I am crazy angry right now... The mudderfudgers at plitron are still twidling their thumbs, one office blameing the other, with nothing being done... I have had to phone so many times the girl at the switchboard knows my voice allready...
Finaly spoke to sales manager today who then got the branch manager to phone me... handy experience haveing worked in large corporate world before.... So here we are waiting again, while everyone listens to their DXes... Oh well at least I'm getting a good discount now.
Is it just the two trimpots I need to adust to run with the 25V AC transformer instead of 24V one...? I'm am so gatvol (fedup) I can throw up... If I can find 2 large enough resistors and some extra thermal compound, I may just test the ******* thing with my GC transformer for real...
Bad weather not doing much for my back and mood either...
Finaly spoke to sales manager today who then got the branch manager to phone me... handy experience haveing worked in large corporate world before.... So here we are waiting again, while everyone listens to their DXes... Oh well at least I'm getting a good discount now.
Is it just the two trimpots I need to adust to run with the 25V AC transformer instead of 24V one...? I'm am so gatvol (fedup) I can throw up... If I can find 2 large enough resistors and some extra thermal compound, I may just test the ******* thing with my GC transformer for real...
Bad weather not doing much for my back and mood either...
Do not worry about me dear Nordic...the amplifier was tested in this forum by Klaas,
so, it is checked and passed.
I am not eagger to see your amplifier running.
You can use the time you need, and to wait the parts you want.
I just cannot understand why you cannot( and you could not during last three weeks) solder three wires from your chip amplifier supply and put Dx amplifier to work?
This is extremelly strange to me, as i am fast as a ligthning, and now i days i would be constructing the twentieth amplifier counting the Dx amplifier as number one, the first......
This is your decision, as Klaas and i have already suggested that, and it is extremelly obvious that other supply will give the needed electrons to the amplifier... i have to accept your decisions, but i cannot understand them.
Also Dx amplifier can work from 15 volts to 40 volts without too much modifications,...only the offset adjustment and bias adjustment.
Maybe you have decided that this transformer you are waiting for... that this one, this unit in special, is the Dx amplifier power transformer....well...it is up to you to decide that the Chip amplifier transformer do not bellongs to the chip transformer anymore, and decide to call it as the Dx amplifier power transformer and use it... at least while you wait those folks to send your parts.
That transformer you have ordered ,did not born having Dx as family name, nothing will be write above telling that will provide energy ONLY if installed into Dx amplifier..... every source of voltage and current..every DC symetrical will be good to drive the amplifier into sonics...maybe not so good as the transformer you have ordered, but will produce music for you.... even with smaller power and more distortion because of the transformer used.
Man...turn yourself more flexible...life will be easier to you Nordic.
regards,
Carlos
so, it is checked and passed.
I am not eagger to see your amplifier running.
You can use the time you need, and to wait the parts you want.
I just cannot understand why you cannot( and you could not during last three weeks) solder three wires from your chip amplifier supply and put Dx amplifier to work?
This is extremelly strange to me, as i am fast as a ligthning, and now i days i would be constructing the twentieth amplifier counting the Dx amplifier as number one, the first......
This is your decision, as Klaas and i have already suggested that, and it is extremelly obvious that other supply will give the needed electrons to the amplifier... i have to accept your decisions, but i cannot understand them.
Also Dx amplifier can work from 15 volts to 40 volts without too much modifications,...only the offset adjustment and bias adjustment.
Maybe you have decided that this transformer you are waiting for... that this one, this unit in special, is the Dx amplifier power transformer....well...it is up to you to decide that the Chip amplifier transformer do not bellongs to the chip transformer anymore, and decide to call it as the Dx amplifier power transformer and use it... at least while you wait those folks to send your parts.
That transformer you have ordered ,did not born having Dx as family name, nothing will be write above telling that will provide energy ONLY if installed into Dx amplifier..... every source of voltage and current..every DC symetrical will be good to drive the amplifier into sonics...maybe not so good as the transformer you have ordered, but will produce music for you.... even with smaller power and more distortion because of the transformer used.
Man...turn yourself more flexible...life will be easier to you Nordic.
regards,
Carlos
Lol Carlos, mostly fear keeps me working slowly, when I end up building something I don't understand I tend to go find out what I don't before I power up... I am scared of damageing the other transformer and then I have nothing, my wife would beat me, and I would have to keep her entertained until a new transformer is found...
