Mongo no want pictures! Just the mental "visual" I got make head jerk back. And Mongo not that mental.
I believe Rudi is talking about myself with regards to someone else having problems with the amp clipping (kit My_Ref rev C). To clarify I wrote, "I think I may have crossed its [clipping] path yesterday" but hadn't determined if that was actually the case or not, and was going to do some basic listening tests and report back.
After pondering what happened it's entirely possible that the woofer was being driven quite a bit harder. I compare the performance of the My_Ref to a 3886 GC, not because I look at Mauro's amp as a GC but because it's what I was using prior.
So to summarise: Clipping appeared to be an issue on a few recordings - under heavy bass at HIGH volumes. It's entirely possible - and quite likely - that the bass being what is it in this amp, compared to the GC, is driving the poor little 5" woofer all the more harder at it's lower frequencies and it's not the amp that's clipping but the woofer exceeding its Xmax by about 6' (yeah six feet 😉 This could be due somehow, to the more substantial bass Mauro's amp seems to produce.
I recall a few posts where it was said that the bass in this amp was a little lacking. Well compared to what I was using prior this is not the case for me at all. Make of it what you will but the bottom line is that I was uncertain if it was clipping or something else. In retrospect I think it was something else (mid-woofer weeping in pain).
😀
Mauro, your amplifier is a gem. You were challenged over your circuit in many posts, one thing you did was answer them all with both technical and aural evidence. There are quite a few of us that love putting this gear together but don't have the nounce to understand it enough to design something exceptional ourselves. We love the hobby but, myself at least, aren't equipped to really get it and so need folks like your good self.
Yes, this is a semi-guilt trip 😉
After pondering what happened it's entirely possible that the woofer was being driven quite a bit harder. I compare the performance of the My_Ref to a 3886 GC, not because I look at Mauro's amp as a GC but because it's what I was using prior.
So to summarise: Clipping appeared to be an issue on a few recordings - under heavy bass at HIGH volumes. It's entirely possible - and quite likely - that the bass being what is it in this amp, compared to the GC, is driving the poor little 5" woofer all the more harder at it's lower frequencies and it's not the amp that's clipping but the woofer exceeding its Xmax by about 6' (yeah six feet 😉 This could be due somehow, to the more substantial bass Mauro's amp seems to produce.
I recall a few posts where it was said that the bass in this amp was a little lacking. Well compared to what I was using prior this is not the case for me at all. Make of it what you will but the bottom line is that I was uncertain if it was clipping or something else. In retrospect I think it was something else (mid-woofer weeping in pain).
😀
Mauro, your amplifier is a gem. You were challenged over your circuit in many posts, one thing you did was answer them all with both technical and aural evidence. There are quite a few of us that love putting this gear together but don't have the nounce to understand it enough to design something exceptional ourselves. We love the hobby but, myself at least, aren't equipped to really get it and so need folks like your good self.
Yes, this is a semi-guilt trip 😉
I initially stated this amp was fabulous.
I still stand by that statement. The ONLY issue I have had with it was the toroids I (ME, not Mauro, Brian or Russ) had on hand to fire it up. They are a tad bit small, and I knew that going into this project.
They gave me a good sampling of the sound I was to expect from this design before I spend money on larger transformers.
I will be spending that money, and I will continue on the path of installing my Kookaburra in the case.
This amp has become my house reference and I look forward to many years of enjoyment thanks to Mauro's painstaking research and design.
I am sorry to see Mauro go. I hope he continues to share his projects with Russ and Brian who have done a fabulous job of getting his work out to the "common man".
I still stand by that statement. The ONLY issue I have had with it was the toroids I (ME, not Mauro, Brian or Russ) had on hand to fire it up. They are a tad bit small, and I knew that going into this project.
They gave me a good sampling of the sound I was to expect from this design before I spend money on larger transformers.
I will be spending that money, and I will continue on the path of installing my Kookaburra in the case.
This amp has become my house reference and I look forward to many years of enjoyment thanks to Mauro's painstaking research and design.
I am sorry to see Mauro go. I hope he continues to share his projects with Russ and Brian who have done a fabulous job of getting his work out to the "common man".
The standard 3886 gainclone configuration will likely be louder than the My_Ref. The My_Ref uses some of the output power (the seven watt 0R47 ohm resistor) to sense the current in the load and use that information in the feedback loop.
