Hi,
this is my first post. I kept reading for a while but now there are questions coming up and threads concerning the modulus-186 seem to be rather rare.
I'm planning to build an amplifier that will drive the high frequency part of my active speakers. It's a compression driver delivering 110dB from 1W/1m (modified RCF CX15N35). With such a high sensitivity speaker supposed to play at living-room-level I need a dead silent amplifier. Tom's announcement for the modulus-186 gave me something to chew on for my holidays. 45 watts is more power than I would ever need. Meagre 15mW result in 85dB at my listening position. But these 15mW should be of certain quality concerning noise, hum and distortion.
I'm plannung to build a stereo system of 2 modulus-168. Input is coming from a MiniDSP 8x10 (differential at 4V). The minimum gain of 20dB within the modulus-168 should suffice, am I right on this? Power is to be delivered by a conventional toroidal transformer with a Power-86.
Now to my questions:
Im not all new to building, but power amplifers are new to me. So any advice and suggestions are appreciated.
Cheers,
Adrian
this is my first post. I kept reading for a while but now there are questions coming up and threads concerning the modulus-186 seem to be rather rare.
I'm planning to build an amplifier that will drive the high frequency part of my active speakers. It's a compression driver delivering 110dB from 1W/1m (modified RCF CX15N35). With such a high sensitivity speaker supposed to play at living-room-level I need a dead silent amplifier. Tom's announcement for the modulus-186 gave me something to chew on for my holidays. 45 watts is more power than I would ever need. Meagre 15mW result in 85dB at my listening position. But these 15mW should be of certain quality concerning noise, hum and distortion.
I'm plannung to build a stereo system of 2 modulus-168. Input is coming from a MiniDSP 8x10 (differential at 4V). The minimum gain of 20dB within the modulus-168 should suffice, am I right on this? Power is to be delivered by a conventional toroidal transformer with a Power-86.
Now to my questions:
- Is this a useful combination? (Technically. Not in term of good sound, that is a matter of experiment. In case it does not match, the modulus will make good friends with a conventional passive speaker upstairs.)
- I appreciate some amount of smartness. In my case, how useful is a softstart like the neurochrome ISS?
- How useful do you estimate a protection circuit like the Guardian-86?
Im not all new to building, but power amplifers are new to me. So any advice and suggestions are appreciated.
Cheers,
Adrian
Sure, my demands seem closer to attenuation than amplification
.
In fact my setup is all digital, the MiniDSP serving as crossover, RoomEQ, DAC AND Preamplifier. Usually attenuation is around 25dB, depending on recordings. Amplification - even on an extremly low scale - is needed.
Thank you, and now we should be back in New Year's Eve party business.
.In fact my setup is all digital, the MiniDSP serving as crossover, RoomEQ, DAC AND Preamplifier. Usually attenuation is around 25dB, depending on recordings. Amplification - even on an extremly low scale - is needed.
Thank you, and now we should be back in New Year's Eve party business.
How much power is your amp for your woofer, and what's your woofer sensitivity? You might calculate the max dBSPL of your woofer, then add an L pad/resistor divider on your tweeter amp to make the tweeter then same max volume, something like 4 ohms and 1/2 ohm, presuming the tweeter works well driven from a 1/2 ohm source impedance. This would reduce the amplifier's residual noise as well as limit the tweeter's output and help protect your hearing (!).
Happy new year everybody!
That parallel-OpAmp-thing gave me a decent read, thank you! After all it's an interesting approach but well beyond me, sorry.
Regards,
Adrian
That parallel-OpAmp-thing gave me a decent read, thank you! After all it's an interesting approach but well beyond me, sorry.
Regards,
Adrian
Sensitivity-matching is all done in the digital domain of the miniDSP.
Maybe I should provide some more info on the whole thing: My loudspeakers are active Martion Bullfrogs with a 15" Woofer (94dB/W/m) and the aforementioned coaxial horn (110dB/W/m).