It is so depressing, for weeks now, I am looking at my completed circuit board without the guts to plug it in and play...
I'm a poor man, blowing up parts is not something I can easily afford...
P.S. Thanks Graham, nice to see you are still with us...
Oh and Carlos, you are right about how my mind works about the transformers... stupid realy, I will get and and beat myself up just now, when my coffee is done...
Also out of dumness I thought for a long time the amp is class A and would draw 5A continuous, which would probably kill my transformer if I had to guess...Now I understand the biasing stuff a bit better I see that is only Peak at peak, but that low volume or no signal is only 50 to 100mA per channel... Took very long to sink in , but my mind finaly grasped this while I was working on Greg's project with the relays which is now on the 6th PCB/circuit version...
It is so depressing, for weeks now, I am looking at my completed circuit board without the guts to plug it in and play...
I'm a poor man, blowing up parts is not something I can easily afford...
P.S. Thanks Graham, nice to see you are still with us...
Oh and Carlos, you are right about how my mind works about the transformers... stupid realy, I will get and and beat myself up just now, when my coffee is done...
Also out of dumness I thought for a long time the amp is class A and would draw 5A continuous, which would probably kill my transformer if I had to guess...Now I understand the biasing stuff a bit better I see that is only Peak at peak, but that low volume or no signal is only 50 to 100mA per channel... Took very long to sink in , but my mind finaly grasped this while I was working on Greg's project with the relays which is now on the 6th PCB/circuit version...
hehe...you have some "ritual" in your life.
related your wife...replace her by another one less strong...or much better, replace the 36 years old one by two others having 18 years old.....
Life will turn better with young girls around.....no!...negative, you do not need stay too much distant from the old wife....you can tell that you change religion, and some of them accept multiple wive.
Smaller womans, in size, will not produce big punches, but they can bite you.
You will need to know the girls secret...the problemis that they talk too much...you have to find her "mains plug"...and removing from the outlet they will stop talking finishing with a nice decay of speed in her speach sonics..the same you have when you remove mains from a turntable.....aahahahahah
I will send you the Ianomani indian music to call rains and to protect ourselves against lighnings.... singing that, no transformer will burn around....hehe.
- "Dx amplifier, the only one that carries "big magic" with it"
Marketing department...number E-0357574763847348.
regards,
Carlos
related your wife...replace her by another one less strong...or much better, replace the 36 years old one by two others having 18 years old.....
Life will turn better with young girls around.....no!...negative, you do not need stay too much distant from the old wife....you can tell that you change religion, and some of them accept multiple wive.
Smaller womans, in size, will not produce big punches, but they can bite you.
You will need to know the girls secret...the problemis that they talk too much...you have to find her "mains plug"...and removing from the outlet they will stop talking finishing with a nice decay of speed in her speach sonics..the same you have when you remove mains from a turntable.....aahahahahah
I will send you the Ianomani indian music to call rains and to protect ourselves against lighnings.... singing that, no transformer will burn around....hehe.
- "Dx amplifier, the only one that carries "big magic" with it"
Marketing department...number E-0357574763847348.
regards,
Carlos
Hi, all.
I've been following Carlos' DX thread from the beginning and decided to build a pair for myself. I'd like to try something a bit different and use some parts I salvaged from a Sansui SA-500 receiver. The picture shows a fairly large heatsink, 32-0-32 vac transformer, a pair of 10,000uF capacitors, two pairs of 2SC1913 and 2SA913 driver transistors, two pairs of 2SB541A and 2SD338A output transistors, all salvaged and a pair of slightly modified circuit boards from the DX web page. I don't think I'll use the capacitors or driver transistors for this amplifier.
There's not a lot of information on the net on the power transistors. About all I could find was cut and pasted from here: The 2SD388A is an NPN type (110V, 8A, 80W). Types to compare for sub are 2B3442, 2SD551, 2SD732, MJ15001. The 2SB541A is the PNP complement. Types to compare here are 2SA981, 2SA982, 2SA1141, 2SB681.
The original receiver was rated at 55 watts/channel so I don't expect this to be a high powered amplifier, hopefully just a good sounding amplifier. I can always find a use for another one.
