Check input condenser value or increase the value
Also check emitter resistances.... good idea to be lower than 0.47 ohms each one.
Check heat into fuses and solder very thin wire over them or into the fuses holders to guarantee low resistance.
Every small resistance into the output line may kill the bass.
Check speaker wiring for non soldered joints
Check the speaker itself, as you may have partially burned the speaker voice coil...them impedance will go down and bass will turn very weak.
Check if you have changed speaker position or some substitution
related the audio source.
Precision has huge power into the bass.
measure your speaker....it may be already damaged... post a picture, let me see your speaker.
regards
Carlos
Also check emitter resistances.... good idea to be lower than 0.47 ohms each one.
Check heat into fuses and solder very thin wire over them or into the fuses holders to guarantee low resistance.
Every small resistance into the output line may kill the bass.
Check speaker wiring for non soldered joints
Check the speaker itself, as you may have partially burned the speaker voice coil...them impedance will go down and bass will turn very weak.
Check if you have changed speaker position or some substitution
related the audio source.
Precision has huge power into the bass.
measure your speaker....it may be already damaged... post a picture, let me see your speaker.
regards
Carlos
space2000, in post #1052 you wanted to know if the B/E voltage you got for BC547 of 0.197 was correct.
Carlos has posted many Precision1 circuits with spot voltages and currents, but using a larger DC supply of +/-70V and +/-62V on the input rails.
He had a B/E voltage of 0.233V for BC547 (-62V rail to GND, minus -61.767V base to GND).
Allowing for your lower rail voltage, your B/E V would be about right.
I am curious that you were 0.5V higher at the base of Bc547/top of R19, than the rail voltage ( both measured to GND). Was that just a reading error?
Carlos has posted many Precision1 circuits with spot voltages and currents, but using a larger DC supply of +/-70V and +/-62V on the input rails.
He had a B/E voltage of 0.233V for BC547 (-62V rail to GND, minus -61.767V base to GND).
Allowing for your lower rail voltage, your B/E V would be about right.
I am curious that you were 0.5V higher at the base of Bc547/top of R19, than the rail voltage ( both measured to GND). Was that just a reading error?
The idea behind ground stars is that current flows in a complete loop... for instance during idleing the output transistors sits in a loop that circulates say 50mA... the inputs also sit in loops but at MUCH lower levels.... so if something shares the high current loop
it is going to be affected....
I think Carlos is lucky in that he once told me he has never experienced a ground loop hum...
it is going to be affected....
I think Carlos is lucky in that he once told me he has never experienced a ground loop hum...
When we have errors, all voltages turns unballanced
they all go crazy... some VBEs increases and other decreases....
This is NORMAL and do not worries me, as indicates that there are errors into the circuit.... after you find the error, voltages goes correct..... so, it is NORMAL to have strange VBEs when something is WRONG....this do not mean amplifier is NORMAL.... just tell us something is NORMALLY WRONG there.
Message to Billabong, this one upper and lower.
heheheheh.
It is a hell to find errors using voltages...as one depends from the other.... you may turn yourself (i turn myself) crazy trying to use my three half speed old workable neuroniuns, and short imagination, to understand several logical sequences aligned into a very long strip of sequential logics.
alike:
-"This has lower VBE because that one had higher, and that one had higher because probably the rigth one had lower...and all that because something must be wrong in point A, or B, or C or D , or E, or F"
I use to check continuity to debugging...to check if points are connected one to the other, to remove transistors and to check if they are the correct ones, if they are really NPN when you need a NPN or a PNP when you need a PNP...... if they have internal conduction in order, if shorted, if has leakages or something strange from Colector to emitter....well.... the easy thing...and always tracing red line into a printed schematics.... also i check for shorts and resistances from plus to minus... from negative line to ground and from positive to negative... also i use to check resistance from the output line to the ground.
This is the fastest way, we use to find all error we use to make...shorts, solder errors, open traces, wrong transistor leads..all stuff appear.
Into reparations, service, something i have made for Motorola for some time, i found this method faster... two to three times faster..better results than try to find errors using voltages.
