It ain't pretty...part 2
The Power Supply:
Note that the transformers aren't what will be used in the end, but they were lying around with the right voltage specs. I have no plans to rock until the bigger transformer(s) are in place.
The power supply caps are 12,000 uF 50V Nichicon snap-ins from ApexJr's website. Not a bad deal considering they are $1.99 each. Compared to the $6.50 each for 10,000 uF Panasonics, it was a no-brainer for me. Your mileage may vary.
I'll take pictures of any smoldering wreckage after I power up here in a bit.
The Power Supply:
Note that the transformers aren't what will be used in the end, but they were lying around with the right voltage specs. I have no plans to rock until the bigger transformer(s) are in place.
The power supply caps are 12,000 uF 50V Nichicon snap-ins from ApexJr's website. Not a bad deal considering they are $1.99 each. Compared to the $6.50 each for 10,000 uF Panasonics, it was a no-brainer for me. Your mileage may vary.
I'll take pictures of any smoldering wreckage after I power up here in a bit.
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Guys I have been reading several pages of this post. It seems that the designer felt this amp sounded better than many chip amps. That sounds reasonable. There is a lot of talk, obviously, about Peter Daniel's LM3875 and LM4780 amps. I was going to build a LM3875 but this amp you all are working on sounds like it might be great.
I am new to this and have only built one amp... a tube amp. I like it and it was a lot of fun. Its going to the wife for her birthday along with a pair of DIY speakers once I get them looking pretty. So I need to build something for myself, but budget will restrict me to ONE project right now. Would you all recommend this over the gainclones? I know it is more difficult than a gainclone but thats part of the fun. I am most concerned about sound quality. I will be powering DIY Fostex 8" speakers of about 93db sensitivity and 8ohm. I hope my question is not intruding on the line of logic and discussion this post has been following.
Regards,
Uriah
I suppose I should ask also: If the preference were for a DX amp, would ones preference be the DX HRII or the Precision 1?
Guys I have been reading several pages of this post. It seems that the designer felt this amp sounded better than many chip amps. That sounds reasonable. There is a lot of talk, obviously, about Peter Daniel's LM3875 and LM4780 amps. I was going to build a LM3875 but this amp you all are working on sounds like it might be great.
I am new to this and have only built one amp... a tube amp. I like it and it was a lot of fun. Its going to the wife for her birthday along with a pair of DIY speakers once I get them looking pretty. So I need to build something for myself, but budget will restrict me to ONE project right now. Would you all recommend this over the gainclones? I know it is more difficult than a gainclone but thats part of the fun. I am most concerned about sound quality. I will be powering DIY Fostex 8" speakers of about 93db sensitivity and 8ohm. I hope my question is not intruding on the line of logic and discussion this post has been following.
Regards,
Uriah
I suppose I should ask also: If the preference were for a DX amp, would ones preference be the DX HRII or the Precision 1?
Hi Uriah, yes, I have no reservations saying these amps sound better than most chipamp implementations by quite a bit.
The path I would follow is to build the standard DX first, it is a simpler schematic, with fewer tricky sections to get right. Also replacement transistors are cheap for the innevitable error or 2.
These amps have a strong "long" bass and very low parts cost.
The original DX is medium power 50W @ 8R, 100W @4 R
The HRII is a little diffirent and lower power, with some of the supply rails regulated down in voltage, the result is a lower powered output, but a much improved fidelity, realy nice trebles and details, it is definately the lady amp of the bunch. providing about 40W@8R per channel in its basic form. I have a strong love for this one. This 40W of undistorted power and seem much much, much, more powerfull in real life.
Build cost is a little higher due to extra transistors, but not by much and the original DX supply can still be used.
The PI is the butch of the batch at about 250W@4R, very powerfull pushing bass from almost DC, with astounding detail in mid and bass regions. Construction costs are in the high-ish category as the power supply caps, transformers and heatsinks almost all double in size, not to mention the 4 extra output pairs...
I would suggest you aim for the HRII, I think it will complement those high efficiency drivers very well.
The path I would follow is to build the standard DX first, it is a simpler schematic, with fewer tricky sections to get right. Also replacement transistors are cheap for the innevitable error or 2.
These amps have a strong "long" bass and very low parts cost.
The original DX is medium power 50W @ 8R, 100W @4 R
The HRII is a little diffirent and lower power, with some of the supply rails regulated down in voltage, the result is a lower powered output, but a much improved fidelity, realy nice trebles and details, it is definately the lady amp of the bunch. providing about 40W@8R per channel in its basic form. I have a strong love for this one. This 40W of undistorted power and seem much much, much, more powerfull in real life.
Build cost is a little higher due to extra transistors, but not by much and the original DX supply can still be used.
