Reminds me of a set up I saw many years ago. They would set up out of a truck with piles of speakers in "store brand" boxes and piles of off branded electronics. They gave the impression everything was hot. In actuality, it was just really really cheap junk and they were making a killing selling to people who bought the idea "PNR" was a customer branded same as Pioneer, and they were getting stolen high end for a song. I am not sure who had less morals, seller or buyer.
"We have met the enemy, and he is us" POGO
"We have met the enemy, and he is us" POGO
Almost there.
Well, here is for the effort. It's a mess but I fired up the main board and used it as a headphone/preamp with 20volts and 1.5A from variable power supply while hooked up to an iPod, Allman Bros' 'Eat a Peach'. Really nice. Sounding very aggressive, robust, with no noise. Next step is to hook it all up to can caps, output transistors and heat sinks. This will be my last 'STOLEN' bought project though. In the last year and a half, I have learn much and entered into a new world that I will never forget and thank all those you threw their kind help this way.
Well, here is for the effort. It's a mess but I fired up the main board and used it as a headphone/preamp with 20volts and 1.5A from variable power supply while hooked up to an iPod, Allman Bros' 'Eat a Peach'. Really nice. Sounding very aggressive, robust, with no noise. Next step is to hook it all up to can caps, output transistors and heat sinks. This will be my last 'STOLEN' bought project though. In the last year and a half, I have learn much and entered into a new world that I will never forget and thank all those you threw their kind help this way.
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Nice work David! Glad to hear it is working okay. Finally you can enjoy the sound that this wonderfull amp conducts. Now it is time to mount everything into a nice cabinet 
It has been a while since I have posted over here. Busy times for Kaplaars. It suprises me is that someone choose to rename this tread. 'Stolen trademark'... so we are thieves now. Classy...
David, hey, don't let them knock you down. We have to complete that Goldmund clone in the future!
Remember, there are billions of people, and billions of different opinions. Most of them are (unfortunatelly) biassed because people tend to react emotional, which now and then results in childish, unrational, (jealous?) and dictatorial behavoir. There are always people who need to nag. So a rational discussion based on facts is not always possible. This forum seems to be no exeption. Which I actually did not expect. After all, we share more or less the same interests.
Before someone thinks it is needed to intervene; it is not my intention to start the previous discussion again, and I wont respond on further comments about this quarrel.
But I do like to say; David, keep up the good work! Don't stop building, cloning, or how they call it over here, stealing. You and I know it is different, and that is what matters!
It has been a while since I have posted over here. Busy times for Kaplaars. It suprises me is that someone choose to rename this tread. 'Stolen trademark'... so we are thieves now. Classy...
David, hey, don't let them knock you down. We have to complete that Goldmund clone in the future!
Remember, there are billions of people, and billions of different opinions. Most of them are (unfortunatelly) biassed because people tend to react emotional, which now and then results in childish, unrational, (jealous?) and dictatorial behavoir. There are always people who need to nag. So a rational discussion based on facts is not always possible. This forum seems to be no exeption. Which I actually did not expect. After all, we share more or less the same interests.
Before someone thinks it is needed to intervene; it is not my intention to start the previous discussion again, and I wont respond on further comments about this quarrel.
But I do like to say; David, keep up the good work! Don't stop building, cloning, or how they call it over here, stealing. You and I know it is different, and that is what matters!
Yes. I am interested in the Goldmund clone. When I test the main board without connecting the outputs and play music with headphones to drivers pads 1 or 2 I get clean sounds with absolutely no noise. But when I connect outputs I get just a very little rush sound at speaker biased to 250mV. Now remember, I am using a DC variable power supply @ 20 to 30V/1.5 to 2amps. Maybe power supply I injecting noise. Will check with oscilloscope later. I came to believe that some of the criticisms are valid using bought clones. As I read other threads--such as MPP (My Personal Preamp) thread and especially the first KSA-100 thread, there were those who built the PCBs mainly with the intent to share their efforts only charging DIYers production cost and shipping. With this in mind, AndrewT is right....... So I just recently purchased some Pinkmouse KSA-50 PCBs for a later build (right now I am overwhelmed). But if it weren't for your technical abilities and willing to share, we (and the Asian vendor), would never have figured out Asian manufacture's print and physical mistake on the PCBs. But, like you said, for a retired guy who needed something to do during the winter and allow me to reminisce the old days in the Army's 11th Signal Battalion helping the radio repair tech (1973-75 in Germany.
Sounds wonderful
After insuring the mainboard behaves , I connected it to the output transistors/heat sinks. It sounds wonderful. I have never heard such warm, robust sounds with crisp cymbals in the background. It's only running on a 24cvt/2Amps transformer with 18000uf/75v caps with ~15vdc on rails. After I hook each channels to their PSU (40v/1kVA), I realize these transfos are very big and after hearing how this amp sounds with only ~15volts/2amps, I also realize I need maybe just 33 to 35volts. Then I will need to find a good DAC. I need to match analog lossless music to the analog capability of this class A amp.
