Here is the updated schematic with ,hopefully, one less error. I have updared the Zip file as well.
Hi troystg. How are your amps progressing?
What they have pointed out IS a mistake. That is a voltage doubler to provide a higher voltage for regulation to the VGA. You are correct that the resistors are for current limiting. You are also correct about the caps.
What they have pointed out IS a mistake. That is a voltage doubler to provide a higher voltage for regulation to the VGA. You are correct that the resistors are for current limiting. You are also correct about the caps.
ostripper,
The general consensus when I ask originally was that most of the people here wanted 50W amps. I have now received several E-mails asking if higher power such as 200W of even 300W is possible with this design. The short answer is yes. Both the board I am selling and the heat sink were used in a production 100W mono amp. This amp would do 200W at 4 ohm and 300 at 2 ohm. At 2 ohm the heat sink was a little inadequate for long term output at that power. Short term was no problem.
I will make the changes necessary on the schematic (very minor) and post a 100W, 200W and 300W version. Those are of course 8 ohm ratings. If that isn't enough, then I can do any power up to 1200W at 8 ohm. So far that is the largest I have built, but I built several and they are all still working.
If THAT isn't enough, I am pretty sure I can go to at least 2500W at 8 ohm. That does take slightly more heat sink.
The general consensus when I ask originally was that most of the people here wanted 50W amps. I have now received several E-mails asking if higher power such as 200W of even 300W is possible with this design. The short answer is yes. Both the board I am selling and the heat sink were used in a production 100W mono amp. This amp would do 200W at 4 ohm and 300 at 2 ohm. At 2 ohm the heat sink was a little inadequate for long term output at that power. Short term was no problem.
I will make the changes necessary on the schematic (very minor) and post a 100W, 200W and 300W version. Those are of course 8 ohm ratings. If that isn't enough, then I can do any power up to 1200W at 8 ohm. So far that is the largest I have built, but I built several and they are all still working.
If THAT isn't enough, I am pretty sure I can go to at least 2500W at 8 ohm. That does take slightly more heat sink.
"If THAT isn't enough, I am pretty sure I can go to at least 2500W at 8 ohm. That does take slightly more heat sink."
I'm pretty sure if your using 2.5K @ 8 Ohms they would not be able to hear a fan... 😉
As for your PCB's, I moved over the holidays and am still trying to unpack, sort, and stuff all my crap into corners...
Once I finish settling in (May 2011) then I will order components for the PCB's.
No, actually I do plan on building them as soon as possible but considering the move / mess / work I don't anticipate any DIY audio be done until Feb.
That is except the dedicated 20 amp circuit I am pulling through the attic for the TV / stereo. I pulled twisted 10/3. That was the most I was going to spend on "audiophile" power cable in a rental house.
I'm pretty sure if your using 2.5K @ 8 Ohms they would not be able to hear a fan... 😉
As for your PCB's, I moved over the holidays and am still trying to unpack, sort, and stuff all my crap into corners...
Once I finish settling in (May 2011) then I will order components for the PCB's.
No, actually I do plan on building them as soon as possible but considering the move / mess / work I don't anticipate any DIY audio be done until Feb.
That is except the dedicated 20 amp circuit I am pulling through the attic for the TV / stereo. I pulled twisted 10/3. That was the most I was going to spend on "audiophile" power cable in a rental house.
35 volts amplifiers, or 50 to 100 watts amplifiers are deeply used into our forum
There are many using this voltage... the same power also.
This helps to compare....helps folks to build as they already have supply at home...they need only to run three wires from their former, or previous amplifier to feed a new one.
So, this makes everything easier to almost everyone...also junk transformers, old audio amplifiers use such level of voltage... easy to find...something almost standartised into the market...almost standard that 100 watts of power into 4 ohms loads.
The selection of this voltage and power will be good to hundreds of folks.... and more than that may be dangerous to several nice speaker you see around.
regards,
Carlos
There are many using this voltage... the same power also.
This helps to compare....helps folks to build as they already have supply at home...they need only to run three wires from their former, or previous amplifier to feed a new one.
So, this makes everything easier to almost everyone...also junk transformers, old audio amplifiers use such level of voltage... easy to find...something almost standartised into the market...almost standard that 100 watts of power into 4 ohms loads.
