Hi Russ,
Thanks a lot, in a few weeks, I'll be starting to build this project and when have a pair of photos ( pcb's first of all ) I promise I'll post them.
Cheers
Iván Francisco
Thanks a lot, in a few weeks, I'll be starting to build this project and when have a pair of photos ( pcb's first of all ) I promise I'll post them.
Cheers
Iván Francisco
I think its a great idea, if you want some help with the schematics feel free to email me, or even post them here.
Cheers!
Russ
Cheers!
Russ
Finally I built this circuit since I found someone in Mainland China copy the ciruit and sell the bare PCB, although should be a illegal copy, but save me lots of shipping and payment costs, which cost me total no more then USD10 for one bare PCB, therfore, let me say sorry to the deisgner.....🙁
Here is the link of the bard PCB board:
http://bbs.hifidiy.net/viewthread.php?tid=79302&highlight=+HIFIME
The bare PCB itself only cost around USD5.xx something, if I order from mauropenasa or Russ, only shipping cost will be over USD1x to Hong Kong, so please understand me.... 😛
I use Philips caps in PSU section (just 1600uF x 4 per channal), all Dale reisistors, all Nover caps in amp section, and all Rifa caps for coupliing, and a 150VA transformer, I found that this amp is dead quiet, very nuetral and balance, almost as clear water, all what I heard is exactly what my front ends charater, I am very exciting for the performance.
However, I want it to be a bit more puchy and dynamic for the bass, but without changing the sound character, should I simply add more caps in PSU section with a bigger transformer? Or I bulit on more borad, with a balanced/BTL buffer input stage, double the power by BTL configuration? I am using ProAc Response 1SC speakers.
Thanks for any advise and again, sorry for I encourage the copy cat as I buy from them.......
😛
Here is the link of the bard PCB board:
http://bbs.hifidiy.net/viewthread.php?tid=79302&highlight=+HIFIME
The bare PCB itself only cost around USD5.xx something, if I order from mauropenasa or Russ, only shipping cost will be over USD1x to Hong Kong, so please understand me.... 😛
I use Philips caps in PSU section (just 1600uF x 4 per channal), all Dale reisistors, all Nover caps in amp section, and all Rifa caps for coupliing, and a 150VA transformer, I found that this amp is dead quiet, very nuetral and balance, almost as clear water, all what I heard is exactly what my front ends charater, I am very exciting for the performance.
However, I want it to be a bit more puchy and dynamic for the bass, but without changing the sound character, should I simply add more caps in PSU section with a bigger transformer? Or I bulit on more borad, with a balanced/BTL buffer input stage, double the power by BTL configuration? I am using ProAc Response 1SC speakers.
Thanks for any advise and again, sorry for I encourage the copy cat as I buy from them.......
😛
goldkenn said:
yes... 1,600uF is definitely way too little to have decent bass. Mauro recommends 10,000uF caps, and you should go for it.
Also the 150VA power transformer is definitely scarce... if you want to keep using the one you have you may try to add another (identical) one and go for a fully dual mono configuration (if you have copied the original PCB design, you'll have to slightly modify it to allow for that).
Otherwise, strictly follow Mauro's recommendations and use a much bigger single PT.
More Slam
Try 10 - 22 ufd caps right on the power pins of the LM3886's also. These need to go to ground.
Try 4.7 - 10 ufd on the pins of the LM318 too. These small value caps with little lead trace can make the amp sound much stronger.
Btw, do take the advice and increase the value of the main filter caps.
George
Try 10 - 22 ufd caps right on the power pins of the LM3886's also. These need to go to ground.
Try 4.7 - 10 ufd on the pins of the LM318 too. These small value caps with little lead trace can make the amp sound much stronger.
Btw, do take the advice and increase the value of the main filter caps.
George
One thing to keep in mind about MyREF(any version) is that the Damping Factor is not exactly high.... I believe on some speakers this can leave some folks feeling like the bass is not "punchy" or lacks slam. Unfortunately this cannot really be corrected without a completely new circuit.
I certainly don't care that you have made a PCB. Just be sure that you get appropriate permissions from Mauro. He can be emailed through his site.
Cheers!
Russ
I certainly don't care that you have made a PCB. Just be sure that you get appropriate permissions from Mauro. He can be emailed through his site.
Cheers!
Russ
Thanks for all suggestions, I will try and post result.
By the way, Russ, please notice I did not made the PCB.
Regards.
By the way, Russ, please notice I did not made the PCB.
Regards.
Hi,
I put 470uF instead of 220uF, Rubycon ZL caps near the power pins, on my second MyRef and it has very good bass but I fear that HF noise could have increased, as Mauro discusses on his site. Instead going back to 220uF maybe I could use a 4.7uF SMD cap directly on the pins--> 470uF->4.7uF->0.1uF.
