Definetely don't waste your money on 'audiophile' caps for line conditioning caps and the snubber position across the bridge rectifier... Keep the 1.5uF cap and purchase a 0.1-0.33 uF/at least 400V. In regards to counterfeit components one is none the wiser as to what is inside the 'component' itself (unless one can spot the wrong etching/labelling comparing the Reseller's product and the original one). The counterfeited products usually work as the electric current passes through but the specifications listed by the original component are not met by a distance (specific measuring devices needed and knowledgeoe needed). Some times, in the case of cheaply designed and manufactured clones of kits or readily-populated boards/devices a counterfeit component may be of a better quality than the one it has replaced thus a sense of satisfaction from the DIYer. @phase I salute your cautious stance in the description of the vagaries of sourcing components.
For the .1uf capacitor that is on the incoming ac power, you really want to use one that is fire rated, polypropylene is preferable.
http://www.kemet.com/Lists/Filestore/EvoxRifaRFIandSMD.pdf
As for the snubber, a decent polypropylene will be fine, I use surplus Russian polystyrene parts here since they are reasonable and sound better(faster rise times), yet take about twice as long to settle in.
The Diyink site is where some were getting their Crysek clocks from, are a legitimate vendor, however, it would be better to find out if they sell on a site like ebay. I don’t like giving my credit card information out to small businesses anymore. The price is in line with what you’d expect for that part.
Keep in mind that the holiday is still going on over there also, likely to be a delay in receiving.
http://www.kemet.com/Lists/Filestore/EvoxRifaRFIandSMD.pdf
As for the snubber, a decent polypropylene will be fine, I use surplus Russian polystyrene parts here since they are reasonable and sound better(faster rise times), yet take about twice as long to settle in.
The Diyink site is where some were getting their Crysek clocks from, are a legitimate vendor, however, it would be better to find out if they sell on a site like ebay. I don’t like giving my credit card information out to small businesses anymore. The price is in line with what you’d expect for that part.
Keep in mind that the holiday is still going on over there also, likely to be a delay in receiving.
Actually, I have one of those and think I wrote about it at some point in the ES9038Q2M thread. Bottom line is that it didn't sound very good at all. The buttons on the side are for volume control, nothing else can be controlled such as there is no choice between the seven different interpolation filters in the dac chip. There is a also a little SMPs used to give the opamps bipolar power. Like most super cheap SMPS it sounded bad.
The reason 1.07 boards (not 1.06 any more) are often recommended is because they are the ones most suitable for modding. If over time as you have time and a little money to put into it, you can modify the dac board to sound much, much better. Eventually, they can sound like a pretty expensive $1,000+ dac, but to get that far is a lot of work.
Would this work ? Its 0.33uF but has X2 rating !
Need help on the snubber circuit !
From what I understand from the internet, a snubber is a circuit designed for smoothing spikes in voltages/current for a 'switch'. So, in my case, I have to put two snubbers across two rectifier diodes in the DAC PCB, right ?
So, for designing a snubber, I have to know the capacitance of the diode as well as the resistance ? I think I'll have to learn a lot of stuff to even think about the design ! No more Shadow of War for me this week then !!
A snubber is away of suppressing high frequency ringing transients due to sudden shut of current exciting parasitic reactances in transformers. The transients can sneak past voltage regulators and cause problems in audio circuits. The thing about snubbers is they need to be tuned to the particular transformer for best results. You need an oscilloscope to see the ringing. An alternative approach that can work quite well is to use ultra-soft recovery rectifier diodes, which are much less prone to excite ringing as compared to common rectifier diodes like 1N4007. Perhaps the best type are called hexfreds, but they can be kind of expensive. Also, you should check the data sheets for forward drop to see if they would be compatible with your application. If the rectifiers you use are good enough, then snubbers would likely be redundant. In some cases people will use both soft recovery diodes and snubbers. I will say this: hexfred rectifiers are cheaper than buying a scope and faster to get working that tuning snubbers by hand. However, there are calculators to estimate snubber values, although probably still wise to verify proper performance with a scope in that case. Good ultra soft recovery rectifiers can be nearly as good as hexfreds too, so good to look around and read data sheets if considering that approach.