Right now the system is driven by the stock 4-channel amplifier from Martion. LF is 2x 350W class AB, HF is 2x 10W class A. Latter is a wonderful sounding device that just makes a little bit too much noise to my taste. Since it's a commercial product with all its parts in one enclosure one can only speculate on concurrent causes.
So that's where my idea of a separate low noise amplifier comes from.
Hummm... you need much more than 15 mWatts with your woofer.
15" Woofer (94dB/W/m)
Pro-Audio and lighting Calculators. Calculator page
94 dB, 5 watts, 2 speakers, random phase
* 2 m -> 98 dB
* 3 m -> 94.5 dB
* 4 m -> 92 dB
* 5 m -> 90 dB
Usually I listen to about 65 dBSPL continuous. I listen to music with high/very high DR (dynamic range). Then I need about 80 dBSPL peak.
80 dBSPL continuous is loud in a house. To heal in health, I want 95 dBSPL peak in my calcs.
With your woofer, at 3m -> 94.5 dB
If you listen to recordings with low DR < 10 dB you need less power off course.
Note: in phase, the power is +3 dB.
15" Woofer (94dB/W/m)
Pro-Audio and lighting Calculators. Calculator page
94 dB, 5 watts, 2 speakers, random phase
* 2 m -> 98 dB
* 3 m -> 94.5 dB
* 4 m -> 92 dB
* 5 m -> 90 dB
Usually I listen to about 65 dBSPL continuous. I listen to music with high/very high DR (dynamic range). Then I need about 80 dBSPL peak.
80 dBSPL continuous is loud in a house. To heal in health, I want 95 dBSPL peak in my calcs.
With your woofer, at 3m -> 94.5 dB
If you listen to recordings with low DR < 10 dB you need less power off course.
Note: in phase, the power is +3 dB.
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TDA6120
Thanks,
Adrian
Stacking TPA6120's sounds very interesting. Seems there is plenty to read and learn about them.
Thanks,
Adrian
Only a strong advise: avoid class D with tweeters.
It is very important to keep in mind what type of recordings you listen to, their sound quality, antiquity, format, DR ... To play modern/commercial music, as badly recorded and with low/very low DR, any decent amplifier is valid.
But if you like good/very good recordings with high/very high DR, with natural voices and acoustic instruments like me... is other story.
Today I listen to these very/very good recordings:
Now Playing + What are you listening to?
Welcome aboard!
Well... Give it time.
I announced the amp in October and started shipping by the middle of December. The modules have started to arrive in people's mailboxes, so I expect we'll see a few build threads pop up soon - or at least some build pictures in the Modulus-186 vendor thread. Low noise and low distortion will definitely be key with high-efficiency speakers. With the Modulus-186 at 20 dB gain, you'll get 17 µV RMS (A-weighted) of noise. You'll be hard pressed to find a speaker amp that provides lower noise.
The error correction used in the Modulus amps is responsible for the low distortion and low noise.
You'll also want low gain so you don't amplify the noise of the source. Keep the MiniDSP 8x10HD set to 4 V output as that's the lowest noise.
20 dB gain is what you want. The Power-86 with a 2x22 VAC transformer will result in an amp that can deliver 40 W into 8 Ω and 65 W into 8 Ω. With your much lower power requirements, you could easily build the amp with lower voltage rails. ±24 V would give you 28 W into 8 Ω. You could even go down to ±21-22 V if you want to cut back further on the power.
The lower supply voltage results in less power dissipated in the amplifier, so you can use a smaller heat sink, but that is really the only (or at least primary) advantage of the lower supply rails. If you're planning to use a chassis with heat sinks along the sides, such as the ModuShop Mini Dissipante, there is really no advantage of the lower power supply voltage. In that case, I'd build for ±24 V or ±30 V rails. Take the larger headroom! You'll need it more than you think.
You may find my SMPS-86 to be a good fit for your needs. International mains voltage in, ±24 V out at 2.5 A. Powering one Modulus-186 channel with the SMPS-86 will result in an amp that can deliver 28 W into 8 Ω. Due to the 2.5 A current limit, you'll only get 28 W into 4 Ω. Either is probably more than enough for your needs, though.