The transformer has a higher voltage and the output transistors have lower power dissipation than the DX amp specs. Should I be worried about burning transistors and a room full of magic smoke? Will a VBE multiplier on the heat sink save the day?
I need to order parts this weekend, then drilling, soldering, bending, tapping...good times ahead.
Edit: A question for the group. What is the name of the spade terminals used for the power and speaker connections on Greg's PCB? Extra credit given for a Mouser or Digikey part number.
I've been following Carlos' DX thread from the beginning and decided to build a pair for myself. I'd like to try something a bit different and use some parts I salvaged from a Sansui SA-500 receiver. The picture shows a fairly large heatsink, 32-0-32 vac transformer, a pair of 10,000uF capacitors, two pairs of 2SC1913 and 2SA913 driver transistors, two pairs of 2SB541A and 2SD338A output transistors, all salvaged and a pair of slightly modified circuit boards from the DX web page. I don't think I'll use the capacitors or driver transistors for this amplifier.
There's not a lot of information on the net on the power transistors. About all I could find was cut and pasted from here: The 2SD388A is an NPN type (110V, 8A, 80W). Types to compare for sub are 2B3442, 2SD551, 2SD732, MJ15001. The 2SB541A is the PNP complement. Types to compare here are 2SA981, 2SA982, 2SA1141, 2SB681.
The original receiver was rated at 55 watts/channel so I don't expect this to be a high powered amplifier, hopefully just a good sounding amplifier. I can always find a use for another one.
The transformer has a higher voltage and the output transistors have lower power dissipation than the DX amp specs. Should I be worried about burning transistors and a room full of magic smoke? Will a VBE multiplier on the heat sink save the day?
I need to order parts this weekend, then drilling, soldering, bending, tapping...good times ahead.
Edit: A question for the group. What is the name of the spade terminals used for the power and speaker connections on Greg's PCB? Extra credit given for a Mouser or Digikey part number.
Attachments
Hi BillH,
I'll leave it to Carlos, the parts substitution king, to help you with parts selection. The parts specified by Carlos are only a few dollars Digikey, mine just arrive today.
This is were I buy my spade terminals from:
http://www.altronics.com.au/index.asp?search=spade&area=srch&option=and
Happy building.
regards
I'll leave it to Carlos, the parts substitution king, to help you with parts selection.
The parts specified by Carlos are only a few dollars Digikey, mine just arrive today.This is were I buy my spade terminals from:
http://www.altronics.com.au/index.asp?search=spade&area=srch&option=and
Happy building.
regards
I bought my first bag of spade connectors for the DX....Think I'm set for a long time now... 100 spades
And it is called vertical PCB to spade or spade to pcb connectors, i.e. they point up...
I.f you have $20 to $30 you can go out and buy almost all the components for the electronic side of things...
And it is called vertical PCB to spade or spade to pcb connectors, i.e. they point up...
I.f you have $20 to $30 you can go out and buy almost all the components for the electronic side of things...
Uops....it seems your informed voltage is AC
This way you will have something alike 45 plus 45 volts....hehe..even loosing some volts because of the load, your transistors will hold a lot of energy...you will submit, expose, your transistors to a lot of "stress"....they may result burned.
Forget to use 4 ohms of 6 ohms speakers..for sure you will have smoke.
Using 8 ohms, normal music levels will not be a problem...but if you install a guitar, a sinthetizer or a continuous test signal...hehe..this way will see smoke too.
Use 2.5 amperes in series with your outputs, fast blow fuses, and pray that your supply may help you loosing a lot of volts during dinamic operation.....because if the opposite happens, a huge supply, able to keep the voltage without too much losses...than...boooom!
Your Dx amplifier will not be guaranteed using those output transistors...unless you use those two pairs in parallel to one channel only...using emitter resistances to each one of those output transistors...0.22 ohms will be good enougth.
70 watts over 8 ohms and 140 watts over 4 ohms during the peaks...with the supply condensers charged.... musical introductions of small moments without sound and than a "fortíssimo"...hehe...will kill your transistors if you use a single pair.