What do you guys think?
(in fact I was about to desolder the caps when I saw this post 😀 )
M
I put 470uF instead of 220uF, Rubycon ZL caps near the power pins, on my second MyRef and it has very good bass but I fear that HF noise could have increased, as Mauro discusses on his site. Instead going back to 220uF maybe I could use a 4.7uF SMD cap directly on the pins--> 470uF->4.7uF->0.1uF.
What do you guys think?
(in fact I was about to desolder the caps when I saw this post 😀 )
M
He, he...probably, but I hope not. Bass and clarity together.
I found an interesting 10uF/50V X7R cap (expensive) that is actually two 5uF caps in parallel:
RS Stock No. 547-7219
http://www.rs-export.com/cgi-bin/bv...mfmeldmmcefeceeldgondhgk.0&cacheID=gxnetscape
I'll better finish these articles:
http://www.planetanalog.com/showArticle.jhtml?articleID=199905522
(4 parts, so far)
Cheers,
M
I found an interesting 10uF/50V X7R cap (expensive) that is actually two 5uF caps in parallel:
RS Stock No. 547-7219
http://www.rs-export.com/cgi-bin/bv...mfmeldmmcefeceeldgondhgk.0&cacheID=gxnetscape
I'll better finish these articles:
http://www.planetanalog.com/showArticle.jhtml?articleID=199905522
(4 parts, so far)
Cheers,
M
One more question;
If I add the bypass caps for LM318 (10uF/63V) and LM3886 (22uF/63V), should I simply grounded to the singal ground before the 1 ohm resistor, or directly to the power ground after the 1 ohm resistor?
If I add the bypass caps for LM318 (10uF/63V) and LM3886 (22uF/63V), should I simply grounded to the singal ground before the 1 ohm resistor, or directly to the power ground after the 1 ohm resistor?
Nordic wrote
Don't spend too much money Max. You are going to retire that amp when you get your DX...
Mauro's rev c sounds great with my speakers, so it would be interesting to compare it to the DX. Then it will be interesting to compare the DX to Mauro's Evolution full version amp (eventually).
Don't spend too much money Max. You are going to retire that amp when you get your DX...
Mauro's rev c sounds great with my speakers, so it would be interesting to compare it to the DX. Then it will be interesting to compare the DX to Mauro's Evolution full version amp (eventually).
goldkenn said:
I ran mine to signal ground because it was closer and I like to keep the leads as short as possible. The LM3886 is easy, solder to the pinns. There is a ground right there at the pins. The LM318 requires a little more work.
I did this to a couple stereo versions, a TP Mono, and a full Evo. The Evo requires small caps for the LM318, mine started to low frequency occilate with 10 ufd for + to ground, - to ground, and rail to rail. Changed out to 2.2 ufd rail to rail, and 10 ufd for the rails to ground. There are holes in the pcb that allow inserting the cap leads where needed.
To my ears, small value low impedance electrolytics on the chips is the ticket. Swapped all the amps to Pana 22 ufd 50V FM for the LM3886's. Using Slimic II's for the LM318'S. The Silmics are 7.5 cents at Digikey, cannot pass on a bargain.
George
Panelhead said:
Thanks, the 22uF on LM3886 I will surly need tosolder on pins since it is place far away from power ground, but the LM318 have about 3cm from the power ground, compare with few mm to singal ground, will it still too far from "short trace"? Since from your words sounds like the bypass caps on LM318 will be more most improvment then on LM3886, therfore I want to do the best on the LM318, please kindly advise.
By the way, I am still confuse about the 1 ohm resistor, should it be an isolation or protection? If as isolation between AGND and PGND, will it be better to use a small value cap such as 0.01uF?
Do not read too much into my comments
My work on these is just my opinion. Others may have found out that they get the opposite results.
I think the small value caps on the LM3886 are more critical. I do not think the small film caps used help by delivering any current. The 10 - 22 ufd electrrolytics can deliver. I think that much larger caps have too much inductance. There are already 22- -470 ufd caps, but at a distance.
On the LM318, the effect of smalls caps really close does improve the soiund. But as much as it does on the LM3886. And it is a lot more work to install them.
I lent out a stereo My_Ref to someone with the LM3886 bypasses and he said it had the best bass he had heard from a 50 watt amp. I think it was all due to the bypasses. Before the bass was the area where the My_Ref was the weakest. There is a large output impedance. Not up to tube amp levels, but high for solidstate.
Prior to adding the bypasses I sent it to MikeW and he said it had great mids and highs. No comment on the low end.
