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Power supply
I will be running two transformers with two rectifier bridges for each transformer. I cannot comment on the GC driving different speakers as I only drive BOSE and now my main speakers are IMAGE LOUDSPEAKERS. These are not known to people outside New Zealand. www.imageloudspeakers.co.nz if you want to have a look. Mine are the 416's. But all i can say is when i built a more comprehensive power supply for my second amp using the same chips(Lm3875), ........wow what a difference. especially in the bass, totally amzing...... So it will ineresting to see how this LM4780 sounds compared to the 3875.
Transformers are 300va 25-0-25
Rectifier bridges are 35A 400V
I will be running two transformers with two rectifier bridges for each transformer. I cannot comment on the GC driving different speakers as I only drive BOSE and now my main speakers are IMAGE LOUDSPEAKERS. These are not known to people outside New Zealand. www.imageloudspeakers.co.nz if you want to have a look. Mine are the 416's. But all i can say is when i built a more comprehensive power supply for my second amp using the same chips(Lm3875), ........wow what a difference. especially in the bass, totally amzing...... So it will ineresting to see how this LM4780 sounds compared to the 3875.
Transformers are 300va 25-0-25
Rectifier bridges are 35A 400V
Peter Daniel said:
My speakers are also ProAc and sound really great with the LM3875 premium kit from Peter. I use the kit with a passive pre (Alps blu pot). The kit is feeded with signals from a Pioneer PDS-06 cd player and Peters DAC. I don't miss the bass or something else. Very good, indeed
jan ove
I've been listening to my BrianGT LM3875 gainclone (both classic and snubberized 10 mF PS options) for a few days and I must say I am suprised with the quality of sound. I didn't expect much but I still built the amp with good quality materials and put some thought into amp structure also.
My speakers (Zu Druid MK4) are almos perfect match for LM3875. Efficiency is 97 dB and impedance stays above 8 ohms at all frequencys. System synergy is very important.
The sound is not boring clinical hifi. It's much much better. It can really play music. I think it's right up there with the best matched hybrid and all tube amps which I have heard with Druids.
I also have Jordan JX92S MLTL speakers. I'll have to try those too with the GC. They also should perform really well together.
I use the GC with 10 kohm DACT CT2 and intend to build a tube preamp. And I will also order a second pair of LM3875 and start experimenting.
I'm not sure if these links work:
http://koti.kontu.la/jsalonen/cgi/board_att.pl?action=4803471143484350
http://koti.kontu.la/jsalonen/cgi/board_att.pl?action=9979971143657073
My speakers (Zu Druid MK4) are almos perfect match for LM3875. Efficiency is 97 dB and impedance stays above 8 ohms at all frequencys. System synergy is very important.
The sound is not boring clinical hifi. It's much much better. It can really play music. I think it's right up there with the best matched hybrid and all tube amps which I have heard with Druids.
I also have Jordan JX92S MLTL speakers. I'll have to try those too with the GC. They also should perform really well together.
I use the GC with 10 kohm DACT CT2 and intend to build a tube preamp. And I will also order a second pair of LM3875 and start experimenting.
I'm not sure if these links work:
http://koti.kontu.la/jsalonen/cgi/board_att.pl?action=4803471143484350
http://koti.kontu.la/jsalonen/cgi/board_att.pl?action=9979971143657073
Why don't you lower the capacitance near the chip to 1000uF and build a proper PSU ?!?
You need a large capacitace PSU, this way you will get a punchy and deep bass
But remember, large capacitance caps are rubbish in high frequencies
I use a downgrade of capacitance because of this " bad caracteristic".
You can start with some of 10.000uF(or less F) in parallel and then go down to 6800uF .... till 680uF! ( lots of them in parallel ).
This will give you a punchy and deep bass but also very good treble
PS: large capacitance also reduces da voltage drop in the PSU
You need a large capacitace PSU, this way you will get a punchy and deep bass
But remember, large capacitance caps are rubbish in high frequencies
I use a downgrade of capacitance because of this " bad caracteristic".
You can start with some of 10.000uF(or less F) in parallel and then go down to 6800uF .... till 680uF! ( lots of them in parallel ).
This will give you a punchy and deep bass but also very good treble
PS: large capacitance also reduces da voltage drop in the PSU
XELB said:Why don't you lower the capacitance near the chip to 1000uF and build a proper PSU ?!?
You need a large capacitace PSU, this way you will get a punchy and deep bass
But remember, large capacitance caps are rubbish in high frequencies
I use a downgrade of capacitance because of this " bad caracteristic".
You can start with some of 10.000uF(or less F) in parallel and then go down to 6800uF .... till 680uF! ( lots of them in parallel ).
This will give you a punchy and deep bass but also very good treble
PS: large capacitance also reduces da voltage drop in the PSU
http://www.diyaudio.com/forums/showthread.php?postid=882074#post882074
karma said:
I was going to use MDF and line it with foil to shield it. Any other considerations?
A PCB keeps my signal path short, anything else? Quality of wires? Length?
I want to keep it small so I was going to put a large heatsink between the transformer and the chips (because I gather the transformer should either be distanced or shielded from the chips to avoid some kind of noise?) Anything else to consider?
That's what I'm after!
no lifeless chipamps here
Upupa Epops said:Guys, what did you using before, when you are in trance with this quasicomplementary circuit, primarily designed for commercial electronic ? Do you really mean, that it is " sound end station " ?
For your information: Before the LM3875 I used a heavily modified Dynaco ST70 and PAS3 [also commercial electronics
] The main reason for switching amps was not whether or not they are commercial , but how they communicate the artistic intents and musical emotions captured on the LP or CD. So far the LM3875 kit does that better than other amps that I can afford. Of course, this is not "sound end station". If you have made some kits or constructions that outperform Peters kits, I will be happy to try them out. best wishes
Jan Ove
mdf is fine you can always use solid wood when its finished. try making a two piece chipamp amplifier and psu
that way you dont need shielding. to much shielding really does change the sound and not in a good way. if you make it one piece
a simple piece of grounded copper or aluminum between the tranformer and the chips is fine.
this amp is next in line for a new case
that way you dont need shielding. to much shielding really does change the sound and not in a good way. if you make it one piece
a simple piece of grounded copper or aluminum between the tranformer and the chips is fine.
this amp is next in line for a new case
Attachments
Thanks Karma. I will see what I can do. I might post some pics before I start drilling any holes.
BTW - Loving the retro gauges on that amp!
Upupa Epops, I'm new to this DIY stuff. What do you use?
BTW - Loving the retro gauges on that amp!
Upupa Epops said:Jan, Dynaco is old crap and effort for upgrade is useless... Pass 3 - look at distortion and you will see...From this look are chips amps more better...But they are quasicomplements and it give limits in quality. Certainly they are easy to use, but factual quality is little bit far...
Upupa Epops, I'm new to this DIY stuff. What do you use?
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