Those transistors are not a good idea.... better to find others.
regards,
Carlos
This way you will have something alike 45 plus 45 volts....hehe..even loosing some volts because of the load, your transistors will hold a lot of energy...you will submit, expose, your transistors to a lot of "stress"....they may result burned.
Forget to use 4 ohms of 6 ohms speakers..for sure you will have smoke.
Using 8 ohms, normal music levels will not be a problem...but if you install a guitar, a sinthetizer or a continuous test signal...hehe..this way will see smoke too.
Use 2.5 amperes in series with your outputs, fast blow fuses, and pray that your supply may help you loosing a lot of volts during dinamic operation.....because if the opposite happens, a huge supply, able to keep the voltage without too much losses...than...boooom!
Your Dx amplifier will not be guaranteed using those output transistors...unless you use those two pairs in parallel to one channel only...using emitter resistances to each one of those output transistors...0.22 ohms will be good enougth.
70 watts over 8 ohms and 140 watts over 4 ohms during the peaks...with the supply condensers charged.... musical introductions of small moments without sound and than a "fortíssimo"...hehe...will kill your transistors if you use a single pair.
Those transistors are not a good idea.... better to find others.
regards,
Carlos
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My dear friend Phong Vu Tuang disappeared..he dissipated alike smoke
I could not read him once more.... i have found him posting in Symassym, that other model with bigger supply voltage.
The last news he told me was that a Dx amplifier was playing loud into a Restaurant or something alike.
The informs i have, if not wrong, was that the supply was 55 plus 55 volts.... also he informed that had burned transistors with the Dx schematic, well..he burned transistor with his supply schematic.
With this voltage, will be easy to produce 250 watts RMS over 4 ohms...and something alike the half of it when using 8 ohms.
And this is undistorted sound!
Now try to imagine the real conditions, of a restaurant, when the environment is noisy..volume up the limit to distribute sound to the entire room...if people is dancing...well, things goes harder and harder, as they will absorb sound and will block sound alike a wall.
Speakers, even beeing specified as 8 ohms, they are not really that impedance in entire bandwidth..some of them have valleys of impedance, and 3 ohms is not impossible....this may result in more than 300 watts of power.
Under 8 ohms, dissipation will be something near 200 watts....and under 4 ohms will reach 400 watts.
If Phong used a single pair into the output..for sure the amplifier is now a days burned..and this may explain why he disappeared...not to bring bad news....and not to feel ashamed too.
This happens, as people force amplifiers above the limits.
"Dx amplifier is huge and reliable..but cannot hold those excesses"
regards,
Carlos
I could not read him once more.... i have found him posting in Symassym, that other model with bigger supply voltage.
The last news he told me was that a Dx amplifier was playing loud into a Restaurant or something alike.
The informs i have, if not wrong, was that the supply was 55 plus 55 volts.... also he informed that had burned transistors with the Dx schematic, well..he burned transistor with his supply schematic.
With this voltage, will be easy to produce 250 watts RMS over 4 ohms...and something alike the half of it when using 8 ohms.
And this is undistorted sound!
Now try to imagine the real conditions, of a restaurant, when the environment is noisy..volume up the limit to distribute sound to the entire room...if people is dancing...well, things goes harder and harder, as they will absorb sound and will block sound alike a wall.
Speakers, even beeing specified as 8 ohms, they are not really that impedance in entire bandwidth..some of them have valleys of impedance, and 3 ohms is not impossible....this may result in more than 300 watts of power.
Under 8 ohms, dissipation will be something near 200 watts....and under 4 ohms will reach 400 watts.
If Phong used a single pair into the output..for sure the amplifier is now a days burned..and this may explain why he disappeared...not to bring bad news....and not to feel ashamed too.
This happens, as people force amplifiers above the limits.
"Dx amplifier is huge and reliable..but cannot hold those excesses"
regards,
Carlos
There are discussions about were to ground the Zobel, some people
prefer the transformer center tape ground, others prefer the lifted ground.
To avoid to discuss those things, as this is more a matter of preference than a matter of sonics (tested), we include this Ze points...so you can run your ground wire the way you want.
Doctor Graham Maynard, if i am not wrong, prefer star ground points and zobel connected into the lifted earth point.
So, dear Ritchie...do what you prefer, or what you think that will be better.
regards,
Carlos
prefer the transformer center tape ground, others prefer the lifted ground.
