HRII Progress
I just wanted to updated everyone on my progress. The last time I checked in, I had released a bit of magic blue smoke from one of the driver transistors on one board, and I had 20VDC on the OUTPUT of the other board.
I looked and looked at the transistor placement and part numbers to find any that were placed backwards, but I couldn't find anything. So I placed an order with Mouser for transistors. I ordered a bunch of the 556As and 546Bs. They were dirt cheap, less than 5 cents each! I got 50 of each of those so I could match them. I also ordered a nice supply of BD139 and BD140. I scrimped and just bought 1 each of the output devices just to have on hand. While I was at it, I bought some extra fuses for the power supply and in-line fuse holders for the speaker output.
I have a meter that will measure hfe, so I used it to match the 556As. I realize there are more accurate methods of matching, but that seems a bit out of my comfort zone. I carefully removed the transistors from their bag without touching them. Using a pair of needle nose pliers, I placed them into the socket on the meter, noting the reading of each transistor after 5 seconds. You don't want to touch the transistors, because any heat transfer from your fingers will alter the reading on the meter. After doing the batch of transistors, I picked pairs that had the same hfe. Then I repeated for the 546Bs.
I replaced all the transistors, except for the output devices. They still seemed OK when I did a diode check on them, so I proceeded with my fingers crossed that any problems I had previously didn't cook them. Again, I tried to be very careful determining the emmiter pin on each device and orienting it properly.
During the multiple solderings on the boards, I noticed that a few solder pads were pulled off the board with the solder wick (and probably a poor solder technique). I carefully identified these with a magnifying glass (these eyes ain't what they used to be!). I then added a wire connecting the pin to the device it should have been connected to. It was tedious work, but it could be a show stopper if you have a missing solder pad.
During all of this inspection, I found that R16 (180R) had been burned during one of my failed power up attempts. Lucky for me, I actually had that value in my stash.
Also, as I inspected the solder on the back of the board, I identified a few pins that hadn't been soldered to my liking. They had a bit of missing solder or a dull finish. I touched these up for good measure. Looking at the board from multiple angles would reveal issues I hadn't seen before.
Next, using DISTILLED water, Isopropyl alcohol, and a toothbrush, I cleaned the flux off of the boards. I would use the alcohol to clean the flux, then rinse and scrub again with the water to remove the residue that the alcohol left behind. I had to repeat a few time to get it nice and clean. Do not use any water other than distilled for cleaning the boards.
I powered the boards up one at a time, and I could now trim the Vbe of the output devices to around 570mV. Now, when I measured for DC on the output, there was none. And there was none of that annoying blue smoke this time.
Then I removed my shorting plug and added some input, and Voila! Music!
I never could identify a transistor that I placed incorrectly, but now things seems to be fine.
I will be firing the boards up today as a stereo pair and see what they sound like as they warm up.
Dave
I just wanted to updated everyone on my progress. The last time I checked in, I had released a bit of magic blue smoke from one of the driver transistors on one board, and I had 20VDC on the OUTPUT of the other board.
I looked and looked at the transistor placement and part numbers to find any that were placed backwards, but I couldn't find anything. So I placed an order with Mouser for transistors. I ordered a bunch of the 556As and 546Bs. They were dirt cheap, less than 5 cents each! I got 50 of each of those so I could match them. I also ordered a nice supply of BD139 and BD140. I scrimped and just bought 1 each of the output devices just to have on hand. While I was at it, I bought some extra fuses for the power supply and in-line fuse holders for the speaker output.
I have a meter that will measure hfe, so I used it to match the 556As. I realize there are more accurate methods of matching, but that seems a bit out of my comfort zone. I carefully removed the transistors from their bag without touching them. Using a pair of needle nose pliers, I placed them into the socket on the meter, noting the reading of each transistor after 5 seconds. You don't want to touch the transistors, because any heat transfer from your fingers will alter the reading on the meter. After doing the batch of transistors, I picked pairs that had the same hfe. Then I repeated for the 546Bs.
I replaced all the transistors, except for the output devices. They still seemed OK when I did a diode check on them, so I proceeded with my fingers crossed that any problems I had previously didn't cook them. Again, I tried to be very careful determining the emmiter pin on each device and orienting it properly.
During the multiple solderings on the boards, I noticed that a few solder pads were pulled off the board with the solder wick (and probably a poor solder technique). I carefully identified these with a magnifying glass (these eyes ain't what they used to be!). I then added a wire connecting the pin to the device it should have been connected to. It was tedious work, but it could be a show stopper if you have a missing solder pad.
During all of this inspection, I found that R16 (180R) had been burned during one of my failed power up attempts. Lucky for me, I actually had that value in my stash.