After insuring the mainboard behaves , I connected it to the output transistors/heat sinks. It sounds wonderful. I have never heard such warm, robust sounds with crisp cymbals in the background. It's only running on a 24cvt/2Amps transformer with 18000uf/75v caps with ~15vdc on rails. After I hook each channels to their PSU (40v/1kVA), I realize these transfos are very big and after hearing how this amp sounds with only ~15volts/2amps, I also realize I need maybe just 33 to 35volts. Then I will need to find a good DAC. I need to match analog lossless music to the analog capability of this class A amp.
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I don't care what anyone says. This setup sounds fantastic. The biggest cost was the transformers and that would be for any amplifier setup. It has sounds that takes me back 45 years. It is my first amp project and realize I jumped in head first and began to think I bit off more than I could chew, but now I am really glad I did. I have learned so much and the best part, I have much more to learn. Thanks to all that helped. You know who you are. The rest..... You can attract more bees with honey than with vinegar.
What else is a retired man to do? Plant sunflower seeds and watch them grow? What would I do during the winter? Ice fishing? Now-a-days you can't even eat the fish you catch.
What else is a retired man to do? Plant sunflower seeds and watch them grow? What would I do during the winter? Ice fishing? Now-a-days you can't even eat the fish you catch.
Whew!!!!
Everytime I read this, I wonder if Andrew is still alive. God bless the man for his conviction none pass on I hope. I have been band for a time and now know he is on board. Politics I do not like in the USA, but would somebody buy the poor man some toilet paper?Andrew, Andrew, Andrew... what is your problem. You keep nagging that it is a bad idea to place NTC's parallel. OK maybe, but why? Is it that hard to underpin your theorem? I don't know.... but you keep refusing to give a constructive answer. It is like I state driving on 3 wheels is a bad idea, but I don't say why it is a bad idea. A critic dutchman asks why, but all I say, read the English. What English, were is the explanation? Luckaly CBS240 explained it, so it is no longer necessairy.
Other thing, you state that bypassing the rectifier diodes with capacitors is a bad idea. Again, OK, can be, but why? Still got no answer from you. Again CBS240 was the helping friend. Is it that strange to ask why?
But Andrew, lets not spoil this threat with our little discussion. To be fair my initial question had nothing to do with the NTC's. My initial question was about the series capacitor. The NTC's are NOT really my problem, and to be fair this config works perfect, it switches the two 1 KVA toroids perfectly on, and no fuse is spoiled.
Hi All,
Using the NTC's in parallel is 'dangerous' because as soon as one becomes hotter than any of it's peers, it hogs the current, becoming hotter in the process, lowering it's resistance further, grabbing more current, basically until it overheats and in my case desolders itself... then the next parallel device gets all the current and desolders itself...I only used them in pairs.
Good luck.
Stuart
Using the NTC's in parallel is 'dangerous' because as soon as one becomes hotter than any of it's peers, it hogs the current, becoming hotter in the process, lowering it's resistance further, grabbing more current, basically until it overheats and in my case desolders itself... then the next parallel device gets all the current and desolders itself...I only used them in pairs.
Good luck.
Stuart
Okay. I have wonderful music. More treble than bass at 350mV bias. Mark G. said he got "slammin'" bass way back then. Could I drop the value of the 1ohm emitter resistor to the .6ohm resistors Stuart gave me or should I wait until I get the bias up to +- 600 bias for the current value of .6 for 100w with 40V at rails? At 350mV, MJ15003/4 temps are at ~100degrees F or 37.7C. with fan or without somewhat. The 32/33 are at 84F. Today I will raise the bias to 425 and see how high the temps go and if the bass decides to go "slammin'.
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Transformers
I think I am going to get new transformers for the klone so that I can get 40v secondaries instead of the 56v secondaries I current get from the 40v transformer I have now. Can I use the 40v/1kVA for the Goldmund project? I have been using a variac to get the 40v transformer to put out 40volts secondaries adjusting the variac at 90volts into the soft start. Man is the beast loud. I can only raise the all dale resistor stepped attenuator to five of the 23 clicks before the windows will blow or my wife getting the double barrel shot gun. This at 350mV bias!!! I know my speakers are old, but for now I am using the 3-way Altec Lansing Mantaray Model 8 or my old Japanese 5-way BX-1201 Carol speakers (41 years old. I bought them when I was stationed in Wurzburg, Germany), --both 100watts. With the 1KVA transformers, I should be able to drive both speaker pairs in parallel?Nice work David! Glad to hear it is working okay. Finally you can enjoy the sound that this wonderfull amp conducts. Now it is time to mount everything into a nice cabinet
It has been a while since I have posted over here. Busy times for Kaplaars. It suprises me is that someone choose to rename this tread. 'Stolen trademark'... so we are thieves now. Classy...