To avoid to discuss those things, as this is more a matter of preference than a matter of sonics (tested), we include this Ze points...so you can run your ground wire the way you want.
Doctor Graham Maynard, if i am not wrong, prefer star ground points and zobel connected into the lifted earth point.
So, dear Ritchie...do what you prefer, or what you think that will be better.
regards,
Carlos
BillH, i was thinking on you, and i remember that you will have reduced sensitivity
into the input..this is great to avoid overdrive the amplifier...will be another helping hand to you....i mean, the maximum standard pre amplifier output will not be able to drive the power amplifier into it's maximum power...and this maximum power is something you will need to avoid.
The increase of supply voltage compared to original will make the amplifier less sensitive.
The solution to increase the sensitivity to standard value is to decrease R10 value to 1K8 or even 1K5..... better not to have standard sensitivity with those transistors you shown us.
So, keep the R10 as 2K2 as standard.... will be more safe.
But i think your output transistors may short...this way, do not forget the output fuse to avoid to have burned speakers too.
Better to find stronger output transistors....80W is not enougth..better if you find 160 watts and up.... but, beeing your supply voltage bigger...good idea to you is to use Sankens (one of the strongest workhorses, an enormous beast, a strongly powerfull transistor for audio..a powerfull heavy duty "panzer" devices")
2SC2922 and its complementary is one of those "hard to kill" units....the image is showing you one of the possible complementary to this NPN above...my personal dream is to obtain more units alike this one.
regards,
Carlos
into the input..this is great to avoid overdrive the amplifier...will be another helping hand to you....i mean, the maximum standard pre amplifier output will not be able to drive the power amplifier into it's maximum power...and this maximum power is something you will need to avoid.
The increase of supply voltage compared to original will make the amplifier less sensitive.
The solution to increase the sensitivity to standard value is to decrease R10 value to 1K8 or even 1K5..... better not to have standard sensitivity with those transistors you shown us.
So, keep the R10 as 2K2 as standard.... will be more safe.
But i think your output transistors may short...this way, do not forget the output fuse to avoid to have burned speakers too.
Better to find stronger output transistors....80W is not enougth..better if you find 160 watts and up.... but, beeing your supply voltage bigger...good idea to you is to use Sankens (one of the strongest workhorses, an enormous beast, a strongly powerfull transistor for audio..a powerfull heavy duty "panzer" devices")
2SC2922 and its complementary is one of those "hard to kill" units....the image is showing you one of the possible complementary to this NPN above...my personal dream is to obtain more units alike this one.
regards,
Carlos
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Take a good look at those wonderfull devices.
Compared with 2SC5200 they are more huge, and seems that can reproduce a sligthly higher level of trebles without distortions.
You know...that realistic sonics of a bell...that brigth you may perceive if your amplifier was able to reproduce some harmonics...and metals...in special bells, are rich of harmonics.
But take a look at the size of this working animal...observe the metalic back size...this enormous area will transfer heat in the order of 200 watts very easy...depending how the die is fixed internally to this back metal plate.
It was sanded, waterproof Norton sandpapper, grain 500, to obtain a very flat surface to transfer heat to the heatsink...those ones are not always flat enougth.
Sand them over a glass..because it is flat enougth...install sandpapper with some watter and distribute power using three fingers....do circle movements without strength...more patience than strengh.
And be happy...those transistors are very special.... in my point of view...weathy, rich people, are the ones have those ones.
Enormous, green envy i have related Jacco Vermeullen...he has many of those folks....my God!
To the "fake hunters" i have to say that my transistors were obtained inside a dismounted Pionner power amplifier...i am sure nobody touched this amplifier but the factory..screws made that noise that ensure us that they were fixed using electrical screwdrivers....any signs that someone could ever open it...so...as Pionner do not use fake units...mine units may not be fake too.....well..if fake they had worked with more than 30 amperes and i have surpassed the maximum voltage and maximum dissipation many times...as i use those ones to my amplifiers testings.
regards,
Carlos
Compared with 2SC5200 they are more huge, and seems that can reproduce a sligthly higher level of trebles without distortions.
You know...that realistic sonics of a bell...that brigth you may perceive if your amplifier was able to reproduce some harmonics...and metals...in special bells, are rich of harmonics.