But.... trying to analise reason why A is low in VBE, when you have B, C, D, E, F, G and all those interactions in combinations, exponential possibilities.... many chances of arrangements that may produce errors, use to spend much more time and need much more knowledge than i have.
My life shows me that is "normal" to humans, to make mistakes, several each day....into normal life they do not even care about..but into electronics our human failures appear immediatelly...so.... my word "normal" goes to people presenting problems, as assemble and "not to face" problems is really abnormal.... a big rarity.
Sorry for that, but now you may understand me better.
bye
Carlos
they all go crazy... some VBEs increases and other decreases....
This is NORMAL and do not worries me, as indicates that there are errors into the circuit.... after you find the error, voltages goes correct..... so, it is NORMAL to have strange VBEs when something is WRONG....this do not mean amplifier is NORMAL.... just tell us something is NORMALLY WRONG there.
Message to Billabong, this one upper and lower.
heheheheh.
It is a hell to find errors using voltages...as one depends from the other.... you may turn yourself (i turn myself) crazy trying to use my three half speed old workable neuroniuns, and short imagination, to understand several logical sequences aligned into a very long strip of sequential logics.
alike:
-"This has lower VBE because that one had higher, and that one had higher because probably the rigth one had lower...and all that because something must be wrong in point A, or B, or C or D , or E, or F"
I use to check continuity to debugging...to check if points are connected one to the other, to remove transistors and to check if they are the correct ones, if they are really NPN when you need a NPN or a PNP when you need a PNP...... if they have internal conduction in order, if shorted, if has leakages or something strange from Colector to emitter....well.... the easy thing...and always tracing red line into a printed schematics.... also i check for shorts and resistances from plus to minus... from negative line to ground and from positive to negative... also i use to check resistance from the output line to the ground.
This is the fastest way, we use to find all error we use to make...shorts, solder errors, open traces, wrong transistor leads..all stuff appear.
Into reparations, service, something i have made for Motorola for some time, i found this method faster... two to three times faster..better results than try to find errors using voltages.
But.... trying to analise reason why A is low in VBE, when you have B, C, D, E, F, G and all those interactions in combinations, exponential possibilities.... many chances of arrangements that may produce errors, use to spend much more time and need much more knowledge than i have.
My life shows me that is "normal" to humans, to make mistakes, several each day....into normal life they do not even care about..but into electronics our human failures appear immediatelly...so.... my word "normal" goes to people presenting problems, as assemble and "not to face" problems is really abnormal.... a big rarity.
Sorry for that, but now you may understand me better.
bye
Carlos
Carlos.
Thanks for sharing your knowledge on trouble-shooting. I'm sure most here will find it very useful ,and enable us to do more ourselves, before asking for help.
Re. the VBE of BC547:
space2000 said all his VBEs were normal, around 500mv, except his BC547, which was only 197mv and asked if this was the correct VBE.
I was just pointing out to him that 197mv would be normal for 57V rail, as the VBE of the BC547 you posted was 233mv for 62V input section rail (+/- 70V P/S)
I assumed that you posted voltages for a correctly functioning amp, and that the VBE you had for BC547 is correct ( for 62V input section rails).
As in your drawing:
http://www.diyaudio.com/forums/attachment.php?s=&postid=1427833&stamp=1202949319
Regards,
billabong.
Thanks for sharing your knowledge on trouble-shooting. I'm sure most here will find it very useful ,and enable us to do more ourselves, before asking for help.
Re. the VBE of BC547:
space2000 said all his VBEs were normal, around 500mv, except his BC547, which was only 197mv and asked if this was the correct VBE.
I was just pointing out to him that 197mv would be normal for 57V rail, as the VBE of the BC547 you posted was 233mv for 62V input section rail (+/- 70V P/S)
I assumed that you posted voltages for a correctly functioning amp, and that the VBE you had for BC547 is correct ( for 62V input section rails).
As in your drawing:
http://www.diyaudio.com/forums/attachment.php?s=&postid=1427833&stamp=1202949319
Regards,
billabong.
To add to my last post, space 2000 reported that the VBE remained the same after he replaced the BC547 with BC546.