Also, as I inspected the solder on the back of the board, I identified a few pins that hadn't been soldered to my liking. They had a bit of missing solder or a dull finish. I touched these up for good measure. Looking at the board from multiple angles would reveal issues I hadn't seen before.
Next, using DISTILLED water, Isopropyl alcohol, and a toothbrush, I cleaned the flux off of the boards. I would use the alcohol to clean the flux, then rinse and scrub again with the water to remove the residue that the alcohol left behind. I had to repeat a few time to get it nice and clean. Do not use any water other than distilled for cleaning the boards.
I powered the boards up one at a time, and I could now trim the Vbe of the output devices to around 570mV. Now, when I measured for DC on the output, there was none. And there was none of that annoying blue smoke this time.
Then I removed my shorting plug and added some input, and Voila! Music!
I never could identify a transistor that I placed incorrectly, but now things seems to be fine.
I will be firing the boards up today as a stereo pair and see what they sound like as they warm up.
Dave
HRII Opinion - Your mileage may vary!
Well...I got everything put together today so I could listen to my two HRII modules together as a stereo pair.
It has a very good sound. A bit more punchy than I expected. The bass is tight and very detailed. The mids punch right through the way they should, but rarely do with most amps. And the highs are extended without being hard. The sound isn't like anything I've used before. The best way for me to describe it would be the sound of a classic Naim NAP-140, but a bit bouncier. It's an "instant party".
I'm looking forward to seeing how the sound matures as I break it in. All you users of the DX flavored amp users out there: Does break-in effect the sound?
Congratulations Carlos on a great design. Your years of experience shine through.
Many thanks to Nordic for the countless hours he put into designing the board layout and getting them manufactured. I can attest first hand just how hard it is when dealing with prototype and production PC Boards. The board houses can be a giant pain. Your work is very appreciated. I couldn't have built this amp without all of the work you have done for your love of this hobby. Best of luck with your Precision and Protection boards.
Dave
Well...I got everything put together today so I could listen to my two HRII modules together as a stereo pair.
It has a very good sound. A bit more punchy than I expected. The bass is tight and very detailed. The mids punch right through the way they should, but rarely do with most amps. And the highs are extended without being hard. The sound isn't like anything I've used before. The best way for me to describe it would be the sound of a classic Naim NAP-140, but a bit bouncier. It's an "instant party".
I'm looking forward to seeing how the sound matures as I break it in. All you users of the DX flavored amp users out there: Does break-in effect the sound?
Congratulations Carlos on a great design. Your years of experience shine through.
Many thanks to Nordic for the countless hours he put into designing the board layout and getting them manufactured. I can attest first hand just how hard it is when dealing with prototype and production PC Boards. The board houses can be a giant pain. Your work is very appreciated. I couldn't have built this amp without all of the work you have done for your love of this hobby. Best of luck with your Precision and Protection boards.
Dave
Thank you very much Dave, i am glad you have appreciated
Yes, the sound has a "character", it is shinny and different, pleasant having special "presence" and punchy bass... the power surprise us a lot, beeing 35 watts we cannot believe so loud it can play without distortions.
Thank you, the review show your satisfaction, and this is my pleasure.
Enjoy Dx Amplifier and start to think on Precision, this one will make you fell down from your chair.
regards,
Carlos
Yes, the sound has a "character", it is shinny and different, pleasant having special "presence" and punchy bass... the power surprise us a lot, beeing 35 watts we cannot believe so loud it can play without distortions.
Thank you, the review show your satisfaction, and this is my pleasure.
Enjoy Dx Amplifier and start to think on Precision, this one will make you fell down from your chair.
regards,
Carlos
Got my Kit 
I got my kit today! Much smaller than I had imagined. Thats great for enclosures. I will have to be careful with my soldering. I think I need a new solder iron. I dropped it a few days ago and stepped on it while looking to see where it went. So thats fine since I have to order caps and such anyway. I have been reading more of the threads and printing lots of things that I think will help. Probably will be 2 weeks til I first try to turn it on. Cant wait til my new transformers get here and I can start to decide what enclosure to use.
Uriah
I got my kit today! Much smaller than I had imagined. Thats great for enclosures. I will have to be careful with my soldering. I think I need a new solder iron. I dropped it a few days ago and stepped on it while looking to see where it went. So thats fine since I have to order caps and such anyway. I have been reading more of the threads and printing lots of things that I think will help. Probably will be 2 weeks til I first try to turn it on. Cant wait til my new transformers get here and I can start to decide what enclosure to use.
Uriah
I am slowly invading my own country, Dx Amplifier will be alike a flu vírus that will
contaminate my population with nice sound devices.