But take a look at the size of this working animal...observe the metalic back size...this enormous area will transfer heat in the order of 200 watts very easy...depending how the die is fixed internally to this back metal plate.
It was sanded, waterproof Norton sandpapper, grain 500, to obtain a very flat surface to transfer heat to the heatsink...those ones are not always flat enougth.
Sand them over a glass..because it is flat enougth...install sandpapper with some watter and distribute power using three fingers....do circle movements without strength...more patience than strengh.
And be happy...those transistors are very special.... in my point of view...weathy, rich people, are the ones have those ones.
Enormous, green envy i have related Jacco Vermeullen...he has many of those folks....my God!
To the "fake hunters" i have to say that my transistors were obtained inside a dismounted Pionner power amplifier...i am sure nobody touched this amplifier but the factory..screws made that noise that ensure us that they were fixed using electrical screwdrivers....any signs that someone could ever open it...so...as Pionner do not use fake units...mine units may not be fake too.....well..if fake they had worked with more than 30 amperes and i have surpassed the maximum voltage and maximum dissipation many times...as i use those ones to my amplifiers testings.
regards,
Carlos
Attachments
Re: There are discussions about were to ground the Zobel, some people
I see, so that is for the zobel. But what about the ELINK points?
Technically a star ground is better and each dirty part should have it's own path back to the star. However, I have not had a problem with sharing all grounds on a PCB. Maybe because I keep PSU wires short and thickd and keep to main star grounds for each amps, it is OK.
destroyer X said:
I see, so that is for the zobel. But what about the ELINK points?
Technically a star ground is better and each dirty part should have it's own path back to the star. However, I have not had a problem with sharing all grounds on a PCB. Maybe because I keep PSU wires short and thickd and keep to main star grounds for each amps, it is OK.
richie00boy said:
Hi richie00boy,
Thanks for your interest.
Earlier on in the post, there were discussions on proper grounding methods. We've all read Douglas Self's 8 casuses of distortion in amplifier and know incorrect grounding in one of the causes. I made the PCB so you could separate the signal ground from the power ground by cutting one trace at the bottom centre of the PCB and then run two wires back to the star earth. I then added the ELINKs to allow you to run separate earth wires back from each filter cap. It might make a difference (or not).
As Carlos explained, the Zobel earth can be run to where you like. I didn't want a Zobel on the PCB at all, but most people like it there. There were conflicting opinions of were the zobel earth should go and because it was a late addition we came up with this flexible solution.
regards
Dear Greg said...i agree..and my signature is under everything my partner Greg says.
Thank you dear Greg.
It is good to have you around.
I do also think that zobel could be splitted..one for speaker terminals (more logical place) and other to the amplifier, to help to drain EMF and also to "suck" oscilations to ground, as fast as it try to start, the zobel "eat" that fluctuations of voltages (AC) or DC unstabilities.
There are never ending discussions.
Yes for zobel
No for zobel
Install it into speaker terminal
Install it into your amplifier board
Split it into two halves.
Also ground we have different ideas...and Dx amplifier, the happy amplifier, will make everyone smile, as it provide options to everyone ideas, feeling, tastes and electronic knowledge development levels.
"Dx amplifier, the real democratic amplifier"
Marketing group; text number E038857773666265653
I have to tell you Ritchie, to make justice to you, that i feel very...very...very happy to have you here...i use to read your posts.
regards,
Carlos
Thank you dear Greg.
It is good to have you around.
I do also think that zobel could be splitted..one for speaker terminals (more logical place) and other to the amplifier, to help to drain EMF and also to "suck" oscilations to ground, as fast as it try to start, the zobel "eat" that fluctuations of voltages (AC) or DC unstabilities.
There are never ending discussions.
Yes for zobel
No for zobel
Install it into speaker terminal
Install it into your amplifier board
Split it into two halves.
Also ground we have different ideas...and Dx amplifier, the happy amplifier, will make everyone smile, as it provide options to everyone ideas, feeling, tastes and electronic knowledge development levels.
"Dx amplifier, the real democratic amplifier"
Marketing group; text number E038857773666265653
I have to tell you Ritchie, to make justice to you, that i feel very...very...very happy to have you here...i use to read your posts.
regards,
Carlos
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