This transistor operates switched of.... have some bias but not enougth
to conduct.... it is a control....when current, in excess, cross the resistance you have from base to emitter, then the voltage will increase and the unit will start to conduct when reach something near 500 milivolts (or a little bit less).... then the colector to emitter junction will reduce its resistance and audio will be drained to negative line.... this is an automatic over current control, placed there after some suggestions folks made.
This may protect the big 2SC4793 or others... better units with higher VCE voltage and lower capacitance,.... the exciting transistor, the master VAS transistor, the second one... also helps the other one too....But... this is in the real world a dinamic killer... a sound smasher... works compressing audio... was a politically correct behavior to include it...but sonically it is terrible...better to supress this transistor to avoid losses of audio quality.
When you have peaks of power, the current that will cross the master VAS will be big .... but not enougth to kill the unit...i have tested that...but some "panic" was created, suggestions of Andrew T (not sure) and Graham Maynard (sure) was about that.... Nico turns afraid.... started to thing about loose his speaker and one accident he had in a friend's home..... so... the panic was created..... to extinguish the fire i have included this thing.... very force.... very sad to do that....but this have ended to controversies about...and peace took place into the thread once again.
I strongly suggest folks not to use this transistor...
Continuing...... well... when the big peak of power is amplified, the big current will cross the master VAS (at your rigth, the second one, the bigger transistor) will develop, will create, bigger voltage into the resistance... that is placed in series with the coletor an emitter circuit.... this bigger voltage will make the small transistor on, and conduction will send some audio to ground...this will control the next microseconds of audio that will enter... and will keep this control till the overvoltage (more than 500 milivolts) is developed into the sensor resistance.
This means "KILL THE PEAKS".... this means... "BLOCK THE DINAMICS".... an amplifier murderer.... good technically not to bother the transistor and terrible to bother audiophiles.
Voltage there can be anything from 100 to 400 hundred milivolts...this will only antecipate or delay the action of the circuit murderer.
I do not like the "calculator machines" behavior about that...they put the operational points and DC calculations and overcurrents and protections and safety in first position.... and if this left some room to audio quality it is good to them...but they do not think the sonics as the first thing...they use to enter with those darn mathematics and create panic...people alike Nico starts to shake his bones and to think about all accidents he had with electronics..and the mess is created.
Some of those folks..... Graham i know very well that is sonically addicted, but the other one i do not know.... some of them, maybe no one of those ones...but the Masters of electronic...some of them knows sonics results less than their 90 years old grandmothers.
regards,
Carlos
to conduct.... it is a control....when current, in excess, cross the resistance you have from base to emitter, then the voltage will increase and the unit will start to conduct when reach something near 500 milivolts (or a little bit less).... then the colector to emitter junction will reduce its resistance and audio will be drained to negative line.... this is an automatic over current control, placed there after some suggestions folks made.
This may protect the big 2SC4793 or others... better units with higher VCE voltage and lower capacitance,.... the exciting transistor, the master VAS transistor, the second one... also helps the other one too....But... this is in the real world a dinamic killer... a sound smasher... works compressing audio... was a politically correct behavior to include it...but sonically it is terrible...better to supress this transistor to avoid losses of audio quality.
When you have peaks of power, the current that will cross the master VAS will be big .... but not enougth to kill the unit...i have tested that...but some "panic" was created, suggestions of Andrew T (not sure) and Graham Maynard (sure) was about that.... Nico turns afraid.... started to thing about loose his speaker and one accident he had in a friend's home..... so... the panic was created..... to extinguish the fire i have included this thing.... very force.... very sad to do that....but this have ended to controversies about...and peace took place into the thread once again.
I strongly suggest folks not to use this transistor...
Continuing...... well... when the big peak of power is amplified, the big current will cross the master VAS (at your rigth, the second one, the bigger transistor) will develop, will create, bigger voltage into the resistance... that is placed in series with the coletor an emitter circuit.... this bigger voltage will make the small transistor on, and conduction will send some audio to ground...this will control the next microseconds of audio that will enter... and will keep this control till the overvoltage (more than 500 milivolts) is developed into the sensor resistance.
This means "KILL THE PEAKS".... this means... "BLOCK THE DINAMICS".... an amplifier murderer.... good technically not to bother the transistor and terrible to bother audiophiles.