The selection of this voltage and power will be good to hundreds of folks.... and more than that may be dangerous to several nice speaker you see around.
regards,
Carlos
"No, actually I do plan on building them as soon as possible but considering the move / mess / work I don't anticipate any DIY audio be done until Feb.
That is except the dedicated 20 amp circuit I am pulling through the attic for the TV / stereo. I pulled twisted 10/3. That was the most I was going to spend on "audiophile" power cable in a rental house."
Moving is a real pain. When we bought this house I swore we would never move again. Of course that was the third move in three years. It gets old after a while.
Just for the record, I ran a 50A 240V dedicated line to just my stereo. I just hate when my speakers run out of power. Of course I sometimes run more amp than most people.
And yes the 1200W amps were fan cooled with 3 110CFM fans under the heat sinks. Nobody complained about fan noise drowning out the band.
That is except the dedicated 20 amp circuit I am pulling through the attic for the TV / stereo. I pulled twisted 10/3. That was the most I was going to spend on "audiophile" power cable in a rental house."
Moving is a real pain. When we bought this house I swore we would never move again. Of course that was the third move in three years. It gets old after a while.
Just for the record, I ran a 50A 240V dedicated line to just my stereo. I just hate when my speakers run out of power. Of course I sometimes run more amp than most people.
And yes the 1200W amps were fan cooled with 3 110CFM fans under the heat sinks. Nobody complained about fan noise drowning out the band.
Here is the schematic for a 100W version of the Krill. Besides voltages and number of outputs you will notice I have moved one trim pot and added two. Some of the resistors have gone to 1% to get values closer to what is needed. The trim pot that was moved (R60 on the schematic) is for DC offset adjust of the VGA. The resistor in series with R60 (R22) prevents dangerous over adjustment. The two trim pots that were added start at minimum resistance and one is adjusted until DC offset on the output is acceptable. Which one is adjusted depends on what the polarity of the offset is. R15 has been split into two resistors, R15 and R25 so you can continue to use .25W resistors in all locations except emitter resistors and the current limiting resistors in the power supply voltage doubler. A couple of resistor values were changed to keep current for the diodes in the current sources at the desired level.
This will of course require more transformer than the 50W amp. If you make or buy your own heat sink, it will need to be sized for your output impedances. If heat sink and power supply are adequate this amp will easily do 200W at 4 ohms. If you plan to drive 2 ohm or lower, you should add another pair of outputs. There are no stability issues with low impedances, only thermal ones.
This will of course require more transformer than the 50W amp. If you make or buy your own heat sink, it will need to be sized for your output impedances. If heat sink and power supply are adequate this amp will easily do 200W at 4 ohms. If you plan to drive 2 ohm or lower, you should add another pair of outputs. There are no stability issues with low impedances, only thermal ones.
SteveSteve Dunlap said:
That would be a nice thing to learn about.
Regardless where it ends up being posted, I am sure lots of people will follow (and benefit from).
Thanks!
Re: I have no prevision when my boards will arrive.
Uncle Charlie
I have all your components and boards here.
I am still under the gun so to speak, but making arrangements to be in Brazil before mid February. I will keep you posted.
Miss Scope sends regards.
destroyer X said:
Uncle Charlie
I have all your components and boards here.
I am still under the gun so to speak, but making arrangements to be in Brazil before mid February. I will keep you posted.
Miss Scope sends regards.
Carlos (destroyer X)
Is it the cost of customs from ANY country or the US specifically that makes the shipping of boards prohibitive?
A good friend of mine has family in Costa Rica and if import taxes are cheaper from there I can have them ship the parts to you.
I feel you are the one who deserves this amp the MOST since it was you that found Mr. Dunlap (I don't know if he considered himself lost 😀 ) and made this amps availability to us possible.
Is it the cost of customs from ANY country or the US specifically that makes the shipping of boards prohibitive?
A good friend of mine has family in Costa Rica and if import taxes are cheaper from there I can have them ship the parts to you.
I feel you are the one who deserves this amp the MOST since it was you that found Mr. Dunlap (I don't know if he considered himself lost 😀 ) and made this amps availability to us possible.
Carlos will provide his perspective on this issue for sure, but I will share mine.
