Hi, Mauro,
What is the output impedance of "MyReferenceRev3"?
I finally got the point of what you mean by "Statis" GC 😀. (In your other thread). Your "Statis" design is quite different from MyreferenceRev3. Which one do you like personally? (From the quality of sound that produced by these 2 amps, which is better?). Your Statis have no global feedback.
What is the output impedance of "MyReferenceRev3"?
I finally got the point of what you mean by "Statis" GC 😀. (In your other thread). Your "Statis" design is quite different from MyreferenceRev3. Which one do you like personally? (From the quality of sound that produced by these 2 amps, which is better?). Your Statis have no global feedback.
Dear Lumanauw,
am happy that some has understanded the operation of the valuational circuits that has introduced.
How to say you, the two circuits are a lot of different, as diverged are the operations of the My_Ref variations. I say you at once that have done the tests of Back_EMF even to the "stasis" circuit, but the level of IMD is analogous to My_REF ( and other ).
For what concerns the sound, I prefer that of My_Ref ( to parity of components ), but the dynamics of operation of MY_REF has an enough similar behaviour to "stasis" and " current dumping " even if the final result it is typical of a " voltage amp ".
I have explained this concept ( In my Language ) on an Italian forum, and is seemed interesting even to the friend George (Josef_K).
I have the problem to explain well my concepts in English, for which among a little, and with the help of the Italian friends, I think to show to the forum all the technical descriptions of my project...
Ciao
Mauro
am happy that some has understanded the operation of the valuational circuits that has introduced.
How to say you, the two circuits are a lot of different, as diverged are the operations of the My_Ref variations. I say you at once that have done the tests of Back_EMF even to the "stasis" circuit, but the level of IMD is analogous to My_REF ( and other ).
For what concerns the sound, I prefer that of My_Ref ( to parity of components ), but the dynamics of operation of MY_REF has an enough similar behaviour to "stasis" and " current dumping " even if the final result it is typical of a " voltage amp ".
I have explained this concept ( In my Language ) on an Italian forum, and is seemed interesting even to the friend George (Josef_K).
I have the problem to explain well my concepts in English, for which among a little, and with the help of the Italian friends, I think to show to the forum all the technical descriptions of my project...
Ciao
Mauro
Hi, Mauro,
What I see in your 2 schematics : MyRef is a typical Voltage amplifier, because the feedback to 318 is taken from output node, this means the whole MyRef will have low output impedance, because the whole thing is actually controlled by the 318.
What is the output impedance of MyRef?
Your Statis design is different. The output impedance is big (22-100ohm maybe?) and it have no feedback to the input stage.
This properties alone definitely will give different sound characteristic, that is why I asked you which one you like more (better sound). You said you likes MyRef better.
Mauro, I think you have experimented alot with Audio Amplifer output impedance and it's effect to the sound. From your point of view, what output impedance value (how many ohms output impedance) gives the best sonic / audio reproduction characteristic?
Is it as small as possible (approaching 0 ohm output impedance), or is it like tube amps (around 1-6ohm output impedance), or it is better like your Statis (above 20ohm-200ohm) output impedance?
Which is giving the real pleasure in sound reproduction?
It takes me quite a long time to know how your statis works😀 The difference with MyRef is only one 100ohm resistor and feedback / non feedback, but it makes a BIG difference in operation in both your MyRef and Statis.
What I see in your 2 schematics : MyRef is a typical Voltage amplifier, because the feedback to 318 is taken from output node, this means the whole MyRef will have low output impedance, because the whole thing is actually controlled by the 318.
What is the output impedance of MyRef?
Your Statis design is different. The output impedance is big (22-100ohm maybe?) and it have no feedback to the input stage.
This properties alone definitely will give different sound characteristic, that is why I asked you which one you like more (better sound). You said you likes MyRef better.
Mauro, I think you have experimented alot with Audio Amplifer output impedance and it's effect to the sound. From your point of view, what output impedance value (how many ohms output impedance) gives the best sonic / audio reproduction characteristic?
Is it as small as possible (approaching 0 ohm output impedance), or is it like tube amps (around 1-6ohm output impedance), or it is better like your Statis (above 20ohm-200ohm) output impedance?
Which is giving the real pleasure in sound reproduction?
