| digi01 |
What I made is an integrated amp.I use one 240VA 2 X 22VAC toriod, for power supply.
the attached drawing show the psu connections.
P.S.
I have collected almost all parts.but the sop-4 3-t packaged lm317/337 can not be find at my home town.who knows where to buy these two components? |
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| peranders |
| I wish you good luck with the grounding becasue the pcb is made for one transformer per pcb. If you succeed to make a silent and humfree amp you have succeeded. |
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| rabstg |
| quote: | Originally posted by peranders
I wish you good luck with the grounding becasue the pcb is made for one transformer per pcb. If you succeed to make a silent and humfree amp you have succeeded. |
Just like designing an amplifier, grounding is also an art form.
Some people fight with it forever, some get it with minimal fuss.
:) |
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| peranders |
The thing was that I designed this board for one transformer each just because of the grounding problems people have with other designs.
If you only connect one transformer per pcb you will get a hum/thump/click free amp! :) The grounding is ready and you don't have to think about this. |
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| digi01 |
Beijing is wind today,so I can stay home enjoy this diy.
my tools below, |
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| digi01 |
tow hours later,the boards completed:cool: but,smd packaged lm317/337 still cannot find:bawling:
ZANG |
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| digi01 |
| my overkiller case.is the inner layout all right? |
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| digi01 |
| top view,all parts 70% completed.I can not help to hearing its sing. |
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| kelticwizard |
| quote: | Originally posted by Digi01:
Beijing is wind today,so I can stay home enjoy this diy.
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Surely work did not close down just because of some wind. Was there rain or snow with it? We call them hurricanes with rain, blizzards with snow.
| quote: | Originally posted by digi01
I have collected almost all parts.but the sop-4 3-t packaged lm317/337 can not be find at my home town.who knows where to buy these two components? |
Don't know if you want to go that far, but Digi-Key in America seems to have them. This is the LM 317 in the sop 4 3 term package.
Part # 296-12631-1-ND
American Page:
http://rocky.digikey.com/scripts/Pr...96&M=LM317MDCYR
Digi-Key Japanese Distributor Home Page:
http://dkc1.digikey.com/jp/digihome.html
Hope this helps. :) |
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| digi01 |
The wind in Beijing is not terrible,but it come with sand.Originally I planned to do shopping with my girlfriend.because of the wind,we have to stay home do own thing liked:D
thank you for your informations,I will check them.
ZANG |
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| Enrico |
My gainclone was already playing music for some time. NO click/ thump during power on/off and specially no hum. :-)
During testing of the first pcb, the voltage at the speaker output, it reads 36V. But after replacing the LM3886, the voltage becomes 0V, I mean 0mV.
As of now, I am using a 22k volume as a passive pre-amp between the cd player and amplifier. The sound is very natural and relaxing. I can listen to it continously the whole day.
I have the AKSA amplifiers driving the Linkwitz Orion speakers, sometimes I compare one of the 55W Aksa with the gainclone. The 55W Aksa is higher is power compared to the gainclone( by applying the same signal from the test cd supplied by Mr. Linkwitz, the Aksa 55W is 2x). The Aksa is slightly better in terms of high, mid, and bass but sometimes, I feel that it is a bit bright.
I am going to built an 8 channel gainclone to try to my Linkwitz Orion speaker. I am thingking of a "module" LM3886 approach. |
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| Enrico |
| after trying for sometime, here is the picture! |
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| peranders |
Enrico, the gain is not so high. I have chosen to have the gain enough for 0.7-1 V signal. This for not to get to much noise from the signal sources but it's very easy to increase the gain. This will be done by changing one resistor in the feedback of the input buffer.
One more thing: Be careful with your input connectors. You can tear away the copper pretty easy with your arrangement. |
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| karahara |
Really nice Case :bigeyes:
Keep on soldering:smash: :) |
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| Jamh |
Here's mine.
I just finished them. The chassis is made of an aluminum square beam (hollow in the middle) 1/4in thickness. The sides are 1/2in thick. I cut the squares 12 3/4in wide, and cut the bottom out to install the components.
My transformers are hand wound (by me!) and they provide 2 secondaries of 25.75vac and a 6v for a diode and led. I installed the red leds in an antique light housing.
All power wires are solid copper, signal wires are cat6. |
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| Jamh |
| Picture of the inside. |
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| Jamh |
| Picture of the back. |
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| Jamh |
One last one.
An ipod for testing. Thin Hat Trio is playing the Book of Silk. |
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| Jamh |
The black holes on top are spring mounted fuses, so you don't have to open the amp when you have to change them.