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@Markw4
OK, I'll look for the hexfreds !
By the way, can I move the powersupply setup out of the main DAC board ?
Wouldn't it be good ?
Would this rectifier work ? Its no hexfred BTW. ON Semiconductor MUR1560G 15A 600V Ultrafast Rectifiers
Found an another one but not a hexfred either ! Purchase online RHRG30120 Hyper-fast Diode in India at low cost from DNA Technology,Nashik.
One more ! MUR860 (DIODE, ULTRA-FAST, 8A, 600V)
One more query ! Is there any decent OP-AMPs in this link ? Check out our stock of Operational Amplifier . You can buy it online in India. Great prices with fast delivery. ORDER NOW!!!
OK, I'll look for the hexfreds !
By the way, can I move the powersupply setup out of the main DAC board ?
Wouldn't it be good ?
Would this rectifier work ? Its no hexfred BTW. ON Semiconductor MUR1560G 15A 600V Ultrafast Rectifiers
Found an another one but not a hexfred either ! Purchase online RHRG30120 Hyper-fast Diode in India at low cost from DNA Technology,Nashik.
One more ! MUR860 (DIODE, ULTRA-FAST, 8A, 600V)
One more query ! Is there any decent OP-AMPs in this link ? Check out our stock of Operational Amplifier . You can buy it online in India. Great prices with fast delivery. ORDER NOW!!!
Ok, I'll try it.
The spec says video opamp by the way
So, both are single channel ?
Thanks for the recommendations guys.
One interesting thing I noted is that the other fast rectifiers whose links I posted above have better recovery time than this one, RHRG75120.
But, none of them are claiming soft recovery. So, I should buy it ( RHRG75120) even though its recovery speed is more than the other two, right ?
EDIT:
@abraxalito
Oh ! Didn't know that. Thanks for the reply !
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Hi all !
I have a noob question to ask. The 'max. forward voltage' for all those rectifiers is 3.3V. What does this mean? Would it cause 3.3Volt voltage drop ? Compared that of the 1N4007 diode with its 1 Volt drop this is significant ! Shall I use the 12V transformer then ?
It probably wouldn't hurt, but you are starting with a low cost dac board and you probably can only improve it so much. Going to heroics with the power supply should help, but may be more than that rest of the project will fully be able to benefit from. Don't know.
Regarding rectifiers, 'fast' rectifiers can help since their stored charge is less, so less reverse current flows before the final stop. That helps to reduce transients. Soft recovery also helps, which means the stored charge doesn't get swept out in a large current then stop suddenly, it kinds of fades out more slowly. Hexfreds have both properties. Of the two, soft recovery probably usually helps more than fast, but it is common to use Schottky diodes at low enough voltages (they can't stand too much reverse voltage) because they are efficient with low forward drop and fast with little stored charge.
Oh oh
I jumped the gun and purchased two AD811 along with a dual to single DIP8 socket
I'm not sure if my can DAC work with a current feedback OP-AMP.
All I know it used a single JRC 5532 OP-AMP.
Yeah, I agree.
Actually my DAC is using Schottky diodes (SR2100 ?)for rectification.
BTW guys, anyone need a pair of AD811 ?
But the soft recovery diode was suggested as I don’t know how to design a snubber. It’s costly but not that costly but the ad811 on the other hand.....
The opamps suggested by Keith is very cheap though. So, I’ll surely get it. I’ll also get the 0.33uF X2 polypropylene cap as well (can’t find 0.1uF cap).
The opamps suggested by Keith is very cheap though. So, I’ll surely get it. I’ll also get the 0.33uF X2 polypropylene cap as well (can’t find 0.1uF cap).
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