If it is raw power that is your goal, this probably isn't the design you are looking for. You guys could bridge two 3886 chips in a conventional GC design and get lots power for bass.
For me, the current sense topology is a lot of the of the appeal to the My_Ref design. It doesn't just use a brute force low impedance output to drive the load, it is intelligent control. This is the stuff that advances in audio are made from.
It will be hard to scale this design up in power without heat problems. I don't know if I want to try. The power now is enough for reasonable listening volume with a lot of speaker designs.
I would hope that Mauro would just ignore criticizm from certain posters and stay with us. In that other thread, rudi just admitted that his clipping problem went away by changing R41 and R42 to 47R, something that was discussed here weeks ago and about 100 pages back.
see post 68 in the thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=69167&perpage=10&pagenumber=7
Interesting post rossl.
Raw power isn't what I'm after (only speaking for myself), besides the amp is plenty loud enough in the lounge room it's in. The output levels of this amp are different to what it's replaced. Mauro's amp is one of those amps that doesn't appear to be putting out as many SPL's as it really is and is quite deceptive!
Another amplifier example that has this attribute is the Aksa. That little monkey can be up loud, but it doesn't appear so, or rather, there's nothing offensive in its nature that pierces the auditory senses into thinking your choclea has just self-destructed. This is perhaps just down to really well balanced circuits. Dunno.
The concern I have is some junior family member could easily turn the amp up really loud really quickly. I've no idea if reducing gain, giving the pot more control and avoiding a potential melt-down, is advisable. The pot gets a little over half-way and I begin to panic a bit. I'd be quite happy having the pot at the same output levels at its halfway point at full travel but don't know the best way to do this.
I think we all hope Mauro ignores the criticism but I guess it would be difficult not to take comments to heart when you've put so much effort into something, offered it to all and sundry and asked for nothing in return. Hugh Dean and Rod Elliot have and still receive criticism and often from someone who's never heard the circuit/s. Mauro seems to suffer the same - which is, well, a crap attitude.
Raw power isn't what I'm after (only speaking for myself), besides the amp is plenty loud enough in the lounge room it's in. The output levels of this amp are different to what it's replaced. Mauro's amp is one of those amps that doesn't appear to be putting out as many SPL's as it really is and is quite deceptive!
Another amplifier example that has this attribute is the Aksa. That little monkey can be up loud, but it doesn't appear so, or rather, there's nothing offensive in its nature that pierces the auditory senses into thinking your choclea has just self-destructed. This is perhaps just down to really well balanced circuits. Dunno.
The concern I have is some junior family member could easily turn the amp up really loud really quickly. I've no idea if reducing gain, giving the pot more control and avoiding a potential melt-down, is advisable. The pot gets a little over half-way and I begin to panic a bit. I'd be quite happy having the pot at the same output levels at its halfway point at full travel but don't know the best way to do this.
I think we all hope Mauro ignores the criticism but I guess it would be difficult not to take comments to heart when you've put so much effort into something, offered it to all and sundry and asked for nothing in return. Hugh Dean and Rod Elliot have and still receive criticism and often from someone who's never heard the circuit/s. Mauro seems to suffer the same - which is, well, a crap attitude.
And like this:
Rudi said:
When Rudi has never built any amp but his own, and even if he had, and letsgive him the benfit of the doubt and say he was right (which he is not) the comment is obnoxious, and detracts greatly from any shred of credibility which may have been found. 🙂
This is why I cannot take it very seriously when I read comments like this:
Rudi said:
Notice HUGE!!!!
The only huge differences you could make to this amp would have to be in the opposite direction from better. 🙂 Now very small I could accept. 🙂 Huge, now that's ridiculous.
There are other quotes I could go into, but I will spare you all.
I am sure Rudi means well, but this kind of rhetoric is silly and counter productive.
Now, let all do something really useful and open another bottle of Becks.
Cheers!
Russ
Rudi said:
When Rudi has never built any amp but his own, and even if he had, and letsgive him the benfit of the doubt and say he was right (which he is not) the comment is obnoxious, and detracts greatly from any shred of credibility which may have been found. 🙂
This is why I cannot take it very seriously when I read comments like this:
Rudi said:
Notice HUGE!!!!
The only huge differences you could make to this amp would have to be in the opposite direction from better. 🙂 Now very small I could accept. 🙂 Huge, now that's ridiculous.
