Hello and thanks.
Greg, in the newest Eagle 3D the solders is added i guess.
It is somewere around the 20th line in your created file.
#declare global_solder = on;
KT: Nope, don't even know if I'm gonna do one
it was just as a inspiration for people
motherone: thanks m8
Edit:
Oh, in the above renderings Carlos name was missing
http://www.ettnet.se/~tobias/diy/lm3886/psu_reg7.jpg
Cheers
Greg, in the newest Eagle 3D the solders is added i guess.
It is somewere around the 20th line in your created file.
#declare global_solder = on;
KT: Nope, don't even know if I'm gonna do one
it was just as a inspiration for people motherone: thanks m8
Edit:
Oh, in the above renderings Carlos name was missing
http://www.ettnet.se/~tobias/diy/lm3886/psu_reg7.jpg
Cheers
carlosfm mentioned that a preamp with a gain of 3x is optimal for his lm3886 designs..
i wish to go about making carlos's regulated lm3886 snubberized design but wish to use Nuuks transistor buffer circuit since its easy to make and allot of people liked it... (however the comments were in the context of briangt's lm3886 amps rather than carlos's latest snub amps)
any comments people want to add? shall i go with buffered circuit or a preamp with a gain ~3x? (i wouldn't say my speakers are hard to drive, so nuuks buffer seems like it would suffice for my needs, but maybe i'm not considering something?)
tobias, could you post the layers individually for your regulated PCB design? (for those that make double sided PCB's at home)
-----------
and for the newcomers reading about the different lm3886 configurations: here is my basic conclusions gleaned from posts by various users.
it seems carlos made a reference that both the regulated and un-regulated sounds about the same. (as in they are both excellent choices... but the regulated holds the voltage pretty much rock steady... and it was implied the unregulated may have some voltage sags, it is not noticeable when one is listening)
nuuk seems to like a +/-12 smps a tad more than the regulated (or maybe it was the unregulated), he attributed to maybe feeling a little ill that day and mentioned that he would follow up... i never found his follow up post, but carlos mentioned that nuuks smps supply may only be suitable for very efficient speakers and i believe in the same post carlos claimed that a reg/unreg power supply would pretty much work with a wide range of speakers types. (especially his hard to drive epos speakers)
my_ref: seems like a good amp as well, comes in a kit. i do not believe anyone did an A/B comparison between the latest iteration of a snubbed lm3886 and the latest my_Ref amp and discussions regarding the two get rather heated.
after reading many posts my memory is blurred, so some things maybe innaccurate.
i wish to go about making carlos's regulated lm3886 snubberized design but wish to use Nuuks transistor buffer circuit since its easy to make and allot of people liked it... (however the comments were in the context of briangt's lm3886 amps rather than carlos's latest snub amps)
any comments people want to add? shall i go with buffered circuit or a preamp with a gain ~3x? (i wouldn't say my speakers are hard to drive, so nuuks buffer seems like it would suffice for my needs, but maybe i'm not considering something?)
tobias, could you post the layers individually for your regulated PCB design? (for those that make double sided PCB's at home)
-----------
and for the newcomers reading about the different lm3886 configurations: here is my basic conclusions gleaned from posts by various users.
it seems carlos made a reference that both the regulated and un-regulated sounds about the same. (as in they are both excellent choices... but the regulated holds the voltage pretty much rock steady... and it was implied the unregulated may have some voltage sags, it is not noticeable when one is listening)
nuuk seems to like a +/-12 smps a tad more than the regulated (or maybe it was the unregulated), he attributed to maybe feeling a little ill that day and mentioned that he would follow up... i never found his follow up post, but carlos mentioned that nuuks smps supply may only be suitable for very efficient speakers and i believe in the same post carlos claimed that a reg/unreg power supply would pretty much work with a wide range of speakers types. (especially his hard to drive epos speakers)
my_ref: seems like a good amp as well, comes in a kit. i do not believe anyone did an A/B comparison between the latest iteration of a snubbed lm3886 and the latest my_Ref amp and discussions regarding the two get rather heated.
after reading many posts my memory is blurred, so some things maybe innaccurate.
Yes, I do prefer the sound of the SMPS with the GC's but obviously there is nowhere near as much power as when using a regulated supply with beefy transformers. So that option is really only for those with efficient or easy to drive speakers!
I've been so busy with the class-T amps that I haven't had time to go back and try the GC's again (but hope to soon)!
frdchang said:
Hi frdchang,
Let me explain: my speakers are 86~87db.
I use 20x gain on ther power amp and 3x gain on my AD815 pre.
If your speakers are much more sensitive (90db and above) you can go with a buffer, and 22x gain on the amp.
What I pointed out is that, if needed, the extra gain must be used on the pre, because the LM chips sound better to me at lower (normal) gains (18~22x).