Very slowly i am progressing, one month work and had 6 orders and 5 guys have constructed..... it is increasing, i hope in a geometric progression.
This one have build inside a famous Brazilian Amplifier case, the Cygnus, normally used to Professional Applications, Wagner told the sound is much better and the bass is huge.
He had posted into Youtube a small video, you know how bad are those videos and the awfull sound they reproduce.
Also how bad photo cameras do audio recordings using Wave, small sample and electret (easy saturated) condenser microfones....audio has compressor and frequency response starts around 150 hertz and finishes around 3Khz i think.... very bad, but even this way you can feel the punch of bass you have around 100 hertz from Dire Straits.
Enjoy the nice sound from a Dx Amplifier into a bad recording and bad audio and video format from Youtube.
http://www.youtube.com/watch?v=Z1FIziTwuyg
regards,
Carlos
contaminate my population with nice sound devices.
Very slowly i am progressing, one month work and had 6 orders and 5 guys have constructed..... it is increasing, i hope in a geometric progression.
This one have build inside a famous Brazilian Amplifier case, the Cygnus, normally used to Professional Applications, Wagner told the sound is much better and the bass is huge.
He had posted into Youtube a small video, you know how bad are those videos and the awfull sound they reproduce.
Also how bad photo cameras do audio recordings using Wave, small sample and electret (easy saturated) condenser microfones....audio has compressor and frequency response starts around 150 hertz and finishes around 3Khz i think.... very bad, but even this way you can feel the punch of bass you have around 100 hertz from Dire Straits.
Enjoy the nice sound from a Dx Amplifier into a bad recording and bad audio and video format from Youtube.
http://www.youtube.com/watch?v=Z1FIziTwuyg
regards,
Carlos
I have developed an oxidation method to produce boards
And i am still making some for testing purposes.
As it is faster and cheaper to make them this way, maybe i will start to make all boards here.... but, i do not have the same quality we use to have with the traditional standard methods.
This method is "in development".... eletro chemical way to produce boards.
I am using Greg Boards design for this purpose, as they were hardly tested.
regards,
Carlos
And i am still making some for testing purposes.
As it is faster and cheaper to make them this way, maybe i will start to make all boards here.... but, i do not have the same quality we use to have with the traditional standard methods.
This method is "in development".... eletro chemical way to produce boards.
I am using Greg Boards design for this purpose, as they were hardly tested.
regards,
Carlos
Attachments
Re: I am slowly invading my own country, Dx Amplifier will be alike a flu vírus that
You should hear that video on my 1" laptop speakers. Haha.
Near-CB quality. That's being generous. In fact, I think my microwave oven sounds more musical.
Not your problem Carlos, just the video - and my laptop a bit.
..Todd
destroyer X said:
You should hear that video on my 1" laptop speakers. Haha.
Near-CB quality. That's being generous. In fact, I think my microwave oven sounds more musical.
Not your problem Carlos, just the video - and my laptop a bit.
..Todd
Hello Carlos & friends.
Completed a working HRII last night, after stomping a few (annoying) bugs. Ah well I guess that's the way to learn.
Will post some photos tomorrow.
Did not have too much time to listen (it was getting late) but I noticed the bass was deep and tight! I only used 3uf on DC blocking input cap but bass still went very deep.
Will do some serious listing tonight -- will post tomorrow with pics.
Take Care All
Andrew (the GOOD-buyer)
Completed a working HRII last night, after stomping a few (annoying) bugs. Ah well I guess that's the way to learn.
Will post some photos tomorrow.
Did not have too much time to listen (it was getting late) but I noticed the bass was deep and tight! I only used 3uf on DC blocking input cap but bass still went very deep.
Will do some serious listing tonight -- will post tomorrow with pics.
Take Care All
Andrew (the GOOD-buyer)
I am very happy Nowgoodbuyer.... please my dear, send me pics, from you to, as i want
Your smilling pretty face to put into my Orkut as a friend and Dx constructor.... a nice crew member i have with pride!
Your constructions are nice, your house is nice too and you look very well.
Also has passion...this is wonderfull.... love is the answer to all our human needs, and passion is what move us!
If you take a good look you have almost the Dx amplifier into the HRII schematic.
Diferences are the current sink you have as differencial transistor colector load and some "retuning" into the bootstrapp"... some phase advance into treble (Sansui very old idea from the eigthies), and the rail electronic voltage stabilizer.
Power is lower...now you have 35W into 8ohms and 70W into 4 ohms...or something around that (38.5 into 8 ohms)... but the unit plays louder....it seems the current sinks made the difference related that..also the better precision into the tones and lower distortion into the bass.