David, hey, don't let them knock you down. We have to complete that Goldmund clone in the future!
Remember, there are billions of people, and billions of different opinions. Most of them are (unfortunatelly) biassed because people tend to react emotional, which now and then results in childish, unrational, (jealous?) and dictatorial behavoir. There are always people who need to nag. So a rational discussion based on facts is not always possible. This forum seems to be no exeption. Which I actually did not expect. After all, we share more or less the same interests.
Before someone thinks it is needed to intervene; it is not my intention to start the previous discussion again, and I wont respond on further comments about this quarrel.
But I do like to say; David, keep up the good work! Don't stop building, cloning, or how they call it over here, stealing. You and I know it is different, and that is what matters!
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I have (accidentally) driven ~1ohm resistance with my amp with no obvious problems, though you will need to make sure your cooling is up to it. In all the cases I ever 'tested' the fuses and/or breaker popped prior to the amp dieing.
The bias being higher or lower will not change the overall gain, and therefore the volume achieved for any given level of input. It sounds like your speakers are quite efficient, I'm 100% certain you can drive both pairs in parallel, just monitor the temperature the first time to make sure you are not cooking the outputs too much.
If you get the lower voltage transformers, you can likely go with smaller capacity, perhaps 650 or 800va per channel...
From my experience, removing the variac will give a considerable improvement in dynamics and ease of delivery.
Good luck
Stuart
The bias being higher or lower will not change the overall gain, and therefore the volume achieved for any given level of input. It sounds like your speakers are quite efficient, I'm 100% certain you can drive both pairs in parallel, just monitor the temperature the first time to make sure you are not cooking the outputs too much.
If you get the lower voltage transformers, you can likely go with smaller capacity, perhaps 650 or 800va per channel...
From my experience, removing the variac will give a considerable improvement in dynamics and ease of delivery.
Good luck
Stuart
Working out the bias
Working out the bias and DC offset. The adjustment was easy except I had to put in higher amperaged fuses--4amp to 5 amp fuses when I got to 630mV bias.
Stuart. I will start up the amp tomorrow without the variac and cross my fingers. The transfos are 40v for 56volts at the rails. Way to high, no? But I only have to worry about the temperatures generated by the high voltage, no? How high (max) of a T03 temperature can I be safe with with this high of a voltage at rail?
Working out the bias and DC offset. The adjustment was easy except I had to put in higher amperaged fuses--4amp to 5 amp fuses when I got to 630mV bias.
Stuart. I will start up the amp tomorrow without the variac and cross my fingers. The transfos are 40v for 56volts at the rails. Way to high, no? But I only have to worry about the temperatures generated by the high voltage, no? How high (max) of a T03 temperature can I be safe with with this high of a voltage at rail?
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I didn't use the 1N5309/CR300 setup as the parts were expensive. Here is the comment from Jim's Audio on ebay at the bottom of the BOM as optional:
When 1N5309/CR300 is used (D5,D6), LM334 should be left open. Otherwise D5,D6 to be replace with 33ohm Dale RN60D and LM334 should be put on
Well, I took the variac off and running amp with straight main line at 118volts. The bias edged up just a little. Trimmed it back to 630mV and trimmed DC at speakers to zero. Funny thing is that the MJ15003/4 for the right channel run at 101degrees F and the Left channel the TO3s run at 94F. Less current? I have, as of today, about 7 hours of burn-in time and already the bass is slowly maturing--very robust. I have been playing Joan Armatrading mainly because she works in a quiet studio to make sure there aren't foreign sounds being added. Clean as a whistle. Kaplaars. I been reading about the zobel network, and it says that the tweeter does not need it, only the woofer. That you can put it direct across the woofer's leads. "The Crossover Component Selection Guide, as with all crossover formulas, assumes that the crossover network is terminated with a purely resistive load, but a loudspeaker is not even close to being purely resistive! Due to voice coil inductance, the impedance is constantly rising with frequency. To remedy this, a simple capacitor and resistor impedance equalizer called a Zobel network is placed across the positive and negative leads of the woofer. The Zobel is not usually necessary with a tweeter network, so we will design one for our Morel woofer using this formula." I got this from PartsExpress.com at "Build your own loudspeakers" url is Resources - Build A Speaker. If you have 8ohm impedance woofers, you use 8 ohm resistor and then it give you a formula to figure what capacitance you need for the RC zobel network. Almost forgot, as I increase the bias to 630mV, it kept blowing the main slow-blow fuse (5amps). So I put a higher 7amps slow-blow fuse and it is holding it's own. I am using one soft-start for both channels and 2x110v cooling fans. How high amperage of a fuse can I use at the main before the soft-start? Thank you.
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