It's a Rifa PFE225 10nF/2% styroflex - described in some audiophile circles as a 'rare delicacy'. It should ideally be mounted at C23 (present only on the V1.4 PCB) as Mark (Hypertune) has done, rather than diagonally at C7 - however, there's no problem because C7 and C23 are in parallel.
Sonically, it's very similar to a 10nF/630V Wima FKP2 at C7, but maybe a bit more transparent and micro-detailed in the highs.
Another nice-sounding value-oriented alternative at C7 is a 10nF/100V Evox/Rifa PHE426 in 5mm pitch. It sounds very open and airy.
Try to use star- or tree-grounding, and avoid running ground loops. Search on this forum for 'star grounding" - there should be many threads on the topic.
C34 can be a 10pF Silver Mica of any voltage rating (say 50V or higher), in 3.5 or 5mm pitch. CDE, Saha, El Menco or Sangoma brands should be fine.
In a pinch, a C0G/NP0 ceramic will be fine at C34. Kemet, AVX, TDK, Murata or similar brands should be fine.
Thanks Siva, I'll keep those in mind for my next mod/build.
I finally got the second pair of Mundorf M-Lytic AG power caps and am looking forward to discovering their impact.
Using a Battery or AC source in my earlier post probably doesn't make a bit of difference, but it makes me feel safer. Heaven knows we can use all the "comfort" we can get when we're still learning 🙄
I finally got the second pair of Mundorf M-Lytic AG power caps and am looking forward to discovering their impact.
Using a Battery or AC source in my earlier post probably doesn't make a bit of difference, but it makes me feel safer. Heaven knows we can use all the "comfort" we can get when we're still learning 🙄
Not sure if this is the right thread to post this - I'll post it later in it's own new thread if sufficient interest develops.
This is a preliminary schematic of a MyRef RevC derivative amp using 2 x LM3886 in parallel for delivering ~80W into 4 ohms. The compensation schema is subject to revision, and is a modified (after simulation) version of Dario's RevO/RevFE compensation.
If implemented, this will be an incremental evolution of the stock RevC board, and will be DIY-friendly. I will continue to use a socketed DIP-8 LM318, through-hole parts, etc. SMD parts, if any, will be limited to a plug-in module like the LF01 hybrid opamp. The board will be slightly bigger than the current RevC V1.4 boards (say ~1.25x the current board area).
The name of this project will either be MyRef Rev E or the MyRef Evo2, subject to approval from Mauro Penasa.
This is a preliminary schematic of a MyRef RevC derivative amp using 2 x LM3886 in parallel for delivering ~80W into 4 ohms. The compensation schema is subject to revision, and is a modified (after simulation) version of Dario's RevO/RevFE compensation.
If implemented, this will be an incremental evolution of the stock RevC board, and will be DIY-friendly. I will continue to use a socketed DIP-8 LM318, through-hole parts, etc. SMD parts, if any, will be limited to a plug-in module like the LF01 hybrid opamp. The board will be slightly bigger than the current RevC V1.4 boards (say ~1.25x the current board area).
The name of this project will either be MyRef Rev E or the MyRef Evo2, subject to approval from Mauro Penasa.
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Siva, Big Surprise !
From what I'm hearing and doing over on the PBA threads, this will be the exact combination of amp characteristics many new builders are looking for. Have you gotten to a hardware prototype yet or are you still in simulation?
From what I'm hearing and doing over on the PBA threads, this will be the exact combination of amp characteristics many new builders are looking for. Have you gotten to a hardware prototype yet or are you still in simulation?
I have built a HTPC and would like to run a myref Rev C off of the sound card . Would I need to build some sort of gain control? I'd like not to have to as I already have gain control via software. What sort of gain would I get without adding a preamp? (it runs my headphones just fine)
Thanks in advance.
Thanks in advance.
anonomouse - I have had excellent results driving the MyRefs with USB units like the Lexicon Omega and Digidesign Mbox 2 . They are both external boxes and my not be what you want but the quality of the sound and gain really enhance the computer output. If your motherboard has S/PDIF out via either port or MB pins, a complete 7.1 system can be driven by a laptop or desktop.