There are other quotes I could go into, but I will spare you all.
I am sure Rudi means well, but this kind of rhetoric is silly and counter productive.
Now, let all do something really useful and open another bottle of Becks.
Cheers!
Russ
Hi All...
I only came upon this thread a few weeks ago, and was intrigued enough by the design (and by user comments), to purchace a kit from twisted pear (which I received last week).
I must admit that I too had thoughts about 'hot rodding' it, (MUR860's etc.) but while I was sitting down to 'stuff' the boards I had another thought. I sort of felt like I was doing one of those paint by number kits. It was sort of unnerving, so I stepped back a little, and spent some time 'admiring' the layout of the PCB, and then had this 'epiphony'; why would someone put such care into the ground plane scheme and then choose 'substandard' caps or diodes.
Unfortunatly my boards are still sitting on my bench waiting for a case, so I can't comment on there sound quality... but they sure are pretty, and at least for now I think I'll do my best to 'stay in side the lines'.
More horsepower doesn't always improve the driving experience...
Steve
(I've tried to fight the temptation to layout the amp on a piece of plywood while I build the chasis.... but plywood is looking better and better.....)
I only came upon this thread a few weeks ago, and was intrigued enough by the design (and by user comments), to purchace a kit from twisted pear (which I received last week).
I must admit that I too had thoughts about 'hot rodding' it, (MUR860's etc.) but while I was sitting down to 'stuff' the boards I had another thought. I sort of felt like I was doing one of those paint by number kits. It was sort of unnerving, so I stepped back a little, and spent some time 'admiring' the layout of the PCB, and then had this 'epiphony'; why would someone put such care into the ground plane scheme and then choose 'substandard' caps or diodes.
Unfortunatly my boards are still sitting on my bench waiting for a case, so I can't comment on there sound quality... but they sure are pretty, and at least for now I think I'll do my best to 'stay in side the lines'.
More horsepower doesn't always improve the driving experience...
Steve
(I've tried to fight the temptation to layout the amp on a piece of plywood while I build the chasis.... but plywood is looking better and better.....)
Hi Steve, Plywood is not a bad option. 🙂 You should see how many amps I have built on plywood and MDF. 🙂 Currently a Twisted XBOSOZ preamp.
I appreciate your enthusiasm and encouragement.
Cheers!
Russ
I appreciate your enthusiasm and encouragement.
Cheers!
Russ
more supply cap
I guess I can post this here. I just added these stm caps, 6800uf. They were the total ps caps of a 400 watt phase linear amp. I
a-b'd the channels with the same input and there is an improvement,a fuller sound,better defined bass. Early days yet, will try bypassing with different values metal poly caps.
cheers
doggy 😀
I guess I can post this here. I just added these stm caps, 6800uf. They were the total ps caps of a 400 watt phase linear amp. I
a-b'd the channels with the same input and there is an improvement,a fuller sound,better defined bass. Early days yet, will try bypassing with different values metal poly caps.
cheers
doggy 😀
Attachments
Ever seen that movie Lost in translation....?
I just want to say I have gotten to know Rudi quite well as he is realy an above average helpfull person....
I have had many phone conversations with him, and I realy think the major problem is just a case of expression... I have never read the negative vibes you all seem to be getting....
Just like Mauro, we are also not first language users, and to compound this, the harsh african envorinment, also has us using a bit harsher language, I have a couple of times seen foreigners eyes stretch for instance when they hear a local say "I will kill for this or that", it is just figurative speech....
I think both Mauro and Rudi are great guys....!!!!!!!!!
Would be great if we could burry the imaginary hatchet.
Its almost chrsitmas and all that guys 🙂
I just want to say I have gotten to know Rudi quite well as he is realy an above average helpfull person....
I have had many phone conversations with him, and I realy think the major problem is just a case of expression... I have never read the negative vibes you all seem to be getting....
Just like Mauro, we are also not first language users, and to compound this, the harsh african envorinment, also has us using a bit harsher language, I have a couple of times seen foreigners eyes stretch for instance when they hear a local say "I will kill for this or that", it is just figurative speech....
I think both Mauro and Rudi are great guys....!!!!!!!!!
Would be great if we could burry the imaginary hatchet.
Its almost chrsitmas and all that guys 🙂
Well there seems to be sour grapes in the twisted pear camp.