The PI is the butch of the batch at about 250W@4R, very powerfull pushing bass from almost DC, with astounding detail in mid and bass regions. Construction costs are in the high-ish category as the power supply caps, transformers and heatsinks almost all double in size, not to mention the 4 extra output pairs...
I would suggest you aim for the HRII, I think it will complement those high efficiency drivers very well.
Those chips are good, but, they cannot be better than discrete amplifiers... and this
Because the size limits.
If you try to touch a soldering iron, the small soldering iron tip, into a big heatsink, you will find that cannot transfer heat to the heatsink, or, the transference will be bad.
The correct transference may exist if you make a hole, the same shape and same dimensions of your soldering iron tip point, and introducing it into the heatsink hole you gonna have more contact area to heat transference... this way you gonna have, as a result, better heat transference.
The small case you have into those chips (exception are the better ones, in my point of view, some models from Sanyo, STK4141, for instance, sounds good)... the small metal cases, the small metal block you have into the chip back side is too small to allow you to transfer a big ammount of heat and very fast... this will limit the power transference...the maximum heat transfered.
You see that when you have an amplifier, alike the LM3875, or LM3886....well.... someone that can produce 50 watts clean, it will be dissipating more than that in heat..... because efficiency of class AB amplifiers that are around 65 percent maximum...so....there's a lot of heat to transfer to the heatsink to allow the unit to work into 55 degrees celsius...and the internal chip will be much more hot, maybe reaching the metal melting point.... the metal fusion point because heat..the junction damage may happens...so...this limits the power..... you see those chips have the same power into 8 ohms and 4 ohms....why?...because limited internally to avoid heat and problems.... those units, because of the limits they have, cannot pump big power into dinamic transientes...the chip will "eat", will block the peak, the overcurrent, overvoltage, over temperature, all this will enter in action to huck your sound.
The small distance from input to output can peak signal, and because of that, internal circuit is hardly compensated to avoid this pickup.... hardly compensated circuits do not sounds very well into high frequencies....and this happens...the treble is a little bit...very little bit...harshing.
The result of that, it that even sounding EXCELENT, those amplifiers, into chip form, cannot win ANY good discrete design...because the dinamic headroom you may have into discrete units...because the protection they have..and because the small distance between input and output.
I have, almost all chip amps here...i have listened all them, and tested, and compared....they are good, or very good, or even excelent, they are simple to assemble, they are very pretty, they are very cheap, very convenient to build pretty amplifiers, nice to multichannel amplifiers because very small, also easy, small parts count....but, in my point of view...subjective...hundreds may think the opposite (in special the ones have bougth those chip amplifiers)...but it is my point of view.... cannot beat a GOOD discrete design.
Not my designs beat those chips...i am saying that ALL GOOD discrete design can do that..because the dimension limits, and protections the chip amplifiers use to have, those small ones, the small chip amplifiers have a lot of protections.. each one of them plays some ammount into the highest possible audio quality KILLING.
regards,
Carlos
Because the size limits.
If you try to touch a soldering iron, the small soldering iron tip, into a big heatsink, you will find that cannot transfer heat to the heatsink, or, the transference will be bad.
The correct transference may exist if you make a hole, the same shape and same dimensions of your soldering iron tip point, and introducing it into the heatsink hole you gonna have more contact area to heat transference... this way you gonna have, as a result, better heat transference.
The small case you have into those chips (exception are the better ones, in my point of view, some models from Sanyo, STK4141, for instance, sounds good)... the small metal cases, the small metal block you have into the chip back side is too small to allow you to transfer a big ammount of heat and very fast... this will limit the power transference...the maximum heat transfered.
You see that when you have an amplifier, alike the LM3875, or LM3886....well.... someone that can produce 50 watts clean, it will be dissipating more than that in heat..... because efficiency of class AB amplifiers that are around 65 percent maximum...so....there's a lot of heat to transfer to the heatsink to allow the unit to work into 55 degrees celsius...and the internal chip will be much more hot, maybe reaching the metal melting point.... the metal fusion point because heat..the junction damage may happens...so...this limits the power..... you see those chips have the same power into 8 ohms and 4 ohms....why?...because limited internally to avoid heat and problems.... those units, because of the limits they have, cannot pump big power into dinamic transientes...the chip will "eat", will block the peak, the overcurrent, overvoltage, over temperature, all this will enter in action to huck your sound.
The small distance from input to output can peak signal, and because of that, internal circuit is hardly compensated to avoid this pickup.... hardly compensated circuits do not sounds very well into high frequencies....and this happens...the treble is a little bit...very little bit...harshing.