My experience with the construction was smooth. Digikey had sent me the wrong chip at first for LM337 and they had labelled it wrong. After that got sorted out, everything went smoothly, but it's a lot of work soldering those SMD components. I modified a tweezer to hold them securely before soldering. A magnifying light is a must, IMO. Also, once you're done, make sure to clean with rubbing alcohol. The connections are tiny and rosin can easily get to them. I used a toothbrush and rubbed it really good with alcohol.
Well that's it. Back to enjoying them. |
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| peranders |
My only point of view here is your input cable.
Personally I wouldn't have unshielded cable so close to a 10 A wideband output. I should at least move them away and/or use shielded cable. If you don't experience any problems of this arrangemant I'll guess this isn't anything to worry about.
Otherwise, have you had any chance to listen to the amp yet?
You don't have to clean the pcb but it looks nicer. I always clean my pcb's especially when I'm going to take pictures.
I use a brush with the brush hair cut short, isopropanol, Yes, and water and comressed air to dry the pcb. |
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| Enrico |
Hello Per-Anders,
I would like to ask what resistor number need to be changed to increase the gain.
Also, what is the formula for calculating the gain?
By the way, my Aksa 55W gain is 38 (31dB).
Thank you.
Enrico |
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| peranders |
If you scroll down to the end and look for "Gain" you will find it.
http://home.swipnet.se/~w-50719/hif...hema_qrp02.html
I recommend that you change R4 (lower value).
Total gain is (R5/R4+1)*(R7/R6) = 22.8 (27 dB)
38 in gain (if that is true) seems to be a bit much for normal signal sources but this is only a matter of taste. But you see also that it differs only 4 dB. |
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| Jamh |
| quote: | Originally posted by peranders
My only point of view here is your input cable.
Personally I wouldn't have unshielded cable so close to a 10 A wideband output. I should at least move them away and/or use shielded cable. If you don't experience any problems of this arrangemant I'll guess this isn't anything to worry about.
Otherwise, have you had any chance to listen to the amp yet?
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No, there is absolute no hum or hiss or anything. I have 95db speakers and with the volume cranked up, without music, it's dead quiet.
I'm still breaking in the amps, but they appear to quite clear and smooth. Good bass too, but I'd like to run them for a week or so before making judgement. |
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| Jamh |
| quote: | Originally posted by Enrico
Hello Per-Anders,
I would like to ask what resistor number need to be changed to increase the gain.
Also, what is the formula for calculating the gain?
By the way, my Aksa 55W gain is 38 (31dB).
Thank you.
Enrico |
Does the gain need to be increased just a bit, or it's way too quiet. The reason I'm asking is that I run into a case of one of the amps being way too quiet, and figured it out to be C1 not being soldered properly. The C1 cap that I got was bigger than its area and didn't leave much room to solder to the pads. I ended up twisting it a bit. |
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| Jamh |
| I don't know what it is with my typing these days. As I read my posts, they are full of typos and missing words. Must be the lead... :rolleyes: |
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| digi01 |
to Enrico and Jamh,
congratulations,I hope my amplifier can be finished at once too:)
The experience of soldering:
what I used is 0.8mm solder,0.5mm will be better.
these smd components is very small,so must use the tweezers to take them.I have two tweezers,a elbow tweezer and a stanch tweezer which the doctor used,feel very well.
I have fixed one pin of smd component at first with the tweezers while soldering,then the other pins are easy to solder.
I diy a small spoon(see attached),it can help me to remove any solder excess.
ZANG |
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| digi01 |
the spoon operation method,simply hold the spoon up to the soldered joint,and apply heat with the iron for removing unwanted solder.can add rosins for the soldering with it to
make the process go more smoothly. |
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| peranders |
| quote: | Originally posted by Jamh
Does the gain need to be increased just a bit, or it's way too quiet. The reason I'm asking is that I run into a case of one of the amps being way too quiet, and figured it out to be C1 not being soldered properly. The C1 cap that I got was bigger than its area and didn't leave much room to solder to the pads. I ended up twisting it a bit. |
I doubt very much that this was your problem because if the cap wasn't soldered properly you wouldn't have got any sound at all.
If you feel that you can't drive the amp into clipping, you may increase the gain. |
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| peranders |
| Zang, smart idea with a "spoon" :nod: |
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| Jamh |
| quote: | Originally posted by peranders
I doubt very much that this was your problem because if the cap wasn't soldered properly you wouldn't have got any sound at all.
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Yes, but a fact. There must have been just the slightest contact. |
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| digi01 |
thank you Per.
P.S.
I ask for a singapore diyer to help me buy those to-223 packaged lm317/337,I hope to finish this amplifier soon :)
About grounding,what suggestions do you have? I find you have put several ground pads on board.
