Yeah, all this is too technical for me
The DAM1021 for instance outputs - 1.4V RMS / 625Ω in direct single ended,
- 2V RMS Zout 10Ω in buffered SE, or
- 4V RMS Zout 20Ω in buffered balanced
I'm probably not going to use that DAC but since there is so much variation on the output levels I would expect the Input Sensitivity of 1.8 V RMS would be a guide, not a min or max.
Edited: **** we crossed the replies, posted at the same time, thank you for the answers, all clear now
So, put the other way around, may I infer that putting less than these 1.8VRMS means I will not be able to clip the amp even if I want to, right?
Keep in mind that the output voltage of sources, such as you quote for the DAM1021, are the max output voltage at '0 dB' (full scale) signal. But, yes, if the instantaneous peak voltage of the Mod's input signal is below 1.8V RMS (~2.54V peak), you won't clip the output voltage.
If you're even considering the Soekris DAC, I'd read the assessment at AudioScienceReview.com.
If you're even considering the Soekris DAC, I'd read the assessment at AudioScienceReview.com.
Chip Amp with BrianGT boards chipamp.com kit
Longtime lurker on these forums. About 2 years ago my then 11 yr old daughter suggests that we do an electronics project together. Picked up an LM3886 parts and board kit, a friend donated a XFMR and bought a chassis on ebay.
One of the things I like about these forums is that many folks take as long as I do (or longer) to complete these DIY projects. We had the boards done over a year ago and bought the chassis and power switch at some point. Had something to listen to about 2 months ago and finally put the finishing touches on it a week ago.
I was surprised at how good it sounds. I expected it to sound OK with maybe some noise. But it is dead quiet with no signal. And the sound with some old NHT super zeros was quite good. I am also happy with how it looks with the chassis. Not bad for a first DIY amp build.
No technical insight in this post and not sure if this the right forum, I just wanted to thank all the great folks that do in fact post with some great advice and insight. And also thanks to BrianGT if he is still around.
Longtime lurker on these forums. About 2 years ago my then 11 yr old daughter suggests that we do an electronics project together. Picked up an LM3886 parts and board kit, a friend donated a XFMR and bought a chassis on ebay.
One of the things I like about these forums is that many folks take as long as I do (or longer) to complete these DIY projects. We had the boards done over a year ago and bought the chassis and power switch at some point. Had something to listen to about 2 months ago and finally put the finishing touches on it a week ago.
I was surprised at how good it sounds. I expected it to sound OK with maybe some noise. But it is dead quiet with no signal. And the sound with some old NHT super zeros was quite good. I am also happy with how it looks with the chassis. Not bad for a first DIY amp build.
No technical insight in this post and not sure if this the right forum, I just wanted to thank all the great folks that do in fact post with some great advice and insight. And also thanks to BrianGT if he is still around.
Attachments
Looks like a pretty compact build there. I suggest tidying up the wiring a bit, though. In particular the supply wiring should at least be bundled together to avoid rail-induced distortion.
I suggest placing the LM3886 further down on the heat sink. You're not making good use of the heat sink with the LM3886es that high up. You might have been able to put the LM3886es lower if you'd moved the power switch over to the side and scooted the power transformer to the front of the chassis. That's obviously a bit late now, but I'm leaving this suggestion here in case someone is looking for inspiration for a chassis layout.
I also suggest adding a bracket to hold the board to the heat sink. Cantilevering the board off of the LM3886 is a recipe for metal fatigue and premature failures.
It does look like the chassis has adequate heat sinking. Good choice there!
Note, however, that this is the Modulus-86 Build Thread. A better place for your post would probably be in the Chipamp.com Forum or the Chipamps Photo Gallery. Unfortunately, chipamp.com is now defunct. Whomever bought it from BrianGT promptly drove it into the ground. In fact, that's a large part of the reason for why I now offer an LM3886DR.
Tom
I suggest placing the LM3886 further down on the heat sink. You're not making good use of the heat sink with the LM3886es that high up. You might have been able to put the LM3886es lower if you'd moved the power switch over to the side and scooted the power transformer to the front of the chassis. That's obviously a bit late now, but I'm leaving this suggestion here in case someone is looking for inspiration for a chassis layout.
I also suggest adding a bracket to hold the board to the heat sink. Cantilevering the board off of the LM3886 is a recipe for metal fatigue and premature failures.
It does look like the chassis has adequate heat sinking. Good choice there!
Note, however, that this is the Modulus-86 Build Thread. A better place for your post would probably be in the Chipamp.com Forum or the Chipamps Photo Gallery. Unfortunately, chipamp.com is now defunct. Whomever bought it from BrianGT promptly drove it into the ground. In fact, that's a large part of the reason for why I now offer an LM3886DR.
Tom
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Holy moly. No kidding! Also interesting with their Schiit Yggdrasil vs Soekris measurements: Review and Measurements of Soekris dac1421 Multibit DAC | Audio Science Review (ASR) Forum
Both those DACs offer performance that's 2-3 orders of magnitude worse than the MOD86.
