Sorry for the typo error. The My Reference is rated at 40W/8ohms; 56w/4ohms.
I'm in the middle of building mine. The amp has enough output to drive typical speakers to quite loud volumes, though obviously will not get the deafening volumes that Rudi, and myself in the past, might want/have wanted - did you say something - speak LOUDER.
It does not seem so long ago when 50 watts was considered high power!
Audie.
I'm in the middle of building mine. The amp has enough output to drive typical speakers to quite loud volumes, though obviously will not get the deafening volumes that Rudi, and myself in the past, might want/have wanted - did you say something - speak LOUDER.
It does not seem so long ago when 50 watts was considered high power!
Audie.
well billabong. i certainly do not listen to deafening volumes. but if you use a passive pot with speakers of 88db or less you will quickly get to a point were you would want a touch more and at that point the amp bites back with a awfull crackle "hi fidelity clipping"
in my case it is really not a problem but i have heard it in other systems and then it can be a problem. so i do not want to slag it otherwise i would not have build the X-Calibre. the amp is great.
ideal scenario. this design with more power , i believe that is being addressed by Mauro and Russ.
so bottom line. use it with a very good pre if you do not want to have that problem.
in my case it is really not a problem but i have heard it in other systems and then it can be a problem. so i do not want to slag it otherwise i would not have build the X-Calibre. the amp is great.
ideal scenario. this design with more power , i believe that is being addressed by Mauro and Russ.
so bottom line. use it with a very good pre if you do not want to have that problem.
sagarverma said:
I hope your joking...
The Krell KSA-50 clone thread is OVER 500 pages, more than 5000 posts and more than a quater million views..
You are not seriously suggesting that the quality or type of the pre can make any difference to clipping behaviour?
analog_sa said:
Obviously not. But you will be able to play it a bit loader wouldn't you? Elementary isn't it?
and you quote you. it will still be difficult to get the transparency of a passive pot with a VERY good pre
rudi said:
Rudi, you will be able to play louder, because you have more gain, but it will then clip sooner (when it gets to the same power).
This design does not conform to the standard power figures of the LM3886, which for a PSU voltage of +/-30V produces 45W/8R, and ~85W/4R (almost double).
On Mauro's design apparently you have 40W/8ohms, 56w/4ohms, which certainly must have to do with the output impedance of the amp.
So, don't be surprized if it clips sooner and if it doesn't drive some not-so-hard to drive speakers.
88db speakers are not hard to drive, as long as minimum impedance doesn't fall much below 3.5~4 ohms.
Attachments
hi!
thanks for replys,
as i suspect,it doesn't seems to be totaly secure to try to drive "heavy" load whit this type of amps (chip)
but what a good design!!!!!
greets
fred
thanks for replys,
as i suspect,it doesn't seems to be totaly secure to try to drive "heavy" load whit this type of amps (chip)
but what a good design!!!!!
greets
fred
in the works...
For those of you who are interested in bridged, parallel, and bridged/parallel versions of this amp stay tuned. I think Mauro is up to something which should be able to drive loads even lower than 4ohms.
I have successfully built a paralleled version, but I do not trust the design fully as I do not posses the skill nor the lab to fully test it. But it should theoretically allow for ~100W into 2-4ohms.
Try to encourage him. 🙂 Maybe he will publicly post his new work. I can see why he may be dissuaded to do so right now. I will tell you I have had a peek, but I have agreed not to share it. It will blow you away. 🙂 I am working to understand it enough to build my own, but out of respect I will not post it.
Cheers!
Russ
For those of you who are interested in bridged, parallel, and bridged/parallel versions of this amp stay tuned. I think Mauro is up to something which should be able to drive loads even lower than 4ohms.
I have successfully built a paralleled version, but I do not trust the design fully as I do not posses the skill nor the lab to fully test it. But it should theoretically allow for ~100W into 2-4ohms.