You're doing fine, actually. It is because I'm not using English in daily life (English is not my main language), so sometimes I have difficulties in understanding your post 😀
Are you going to make a new Thread? If so, please inform me when you do. Your projects and your opinions/Thinking always interests me😀
mauropenasa said:
Well, I lost the attachment, but if anyone is building one from Russ's baords do not forget these jumpers wires. It will not work.
The attachment showing the location of the jumper wires is on post #59.
George
It Works Great!
Just a quick note that I got the amp up and running. Worked from first crank of the Variac. Breadboard for now, but need to put it in a case.
Got the board from Russ, thanks, plus all the needed information. Did not see the parts buy until too late, so have some different parts choices, but loyal to original schematic. Most difficult part was finding a suitable heat sink and putting the groove in it for the board. Sits at 40 C during most music into a homemade MTM's with Seas P17REX and Scan-Speak 9300 and the amp does not seem to mind the lower impedance.
First impressions--detailed, quick and very accurate. Will post pictures when I get them working, and at some point some measurements.
Just a quick note that I got the amp up and running. Worked from first crank of the Variac. Breadboard for now, but need to put it in a case.
Got the board from Russ, thanks, plus all the needed information. Did not see the parts buy until too late, so have some different parts choices, but loyal to original schematic. Most difficult part was finding a suitable heat sink and putting the groove in it for the board. Sits at 40 C during most music into a homemade MTM's with Seas P17REX and Scan-Speak 9300 and the amp does not seem to mind the lower impedance.
First impressions--detailed, quick and very accurate. Will post pictures when I get them working, and at some point some measurements.
Member
Joined 2003
Of course you should be able to tell that when you are done soldering everything and there is still unsoldered holes in the board...The only open holes should be the 2 holes for the input coupling capacitor where there is extra holes for different size of caps.Panelhead said:
I am glad that everyone seems very impressed with this amplifier. I cannot wait to get mine finished. I am still waiting for my chassis to arrive so I can measure out the exact size to cut my heatsink.
Hi Lumanauw,
as I have said is 2 different techniques, but in the "Stasis" circuit the current pump is external to the NFB of the voltage amp (LM318+BJT), and the R6 res ( 100 ohms ) is the "current sense " that serve to the stasis circuit to work. The voltage amp (LM318+BJT) furnishes to the load a current that crosses R6 that produces a V(R6) that drives the bridge. Of fact, the LM318 circuit sees a load = Zload * (current pump current gain) and himself you produce the Pass theory.
The Zout of this circuit is not 100 ohms, but it is of about Zload/ (current pump current gain) that in our case is of 8/1000.
A "stasis" circuit ( complete ) is to all the effects a voltage amp. The technique of Pass serves to reduce the dependence from the VAS and the influance of the power BJTs THD on the NFB circuit ( is enough read the objectives in the brevet...).
My bridge( Power Current/Current converter ) is a 1mA/ 1A converter ( current gain = 1000 ) Voltage gain =1, and to depart the global NFB, involves as a voltage follower. The Zinternal is of about 100 ohms, but it is of value only for better the "Stasis" operation (Pass rules of sizing ) for which serve that the Zint >> Zload to work well.
In connection with the "sound", I believe that the parameters of "quality" of the sound of the valvular systems goes across the border to the DF. Then is the Graham theory in connection with the phase of the DF, that it has a weight perhaps greater ( of sound ) of the DF.
I have compact of the searches on this, but I believe in the superiority of the current driven but not in the low DF. A system to understand of thing speak is the study of the "firstwatt". I believe that that technique is excellent to have the advantages of the current driven without sacrifice too the DF. If will have time ( and I doubt ) want develop a "firstwatt" with the " my " current pump...
An other problem is that I am not an audio planner, and as J.L.Hood I have already built my reference amp, and the performances that me from not push me to look for other ameliorations.
I hope to take an new THread with the characteristics of project of My_REF...
Ciao
Mauro
as I have said is 2 different techniques, but in the "Stasis" circuit the current pump is external to the NFB of the voltage amp (LM318+BJT), and the R6 res ( 100 ohms ) is the "current sense " that serve to the stasis circuit to work. The voltage amp (LM318+BJT) furnishes to the load a current that crosses R6 that produces a V(R6) that drives the bridge. Of fact, the LM318 circuit sees a load = Zload * (current pump current gain) and himself you produce the Pass theory.
The Zout of this circuit is not 100 ohms, but it is of about Zload/ (current pump current gain) that in our case is of 8/1000.
