Pedja said:
I'm not going to test two pairs of regs, at least soon, if someone wants to compare single or double pair, it would be nice to know.
t. said:Well I just had to try taking the regulator circuit out of my amp, I replaced the smaller caps on the LM3875 pins with 1000uf and let it run in for a couple of hours.
So now I have normal GC but with buffer,
first impressions areeverything sounds thin, the bass now sounds loose but worst of all those beautiful mids are gone.
The amp is back to normal and is making music again, sorry I just had to make sure
😀 😀 😀 😀
Thanks for all that work, Leon.😎
Well you know how it is😉 I had to try it,
I'm going to take the bits to work tomorrow and build your buffer stage in my lunch break, just intersted to see how it differs to Pedja's
BTW I had a few probs with my regs to start with, nothing popped but the voltage on the output pin (both rails)
only dropped by 1 volt no matter what value resistor I used on the adjust pin.
In the end I fitted my spare pair of regs and they worked fine😕
Better go to bed now, its getting late, work in a few hours
I'm going to take the bits to work tomorrow and build your buffer stage in my lunch break, just intersted to see how it differs to Pedja's
BTW I had a few probs with my regs to start with, nothing popped but the voltage on the output pin (both rails)
only dropped by 1 volt no matter what value resistor I used on the adjust pin.
In the end I fitted my spare pair of regs and they worked fine😕
Better go to bed now, its getting late, work in a few hours
t. said:
That happens if you make a mistake and mount the diode from Adj to Vout in the wrong direction.
t. said:
For better or for worse, I would like to know too, I didn't test Pedja's Jfet buffer, but coming from him, it must be good.😉
I believe in buffers here.
t. said:Well I just had to try taking the regulator circuit out of my amp, I replaced the smaller caps on the LM3875 pins with 1000uf and let it run in for a couple of hours.
So now I have normal GC but with buffer,
first impressions are
The amp is back to normal and is making music again, sorry I just had to make sure
That is interesting. Here's my friend's impression when comparing AC powered, minimized GC (Brian's premium kit with Panasonic caps) to Carlos' circuit (both in a same chassis):
The sound of the new amp is washed out, bass lacking definition, not enough liveliness and sparkle, reduced soundstage (rather flat).
There was no preamp used at all, signal from CDP fed directly to the pots mounted on RCA inputs.
While listening today in my house, I noticed that the sound improved since I tried it last time and mids were indeed somewhat softer and maybe even more pleasing than my Patek, but bass was definitely worse and resolution was lacking.
Nevertheless, this amp is not bad at all, and I've built GCs that sounded much worse. Good work Carlos, with additional tweaks you might even get there😉
Attachments
i was only sort-of joking, carlos 😉
had a great party over here with a couple of portugese friends of mine anyways.
The really good news is that i fanally have a couple of weeks off, so i'm ready to start building my regulated psu. Or actually, a completely new amp. 😉
had a great party over here with a couple of portugese friends of mine anyways.
The really good news is that i fanally have a couple of weeks off, so i'm ready to start building my regulated psu. Or actually, a completely new amp. 😉
corey greenberg knows......and so do i.
carlos, why don't you try bi-amping......your speakers will love it.....
carlosfm said:Nuuk, let's see if we find out what's happening with your regs...
You have 8 diodes (2 bridges) and 2 pairs of regs, right?
That is, the two pairs of regs share the same diodes, right?
Now look at the schematic.
You join the output of one reg with the ground of the other one to make the ground, right?
What happens if on the other board you pick the other two lines to do this?
Nick, it seems important thing was left unsaid explicitly and since you have explained your setup (I think you did, but it is not easy to go back through the thread to check it), I do not know how that passed by… Anyway, with such supply the whole set up before the regulators (windings/rectifier) must be floating. In fact, positive regulators yet can be driven from the same source, but negative can not. Generally: one winding and one rectifier for each regulator.
I just landed a good project today, which will leave me with about $400 that I can safely spend on my system for various things in a few weeks.
I wanna build this so bad, just to see what I can do with it.
I wanna build this so bad, just to see what I can do with it.
That's the perfect solution, a regulated IGC on the tweeters and minimized GC on the mids. 😉 Everyone's happy. 😎
Or is it the other way round.
grege said:
That's the perfect solution, a regulated IGC on the tweeters and minimized GC on the mids. 😉 Everyone's happy. 😎
Or is it the other way round.
Since the bass improves with regulation I'd say the second option...😉
Cheers
Andrea
This listening experience is at total odds to what I hear when using a regulated PSU. I don't understand it. Leo has just reconfirmed to himself of the differences as I did a few weeks ago. I have sat with Leo before and trust his opinion, his findings are the same as mine and of others who found the same when using a regulated PSU. I hope to get together with Leo and some other 'ears' I trust in the near future to compare further. BTW my reg GC is NI and not buffered yet the superiority of a regulated supply is still obvious. And please can we keep the snide remarks to ourselves.
tbla said:carlos, why don't you try bi-amping......your speakers will love it.....
I also suspect that, but I don't see much time to do that soon.
I'm goin' on holidays soon, and just today I received an LC-Audio XO3 (thanks Lars😉 ), I'm flooded with work...
Not to talk about opening my Epos speakers.🙂
I'll just go over my set up again to avoid any confusion.
I am using one 25 VAC 300 VA transformer which feeds two rectifier bridges (MUR860's). This unit supplies two rails of 36 volts and is connected to both the regulator modules in my amp as shown in the circuit diagram.
The only differences to that circuit are that I have 0.47 uF caps from the input pins of the regulators to ground as shown by C5 and C6 and I have used the extra protection diodes.
An externally hosted image should be here but it was not working when we last tested it.
If I break the connection marked X, both positive and negative voltages are correct, ie +/- 26 volts but if I connect the output of the negative side to the ground of the positive side (point X) I get positive voltage on the output of the negative regulator! 😕
I repeat, this is on one module only the other module works fine. Input voltages on both modules are correct (36 volts)
Nick,
With the ground broken at 'X', what voltage do you get with the positive lead of your DVM at the top of C6 and the negative lead at the bottom of C6..........
With the ground broken at 'X', what voltage do you get with the positive lead of your DVM at the top of C6 and the negative lead at the bottom of C6..........
- Status
- Not open for further replies.