The result of that, it that even sounding EXCELENT, those amplifiers, into chip form, cannot win ANY good discrete design...because the dinamic headroom you may have into discrete units...because the protection they have..and because the small distance between input and output.
I have, almost all chip amps here...i have listened all them, and tested, and compared....they are good, or very good, or even excelent, they are simple to assemble, they are very pretty, they are very cheap, very convenient to build pretty amplifiers, nice to multichannel amplifiers because very small, also easy, small parts count....but, in my point of view...subjective...hundreds may think the opposite (in special the ones have bougth those chip amplifiers)...but it is my point of view.... cannot beat a GOOD discrete design.
Not my designs beat those chips...i am saying that ALL GOOD discrete design can do that..because the dimension limits, and protections the chip amplifiers use to have, those small ones, the small chip amplifiers have a lot of protections.. each one of them plays some ammount into the highest possible audio quality KILLING.
regards,
Carlos
Thanks Guys
I sincerely appreciate the quick and thorough reply from you both. Are PCB boards still available for HRII?
It seemed that you may have exhausted the group buy for HRII. IF that is the case do you think that more people would be interested in another group buy? I am in the states and would be happy to have a board house manufacture some.
I sincerely appreciate the quick and thorough reply from you both. Are PCB boards still available for HRII?
It seemed that you may have exhausted the group buy for HRII. IF that is the case do you think that more people would be interested in another group buy? I am in the states and would be happy to have a board house manufacture some.
http://www.4pcb.com/
I dont know what their fees are. But they are offering a $500 coupon for any new customer. I dont know what minimum quantities or minimum dollar value of initial order must be to qualify. Just figured I would mention it if it is necessary to get more boards and if you think enough people would be interested.
Sincerely
Uriah
I dont know what their fees are. But they are offering a $500 coupon for any new customer. I dont know what minimum quantities or minimum dollar value of initial order must be to qualify. Just figured I would mention it if it is necessary to get more boards and if you think enough people would be interested.
Sincerely
Uriah
Hi I still have a small supply and haveing more boards made is normally about a week or less as they allready have prepared screens at the factory.
I would be interested in in a pair if you have some spare, how much and how do I pay?
Cheers Paul
Cheers Paul
Nordic, I sent you an email. Can not find the link to purchase the HRII on your site. Only can purchase the module.
Nordic: Since we are on the subject of orders, are all of the Speaker Protection modules spoken for?
Dave
Dave
Hello,
I will not be able to build my set from the group buy. 2 amp pcb, 2 ps pcb, resistor/transistor kit. $57.50 + shipping. PM or email. payment by paypal.
t
I will not be able to build my set from the group buy. 2 amp pcb, 2 ps pcb, resistor/transistor kit. $57.50 + shipping. PM or email. payment by paypal.
t
Hi there sorry been out of town today.
Also haveing problems with outlook express... not had much time to try and figure it out... I suspect the virus is back.
Hi Paux sorry to keep you waiting, did not see your question, but it wil have to wait until tommorrow so that I can just get a fresh quote on the replacement cost to me, as the boards were form a large batch innitialy, I see 4 boards in the envelope, I normally keep them in , and I think I have two more somewhere.
Will place an order for a handfull more HRII, for those who don't quite have the budget for a PI yet.
I definately have protection modules left, and I think PSU boards too, allthough I will be restocking those automaticaly as they seem pretty popular.
I will doublecheck orders vs stock tommorrow morning.
Also haveing problems with outlook express... not had much time to try and figure it out... I suspect the virus is back.
Hi Paux sorry to keep you waiting, did not see your question, but it wil have to wait until tommorrow so that I can just get a fresh quote on the replacement cost to me, as the boards were form a large batch innitialy, I see 4 boards in the envelope, I normally keep them in , and I think I have two more somewhere.
Will place an order for a handfull more HRII, for those who don't quite have the budget for a PI yet.
I definately have protection modules left, and I think PSU boards too, allthough I will be restocking those automaticaly as they seem pretty popular.
I will doublecheck orders vs stock tommorrow morning.
Nordic,
I bought the unopened box that T-Head got from you earlier. He lives quite near me and I know the shipping will be fast and the quality will obviously be exactly the same 🙂
Thanks
Uriah
I bought the unopened box that T-Head got from you earlier. He lives quite near me and I know the shipping will be fast and the quality will obviously be exactly the same 🙂
Thanks
Uriah
Nordic,
I am considering which transformer to get. You recommend 26-28vac. I am running into plenty of 25v and 30v but nearly nothing in between and nothing that would fit the bill. Any reason NOT to build my own? I found this site which others might find useful and it allows purchasing a primary wound toroid that you have to wind your own secondaries onto. It might be nice because then you could maybe make several secondaries and build a transformer enclosure with several different voltage outputs to use for powering different projects.
http://www.toroid.com/standard_transformers/transformer_kits/transformer_kits.htm
Also, you recommend using two transformers. What is the advantage?