Customs in Brazil have some "strange" practices when it comes to deal with posted packages. They can assign any price to the goods and ignore any documentation that is sent with them. Based on the "assigned price" they charge 60% import tax of the "combined price" (i.e. whatever they thing it costs plus shipping). Anything below 50 bucks is tax-free.
Of course, to make matters worse, depending where you are sending and where the goods are from, the recipient may never get anything and the package is considered as "lost in transit".
I have been on both sides of this situation - a real PITA. 😡
Customs in Brazil have some "strange" practices when it comes to deal with posted packages. They can assign any price to the goods and ignore any documentation that is sent with them. Based on the "assigned price" they charge 60% import tax of the "combined price" (i.e. whatever they thing it costs plus shipping). Anything below 50 bucks is tax-free.
Of course, to make matters worse, depending where you are sending and where the goods are from, the recipient may never get anything and the package is considered as "lost in transit".
I have been on both sides of this situation - a real PITA. 😡
I trust your word and will leave it in your capable hands.
Sorry I can't help in this situation.
Sorry I can't help in this situation.
Those things are terrible here.... too much bureaucratic customs officers
And despite there are rules, they are free to be harder than the rules ask them to be.
Once, years ago, i found beautifull a very old receiver Mr. John Mateus have shown into a picture...was an old Sony Receiver...something he was not using anymore...then he offered the unit as a gift to me... was gladly accepted by me, his offer.
I arrange with him to remove upper cover and down cover, to remove transformer to reduce weigth and he has informed the voltages used.... i have prepared a supply here.... this way the weigth was reduced...and the shipping cost would be smaller because of that...something very old...maybe considered junk in U.S. but very interesting to me, as i have worked for Sony and i have some special appreciation related the way they design panels and electronics...the bass punch (excessive) and some tricky equalization they use.
Mr. John Mateus, from New Jersey, made a nice pack and shipped this wonderfull receiver to me.... the choice was using a ship...monthes passed and nothing happened.
One day the package arrived back to U.S. "non legal exportation" was informed (or something alike that)....Mr John has paid (lost) 35 bucks to deliver and Brazilian Governemnt has spent 35 bucks to send the old receiver back to U.S.
You see how expensive was to John.... and also the Brazilian Government.... only a very old Receiver...without metal cover into the enclosure..without transformers and down cover...considered "non legal exportation"...... as no tax was paid.... back to United States.
So ..... you see what use to happens......
Mr. Klaas Veenstra, from Nederland, decided to send me boards for Cyrus one...he has made nice boards...also he included 2 power transistors... 2 nice lovely Sanken transistors ...... again was blocked by customs... they invited me to go the the central customs office and to pay 50 US buck to have the small envelope.... i apologize myself to Klaas and decided not to pay and we have accepted to loose transistors and boards..... klaas agreed.... and boards and transistors was left there..... one year passed and those things arrived at my home...no more tax!..... no more problems!...... another customs agent replaced the old one that was retired..... then less bureacratic behavior was applied, and the transistors and boards was sent to my home.
Well.... happened more things...the only one knows how to deliver things to me, hidden inside cardboards is Hugh Dean....nothing from him was blocked.... and he used to send me kits and spare parts since 2004.... unfortunattelly no discount..ahahahahah!
Mr. Eduardo has double citizenship....he has an audio company in U.S. Acoustic Engineering Company...world wide know and respected...he has offered himself to bring those things to me..so..he use to travel with a bag with parts in his hand luggage, and when he arrive brazilian airports he use to send them using the excelent internal brazilian mail system..... same day will arrive guaranteed, to all country points guaranteed!.... safe delivery!...even if you leave into the middle of Amazon Jungle inside a boat made using a tree!... waterproof packages... resistant to crashes or bumps.
Now he will bring Protobards, hundreds of transistors (from dear Sean... the "anonimous" from our forum), one Leader double channel, 40 Megahertz Oscilloscope and Dunlap boards and parts.... very kind from all those folks...thank you all by that special kindness to me.
So...now a days i have a rule inside my heart:
- " Never fear, as Duda will bring them here! "
Carlos
And despite there are rules, they are free to be harder than the rules ask them to be.
Once, years ago, i found beautifull a very old receiver Mr. John Mateus have shown into a picture...was an old Sony Receiver...something he was not using anymore...then he offered the unit as a gift to me... was gladly accepted by me, his offer.