George
My work on these is just my opinion. Others may have found out that they get the opposite results.
I think the small value caps on the LM3886 are more critical. I do not think the small film caps used help by delivering any current. The 10 - 22 ufd electrrolytics can deliver. I think that much larger caps have too much inductance. There are already 22- -470 ufd caps, but at a distance.
On the LM318, the effect of smalls caps really close does improve the soiund. But as much as it does on the LM3886. And it is a lot more work to install them.
I lent out a stereo My_Ref to someone with the LM3886 bypasses and he said it had the best bass he had heard from a 50 watt amp. I think it was all due to the bypasses. Before the bass was the area where the My_Ref was the weakest. There is a large output impedance. Not up to tube amp levels, but high for solidstate.
Prior to adding the bypasses I sent it to MikeW and he said it had great mids and highs. No comment on the low end.
George
Finally I modified my Rev_C as follow;
1) Input caps from 1.0uF increased to 2.5uF
2) Direct on pin additional 22uF bypass caps on each LM318
3) Direct on pin additional 47uF bypass caps on each LM3886
4)Each channal Additional 6800uF x 2 supply caps on top of the 1600uF x 4
5) Each channal stand alone LT317/337 regualtor for LM318
6) Each channal 150VA transformer
All these modifications does really rasied the overall performance up to next level, especailly dynamic, control, plus bass punch and extension, however, in terms of "powerful", it is still not up to what I expecting, at least compare with my Naim NAIT-5, Naim's 50W drive my ProAc much easy.
Since the sound quality and overall performance of Rev_C much better then my Naim, but all I need is just some more power, I am switch back to think about BTL the Rev_C by DRV134, but what should I do with the loudspeaker protection section? Simply short the circuit without install will safe or not? Please kindly advise.
1) Input caps from 1.0uF increased to 2.5uF
2) Direct on pin additional 22uF bypass caps on each LM318
3) Direct on pin additional 47uF bypass caps on each LM3886
4)Each channal Additional 6800uF x 2 supply caps on top of the 1600uF x 4
5) Each channal stand alone LT317/337 regualtor for LM318
6) Each channal 150VA transformer
All these modifications does really rasied the overall performance up to next level, especailly dynamic, control, plus bass punch and extension, however, in terms of "powerful", it is still not up to what I expecting, at least compare with my Naim NAIT-5, Naim's 50W drive my ProAc much easy.
Since the sound quality and overall performance of Rev_C much better then my Naim, but all I need is just some more power, I am switch back to think about BTL the Rev_C by DRV134, but what should I do with the loudspeaker protection section? Simply short the circuit without install will safe or not? Please kindly advise.
Hi goldkenn,
Thanks for posting your findings. A couple of photos would be much appreciated.
Just activelly biamp yours Proacs and forgetataboutit 😀
RevC's on top and Naim on bottom...
Sorry, what does BTL mean?
Instead of plain 3X7 regs for LM318 you could consider:
http://www.pinkfishmedia.net/forum/showthread.php?t=39990
...but it rises the cost and complication. I have my parts, safe fets, to try this on another project. Could use bipolar instead of fet. I've used gyrator preceding 3X7 on another project and the bass is superb (film caps; for this one I'll use tants as Teddy Pardo recommends).
Cheers,
M
Thanks for posting your findings. A couple of photos would be much appreciated.
Just activelly biamp yours Proacs and forgetataboutit 😀
RevC's on top and Naim on bottom...
Sorry, what does BTL mean?
Instead of plain 3X7 regs for LM318 you could consider:
http://www.pinkfishmedia.net/forum/showthread.php?t=39990
...but it rises the cost and complication. I have my parts, safe fets, to try this on another project. Could use bipolar instead of fet. I've used gyrator preceding 3X7 on another project and the bass is superb (film caps; for this one I'll use tants as Teddy Pardo recommends).
Cheers,
M
Next step
Are are now ready to try the full version of the Evolution from Mauro. It has paralled LM3886 and other changes. It will bring the power that you are missing. And will drive anything from horns to big current sucking dynamic speakers.
It is tweakable a little also, but do not add much capacitance to the LM318. The regs used will oscillate it too much capacitance is on their outputs. 2.2 ufd works fine, 10 ufd wil motorboat a little.
Gorge
goldkenn said:
Are are now ready to try the full version of the Evolution from Mauro. It has paralled LM3886 and other changes. It will bring the power that you are missing. And will drive anything from horns to big current sucking dynamic speakers.
It is tweakable a little also, but do not add much capacitance to the LM318. The regs used will oscillate it too much capacitance is on their outputs. 2.2 ufd works fine, 10 ufd wil motorboat a little.
Gorge