Voltage there can be anything from 100 to 400 hundred milivolts...this will only antecipate or delay the action of the circuit murderer.
I do not like the "calculator machines" behavior about that...they put the operational points and DC calculations and overcurrents and protections and safety in first position.... and if this left some room to audio quality it is good to them...but they do not think the sonics as the first thing...they use to enter with those darn mathematics and create panic...people alike Nico starts to shake his bones and to think about all accidents he had with electronics..and the mess is created.
Some of those folks..... Graham i know very well that is sonically addicted, but the other one i do not know.... some of them, maybe no one of those ones...but the Masters of electronic...some of them knows sonics results less than their 90 years old grandmothers.
regards,
Carlos
Re: This transistor operates switched of.... have some bias but not enougth
Man I feel stupid now... how could I forget?
destroyer X said:
Man I feel stupid now... how could I forget?
Just join the Club....i use to be stupid my whole life
I would ask you, what design you want to have.... i am not feeling happy to go on with the Precision II...... i have lost interest.
But i remember that i have promissed to you, a tested design, that would be absolutelly free to you to do whatever you want related boards design.... a Nico's property, something to sell in South Africa or Around the whole world....not a DIY design.... your property.
I would like to ask you, publically, what circuit you want.... if you want something....the voltage you want, the power you want, the characteristics you want, the transistors you want, the kind of sonics you want...maybe a powerfull HRII that you love.... the one to you to call the way you want.
I think you deserve that dear Nico.... big help you gave me..... i am ready to do whatever you want.
This is a public proposal.
regards,
Carlos
I would ask you, what design you want to have.... i am not feeling happy to go on with the Precision II...... i have lost interest.
But i remember that i have promissed to you, a tested design, that would be absolutelly free to you to do whatever you want related boards design.... a Nico's property, something to sell in South Africa or Around the whole world....not a DIY design.... your property.
I would like to ask you, publically, what circuit you want.... if you want something....the voltage you want, the power you want, the characteristics you want, the transistors you want, the kind of sonics you want...maybe a powerfull HRII that you love.... the one to you to call the way you want.
I think you deserve that dear Nico.... big help you gave me..... i am ready to do whatever you want.
This is a public proposal.
regards,
Carlos
Thanks Carlos for a the explaination of the function of BC 547C.
I'm sure other builders will appreciate it also.
I doubt I will need to operate the amp at a high enough power that the music peaks would cause BC547 to conduct. This will allow me to remove it. I will initially include it and check the peaks on an oscilloscope at the highest volumes I would use, before deciding if I can remove it.
Thank you again,
billabong.
I'm sure other builders will appreciate it also.
I doubt I will need to operate the amp at a high enough power that the music peaks would cause BC547 to conduct. This will allow me to remove it. I will initially include it and check the peaks on an oscilloscope at the highest volumes I would use, before deciding if I can remove it.
Thank you again,
billabong.
Thanks Uncle Charly I am still in the process of building my latests amp, but I am certainly generateing some ideas as I go along...
It will be one of three things A) a suitable output stage module for a guitar amp... first got to listen to mine to see if it behaves as expected... the goal is the opposite of Hifi.. i.e. sagging supply sound etc...
B would be a slightly higher powered HRII derivative (maybe learning some things from PI output stage) 2 pairs of output trannies max... something around a 30 to 35VAC transformer (which we have not catered for yet)
C would be a hybrid amp also a project in design this side... sadly I have to wait for parts for the DIY transformers from overseas... with this option I would supply the frontend and its High voltage switchmode supply (in stead of transformer), and you would design a very good output stage for this, what currents and voltages it wants to see at signal level where VAS meets drivers...
----------------
As you can see they are interesting and unusual projects, just like me... Some people keep inventing new stuff, others like to refine or find new applications for old things.
I will only be able to advise you in a month or so... sadly you know how slow and boring I can be when makeing choices...and as said two of these are actualy projects allready in early stages of planning/execution.
It will be one of three things A) a suitable output stage module for a guitar amp... first got to listen to mine to see if it behaves as expected... the goal is the opposite of Hifi.. i.e. sagging supply sound etc...