Hi Carlos,
I built your NI3886 and also the AD815. This system replaces just my old basic inverted GC. A little explanation: The amp drives two wonderful Hedlund horns with Lowther (more than 97db) . The first moment I connected the new amp (of course after testing it with a pair of crappy drivers) I realized I had lots of power because I only use the first half of the pot. The pot is not the definitive yet because I had not at home any decent one near the 20k log you have in schematic, now I have a 100k stereo linear faked with a 2k5 res. I wanted to add a buffer, but must confess I was tempted reading your impressions on the AD815 pre (and from others as well) and built it too.
What impresses me most is the absolute powerfull but ultra controled bass and the wide and deep sound stage. All the advantages of the GC are also present. Great amp....Thanks for sharing!!!
Now the newbie's [sorry] question(s)
:
I have the amps in two monoblocks with the unregulated PSU for each channel, and I'd like to try regulated. The toroid trafos are 2x24 v ... your advice is for 2x28-30...
can I use those 2x24 I have without modding the PSU circuit?
The amp was dead quiet before connecting it to the pre (via the variable CD output), but with the pre I have some hiss. I have to be very close to the speakers to notice it but it exists. Is this for normal? Is the AD815 oscillating... or maybe I have to try other interconnects?
What about if I dont use the DC offset correction on the pre? is it dangerous for my speakers? btw... do you use speaker protection?
Carlos, gracias justo desde la parte opuesta de Iberia!!!!! (Valencia-Spain)
Kind regards!
JL
I built your NI3886 and also the AD815. This system replaces just my old basic inverted GC. A little explanation: The amp drives two wonderful Hedlund horns with Lowther (more than 97db)
. The first moment I connected the new amp (of course after testing it with a pair of crappy drivers) I realized I had lots of power because I only use the first half of the pot. The pot is not the definitive yet because I had not at home any decent one near the 20k log you have in schematic, now I have a 100k stereo linear faked with a 2k5 res. I wanted to add a buffer, but must confess I was tempted reading your impressions on the AD815 pre (and from others as well) and built it too.What impresses me most is the absolute powerfull but ultra controled bass and the wide and deep sound stage. All the advantages of the GC are also present. Great amp....Thanks for sharing!!!
Now the newbie's [sorry] question(s)
:I have the amps in two monoblocks with the unregulated PSU for each channel, and I'd like to try regulated. The toroid trafos are 2x24 v ... your advice is for 2x28-30...
can I use those 2x24 I have without modding the PSU circuit?
The amp was dead quiet before connecting it to the pre (via the variable CD output), but with the pre I have some hiss. I have to be very close to the speakers to notice it but it exists. Is this for normal? Is the AD815 oscillating... or maybe I have to try other interconnects?
What about if I dont use the DC offset correction on the pre? is it dangerous for my speakers? btw... do you use speaker protection?
Carlos, gracias justo desde la parte opuesta de Iberia!!!!! (Valencia-Spain)
Kind regards!
JL
Attachments
Hola Juan!
Oh yes, that's it, thanks for reporting.
I would recommend you to change that pot for 10 or 20K.
You may also need to arrange the gounds on the pre, but start with the pot.
With that trafo you would regulate for around +/-24V, but why bother if you have such sensitive speakers and are happy with the sound?
No, I don't use speaker protection.
If you followed my thread (it seems you did), my main goal was to use the AD815 without any input or output stage.
I did use that dc-offset correction circuit to minimize it to much lower levels (It is volume-pot position dependant), and also (very important) to minimize the input dc-offset, that can kill the volume pot.
I don't recommend you to disable that circuit.
What I do recommend is: or you use dc-coupling caps to deal with the remaining DC on the output of the pre, or on the input of the power amps. Not both.
Saludos desde Lisboa y buenas audiciones!
PS: congratulations for the guts to build all that!
JuanLu said:
Oh yes, that's it, thanks for reporting.
JuanLu said:
I would recommend you to change that pot for 10 or 20K.
You may also need to arrange the gounds on the pre, but start with the pot.
JuanLu said:
With that trafo you would regulate for around +/-24V, but why bother if you have such sensitive speakers and are happy with the sound?
JuanLu said:
No, I don't use speaker protection.
If you followed my thread (it seems you did), my main goal was to use the AD815 without any input or output stage.
I did use that dc-offset correction circuit to minimize it to much lower levels (It is volume-pot position dependant), and also (very important) to minimize the input dc-offset, that can kill the volume pot.
I don't recommend you to disable that circuit.
What I do recommend is: or you use dc-coupling caps to deal with the remaining DC on the output of the pre, or on the input of the power amps. Not both.
JuanLu said:Carlos, gracias justo desde la parte opuesta de Iberia!!!!! (Valencia-Spain)
Saludos desde Lisboa y buenas audiciones!
PS: congratulations for the guts to build all that!
mkey.. it took like ten days for my internet to come back
http://www.ettnet.se/~tobias/diy/lm3886/psu_chipamp_lm388.zip
Cheers
http://www.ettnet.se/~tobias/diy/lm3886/psu_chipamp_lm388.zip
Cheers
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