Well let’s put some explanations and some apologies were it is due
1. Mauro. Not for one moment did I claim the amp design as my own. I have always given you credit for the schematic and the ingenious thought of implementation. And I thank you for you that
2. Hot Roding is a term to personalize something to your own tastes. In most case upping power or performance. In this case making a different power supply stage
3. My reference to this being commercial. From the beginning Russ stated that they are not doing it for a profit. I own my own business and not for one moment did the math indicate a profit. The point I am trying to make is that there only seem to be help to the people that build the TP version and it is ONLY about the TP version and if there is a small variation there were no support for this.
4. The X-Calibre is my development just as the current TP Ref C is a Russ White development, (by the sound of it with help from Mauro.), But I did mention that it is done according to Mauro design. Again giving him credit for the Amp part of the design.
5. There have been a lot of questions regarding the tweaking of this amp and I just wanted to satisfy the curiosity, and it actually worked. And it works extremely well.
6. The amp that I have originally implemented does clip, I started of by just mentioning it and there were no help to solve the problem or just a speculation of possible problem. If it were a TP board there would have been A LOT defence and immediate help. So the question is why does it clip so harshly when it gets to its limits. The reality is that I have a 9m x 6.5m x 3.2m listening room. It takes a lot of power to fill that room. And the ref-c is most probably not the amp to fill this space. I am already looking a locally amp that will give me 250w and can drive to 1.2 ohm, so no fear in me pursuing this variation, I will keep it strictly DIY. Just as a matter of interest. I tested the X last night and it got to 56W at 8ohm, then it became totally unstable, not just the normal clipping, I did not test it into 4 ohm
To bring me to the public apology.
Guys I am very sorry that I have pushed Mauro over the edge and robbed you of your new amp project.
I am sorry if I have offended anybody with any of my wild statement. I is my personality to get people to take initiative and to push them a bit
I am sorry if I took a condemning tone. It was uncalled for.
The TP is most probably a fantastic amp and I have never compared it to a X so to say that it will eat if for breakfast is very unfair. But it has been done in innocent competitive spirit.
Lets face the facts.
Musical fidelity came up with the topology. Then Mauro adapted it and implemented a more technical version by removing the mosfets and replacing them with a Lm3886 and documenting it in a fantastic way, I took that again and just implemented some known practices on the power supply.
Well let’s put some explanations and some apologies were it is due
1. Mauro. Not for one moment did I claim the amp design as my own. I have always given you credit for the schematic and the ingenious thought of implementation. And I thank you for you that
2. Hot Roding is a term to personalize something to your own tastes. In most case upping power or performance. In this case making a different power supply stage
3. My reference to this being commercial. From the beginning Russ stated that they are not doing it for a profit. I own my own business and not for one moment did the math indicate a profit. The point I am trying to make is that there only seem to be help to the people that build the TP version and it is ONLY about the TP version and if there is a small variation there were no support for this.
4. The X-Calibre is my development just as the current TP Ref C is a Russ White development, (by the sound of it with help from Mauro.), But I did mention that it is done according to Mauro design. Again giving him credit for the Amp part of the design.
5. There have been a lot of questions regarding the tweaking of this amp and I just wanted to satisfy the curiosity, and it actually worked. And it works extremely well.
6. The amp that I have originally implemented does clip, I started of by just mentioning it and there were no help to solve the problem or just a speculation of possible problem. If it were a TP board there would have been A LOT defence and immediate help. So the question is why does it clip so harshly when it gets to its limits. The reality is that I have a 9m x 6.5m x 3.2m listening room. It takes a lot of power to fill that room. And the ref-c is most probably not the amp to fill this space. I am already looking a locally amp that will give me 250w and can drive to 1.2 ohm, so no fear in me pursuing this variation, I will keep it strictly DIY. Just as a matter of interest. I tested the X last night and it got to 56W at 8ohm, then it became totally unstable, not just the normal clipping, I did not test it into 4 ohm
To bring me to the public apology.
Guys I am very sorry that I have pushed Mauro over the edge and robbed you of your new amp project.
I am sorry if I have offended anybody with any of my wild statement. I is my personality to get people to take initiative and to push them a bit
I am sorry if I took a condemning tone. It was uncalled for.
The TP is most probably a fantastic amp and I have never compared it to a X so to say that it will eat if for breakfast is very unfair. But it has been done in innocent competitive spirit.