I was reading another post of yours "http://www.diyaudio.com/forums/showthread.php?postid=1426463#post1426463 in which you mentioned that it was good to use two separate power supplies, but I also thought I saw a post by you saying to keep them close to the amp if not in the amp enclosure.
Would you be so kind as to clear these up for me?
edit: so what about a 25v-0-25v transformer? Am I giving up anything?
another edit: its for my 8Ohm speakers
I am considering which transformer to get. You recommend 26-28vac. I am running into plenty of 25v and 30v but nearly nothing in between and nothing that would fit the bill. Any reason NOT to build my own? I found this site which others might find useful and it allows purchasing a primary wound toroid that you have to wind your own secondaries onto. It might be nice because then you could maybe make several secondaries and build a transformer enclosure with several different voltage outputs to use for powering different projects.
http://www.toroid.com/standard_transformers/transformer_kits/transformer_kits.htm
Also, you recommend using two transformers. What is the advantage?
I was reading another post of yours "http://www.diyaudio.com/forums/showthread.php?postid=1426463#post1426463 in which you mentioned that it was good to use two separate power supplies, but I also thought I saw a post by you saying to keep them close to the amp if not in the amp enclosure.
Would you be so kind as to clear these up for me?
edit: so what about a 25v-0-25v transformer? Am I giving up anything?
another edit: its for my 8Ohm speakers
Hi Uriah, sorry for delay one of my ex-clients got their website hacked, so now they are back needing urgent attention...
Either of those transformers will work fine, at worst you will have to change the values of the zener rail referances to insure about a 3 to 5V drop.
As a channel puts out a peak the voltage in the supply tends to drop or is modulated in fancier english.
When you have 2 channels connected to the same PSU, peaks on one channel modulates the voltage the other channel sees...
To reduce this you can use 1 transformer and 2 PSUs.
To eliminate this you use 2 transformers and 2 PSUs.
Either of those transformers will work fine, at worst you will have to change the values of the zener rail referances to insure about a 3 to 5V drop.
As a channel puts out a peak the voltage in the supply tends to drop or is modulated in fancier english.
When you have 2 channels connected to the same PSU, peaks on one channel modulates the voltage the other channel sees...
To reduce this you can use 1 transformer and 2 PSUs.
To eliminate this you use 2 transformers and 2 PSUs.
I get it! Thanks Nordic. 🙂
Nordic, I have one more question (at the moment 🙂 probably more to come once I get the kit).
I was thinking of making the PSU separate from the amp. So there might be an enclosure (the PSU) on the bottom of my audio rack and then the amp enclosure a few inches above it, but definitely separate enclosures. Is this distance a bad thing? Whats the max distance you would recommend? I wanted to do this so that I can use it for other projects since similar voltages will work for a lot of the projects I have seen on DIY. OR I could just put the transformers in a separate enclosure and keep the rest of the PSU in the AMP enclosure.
Tell me what you think. Please anyone else chime in as well if you feel inclined.
Thanks
Uriah
Nordic, I have one more question (at the moment 🙂 probably more to come once I get the kit).
I was thinking of making the PSU separate from the amp. So there might be an enclosure (the PSU) on the bottom of my audio rack and then the amp enclosure a few inches above it, but definitely separate enclosures. Is this distance a bad thing? Whats the max distance you would recommend? I wanted to do this so that I can use it for other projects since similar voltages will work for a lot of the projects I have seen on DIY. OR I could just put the transformers in a separate enclosure and keep the rest of the PSU in the AMP enclosure.
Tell me what you think. Please anyone else chime in as well if you feel inclined.
Thanks
Uriah
Hi Carlos!
How are you? Hope it is not to hot for you in Brazil.
A few posts ago you mentioned the Sanyo STK chips. Did you ever build a input/vas section for a STK2040/3040 -- they are just the power amp ones.
I built an amp around one of these, but it does not sound good. I would like to try a different circuit, if not I can just re-use the parts.
The chip was from a 1980's Yamaha unit.
regards
Andrew (nogoodbuyer😀 )
How are you? Hope it is not to hot for you in Brazil.
A few posts ago you mentioned the Sanyo STK chips. Did you ever build a input/vas section for a STK2040/3040 -- they are just the power amp ones.
I built an amp around one of these, but it does not sound good. I would like to try a different circuit, if not I can just re-use the parts.
The chip was from a 1980's Yamaha unit.
regards
Andrew (nogoodbuyer😀 )
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