I arrange with him to remove upper cover and down cover, to remove transformer to reduce weigth and he has informed the voltages used.... i have prepared a supply here.... this way the weigth was reduced...and the shipping cost would be smaller because of that...something very old...maybe considered junk in U.S. but very interesting to me, as i have worked for Sony and i have some special appreciation related the way they design panels and electronics...the bass punch (excessive) and some tricky equalization they use.
Mr. John Mateus, from New Jersey, made a nice pack and shipped this wonderfull receiver to me.... the choice was using a ship...monthes passed and nothing happened.
One day the package arrived back to U.S. "non legal exportation" was informed (or something alike that)....Mr John has paid (lost) 35 bucks to deliver and Brazilian Governemnt has spent 35 bucks to send the old receiver back to U.S.
You see how expensive was to John.... and also the Brazilian Government.... only a very old Receiver...without metal cover into the enclosure..without transformers and down cover...considered "non legal exportation"...... as no tax was paid.... back to United States.
So ..... you see what use to happens......
Mr. Klaas Veenstra, from Nederland, decided to send me boards for Cyrus one...he has made nice boards...also he included 2 power transistors... 2 nice lovely Sanken transistors ...... again was blocked by customs... they invited me to go the the central customs office and to pay 50 US buck to have the small envelope.... i apologize myself to Klaas and decided not to pay and we have accepted to loose transistors and boards..... klaas agreed.... and boards and transistors was left there..... one year passed and those things arrived at my home...no more tax!..... no more problems!...... another customs agent replaced the old one that was retired..... then less bureacratic behavior was applied, and the transistors and boards was sent to my home.
Well.... happened more things...the only one knows how to deliver things to me, hidden inside cardboards is Hugh Dean....nothing from him was blocked.... and he used to send me kits and spare parts since 2004.... unfortunattelly no discount..ahahahahah!
Mr. Eduardo has double citizenship....he has an audio company in U.S. Acoustic Engineering Company...world wide know and respected...he has offered himself to bring those things to me..so..he use to travel with a bag with parts in his hand luggage, and when he arrive brazilian airports he use to send them using the excelent internal brazilian mail system..... same day will arrive guaranteed, to all country points guaranteed!.... safe delivery!...even if you leave into the middle of Amazon Jungle inside a boat made using a tree!... waterproof packages... resistant to crashes or bumps.
Now he will bring Protobards, hundreds of transistors (from dear Sean... the "anonimous" from our forum), one Leader double channel, 40 Megahertz Oscilloscope and Dunlap boards and parts.... very kind from all those folks...thank you all by that special kindness to me.
So...now a days i have a rule inside my heart:
- " Never fear, as Duda will bring them here! "
Carlos
Attachments
Thanks Steve,
You're latest 100W schematic shows a new method of setting the DC offset by varying either pot R32 or R33 - which means that the DC offset is adjustable if using the output stage only (which is something I'll be doing).
Foe those who will be using the input stage also, what role does the pot R60 now have? Previously, I believe, it was used to set the DC offset?
Can you clarify please?
You're latest 100W schematic shows a new method of setting the DC offset by varying either pot R32 or R33 - which means that the DC offset is adjustable if using the output stage only (which is something I'll be doing).
Foe those who will be using the input stage also, what role does the pot R60 now have? Previously, I believe, it was used to set the DC offset?
Can you clarify please?
Re: Those things are terrible here.... too much bureaucratic customs officers
You are correct, Dr. Smith!
destroyer X said:
You are correct, Dr. Smith!
jkeny said:
R60 adjusts the DC offset on the VGA. Since there is no global feedback, each section is independent of the other. Each one needs an adjustment. If you use the output stage only you will still need to provide a DC bias source if you capacitor couple the input. A resistor to ground just like on the input stage will work. Use the lowest value that your front end will drive without problems.
dudaindc said:
Steve
That would be a nice thing to learn about.
Regardless where it ends up being posted, I am sure lots of people will follow (and benefit from).
Thanks!
Lots of people may follow but so far only two have shown any interest. I will probably do it anyway because I need some new cases. I will NOT be using my machine shop as I want to show how easy it is to do with only some inexpensive hand tools.
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