High-End Regulated Buffered Inverted GC

[Peter Daniel]

No Probs Carlos😉

I am using Pedja's Buffer with the regulated amp/clone/mini-Krell and it sounds great, if it wasn't for people like you guys I would still have my standard non inverted GC gathering dust in my parts box😀

Your enthusiasm reminds me of another English guy, who was also very excited about tube buffered GC, in times when JR inroduced his circuit. If it wasn't for that enthusiasm, I would be probably still delaying building the 'Mini Krell'. Well, after hearing that you can virtually sweep the floor with the other amp, I couldn't take it anymore and decided to built one as well.😉

 

[carlosfm]

A little history

Everybody was having "Non-inverted fun" and i reported this:
http://www.diyaudio.com/forums/showthread.php?s=&postid=272320&highlight=#post272320

Unfortunately, (unbuffered) non-inverted was the mood then and it seams it still is now.
At the time nobody cared about a freak still insisting in IGC, and op-amps or whatever as a buffer was a crime for the minimalists.
Much before this I had reported huge improvements with my pre, and insisted that the GC benefits from a good pre.
After that I tested NIGC, BNIGC and it's good, but not like this.
I tested LM3875, LM1875, LM3886, LM4780, OPA548, OPA549.
What I have on my main system is the best combination (of course😀 ), and it's exactly what I reported here: Inverted LM3886 + NI OPA627 buffer + regulated PSU.
The regulated PSU I used first when i made my sub (2//OPA549), and I searched the net for suitable regulators.
I've searched TI, National, LT, On, AD, etc...
I downloaded the datsheets for the LM338 and LT1083 and it seamed fine for the job (I didn't find any good negative reg).
I did the sub, with LM338 (the LT I didn't find here) and the results were very good.
I later found out that Pedja was into this already, and even had a schematic on his site.😀

Then I regulated my amp, several tests with caps, listening tests, etc. and 😱 it was the final touch.😀

mini-Krell.

 

[Peter Daniel]

It's exact replica of Carlos circuit, with special attention to using the average quality parts. I hated installing the regulators I removed from ML preamp, but if it works for Carlos, it will surely work for me. I modified Brian's board and mounted regulator's boards in place of the caps. Another board with OPA627 is mounted between the regulators. I took special care not to exceed the minimum recommended distance between 33u bypass caps at LM3875.

Al in all, it took me almost 10 hours to built that amp. It better be as good, as Carlos claims. It's inverting, BTW.

 

[leadbelly]

Al in all, it took me almost 10 hours to built that amp.

Freak. 🙂

 

[Nuuk]

Al in all, it took me almost 10 hours to built that amp.

That's where you are going wrong Peter! You need to let these things mature over a couple of months like I do! 😀

 

[Peter Daniel]

That's where you are going wrong Peter! You need to let these things mature over a couple of months like I do! 😀

I assume you are still waiting for your regulators😉

 

[Peter Daniel]

Re: A little history

Everybody was having "Non-inverted fun" and i reported this:
http://www.diyaudio.com/forums/showthread.php?s=&postid=272320&highlight=#post272320

Unfortunately, (unbuffered) non-inverted was the mood then and it seams it still is now.
At the time nobody cared about a freak still insisting in IGC, and op-amps or whatever as a buffer was a crime for the minimalists.
Much before this I had reported huge improvements with my pre, and insisted that the GC benefits from a good pre.

To me the eye openening was this thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=22961

If 47Labs Shigaraki could be better than both JLTi and AMP-1, I was suspecting that inverted topology was not up to the task. After building first NI amp we knew right away that the deficiencies we were experiencing so far, were more or less gone. I also sent a conversion kit to Void, and he reported an improvement as well.

IMO, the NI amp actually benefits more from the preamp than an invering. The preamp doesn't have to be exactly at the amp's input. Using average length cables doesn't do anything to reduce the effect.

I tried quite a few preamps, but most of them were worst than a volume control mounted directly at the inputs. It's only with a really good preamps, that the amp begins to truly sing. And when it does, you know you're on a right path.

Now back to testing mini krell. It's quite an advanced circuit and I hope I have my wiring OK😉

 

[LTK]

Your enthusiasm reminds me of another English guy, who was also very excited about tube buffered GC, in times when JR inroduced his circuit. If it wasn't for that enthusiasm, I would be probably still delaying building the 'Mini Krell'. Well, after hearing that you can virtually sweep the floor with the other amp, I couldn't take it anymore and decided to built one as well.😉

I have listened to the valve buffer and didn't like it.
My minimal non inverted clone used 1000uf BG caps, caddock resistors in the fb etc, ok it wasn't bad but to my ears the J-fet, regulated version beats the crap out of it, it also cost me less than what I paid for two of the 1000uf BG caps.
If you prefer the non inverted minimal clone then thats fine. you can stick to throwing expensive parts in it, thats up to you.
I know which version I'll be sticking with😉

 

[Peter Daniel]

than what I paid for two of the 1000uf BG caps.

But you were using 4 of those caps, right?

And what are the speakers that you use?

 

[LTK]

But you were using 4 of those caps, right?

Yes, directly on the pins

And what are the speakers that you use?

IPL S3tlm Ribbons

 

[carlosfm]

Re: Re: A little history

IMO, the NI amp actually benefits more from the preamp than an invering.

😱
Quite the opposite...

