carlosfm said:
Waay off topic, arn't we?
Carlos, do you think bypassing with a ceramic here is better than with a film cap? On my dual bench supply I have just thrown away the 1uF tantalums and fitted 47uF electrolytics bypassed with 470nF MKT. Would 100nF ceramic be good here instead?
(And it doesn't take up too much more space, if the bypass cap is under the board.)
Just my .02
I try to avoid ceramics in audio gear as much as possible..*Especialy* in the signal path.. But,PSU bypassing with them might not be so bad..
I dislike tantalums,except as power supply bypassing in digital circuits,they perform well there aslong as you overspec the voltage 2-3x! I've had 16V tantalums explode at 12V...25V caps were okay though (35V would be safer.) I dunno why tantalums are so picky about the voltage thing.
I try to avoid ceramics in audio gear as much as possible..*Especialy* in the signal path.. But,PSU bypassing with them might not be so bad..
I dislike tantalums,except as power supply bypassing in digital circuits,they perform well there aslong as you overspec the voltage 2-3x! I've had 16V tantalums explode at 12V...25V caps were okay though (35V would be safer.) I dunno why tantalums are so picky about the voltage thing.
falcott said:Waay off topic, arn't we?
Yup.
falcott said:
If the space is small I use multi-layer ceramics.
You can do that across the CAdj. cap.
But the cap at the reg's output, in the case of the LM338 (with LM chips) is the most important, as it has influence on the sound of the whole amp.
Here I use Philips 47nf MKT caps (polyester) with excellent results. Feel free to use polypropilene if you want.
SheldonD said:
Yes, I did.
The tests were made with an LM4870 and a weak PSU, made with two 15V/3A trafos, MUR860s and, initially, 3,300uf caps on the PSU, as you can see on the first post of this thread.
The LM4780 has 100uf+100nf on board.
This PSU, under load, produced around 22.5V, and with music playin' LOUD it sagged to around 18~18.5V.
I know, this PSU was just for test purposes, it's weak, and I don't listen to choral music.
Inserting 10,000uf caps the PSU voltage under load decreased some 0,5 volts, to around 22V.
But with LOUD music it very rarely went below 20V.
Better trafos should be used, this was a test.
Anyway, I prefered the sound of the final PSU (with the big caps added and the snubbers) to the initial low capacitance PSU.
Carlosfm (or anyone for the matter of fact),
have you tried different resistor values ? Especially using the methods described in the article(pdf) posted elsewhere in the thread about "Calculating Optimum Snubbers". I think it was from HagTech.com
Also, did you notice any improvement by simply putting a polyprop cap like 220nf-580nf across the filter caps with NO resistor ? or is the resistor required ?
Wondering what are BrianGT's and Planet10's thoughts about incorporating these mods in the kits ?
have you tried different resistor values ? Especially using the methods described in the article(pdf) posted elsewhere in the thread about "Calculating Optimum Snubbers". I think it was from HagTech.com
Also, did you notice any improvement by simply putting a polyprop cap like 220nf-580nf across the filter caps with NO resistor ? or is the resistor required ?
Wondering what are BrianGT's and Planet10's thoughts about incorporating these mods in the kits ?
I'm not Planet10, but I will comment.
This is definitely an interesting thing to try, but clearly I don't see a reason to incorporate that in a kit. The rectifiers board as it is now, works fine in most cases, and if someone wants to experiment with this supply, it can be built as an addition to an existing setup. Besides, the size of the current rectifier board will not allow using all those components on board anyway.
This is a design that Carlos came up with, and was intended for personal use only and not putting together in a form of a kit. It's up to an individual to try it out and possibly implement if the results are to his taste.
I'm pretty sure that digi01 will be putting it in a form of PCB, at some time
This is definitely an interesting thing to try, but clearly I don't see a reason to incorporate that in a kit. The rectifiers board as it is now, works fine in most cases, and if someone wants to experiment with this supply, it can be built as an addition to an existing setup. Besides, the size of the current rectifier board will not allow using all those components on board anyway.
This is a design that Carlos came up with, and was intended for personal use only and not putting together in a form of a kit. It's up to an individual to try it out and possibly implement if the results are to his taste.
I'm pretty sure that digi01 will be putting it in a form of PCB, at some time
Ooops !
Sorry I was thinking Peter Daniel and typed Planet10 - who is actually the moderator if I am not wrong..Anyhoo, you don't have to use Carlos's design exactly. You and team could experiment and come up with something and maybe create another "new and improved" version of the rectifier pcb. If the snubber really has the advantages as claimed to be then why not ?
well, percy, there are limits to how much help people need, and should be given. you can practically buy an entire amp with all those "group buys" and put it together in 10 minutes.. this is not DIY.
Brian impresses me though, not making printcards of everything he comes across like some others..
well, of to try this snubber thingy now then.. wish me luck..
Brian impresses me though, not making printcards of everything he comes across like some others..
well, of to try this snubber thingy now then.. wish me luck..
demogorgon said:
DIY is do it yourself. If you buy the bits and put it together yourself, its DIY. There no such thing as a 10 minute amp. You might be able the solder the components onto one of BrianGT GC PCB in ten minutes but that's the easy part. Assembling all the mechanical components takes a lot longer.
If you look closely you will see the Brian has made a few PCBs - there not all Gainclones though. There is NOTHING wrong with that. He's offerring a great service to many.
demogorgon, let people do what they want, its good there are simple amps to build that take minimal effort, it is good that some like making PCBs and making them available for those that want them.
demogorgon said:
I dont think this is true - Think of your average audio enthusiast, they generally dont know how stuff works (eg. an amp, or electronics), they read magazine reviews and buy from a shop then read the manual and away they go. Compared to that scenario, buying a kit from BrianGT is VERY DIY!!
grege said:
It's not as if I can stop people now is it? people always do as they want for them selves, or should anyways. I'm just the kind of guy who cant keep his opinions to himself.
maxw said:
I dont think this is true - Think of your average audio enthusiast, they generally dont know how stuff works (eg. an amp, or electronics), they read magazine reviews and buy from a shop then read the manual and away they go. Compared to that scenario, buying a kit from BrianGT is VERY DIY!!
Yes, well been there, done that, and i guess i agree with you.
but still, i think true diy is not buing kits, simply because then you haven't done it all yourself.
and thats what i will always think regardless.
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