A "stasis" circuit ( complete ) is to all the effects a voltage amp. The technique of Pass serves to reduce the dependence from the VAS and the influance of the power BJTs THD on the NFB circuit ( is enough read the objectives in the brevet...).
My bridge( Power Current/Current converter ) is a 1mA/ 1A converter ( current gain = 1000 ) Voltage gain =1, and to depart the global NFB, involves as a voltage follower. The Zinternal is of about 100 ohms, but it is of value only for better the "Stasis" operation (Pass rules of sizing ) for which serve that the Zint >> Zload to work well.
In connection with the "sound", I believe that the parameters of "quality" of the sound of the valvular systems goes across the border to the DF. Then is the Graham theory in connection with the phase of the DF, that it has a weight perhaps greater ( of sound ) of the DF.
I have compact of the searches on this, but I believe in the superiority of the current driven but not in the low DF. A system to understand of thing speak is the study of the "firstwatt". I believe that that technique is excellent to have the advantages of the current driven without sacrifice too the DF. If will have time ( and I doubt ) want develop a "firstwatt" with the " my " current pump...
An other problem is that I am not an audio planner, and as J.L.Hood I have already built my reference amp, and the performances that me from not push me to look for other ameliorations.
I hope to take an new THread with the characteristics of project of My_REF...
Ciao
Mauro
Hi, Mauro,
Thanks, I understand you.
The answer from you will be important, as you have proven in your "MyRef" that complicated amp(I imagine complex cct inside opamp+GC) can be made sound good too. 😀. Don't have to push a certain cct, as long as you understand what you want to do with the cct (I haven't know what is the main criterion in making good sounding audio amp with anything [discrete bipolars, mosfets, GC or anything else, simple or complex cct], what is the criterion)
Thanks, I understand you.
So you think the DF or output impedance is low importance in good sounding audio amplifier, but something else, not the output impedance, is responsible for the good sounding? May I ask what it is?
Some said that tube amp sounds nice because it has output impedance of 1ohm-6ohm, but I feel that you want to say that it is not the damping factor that makes nice tube sound. What is it?
The answer from you will be important, as you have proven in your "MyRef" that complicated amp(I imagine complex cct inside opamp+GC) can be made sound good too. 😀. Don't have to push a certain cct, as long as you understand what you want to do with the cct (I haven't know what is the main criterion in making good sounding audio amp with anything [discrete bipolars, mosfets, GC or anything else, simple or complex cct], what is the criterion)
F1 has output impedance of 80ohm(DF=0,1) and F2 has output impedance of 15ohm (DF=0.5). They both are current drive audio power amp, with no feedback. They have excellent review. But above, you said good sounding is not related to DF/Output Impedance. I'm confused. Which one is making the "good sound", is it the DF/Output impedance figure or something else (current drive, or is it phase accuracy with simple topology, maybe?)
Hi lumanauw,
I understand the confusion of the words that write, but when I will end the relationship on MY_REF is sure that all my thought be clear.
In connection with the DF and Zout, I say that I believe that a Current driver superior being to voltage driver , but is not lifelike on commercial spks. The excessive variation of level to various frequencies frustrate the advantages of driven.
Which solution? For me a good compromise is use techniques of " compensate current driver", similar to firstwatt.
But firstwatt has DF =.5 ?
Yes, but the "differential" structure allows to find un "compromises" among output current and differential Current, and improve the DF ( reducing the Zint of the current generators ). With this hypothesis, has to create an "ibrid" voltage/current with acceptable DF (> 10 ).
Naturally the mine are hypotensive, and doesn't interest me show the quality and the limits of all the audio topologies!
Per hour the better "audio" performances that I am successful to produce in my laboratory have cominged by structures as My_ref ( voltage control /current ouput stage ), and the reasons that have given me will share it with the members of this forum when end my relationship...
Ciao
Mauro
I understand the confusion of the words that write, but when I will end the relationship on MY_REF is sure that all my thought be clear.
In connection with the DF and Zout, I say that I believe that a Current driver superior being to voltage driver , but is not lifelike on commercial spks. The excessive variation of level to various frequencies frustrate the advantages of driven.
Which solution? For me a good compromise is use techniques of " compensate current driver", similar to firstwatt.
But firstwatt has DF =.5 ?
Yes, but the "differential" structure allows to find un "compromises" among output current and differential Current, and improve the DF ( reducing the Zint of the current generators ). With this hypothesis, has to create an "ibrid" voltage/current with acceptable DF (> 10 ).