ZANG |
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| peranders |
| You have missunderstood the grounding concept. The pcb's are mono blocks. As you see you will have both charging current peaks plus speaker ground plus signal ground in the same wire. You may get good results if you have a thing ground wire between the boards but you must be aware of the you will mix different ground currents. If you can dig up an another transformer all problems are gone. |
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| Jamh |
Peranders,
These monoblocks sound amazing! I've been playing them for 12 hours or so, therefore they're not completely broken in, but already they are wonderful. In particular, the highs are not metallic at all, nice and relaxed. The midrange is not as good as SETs, IMO, but not that far behind. A bit analytical, less sexy. The bass hasn't broken in yet. It is powerful but slightly mushy.
My entire system is Sony SCD-1, Bat Vk3i and home made speakers based on vintage coax Altec Theatre drivers. I ended up modifying the crossover, adding a bit more resistance to the tweeters (4ohm) to make them sound right. It could be due to the fact that my speaker cables are now very short, and less high frequencies get lost in the long cables. Or it could be that the amps are brighter than my 2A3s.
I'm listening to the Mozart Requiem, Tin Hat Trio (highly highly recommended), Boris (from Japan), Kip Hanrahan and Bjork.
All in all, I'm extremely pleased. Many thanks. |
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| digi01 |
Hi Jamh,that is great!:cool:
a good news,I got those to-223 packaged 317/337 today,I will continue this amp weekend:cool:
ZANG |
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| huangyong |
| Wow.... really amazing.. you can make such beutiful work with ordinary tools .. that's what i call "SKILL" |
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| Jamh |
For my tweezers, what I did was to bend the ends towards each other so that they are touching with a very small amount of compression force. This way you don't have to hold on to them.
Peranders, one thing I don't understand about your 2 irons is how do you apply the solder. Do you pre-apply it to the iron tips? I mean we humans have only 2 hands! |
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| peranders |
| I apply solder first at the pads, then place the part, then warm it, then move the irons rather horizontally, then the part sucks into place. |
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| jleaman |
| how much ( again ) are these board's going for ? |
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| peranders |
| Look in your mailbox, emailbox :) |
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| Saibot |
digi01,
did you get your amp to work using only one transformer and the wiring shown in the beginning of this thread ?
I have 6 QRP-02 I want to build but I don't want to use a transformer for each of them. It gets too expensive buying a lot of MUR3020:s and transformers...
Anyone else has a solution to grounding problems that may show if only one transformer is used ? There's got to be a solution...
/Tobias |
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| peranders |
You must in some way got the star grounding concept to work.
1: Loose all rectifiers on board
2: Drop the big smoothing caps
3 Use "fat" ground wire
4: Get a rectified and smoothed DC voltage
5: Make a very serious star ground point, maybe use a copper block, like a cube or something. You must see to it that the ground currents don't interfere with each other.
There are reasons why multichannel amps have separate power supplies. This is the reason. |
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| greatestbestest |
I am trying to avoid buy a PPS .1uF capacitor for C1 alone because with min quanity it is $14. There has to be others out there with extra ones I could buy off you. Anybody?
Possible canidates:
Evox Rifa PPS 65-557-59 from Elfa
dimensions 5.7x5.0
from digikey
Panasonic ECH-U PPS film
none fit exactly but I assume will work
2416 6.0x4.1
2820 7.1x5.0
PCF1167CT-ND 2416 .12uf $1.01 2%tol
PCF1158CT-ND 2416 .12uf $0.96 5%tol
PCF1506CT-ND 2820 .1uf $1.41 2%tol 100VDC
PCF1489CT-ND 2820 .1uf $1.31 5%tol 100VDC
Mouser
AVX SMD FILM MKI
581-CF042D0334J 2220 .33uf $.77 polyester and significantly lower fc (but min quanity 1)
Please throw me some ideas or some parts. Thanks |
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| greatestbestest |
Another quick question:
What size fuses are you using?
On the supply rails I assume fast blo would protect amp best, but slow blo would allow transformer inrush current on primary.
secondary fuses ~ output current limit?
for LM3886 this would be 7-12A which seems large for 50W amp
primary fuse
This would vary with number of channels on power switch. For 2 channel 3A slow blow seems good.
Any info on this topic?
Paul |
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| digi01 |
the amp is completed:)
ZANG |
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| digi01 |
| front panel,power on. |
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| digi01 |
| inner connections. |
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| digi01 |
| the detail of poti. |
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| peranders |
| Have you fired up the amp yet? No hum? Sounds good? |
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| jleaman |
| Look's Killer NICE NICE NICE keep it up.. |
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| Franz G |
Looks very professionally, digi01!
- how does it sound, no hum with just one tranny?
- did you produce the smoke recently with this amp?