Tom
I'd use that and move on with my life.
The extra 6 dB (difference between 1.8 and 4.0 V, roughly) will come in handy for those albums that are recorded well below full scale of the DAC. One of my favourite albums, Dire Straits, Brothers in Arms springs to mind.
Tom
The DAM1021 is a real option, I was nearly decided for it, but I'm now considering the TDA1387 route, completely DIY board w/ no active output, only thew roll-off passives. I did a quick test with one chip and it "has something". I want to learn as much as possible w/ it, I can always step back and buy a Soekris next year or so.I'd use that and move on with my life.
The extra 6 dB (difference between 1.8 and 4.0 V, roughly) will come in handy for those albums that are recorded well below full scale of the DAC. One of my favourite albums, Dire Straits, Brothers in Arms springs to mind.
Tom
PS: I love that album as well.
Topping D30 measures well, contains the CS4398, and cost about $100 on Amazon... No differential out, though. You could throw the chassis away and cook your own differential out. Just be careful not to degrade the performance of the DAC.
The MiniDSP SHD has the AKM AK4390 and OPA1612 in it. I designed the analog sections for MiniDSP. I haven't had a chance to measure mine yet, but I know MiniDSP have. The design goal was to maintain the excellent THD and SNR performance of the DAC itself all the way through to the output connector. To the best of my knowledge we accomplished that. The SHD has differential out.
I should have a review of the SHD up before the end of the year.
Tom
The MiniDSP SHD has the AKM AK4390 and OPA1612 in it. I designed the analog sections for MiniDSP. I haven't had a chance to measure mine yet, but I know MiniDSP have. The design goal was to maintain the excellent THD and SNR performance of the DAC itself all the way through to the output connector. To the best of my knowledge we accomplished that. The SHD has differential out.
I should have a review of the SHD up before the end of the year.
Tom
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So have you been using the miniDSP 4x10 as your DAC with the LX-minis or something else?
I have the DAM-1021 board, but I haven't gotten around to finishing it enough to listen to it yet. I will give it a try, but I probably just use my DLCP for the Lx-minis with the Modulus amps.
I liked most of the features of the SHD, but 4 channels is too restrictive for the cost. With 6 channels in the DLCP, I can do 2-way speakers and sub.
I have the DAM-1021 board, but I haven't gotten around to finishing it enough to listen to it yet. I will give it a try, but I probably just use my DLCP for the Lx-minis with the Modulus amps.
I liked most of the features of the SHD, but 4 channels is too restrictive for the cost. With 6 channels in the DLCP, I can do 2-way speakers and sub.
Right now the 4x10HD (which I had no hand in designing). I haven't had a chance to plug in the SHD and get the filter settings transferred over.
Yeah. I would have liked six channels as well. I'd run a bypass (input -> output) on the last stereo pair to drive my HP-1 headphone amp. That's another reason I've procrastinated on putting the SHD into service.
Tom
Tom there is already a dedicated thread here, you have piqued my interest...
https://www.diyaudio.com/forums/ful...d-perfect-waw-fast-systems-9.html#post5625692
Measurements here.
Review and Measurements of miniDSP SHD DAC, DSP And Streamer | Audio Science Review (ASR) Forum
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Tom, when you get the chance, try this experiment with it. Connect up the following: digital source >DAC > amp > speakers that don’t require DSP. Familiarise yourself with how the system sounds. Then insert the SHD between the digital source and the DAC but without any signal processing being done by it i.e. so the digital signal is in theory just passing through it. Compare the sound quality with that of the system without the SHD in the chain.
I’ve done this with a 4x10HD. The difference in SQ is not subtle.
I've done that with the 4x10HD and found an improvement. I subsequently put the "DAC" (actually a Focusrite Saffire PRO 24 external sound card configured as a DAC) on the APx525 and learned that the Saffire would drop a sample every now and then.
I use the 4x10HD in bypass mode with my HP-1 quite frequently as well.
Tom
You found an improvement with 4x10HD in the chain !!?? I found a a significant deterioration.
Have a look at my SMPS-86.
Yeah? What about it?
The Modulus-86 doesn't care about the power supply.That's a really good question. Many laptop bricks have the (-) connection connected to mains earth. That makes it impossible to connect two of them in series as the one used for VEE will have its outputs connected together.
In fact, one of the things I like about the Mean Well supplies (at least the IRM and RPS series) is that the output is galvanically isolated from the input. I think it may be capacitively coupled to the mains ground, but that's it. That makes the supplies rather versatile.
Tom
Yeah but it needs mains input, the question was about feeding from a laptop charger
As expectedYeah? What about it?
OK maybe I did not explain properly. The idea is evaluating the possibility of using 1 laptop charger, not two, going into one DC-DC that outputs ±24V 2.5A. There are "similar" products, with much less power, maybe there exists smth much more expensive though. So the question was, if that DC-DC existed, which I'm not sure at that power output, would the earth connection to chassis be OK?
Thank you again