Naturally the mine are hypotensive, and doesn't interest me show the quality and the limits of all the audio topologies!
Per hour the better "audio" performances that I am successful to produce in my laboratory have cominged by structures as My_ref ( voltage control /current ouput stage ), and the reasons that have given me will share it with the members of this forum when end my relationship...
Ciao
Mauro
Yes, Mauro, I can see your philosophy in "MyRef". The whole amp is voltage feedback amp, by 318 opamp. Inside that loop there is "current pump" by GC.
Your principle of hybrid / voltage control-current output stage needs 2 loops.
Do you have any idea how to make your hybrid only using 1 loop, not 2 feedback loop? Maybe simplicity can result better sound 😀 (But I might be wrong here, you know better on this)
Hi Lumanauw,
the motives of this select ( 2 stages 2 NFBs ) there are, and am extremely valid and serious.
I am finishing my work, still little days and the "secrets" of my circuit will be "publics" 😉
Ciao
Mauro
the motives of this select ( 2 stages 2 NFBs ) there are, and am extremely valid and serious.
I am finishing my work, still little days and the "secrets" of my circuit will be "publics" 😉
Ciao
Mauro
PCB is here
Hello all, Hello Russ and thanks.
PCB is here, and it's quite good.
See you later, in september, with lissening impression.
Bye
R
Hello all, Hello Russ and thanks.
PCB is here, and it's quite good.
See you later, in september, with lissening impression.
Bye
R
Case parts have arrived
Managed to get hold of some copper bus-bar on an interstate trip, and the lasercut panels are deburred. Now comes the part where holes are measured, drilled and tapped...
I'll have to call in some favors for that, I don't have any decent gear for that at home.
Managed to get hold of some copper bus-bar on an interstate trip, and the lasercut panels are deburred. Now comes the part where holes are measured, drilled and tapped...
I'll have to call in some favors for that, I don't have any decent gear for that at home.
An externally hosted image should be here but it was not working when we last tested it.
A pretty nice looking bit o' kit there Michael. 😀 Looks like its coming together. 🙂
Cheers!
Russ
Cheers!
Russ
Re: This is my Layout
Wow, I would say it is excellent!
🙂 The only comment i would make is that you will need to be sure you have adequate ventilation for your heatsinks. This amp tends to run warm.
Cheers!
Russ
riccardo said:
Wow, I would say it is excellent!
🙂 The only comment i would make is that you will need to be sure you have adequate ventilation for your heatsinks. This amp tends to run warm.Cheers!
Russ
Thanks a lot , Russ.
Your suggestion it's right.
i'm thinking about the heat.
Probably i'll make almost 80 holes in the top and bottom, near the heatsink...
Ciao
I'll could say somenthing about "sound" in semptember, i hope...
Could you say something about REV3?
How far the WIki for the new PCB?
(my english it's really rghjtrkinpofnmpomrpt!, sorry!)
Riccardo
Your suggestion it's right.
i'm thinking about the heat.
Probably i'll make almost 80 holes in the top and bottom, near the heatsink...
Ciao
I'll could say somenthing about "sound" in semptember, i hope...
Could you say something about REV3?
How far the WIki for the new PCB?
(my english it's really rghjtrkinpofnmpomrpt!, sorry!)
Riccardo
Re: This is my Layout
What do you think about having the heatsink between transformer and pcb ? So the heatsink would be kinda shielding against the transformer.
What do you think about having the heatsink between transformer and pcb ? So the heatsink would be kinda shielding against the transformer.
Re: Re: This is my Layout
Actually you get better shielding from the big caps than you do from the HS, unless its copper or ferrous. Maruo actually suggested pretty much as Riccardo has it laid out. 🙂 It is also the orientation I am using with very good success.
SmellOfPoo said:
Actually you get better shielding from the big caps than you do from the HS, unless its copper or ferrous. Maruo actually suggested pretty much as Riccardo has it laid out. 🙂 It is also the orientation I am using with very good success.
riccardo said:
Hi Riccardo,
I expect to have my prototype REV C monblocs tested by the end of next week(as long as all my parts get here), after successful tests I will make the design available for a group buy. 🙂 I believe Brian Donegan will be selling parts/PCB kits as well with the PCBs supplied by me, so people purchasing kits with PCBs will only pay one shipping charge for both the PCB and the parts kit. 😀
Cheers!
Russ