Good day everyone, I just designed a PS based on the proposed schematics of Mr. Janusz. I would like to hear your comment on the layout. I have attached some pics. looking for
ward to hearing from you soon.
The gerbers are not for sale and this is a standard policy at the DIYStore too. But the second Wolverine Group Buy is closing very soon and if you are quick you can buy some boards and get access to all the information. The demand for boards is so high that we are limiting access to the BOM etc to those with the courage to buy PCBs in order to minimise any shortages at the component suppliers. That supply constraint seems to be world wide and holding.
Hi James, a CRC configuration is only useful for mains ripple reduction in low to moderate current power supplies. For high current supplies, as in a power amplifier, the R in CRC simply causes the supply voltage to droop and earlier clipping at high loads. For power amplifiers large value, low ESR, screw terminal can types are recommended.
Your layout looks OK but I would add soldering fillets at the mounting holes in the bulk copper areas to help the soldering process (the bulk copper dissipates way too much heat).
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James, just so you know, my preamp uses a very similar layout CRC from the DIY Store and I am very happy with it.
Hello guys,
I've just returned from BAF and as promised I've added the "substitution" for the Wolverine heatsinks in all our Dissipante 3U 400 chassis to make it easier to purchase them https://modushop.biz/site/index.php?route=product/product&product_id=811
I would recommend more output terminals to simplify wiring.
1 for each channel, 1 for a possible speaker protection. So 3 each for +v/-v. Many more gnd outputs too. Typically one might want 6 or 7 gnd outputs to account for all the possible ground connections.
At least if one wants this pcb to not be specific to one implementation.
Otherwise one has to wire multiple wires per spade which gets annoying.
Good day, all.
Going through the BOM atm.
I am not too experienced with DIY, had several builds in the past but not as complicated as this one. So will be asking questions for sure, hope it is not too much trouble.
1. I don't have a preamplifier yet (will be selling my Naim shortly to move back to DIY world, much more fun) so not entirely sure what impedance (10k or 22k ) to choose. I went for 22 for now.
2. For r3,4,7,8 how many resistors to order for matching?
3. I am building 3 pair option. I don't listen to music at high SPL, so am thinking 100 watts should be enough, this makes a 500 VA transformer a correct choice it seems. Does it limit my selection of transistors and if yes what would be a recommendation, please? This is the most difficult question so far, I d appreciate some help here if possible.
4. Excel refers to a power supply and cap selection, but I haven't seen much info on what type of power supply to use. As I understand it is down to me just need to use suggested reservoir caps?
Thank you
Going through the BOM atm.
I am not too experienced with DIY, had several builds in the past but not as complicated as this one. So will be asking questions for sure, hope it is not too much trouble.
1. I don't have a preamplifier yet (will be selling my Naim shortly to move back to DIY world, much more fun) so not entirely sure what impedance (10k or 22k ) to choose. I went for 22 for now.
2. For r3,4,7,8 how many resistors to order for matching?
3. I am building 3 pair option. I don't listen to music at high SPL, so am thinking 100 watts should be enough, this makes a 500 VA transformer a correct choice it seems. Does it limit my selection of transistors and if yes what would be a recommendation, please? This is the most difficult question so far, I d appreciate some help here if possible.
4. Excel refers to a power supply and cap selection, but I haven't seen much info on what type of power supply to use. As I understand it is down to me just need to use suggested reservoir caps?
Thank you
No worries, ask as many as you need. It really seems like a lot at first glance, but once you read the build guide a few times, and just focus on 1 section of the BOM at a time, IE IPS resistors only, then it all falls together pretty well.
1. Pretty much any preamp will be able to drive the 10k input no problem, and you gain roughly 3dB noise floor.
2. If you buy .1% resistors then you won't need to match. If you want to be precise buy at least 10, but to match accurately you would need a 4 wire DMM.
3. 500 VA @ 35 volts would work for you, and no it doesn't limit your choice, but at that power output I would recommend the NJW0281/0302.
4. Any linear supply will work for you, another option is https://micro-audio.com/store/product/cobra-s2/ which I used on 3 builds and are great regulated supplies or https://micro-audio.com/store/product/smps700-pfc/. If you want a linear supply https://diyaudiostore.com/collections/power-supplies-accessories/products/universal-psu.
Thanks Andy.
I assume I need to choose the lowest rail voltage, +- 49.5?
By the way which DMM do you recommend? I need to get a better one than I have now.
I assume I need to choose the lowest rail voltage, +- 49.5?
By the way which DMM do you recommend? I need to get a better one than I have now.
Music with a high dynamic range benefits from a power supply with high rail voltage and low output impedance.
Hi @voxxonline ,
I'm looking at doing the same configuration as you - EF3-3 variant, 35v 500VA transformer, NJW0281/0302 outputs - and I'm in UK as well! I've tried to do a lot of research, read all the Wolverine forum posts, etc. and this seems to be the best option for me ... and so hopefully will be for you too!
For PSU, fortunately I had a spare unpopulated linear pcb from a previous 'Gainclone' build I did, just fitted higher voltage caps and seems to work fine. The DIYAudio psu board seems to also be a good choice, unless you want to go switched mode of course.
Trust @fireanimal's judgement, he knows what he's talking about, as do so many of the other guys on this forum!
Regards component matching - I bought a simple tester from Amazon (https://www.amazon.co.uk/gp/product/B088WKJ4DB/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1). OK, so it's a bit basic but was a total life saver for me, matched resistors and transistor Vbe's and hfe's, etc. easily. May not be the most accurate bit of kit out there, but as has been pointed out before even using something as basic as this is miles better than simply guessing! Whilst each reading may not be totally accurate by itself, at least it enables you to compare 'a' with 'b' and see how they match to each other, which is really all you're looking for at that point.
For resistors, I bought a bulk lot of 100 and matched the best as needed. They were reasonable quality and meant to be 1% tolerance, but around 50% of those were out of spec!
Hope your build goes well!
This is a low cost alternative for a DIY 4 wire measurement.
BTW this guys channel is quite interesting.
4 wire DIY
It is going to be a fun build. I have built myref gainclone in the past too. Though switched to commercial alternatives later, cause my wife did not appreciate my metalworking skills. This time around I will get a proper enclosure made. Still assessing whether I should do an integrated version with just a potentiometer and a mechanical input selection or build another LDR or differed preamp. If I use SMPS I think it will be noisier than linear supply (and not an ideal option for an integrated, all-in-one option) however not too sure.
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