Regards
Franz |
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| digi01 |
thank you.
The amp was finished yesterday,I am listening it at whole night.
Through burn up of 8 hours,the sound is perfect.quality of mid-range left the deepest impression on me,good soundstaging and details.bass control is tight but a tad lightweight.
But I have been already very satisfied,if the power is a bit larger(80W or 100W each channel),then very ideal:)
P.S.
the amp is not hum & hiss when there is not input.even I close up my ears on the loudspeaker,can only hear very faint white noise.
the dc offset of Rch is 5mv,Lch is 12mv.
ZANG |
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| digi01 |
| quote: | Originally posted by greatestbestest
Another quick question:
What size fuses are you using?
On the supply rails I assume fast blo would protect amp best, but slow blo would allow transformer inrush current on primary.
secondary fuses ~ output current limit?
for LM3886 this would be 7-12A which seems large for 50W amp
primary fuse
This would vary with number of channels on power switch. For 2 channel 3A slow blow seems good.
Any info on this topic?
Paul |
Hi Paul,
On the supply rails I use a fast blo 250V1.5A fuse.chinese home is 220VAC.the transformer is 250VA 2x22VAC.I have not set up secondary fuses,just short them.
FYI,main parts list:
C23,28, nippon 3300uf/50v
C22,27, empty
C4, elna cerfine 100uf/35v
C6,C7,wima 1uf/63v
C10,12, elna rjh 100uf/50v
C14-C21,ero 0.1uf/63v
R8(mute resistor)33K
D7,8,9,10,15,16,17,18, BFY6A200V(made in china)
thanks P-A offer all 0805 parts and C1.
ZANG |
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| digi01 |
| quote: | Originally posted by greatestbestest
I am trying to avoid buy a PPS .1uF capacitor for C1 alone because with min quanity it is $14. There has to be others out there with extra ones I could buy off you. Anybody?
Possible canidates:
Evox Rifa PPS 65-557-59 from Elfa
dimensions 5.7x5.0
from digikey
Panasonic ECH-U PPS film
none fit exactly but I assume will work
2416 6.0x4.1
2820 7.1x5.0
PCF1167CT-ND 2416 .12uf $1.01 2%tol
PCF1158CT-ND 2416 .12uf $0.96 5%tol
PCF1506CT-ND 2820 .1uf $1.41 2%tol 100VDC
PCF1489CT-ND 2820 .1uf $1.31 5%tol 100VDC
Mouser
AVX SMD FILM MKI
581-CF042D0334J 2220 .33uf $.77 polyester and significantly lower fc (but min quanity 1)
Please throw me some ideas or some parts. Thanks |
I think C1 can be short.or you can use standard film caps,warp the legs.the attached photo is a illustration,wish that helps. |
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| peranders |
Good to hear that you didn't get any hum. :up:
5 mV and 12 mV at the output, was that without DC servos? :scratch: |
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| peranders |
| digi, some time has gone now. What is your impression now? |
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| XELB |
| quote: | Originally posted by digi01
my overkiller case.is the inner layout all right? |
Where did you find that case :bigeyes:
I'm looking for a nice case and I only find rubbish:dead: |
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| digi01 |
| quote: | Originally posted by peranders
digi, some time has gone now. What is your impression now? |
thank you P-A,the sound really changing,as smooth as glass:D
P.S.
I have make 3 gc amp now(P-A's 3886igc with buffer,BrianGT's 4780nigc,digi01's 3886igc)I like all of these amp.
| quote: | Originally posted by XELB
Where did you find that case :bigeyes:
I'm looking for a nice case and I only find rubbish:dead: |
I buy the case from local,beijing is a diy friendly city:)
rgds
Zang |
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| peranders |
| quote: | Originally posted by digi01
[B]I have make 3 gc amp now(P-A's 3886igc with buffer,BrianGT's 4780nigc,digi01's 3886igc)I like all of these amp.
] |
Are the amps pretty much alike or are you able to detect any differens?
Input buffer v.s none?
Inverting vs. non-inverting?
Big PS vs. not so big?
Snubberized PS vs. unsnubberized if you have tested that? |
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| edjosh23 |
| quote: | Originally posted by XELB
Where did you find that case :bigeyes:
I'm looking for a nice case and I only find rubbish:dead: |
http://www.vt4c.com/shop/index.html
seems to have some nice cases too that look somewhat similar and are pretty low cost.
Josh |
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| XELB |
Thanks :cool:
I'm just waiting for the last components to arrive so that I can finish my amp and see what kind of case I will use.
I olso discovered a small company in Portugal that make custom made cases for audio;)
I will compare the prices, but I liked the chinese aluminum cases of that shop :) |
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