B would be a slightly higher powered HRII derivative (maybe learning some things from PI output stage) 2 pairs of output trannies max... something around a 30 to 35VAC transformer (which we have not catered for yet)
C would be a hybrid amp also a project in design this side... sadly I have to wait for parts for the DIY transformers from overseas... with this option I would supply the frontend and its High voltage switchmode supply (in stead of transformer), and you would design a very good output stage for this, what currents and voltages it wants to see at signal level where VAS meets drivers...
----------------
As you can see they are interesting and unusual projects, just like me... Some people keep inventing new stuff, others like to refine or find new applications for old things.
I will only be able to advise you in a month or so... sadly you know how slow and boring I can be when makeing choices...and as said two of these are actualy projects allready in early stages of planning/execution.
I forgot to say, I sent new drill files to the factory, so that from the batch currently in production, you will have nice big holes, where they are a little small at the moment.
Carlos I have e-mailed you the files for your records.
Carlos I have e-mailed you the files for your records.
Maybe you can design your own...or we can do it together
following your needs and applications...some drop of voltage...some interesting distortions to help guitars...some enrichment in sonics....yeah!... we can do that together...
Something very huge.... hiper strong...alike military things... ready to face high temperature, vibrations, full distortion continuous power with reliability to face a Rock concert...and finally the Guitar man will try to destroy the amplifier and will broke the guitar over the amplifier case... will broke a hammer.... will try a bomb and will not kill the sound!
ahahahahha.
A high powered HRII, a clone that you can put your name on it and use it the way you want, the way you like.
Good.
When decided...you know how to find me.
regards,
Carlos
following your needs and applications...some drop of voltage...some interesting distortions to help guitars...some enrichment in sonics....yeah!... we can do that together...
Something very huge.... hiper strong...alike military things... ready to face high temperature, vibrations, full distortion continuous power with reliability to face a Rock concert...and finally the Guitar man will try to destroy the amplifier and will broke the guitar over the amplifier case... will broke a hammer.... will try a bomb and will not kill the sound!
ahahahahha.
A high powered HRII, a clone that you can put your name on it and use it the way you want, the way you like.
Good.
When decided...you know how to find me.
regards,
Carlos
Questions re P1 board
Bigger holes will be good. I have been stuffing my P1 boards using some Holco 1/4 watt resistors and they don't fit at all - their leads are too thick. I had to re-drill many holes - a real pain.
I have some questions and posting it here since the answers may interest other builder as well.
1. What is the rationale with R28-33 having to go under the board. it seems that they will fit nicely on top.
2. Same question for C23-25.
3. R27 seems to be better off under the board. Either way, it seems that R27 creates a potential short if not handled very carefully.
4. C26 (if used) better under board? Does one loose any performance in sound if C26 is left off?
5. If one wants to use a good film cap for Cin it seems best to mount R1 and Cin off board and connect their output to the jumper by Q1 (eliminating the long on-board trace).
6. Is the hole marked "PROT" (by R6) the source of DC for your protection circuit? Is only one P1 board connected to the DC input for the protection board? Does it matter if DC is taken from only one of the P1 boards? I got a single protection board to handle both P1 boards.
I shall appreciate your responses by question number.
Thanks,
Francois
Nordic said:
Bigger holes will be good. I have been stuffing my P1 boards using some Holco 1/4 watt resistors and they don't fit at all - their leads are too thick. I had to re-drill many holes - a real pain.
I have some questions and posting it here since the answers may interest other builder as well.
1. What is the rationale with R28-33 having to go under the board. it seems that they will fit nicely on top.
2. Same question for C23-25.
3. R27 seems to be better off under the board. Either way, it seems that R27 creates a potential short if not handled very carefully.
4. C26 (if used) better under board? Does one loose any performance in sound if C26 is left off?
5. If one wants to use a good film cap for Cin it seems best to mount R1 and Cin off board and connect their output to the jumper by Q1 (eliminating the long on-board trace).
6. Is the hole marked "PROT" (by R6) the source of DC for your protection circuit? Is only one P1 board connected to the DC input for the protection board? Does it matter if DC is taken from only one of the P1 boards? I got a single protection board to handle both P1 boards.
I shall appreciate your responses by question number.