I hope you will be happy...but if you want to demolish your home, then go to Precision ONE (Roman letters), the Killer!
Audio quality is into the trebles is into the HRII, the best deep uncontrolled and low fidelity basses are into the Dx Standard...the best voices i could listen and controled deep punchy bass goes to the Precision....this last one seems that have more bass than trebles, i think reducing input condenser it works more "ballanced" to forum average folks tastes.
Your images are something i cannot wait...i love to watch your pictures.... i have strong appreciation on you too.
Nico is developing a new HRII board... very pretty one.
regards,
Carlos
Your smilling pretty face to put into my Orkut as a friend and Dx constructor.... a nice crew member i have with pride!
Your constructions are nice, your house is nice too and you look very well.
Also has passion...this is wonderfull.... love is the answer to all our human needs, and passion is what move us!
If you take a good look you have almost the Dx amplifier into the HRII schematic.
Diferences are the current sink you have as differencial transistor colector load and some "retuning" into the bootstrapp"... some phase advance into treble (Sansui very old idea from the eigthies), and the rail electronic voltage stabilizer.
Power is lower...now you have 35W into 8ohms and 70W into 4 ohms...or something around that (38.5 into 8 ohms)... but the unit plays louder....it seems the current sinks made the difference related that..also the better precision into the tones and lower distortion into the bass.
I hope you will be happy...but if you want to demolish your home, then go to Precision ONE (Roman letters), the Killer!
Audio quality is into the trebles is into the HRII, the best deep uncontrolled and low fidelity basses are into the Dx Standard...the best voices i could listen and controled deep punchy bass goes to the Precision....this last one seems that have more bass than trebles, i think reducing input condenser it works more "ballanced" to forum average folks tastes.
Your images are something i cannot wait...i love to watch your pictures.... i have strong appreciation on you too.
Nico is developing a new HRII board... very pretty one.
regards,
Carlos
Attachments
That beach looks nice!! Wish I was there now, I am at work and I am getting a little bored
.
Can you explain the "phase advance" concept, I am always keen to learn things.
I don't think I have photos of myself this time [ the world breathes a sigh of relief ], but if it's not too dark I'll take some "views from my house".
.Can you explain the "phase advance" concept, I am always keen to learn things.
I don't think I have photos of myself this time [ the world breathes a sigh of relief
], but if it's not too dark I'll take some "views from my house".
No, i cannot, i just have find it interesting watching Sansui schematics
And them i have tried and i have found differences into treble, more brigth depending the adjustment you give, and harshing if you adjust in excess.
I will search for the Sansui schematic, i think they have explained a little bit the subject.
As soon as i find the schematic i will come here to give explanations about.
I am not a real designer.... i am just the one that try schematics, sub circuits and i use to test them together to "listen" how they sound..... this is made into a try and error basis.
regards,
Carlos
And them i have tried and i have found differences into treble, more brigth depending the adjustment you give, and harshing if you adjust in excess.
I will search for the Sansui schematic, i think they have explained a little bit the subject.
As soon as i find the schematic i will come here to give explanations about.
I am not a real designer.... i am just the one that try schematics, sub circuits and i use to test them together to "listen" how they sound..... this is made into a try and error basis.
regards,
Carlos
Here is a photo of my new amp (HRII).
I enjoyed a good listening session last night. I was impressed at how far you can get the volume up and still have crystal clarity. Makes the speakers seem bigger. You can really feel the impact on drum skins. I love it!!!!
The only negative is that it is murder on poor quality recordings (hehe)
Thanks for sharing your design Carlos -- this is a hell of an amp!!
I enjoyed a good listening session last night. I was impressed at how far you can get the volume up and still have crystal clarity. Makes the speakers seem bigger. You can really feel the impact on drum skins. I love it!!!!
The only negative is that it is murder on poor quality recordings (hehe)
Thanks for sharing your design Carlos -- this is a hell of an amp!!
Attachments
Wow its been quiet around here. I hope everyone is feeling better.
I was wondering if anyone has any 2SC5200 or SA1943 extras. Only place I can find them both is either EBAY and they are probably fake (all from Hong Kong or China) and also Mouser has them. Price for Mouser is not bad ( think it was 2.48 each) but shipping is killer so my total ends up around $17 before I even buy an extra or two incase of smoke
Uriah
I was wondering if anyone has any 2SC5200 or SA1943 extras. Only place I can find them both is either EBAY and they are probably fake (all from Hong Kong or China) and also Mouser has them. Price for Mouser is not bad ( think it was 2.48 each) but shipping is killer so my total ends up around $17 before I even buy an extra or two incase of smoke
Uriah
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