How many Ref-Cs are you planning to use in your system?
How many Ref-Cs are you planning to use in your system?
to start with I'll be using it on a asus xonar dx internal sound card until i upgrade to an asus xonar essence st. I have no desire to use an external sound card.
You probably wont need any gain. Its got tons of gain. You may consider a good attenuator and leave your htpc at max volume. Digitally adjusting lower than 100% removes bits from the 24bit or 18bits that you have at 100%.
anonomouse
Still a bit curious about your setup. You said HTPC which generally implies a 2.1, 5.1 or 7.1 speaker group. Is that your goal or are you sticking with stereo for now? I don't remember seeing a full HT system with a bunch of MyRefs. That would be an interesting project.😀
I've been very interested in the Xonar cards as a source for the MyRefs but have to sell some of my devices before adding another.
Still a bit curious about your setup. You said HTPC which generally implies a 2.1, 5.1 or 7.1 speaker group. Is that your goal or are you sticking with stereo for now? I don't remember seeing a full HT system with a bunch of MyRefs. That would be an interesting project.😀
I've been very interested in the Xonar cards as a source for the MyRefs but have to sell some of my devices before adding another.
Ideally it would be a four channel system. possibly ending up in a five channel system. I intend on using software decoding to split the center channel voice to go to the to front speakers. The sub channel will also be diverted to the front speakers. I really don't see the point in having a sub if my front speakers already dip down to ~30hz. Also I doubt there is much to be gained by having a seprate voice center channel. The only issues that I could really imagine the system having is that running voice and sub and front channels through the font speakers might be just too many signals at once. So I might add a center channel. So all in all there will be at least two myrefs and maybe a single monoblock for the center channel.
Attenuators seem to be prohibitively expensive. Is there some other way to adjust the gain (volume) on the myref without costing a fortune or reducing sound quality?
Attenuators seem to be prohibitively expensive. Is there some other way to adjust the gain (volume) on the myref without costing a fortune or reducing sound quality?
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Check out this thread for volume control possibilities.
http://www.diyaudio.com/forums/chip-amps/192604-myrefc-volume-control-thread.html
http://www.diyaudio.com/forums/chip-amps/192604-myrefc-volume-control-thread.html
Hi Anybody selling pcb s for these ,would like to build one for my son so he stops borrowing mine 😀 regards john
linuxguru has several flavors of both boards and kits.
Sivasankar Chander <siva.chander@gmail.com>
Sivasankar Chander <siva.chander@gmail.com>
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Hi guys,
(This might not 100% be the right thread but it features the MyREFC, so apologies if misplaced.)
I'm thinking about adding an active preamp (a-la Linkwitz-Riley Electronic Crossover) to two pairs of amps. The problem is that I need to know the capacitance to actually be able to calculate the values for the components (I'm looking at a two way at about 3khz). Any ideas on what those values should be?
Thanks!
(This might not 100% be the right thread but it features the MyREFC, so apologies if misplaced.)
I'm thinking about adding an active preamp (a-la Linkwitz-Riley Electronic Crossover) to two pairs of amps. The problem is that I need to know the capacitance to actually be able to calculate the values for the components (I'm looking at a two way at about 3khz). Any ideas on what those values should be?
Thanks!
Heya fellows, I have a question on the value of R3.
ClaveFremen Ultimate BOM list the Caddock MP915 which is rated at 15W, while Uriah's BOM listed the MP2060 which is 60W.
The MP2060 is larger which makes installation (along with the heatsink quite tricky). But I do like the higher power rating just to be on a safe side.
I believe there's another BOM that uses the Xicon 7W Radial Cement Resistors...
So which one did you guys used?
ClaveFremen Ultimate BOM list the Caddock MP915 which is rated at 15W, while Uriah's BOM listed the MP2060 which is 60W.
The MP2060 is larger which makes installation (along with the heatsink quite tricky). But I do like the higher power rating just to be on a safe side.
I believe there's another BOM that uses the Xicon 7W Radial Cement Resistors...
So which one did you guys used?
Anything from 5W and above is good.
MP915 with the small heatsink you can see in my tutorial is always cold...