Try to encourage him. 🙂 Maybe he will publicly post his new work. I can see why he may be dissuaded to do so right now. I will tell you I have had a peek, but I have agreed not to share it. It will blow you away. 🙂 I am working to understand it enough to build my own, but out of respect I will not post it.
Cheers!
Russ
I hope that Mauro is not disuaded from presenting more amps by the fact that others have taken his truly breakthrough design and are attempting to improve its performance while doubling or tripling parts cost. This is, after all, a DIY forum, so constant tweeking is to be expected and even commended.
What impressed me at the very start of this thread was Mauro's goal of creating a high end amplifier with ample power for most speakers and perfomance that matches the best Class A designs WHILE STILL using a simple circuit and commonly available inexpensive components. There is no question that he has achieved these goals, in spades.
Also impressive is that from the start we were presented with a proven amp tested on real speakers and measured as well as listened to. This was never just a design exercise. Even though the original version achieved his goals, he has taken the input of others and provided further revisions that stayed true to the original goal of Class A sound at a rediculously low cost.
The mods I have see to this design may prove to increase performance or increase output power, but none I have seen will do so without substantially increasing cost or complexity. That's fine, other designs may have different goals.
I would be very interested in seeing a further design from Mauro that maintains the sound quality of the original but handles low impedences or unusually inefficient speakers with only a modest increase in component cost. I have no need for additional power, but I know quite a few people who do.
What impressed me at the very start of this thread was Mauro's goal of creating a high end amplifier with ample power for most speakers and perfomance that matches the best Class A designs WHILE STILL using a simple circuit and commonly available inexpensive components. There is no question that he has achieved these goals, in spades.
Also impressive is that from the start we were presented with a proven amp tested on real speakers and measured as well as listened to. This was never just a design exercise. Even though the original version achieved his goals, he has taken the input of others and provided further revisions that stayed true to the original goal of Class A sound at a rediculously low cost.
The mods I have see to this design may prove to increase performance or increase output power, but none I have seen will do so without substantially increasing cost or complexity. That's fine, other designs may have different goals.
I would be very interested in seeing a further design from Mauro that maintains the sound quality of the original but handles low impedences or unusually inefficient speakers with only a modest increase in component cost. I have no need for additional power, but I know quite a few people who do.
I think another one of Mauro's goals was to make an amp that was wholely stable in a wide variety of circumstances. I believe this is the basis of his hesitation to endorse some of the experimentation: not that people shoudln't play, but that he knows the amp well and can see how some of the changes make the amp less stable than the stated design.
From a kitting point of view, we try to keep a set of parts in the kit that err on the side of stability (conservative design) and leave it to others to select and try experimental parts.
I think Mauro has tried a number of differnet configurations in the lab, some of which he sees repeated, and is just saying, "hey, that's not going to work so well" or "that sounds good, but might lead to problems." But, I think we can all agree it's fun to experiment. That's what it's all about.
From a kitting point of view, we try to keep a set of parts in the kit that err on the side of stability (conservative design) and leave it to others to select and try experimental parts.
I think Mauro has tried a number of differnet configurations in the lab, some of which he sees repeated, and is just saying, "hey, that's not going to work so well" or "that sounds good, but might lead to problems." But, I think we can all agree it's fun to experiment. That's what it's all about.
Found out last night, my rev C doesn't like my Sony DVD player... and I think I now know why I thought it was bassless...
I normaly just hook up test amps to a PC's CD rom, whereas the REV C I got hooked up with the HIFI etc... i.e. 2 difirent sources....
Well last night in boredom I went and scratched out my dad's old playstation one (1998 model)...
Well I was pretty amused at how well it seems the little REV C now works... can't wait to get a preamp.
I normaly just hook up test amps to a PC's CD rom, whereas the REV C I got hooked up with the HIFI etc... i.e. 2 difirent sources....
Well last night in boredom I went and scratched out my dad's old playstation one (1998 model)...
Well I was pretty amused at how well it seems the little REV C now works... can't wait to get a preamp.
What about these speakers ?