Lets face the facts.
Musical fidelity came up with the topology. Then Mauro adapted it and implemented a more technical version by removing the mosfets and replacing them with a Lm3886 and documenting it in a fantastic way, I took that again and just implemented some known practices on the power supply.
rudi said:
First Rudi, any apology followed up by a statement like that is hollow at best and it sheds a lot of light on your character.
Now some key points:
-- My Ref is not a MF clone. It is not simply an MF topology amp with the Mosfets replaced with LM3886, that fact that you think it is calls into question your technical ability to comprehend the amp and the complex nature of the stasis current pump. It is not mear copy as you seem to suggest, but a whole new body of work based on ideas and concepts which came before, just as almost any inovation. MF gave Mauro some inspiration, but the blueprint is his own. You will never find a MF amp with the flat freq/phase response of the MyRef Revision C. It does not exist, it is purely Mauro's work.
-- You present your PCB as if you were the first to apply your "known practices on the power supply", but do you think power supply LRC nets (they are not snubbers) have not been considered, or VREGS? Do you assume that as an architect you know better then the engineer who designed the amp what will give you the most milage in terms of performance? It is your arrogance in spite of your ignorance that is galling. It is your insistance to correct the teacher (in a very real sense) which is unbecoming and rude.
My work on Mauro's amp is directed as a thank you to Mauro, and a service to my firends. I designed my PCB with very much input from Mauro even sending him the eagle files to help me understand some things. It is substantially different from yours, but the work in it is very little mine, I would not be so rude as to attatch much significance to a work which did not originate with me and claim any elementary change I made to the circuit could make a "HUGE" improvement. That statement infers that Mauro's circuit was less than excellent in the first place, but it is a statement you seem to exclaim with every doodad you attach to the PCB.
This is the bottom line - RESPECT. If you have truly learned something of value be confident in what you know and present it with honesty and respect, but be ready to back up your assertions with facts, and not just opinion. Mauro could have marketed this design, but he chose to share it. You have quite frankly used very bad taste, and horrible diplomacy in dealing with this thread and those who have actually tried to help you. That is a shame as I think you are actually better then your have framed yourself and I think things can be improved between us all.
As for me, your assertion that I only answer questions from those who have built Twisted Pear amps is completely false, and I can only think you seek to impune my behavior as "exclusive", well please look back through the thread and you will see this is not the case, and I have answered your posts as well have I not? I have encouraged your work have I not?
It is said that the evidence of a completed engineering work is not when there is nothing left to add, but nothing left to take away. That is the spirit of MyRef. Yes it is more complex than a gainclone, but for what it is, it is a simple work of art. To get back to my Rolls Royce analogy. MyRef as designed is the RollsRoyce with its own RollsRoyce engine. Putting an 850HP NASCAR engine under the hood would not make the Rolls Royce better, it would make it something else, and probably would drive like hell.
To make the Rolls accept such an engine your would need to add sway bars, change rear ends, change shocks and springs, etc... in short make a new car. You can call it a hot rod if you like, but it is not a Rolls Royce. 🙂 And those who love Rolls Royce will not necessarily think the new car is better. In fact they would probably laugh at the absurdity of chopping up what was already excellent. That is the way many of us feel not because you experiment, but because your experiments are so hyped, and so exaggerated as to leave uneducated onlooker baffled. In that the result of the work is not as helpful as it could be if the results were evaluated by those who truly understand the circuit like Mauro and a half dozen or so other very respected participants, and not just your own ears/opinion. Ears are so easily fooled by minds. Does that mean you should not post your opinion? Certainly not, but be careful that you not try to present opinion and speculation as fact, and be careful not to pretend to be authoritative where you have something to learn and we will all be better for it. You stated this once:
here
I say that started out as the most honest thing your have posted, but you contradicted yourself in the end. We all have our limits, mine are especially small, and that should temper your posts, remeber those even less knowledgable than your are reading this stuff.
So no sour grapes here, in fact I have had a lot of great laughs.
We can talk about things together and have a great time building amps. Lets just keep it real, and lets also keep it polite and respectful and we will all have a good time. Maybe we can even get Mauro to come back, there is so much left to learn, at least for me.Cheers!
Russ
I think we are not moveing forward... we have all at some stage put our foot in it, and sometimes put the second foot in too, trying to get the first one out.