Yes.
If you need the features (12 V trigger, low-voltage control of power on/off, etc.) or you are using a transformer larger than about 200 VA, the ISS is highly useful. Smaller transformers have lower inrush current, so inrush limiting (soft start) isn't required, though probably still nice to have. The 200 VA "limit" is by no means a hard limit.
Also note that the inrush current imposes some mechanical stresses on the transformer, which will limit its lifespan. Not dramatically, but after 15-20 years you can expect it to start blowing fuses as the enamel will have worn through. A soft start minimizes that, thus prolongs the service life of the transformer.
In the event of a catastrophic amplifier failure, the protection circuit will be very useful as it'll save your speaker from destruction. In all other scenarios you really don't want it to participate. I designed the Guardian-86 and -686 (stereo/balanced/dual mono version) with this goal in mind.
The odds of a catastrophic amplifier failure are extremely low for the Modulus-186, but not zero. In DIY builds (and budget commercial products) I'd consider speaker protection to be optional. For high-end commercial products, I expect to see a protection circuit. Whether you choose to use one is really up to you. You can always add it later if desired.
One note regarding the various eBay/Alibaba/Amazon/whatever boards: I would shy away from those. I have yet to see one that was well done. I can usually spot several design flaws just from the pictures in the product listing. Also, the fact that you can't buy the parts (even at QTY 1000+) for what the sellers sell these boards for should tell you something about the odds of receiving genuine parts from these vendors.
That's not to say that you can't find a good board out there. I just haven't found one that's up to my quality standards. I also have yet to see any of the eBay/Alibaba/Amazon/whatever vendors back their products up with measurements. They usually just cut-n-paste the specs from the IC manufacturer's spec sheet, regardless of whether their products actually provide the data sheet performance.
Tom
Jazzlampe,
Hi.
I’ve built several of Neurochrome’s designs including the Modulus-86 (thru hole), Parallel 86 (thru hole), 286 v1.0 (SMD) and will be receiving the fully built and tested 286 v2.0 momentarily. I have also listened to the 686 in a colleague’s system (93dB efficient). He also has the ICEEDGE 1200AS, and they are currently left unused. I used to own Hypex NC400’s and have listened to the NC1200 and 500 series as well. My choice continues to be Neurochrome.
All of Neurochrome’s designs are exceedingly neutral and quiet. The 286 and 686 are some of the quietest amps in the industry. My speakers are Geddes NA12’s (96 dB overall efficiency and the tweeter is close to 107dB efficiency). All of Neurochrome’s amps are so quiet that I cannot hear a thing with my ear inside the waveguide/horn at idle. It’s as quiet as a tomb. This is even more important to me because I have a very quiet room. I can hear the overhead lights when they are turned on!
They are my reference amplifiers. All my diy builds are compared to the Neurochrome designs and they are colored in one way or another. That’s okay but that’s why I keep the Neurochrome designs around. As a point of comparison. I do diy cause it’s fun and I get bored easily. In fact my diy builds have slowed down considerably since I discovered Neurochrome!
Just because they are neutral does not mean that they are not dynamic or not musical. Precisely the opposite. The music is effortless and you hear more of what the recording engineer wanted you to hear. The genre of music is immaterial. I hear the transparency, detail, neutrality, dynamics and PRAT regardless of if it is orchestral music (with DR’s as high as 20) or death metal (where DR can be 3).
And yes, the Modulus 186/286/686 are sonically superior to the Modulus 86 & Parallel 86 (discontinued). But the differences are more of an evolution.
The differences between the Modulus Class AB topology versus others is more of a revolution.
Best,
Anand.
P.S. Please be careful of “armchair audiophiles.” I have personally built, listened and made preliminary measurements on nearly all of my builds. There are several on the internet who are pundits who do the “talk” but cannot “walk the walk.” And yet, they very easily criticize. Good luck in the choices you make.
Hi.