Thanks,
Francois
Hi Francois I didn't realise the resistor legs are too thin, I don't have access to resistors other than basic metal foils and carbons, which have thin leads.
You are free to install parts on top or the bottom, It was Carlos's request to draw them on the bottom for a clean look.
There is enough place o top for C26... it is not a function critical component and may be omitted.
Remember the connection to R2 and C6 if you want offboard Cin and R1, I would just install one side of the chain to bottom R1 and the other to bottom Cin... The boards are dead quiet, I dont think 2 cm more input tracewill cause a problem...
Remember to do the little In- modification as per the included printed instructions...
6 Correct, and it will be fine...
You are free to install parts on top or the bottom, It was Carlos's request to draw them on the bottom for a clean look.
There is enough place o top for C26... it is not a function critical component and may be omitted.
Remember the connection to R2 and C6 if you want offboard Cin and R1, I would just install one side of the chain to bottom R1 and the other to bottom Cin... The boards are dead quiet, I dont think 2 cm more input tracewill cause a problem...
Remember to do the little In- modification as per the included printed instructions...
6 Correct, and it will be fine...
Hi Nico,
Thanks for your quick reply. All should be well now with P1.
However, I still have to complete my HRII. My boards are done but I'm still wrestling with an enclosure.
Regards,
Francois
Thanks for your quick reply. All should be well now with P1.
However, I still have to complete my HRII. My boards are done but I'm still wrestling with an enclosure.
Regards,
Francois
P-I Boards arrived
Thanks Nico!
A nice little package with lovely SA postage stamps arrived today.
Cheers,
Ryan
Thanks Nico!
A nice little package with lovely SA postage stamps arrived today.
Cheers,
Ryan
Hi,
I just learned from Dx some valuable idea, that BC547 now BC546 can be removing for btr sound quality. I am waiting for your test conduct on it. Also need to know how we can remove it.
My amp now has more bass. It was cause by thin cable when I used to testing. I change to thick. Still there are more to be done.
Thank and waiting for result for BC546….
*Also I want to ask about, I made two channel amp, one is quiet when I power on it but another one is get loud sound once. There I couldn’t find any things wrong in circuit. Is this cause by cap 470—100v? Or any cap faulty?
Best regards
michael
I just learned from Dx some valuable idea, that BC547 now BC546 can be removing for btr sound quality. I am waiting for your test conduct on it. Also need to know how we can remove it.
My amp now has more bass. It was cause by thin cable when I used to testing. I change to thick. Still there are more to be done.
Thank and waiting for result for BC546….
*Also I want to ask about, I made two channel amp, one is quiet when I power on it but another one is get loud sound once. There I couldn’t find any things wrong in circuit. Is this cause by cap 470—100v? Or any cap faulty?
Best regards
michael
My amplifiers are dead silent, i have spent days removing that.
No one of them produces noises during power on...no "thump" noise.
If you have noise, you have something wrong, or bad component.
the reality is the one is silent...and this indicates the amplifier is silent... search for bugs.
Having two, you can go comparing one to the other.
Amplifiers do not have good or bad days, good or bad mood...if they are silent, they are silent for ever.
regards,
Carlos
No one of them produces noises during power on...no "thump" noise.
If you have noise, you have something wrong, or bad component.
the reality is the one is silent...and this indicates the amplifier is silent... search for bugs.
Having two, you can go comparing one to the other.
Amplifiers do not have good or bad days, good or bad mood...if they are silent, they are silent for ever.
regards,
Carlos
hi,
Just made change a bit as discussed earlier. I removed just BC546 instead of BC547. main volt now count is higher 60.1v but last time it was showing 59v. Sound is much more btr then last time.
I counted voltage into Q10, Q9 E-B
Q10 = 0.549v
Q9 = 0.557v
Q10 2sc4793 gets a bit hotter then last time.
Hope for discussion….
Best regards
michael
Just made change a bit as discussed earlier. I removed just BC546 instead of BC547. main volt now count is higher 60.1v but last time it was showing 59v. Sound is much more btr then last time.
I counted voltage into Q10, Q9 E-B
Q10 = 0.549v
Q9 = 0.557v
Q10 2sc4793 gets a bit hotter then last time.
Hope for discussion….
Best regards
michael
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