I tried quite a few preamps, but most of them were worst than a volume control mounted directly at the inputs.

Of course.🙄

It's only with a really good preamps, that the amp begins to truly sing.

Of course. 🙄
I don't call "high-end" to anything that looks good...

Now back to testing mini krell.

MY amp is the mini-Krell.
You can call yours what you like.

 

[Tor M]

Hi!🙂

This is very off topic (this threat has bee bothered by off topic posts....) but even so: I became a father again today!!!😀 My second doughter! So I`m a very happy man at the moment!!

Back to topic:

Do any of you know the Nippon SMH and KMH series of caps?
They seem to be good caps.

I found a shop in Norway who used to supply a manufactor with theese, the manufactor went out of buisness and the shop is now selling the rest of the caps at low price:

10000uF 80V 85degree SMH series 3,85 euro

6800uF 100V 85degree SMH series 6,38 euro

8200 80V 105 degree KMH series 5,05 euro

Maybe some of theese would be well suited caps regulated supply!😕

I think I`m ordering some, for this project.

If anybody know theese caps, wich do you think would be better, the SMH series or the KMH?

Thanks

Tor Martin

 

[carlosfm]

Hi!🙂 This is very off topic (this threat has bee bothered by off topic posts....) but even so: I became a father again today!!!😀 My second doughter! So I`m a very happy man at the moment!!

Congratulations Tor!!!

Do any of you know the Nippon SMH and KMH series of caps?
They seem to be good caps.

I found a shop in Norway who used to supply a manufactor with theese, the manufactor went out of buisness and the shop is now selling the rest of the caps at low price:

10000uF 80V 85degree SMH series 3,85 euro

6800uF 100V 85degree SMH series 6,38 euro

8200 80V 105 degree KMH series 5,05 euro

Maybe some of theese would be well suited caps regulated supply!😕

I think I`m ordering some, for this project.

If anybody know theese caps, wich do you think would be better, the SMH series or the KMH?

Thanks

Tor Martin

It's not so important the caps you use before the LM338s, you don't need BGs here.
I would pick the 10.000uf or the 8.200uf caps.
Good prices indeed.😉

 

[HDTVman]

Carlos, I've been putting regulated power supplies on audio amps sense 1975. All kinds of amps., Tube amps, FET amps Preamps, power amps., even IC based power opamps as outputs with input buffer amps. I know a lot of other people that have as well. For you to claim this as an original idea is very funny, sad, but funny.

Later BZ

 

[Pedja]

Carlos, I've been putting regulated power supplies on audio amps sense 1975. All kinds of amps., Tube amps, FET amps Preamps, power amps., even IC based power opamps as outputs with input buffer amps. I know a lot of other people that have as well. For you to claim this as an original idea is very funny, sad, but funny.

Later BZ

I've heard one man has been doing this in the days of the King Arthur.

 

[HDTVman]

I've heard one man has been doing this in the days of the King Arthur.

I don't know about King Arthur but I have been building discreet component regulators for 30 years. I had a pair of McIntosh MC-60s that got +B and -C regulators. A pair of Dynaco MKIIIs with +B regulators that I still have. A Hafler DH-200 I built new and put in regulators when I built it. Several tube preamps from scratch with regulated +B. FET preamps and opamp preamps both single supply and dual rail with regulators. All discreet component regulators. I've used chip regs. but just don't like them. I'm not sure why, maybe it's the way feedback is used in the regulator chip. Mine are all brute force type zenor reference emitter followers or source followers.

You may ask how do these regulators sound? I don't know I can't hear them, but I can hear what they do for the amp. Rock solid very low noise power for the amp to work with. A good thing with any amp.

Later BZ

 

[siix]

Reply to Carlos

Carlos -

What I wrote stands. And I originally posted AFTER I read (however hesitantly) the links you posted. Your idea of your "jokes" (after slandering someone) and your interpretation of others "jokes" doesn't seem accurate me.

Not allowed? Really. Interesting. I don't need emoticons to back up my words.

I admire your designs, but there are many good minds currently on this site as well as those that will join it in the future. But there is still a difference between posting in a contributing way and slandering someone.

Greg

 

[Pedja]

From your list only DH-200 qualifies like SS power amp. If you had something to report about the sonic differences between unregulated and regulated supplies used with it, maybe with some slight changes in both versions and get some conclusions, you should do that... 🙄 Then I or someone else might be very glad to jump on your neck shouting some stupidity like "it is ridicilous to say it is original" (I mean stupidity beacuse you have not said that... ) and so on and so on... Then after all your trials and errors and successes you had , you could make similar report about the buffer, that you've used with power IC back in the 70's altogether with regulated supply, just like a lot of other people did then, so we could go another round of jumping on the neck...😎

Pedja

 

[Variac]

In the Lasceaux Caverns there is a cave painting that people assume is a bear, BUT if you tilt your head to the right, it is clearly the schematic for a chip based regulated supply.

 

[Pedja]

i think i will order a 100 pieces of our own (highly proffesional doublelayer) pcb......and just give them away for free....no make that 200, i'll just check the costs and then i'll decide.........🙂

Troels,

I am not sure about the impression you have… I still can make the difference between someone building stuff toward his/her own preferences/criteria/purposes, sharing the experience along the road, and those lurking for something popular at the moment and thus having some trade weight. I know you had your own attitude about regulated PS GC in the time this thing was not so popular. So, I was not talking about you.

Pedja