I´m about to build a RevC for someone who read my review in www.hifi-forum.de, he wants to drive a pair of Celestion SL700 with it. Please have a look at the impedance curve:
Is this speaker critical to drive ?
I´m about to build a RevC for someone who read my review in www.hifi-forum.de, he wants to drive a pair of Celestion SL700 with it. Please have a look at the impedance curve:
Is this speaker critical to drive ?
Hi SOP, for a true REV C that load will be no problem at all. It is not all that disimillar to some speakers I own.
Cheers!
Russ
Cheers!
Russ
analog_sa said:
My answer was only related to the impedance curve, but yes even at 82db is should be OK, as I have never had the clipping issues Rudi has, as I do not bias the LM318. You will still only be able to drive it to ~45-50W. So don't expect to go beyond that.
No Hyperbole here. 😉
72db speakers, look elsewhere for an amp to drive those, at least if you really want to hear them 🙂
Hi Russ
your observations are very interresting. so why do you think it clips in complete standard configuration. and the biasing does not have anything to do with it. i tested that. I ran it with a single bridge etc etc. and your board is not that much different from mine.
I have heard that somebody else also had that problem and i believe it was with a "real" ref-c what is the difference. NOTHING I followed the schematic unless the spirit of DIY has been killed and it has become commercial.
I think i will get one of your boards and test it on a pair of Dahlquist speakers. and anybody that think that Dahlquist isn't "real" speakers need to have a education. if you go back to the 70 you will find one of their true treasures. a 10" speaker with a Fs of 17hz. a speaker very much in demand with the people that know
your observations are very interresting. so why do you think it clips in complete standard configuration. and the biasing does not have anything to do with it. i tested that. I ran it with a single bridge etc etc. and your board is not that much different from mine.
I have heard that somebody else also had that problem and i believe it was with a "real" ref-c what is the difference. NOTHING I followed the schematic unless the spirit of DIY has been killed and it has become commercial.
I think i will get one of your boards and test it on a pair of Dahlquist speakers. and anybody that think that Dahlquist isn't "real" speakers need to have a education. if you go back to the 70 you will find one of their true treasures. a 10" speaker with a Fs of 17hz. a speaker very much in demand with the people that know
rudi said:
and your board is not that much different from mine.
I have heard that somebody else also had that problem and i believe it was with a "real" ref-c what is the difference. NOTHING I followed the schematic unless the spirit of DIY has been killed and it has become commercial.
Errrr yes my layout is significantly different from yours, especially in regard to power and GND traces. I won't go over why they are different, as I am not sure it would matter to you.
Commercial? Who is making a commercial product? 😕 I have not made a dime on Mauro's design. I provide the amp as an extension of my hobby, not as a money making venture.
Over 100 MyRefs have been built based on the PCB which Mauro helped me tweak. And I get emails constantly from happy builders. This is the payoff for me, providing an "everyman's audiophile reference amp" which can be built for less than $300 depending on your scrounging abailities. 🙂
Anyone who has properly built the monoblocs with correct trafos and driving the intended load which is 4-8 ohm speakers which can be utilized in the 40-50W range has had none of the clipping issues you describe. 🙂 In fact most of the them report to me the same audio bliss as the rest of us who care to build it as designed.
You know what they say, "if it aint broke..." and I think you would have to be a fool to say it is broke. Now certainly tweak all you want, but pardon me while I laugh my buttocks off in private at some of the things that are done, and the euphorically posted about with hyporbole as thick as pea soup.
No need to worry Rudi, I am sure your "Hot Rod" will get the attention you crave. Funny though, to me it is like "Hot Rodding" a Rolls Royce, sorta silly.
In the meantime, behind the scenes where significant work is really happening new, creative, and truly innovative circuits based on Mauro's work are in the works and have been built, but the tone of the forum has made it unlikely that it will ever by posted to anyone publicly.
If you only knew what you were missing... 🙂 Sad really, but at least not for me.
Cheers!
Russ