I’ve built several of Neurochrome’s designs including the Modulus-86 (thru hole), Parallel 86 (thru hole), 286 v1.0 (SMD) and will be receiving the fully built and tested 286 v2.0 momentarily. I have also listened to the 686 in a colleague’s system (93dB efficient). He also has the ICEEDGE 1200AS, and they are currently left unused. I used to own Hypex NC400’s and have listened to the NC1200 and 500 series as well. My choice continues to be Neurochrome.
All of Neurochrome’s designs are exceedingly neutral and quiet. The 286 and 686 are some of the quietest amps in the industry. My speakers are Geddes NA12’s (96 dB overall efficiency and the tweeter is close to 107dB efficiency). All of Neurochrome’s amps are so quiet that I cannot hear a thing with my ear inside the waveguide/horn at idle. It’s as quiet as a tomb. This is even more important to me because I have a very quiet room. I can hear the overhead lights when they are turned on!
They are my reference amplifiers. All my diy builds are compared to the Neurochrome designs and they are colored in one way or another. That’s okay but that’s why I keep the Neurochrome designs around. As a point of comparison. I do diy cause it’s fun and I get bored easily. In fact my diy builds have slowed down considerably since I discovered Neurochrome!
Just because they are neutral does not mean that they are not dynamic or not musical. Precisely the opposite. The music is effortless and you hear more of what the recording engineer wanted you to hear. The genre of music is immaterial. I hear the transparency, detail, neutrality, dynamics and PRAT regardless of if it is orchestral music (with DR’s as high as 20) or death metal (where DR can be 3).
And yes, the Modulus 186/286/686 are sonically superior to the Modulus 86 & Parallel 86 (discontinued). But the differences are more of an evolution.
The differences between the Modulus Class AB topology versus others is more of a revolution.
Best,
Anand.
P.S. Please be careful of “armchair audiophiles.” I have personally built, listened and made preliminary measurements on nearly all of my builds. There are several on the internet who are pundits who do the “talk” but cannot “walk the walk.” And yet, they very easily criticize. Good luck in the choices you make.
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Thank you both for your comprehensive replies!
As Tom suggested I will give it some time (well not too much) and wait for the stories to come. In the meantime I make up my mind. Right now I'm in the mood for buildung two small monoblocks with modulus-186 and SMPS.
I'll report on my deciscions and my build.
Cheers,
Adrian
As Tom suggested I will give it some time (well not too much) and wait for the stories to come. In the meantime I make up my mind. Right now I'm in the mood for buildung two small monoblocks with modulus-186 and SMPS.
I'll report on my deciscions and my build.
Cheers,
Adrian
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I use a design that is a conjugate (opamp and LM3886) to drive high efficiency three way horns. It is silent with ear in any of the horns.
The Modulus series are well designed and offer options for different speaker loads. I suspect all available will work fine in your application.
The switching power supply should be fine.
The Modulus series are well designed and offer options for different speaker loads. I suspect all available will work fine in your application.
The switching power supply should be fine.
Some brief feedback
I made my decision. Thank you all for answering and making things clear. I ordered two modulus-186 with 20dB gain, two SMPS-86 and a guardian-86. 9 days later I got mail from customs. After all officers were very nice to me though.
Dear Tom, the PCBs do look wonderful! It's most ecouraging to work on these. I soldered the PSs during the past weekend but did not take the time to perform functional tests.(Since I do not populate the IEC input and switches, testing is not to rush.)
Next weekend I'm going to do some case and panel design and maybe post some pictures.
I made my decision. Thank you all for answering and making things clear. I ordered two modulus-186 with 20dB gain, two SMPS-86 and a guardian-86. 9 days later I got mail from customs. After all officers were very nice to me though.
Dear Tom, the PCBs do look wonderful! It's most ecouraging to work on these. I soldered the PSs during the past weekend but did not take the time to perform functional tests.(Since I do not populate the IEC input and switches, testing is not to rush.)
Next weekend I'm going to do some case and panel design and maybe post some pictures.
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