Hi all,
I've just finished building 2x stereo Mini-A's, which has been my first more serious project.
Everything went OK and they work fine.
DC offset is 39mv and 59mv in each channel on one amp, and 35mv and 89mv in the other. Not perfect but acceptable (I assume), and I may in the future look towards doing better matching.... There is also some very low level hum, audible about 5 inches from a 90db/w/m speaker (the same on each amp, regardless of the offset measurement), which seems fine but I may try to improve.
I'll post some pix when I get the chance. I haven't had a chance to get into critical listening yet, but so far I like what I hear. A lot. even using an iPod direct to single ended input, it is an improvement over my Tripath 2020 (not surprising -- initially impressive with brightness and detail, long-term its too in-your-face) and my point-to-point gainclone. The Aleph design seems to have a way of commanding, gripping the speakers. I can now see what the fuss is about - though no point telling this to the converted.
Just a quick question though -- and a bit of a noob one, I'm still stuck on some little things...
Does the source preceding the Mini-A need to have coupling caps?
I want to use this balanced signal transmitter to output a balanced signal to the Mini-A, which does not have output coupling caps.
Also
if a balanced out need to have coupling caps, do the caps need to be on both the hot and cold signal line (XLR pins 2+3)?
thx a lot in advance for any tips and sorry for the bother.
I've just finished building 2x stereo Mini-A's, which has been my first more serious project.
Everything went OK and they work fine.
DC offset is 39mv and 59mv in each channel on one amp, and 35mv and 89mv in the other. Not perfect but acceptable (I assume), and I may in the future look towards doing better matching....
There is also some very low level hum, audible about 5 inches from a 90db/w/m speaker (the same on each amp, regardless of the offset measurement), which seems fine but I may try to improve.I'll post some pix when I get the chance. I haven't had a chance to get into critical listening yet, but so far I like what I hear. A lot. even using an iPod direct to single ended input, it is an improvement over my Tripath 2020 (not surprising -- initially impressive with brightness and detail, long-term its too in-your-face) and my point-to-point gainclone. The Aleph design seems to have a way of commanding, gripping the speakers. I can now see what the fuss is about - though no point telling this to the converted.
Just a quick question though -- and a bit of a noob one, I'm still stuck on some little things...
Does the source preceding the Mini-A need to have coupling caps?
I want to use this balanced signal transmitter to output a balanced signal to the Mini-A, which does not have output coupling caps.
Also
if a balanced out need to have coupling caps, do the caps need to be on both the hot and cold signal line (XLR pins 2+3)?thx a lot in advance for any tips and sorry for the bother.
Greetings everyone...
Just a quick question... I intend on using a pair of these mini-Alephs to act as headphone amplifiers for my AKG K-271 Studio cans.
The "key" question here is which resistor(s) would need adjusting to drop the bias down to a more sensible (say) 500mA, from the near-2A in the untouched form of the mini-A?
I admit, i don't master much in the way of understanding the exact inner workings of SS amps, but i know enough to build stuff
Just a quick question... I intend on using a pair of these mini-Alephs to act as headphone amplifiers for my AKG K-271 Studio cans.
The "key" question here is which resistor(s) would need adjusting to drop the bias down to a more sensible (say) 500mA, from the near-2A in the untouched form of the mini-A?
I admit, i don't master much in the way of understanding the exact inner workings of SS amps, but i know enough to build stuff
Khron said:Greetings everyone...
Just a quick question... I intend on using a pair of these mini-Alephs to act as headphone amplifiers for my AKG K-271 Studio cans.
The "key" question here is which resistor(s) would need adjusting to drop the bias down to a more sensible (say) 500mA, from the near-2A in the untouched form of the mini-A?
I admit, i don't master much in the way of understanding the exact inner workings of SS amps, but i know enough to build stuff
just be patient ........
Banned
Joined 2002
Khron said:Greetings everyone...
Just a quick question... I intend on using a pair of these mini-Alephs to act as headphone amplifiers for my AKG K-271 Studio cans.
The "key" question here is which resistor(s) would need adjusting to drop the bias down to a more sensible (say) 500mA, from the near-2A in the untouched form of the mini-A?
I admit, i don't master much in the way of understanding the exact inner workings of SS amps, but i know enough to build stuff
Why would you spend and build a Mini A for a headphone amp, that does not make sense to me.