The LM3886 in the MOD86 is un-muted on a much shorter time scale than what was shown in the transient measurements a few posts back.
The best solution is to use the amp the way it was intended: Differential input.
That's not to say that an acceptable pseudo-differential solution cannot be found.
Tom
The best solution is to use the amp the way it was intended: Differential input.
That's not to say that an acceptable pseudo-differential solution cannot be found.
Tom
Excellent suggestion. I found time to try it out while waiting for my morning coffee to cool do comfortable drinking temperature.
10 kΩ across the pseudo-differential inputs (so across the two pins of the RCA connector in a pseudo-differential cable) certainly does reduce the plop. 4.7 kΩ almost eliminates it. I'd go with 4.7 kΩ if your source can drive it.
And, of course, there's no plop when using differential inputs.
Tom
Stuff to use while off? If you can arrange the aerodynamic carbon fiber kickstand for my bicycle then I'm all for it. Otherwise I lack for a need to compromise the on function in trade for a better off function. Stuff to use while off doesn't go on anything that must be first-class while on.
I promise that this was much better than explaining the larger value delay cap at the location of small signal wasn't worth degrading the small signal. See? Yeah, explaining why racing bicycle doesn't have kickstand was so much better than that other thing.
You guys might be cousins. The only thing I have to add to that is the stern briefing I got from speaker designers. Those speaker requirements will be thoroughly accommodated by Tom's parallel amplifier offerings.
What?Stuff to use while off? If you can arrange the aerodynamic carbon fiber kickstand for my bicycle then I'm all for it. Otherwise I lack for a need to compromise the on function in trade for a better off function. Stuff to use while off doesn't go on anything that must be first-class while on.
I promise that this was much better than explaining the larger value delay cap at the location of small signal wasn't worth degrading the small signal. See? Yeah, explaining why racing bicycle doesn't have kickstand was so much better than that other thing.
Another alternative may be to use a
Flux Capacitor, at 88 MPHMyself, I have no plop sounds at all. My 4 channel Mod86 has been in service for almost a year now. I could not be happier with it, no plops, farts, quarks, whatsoever.
I just ordered 2 more Mod86 boards. Soon all six of my amp channels will match.
I'm doing tri-amp to a Stereo pair of 3-way speakers.Pops will be gone... Just built my THAT driver and Mezmerize is back
An externally hosted image should be here but it was not working when we last tested it.
Is it possible to install a THAT Driver parallel to single-ended outputs?
In my case, I want to add a balanced connection to go to my Mod-86 amp, but I want to retain the single-ended output to connect to a second device (preamp).
The source output impedance would be 100 ohm. The input impedance for single-ended preamp would be 10k, and the input impedance of the THAT Driver is 100k. I am thinking that the source would see ~9k if the preamp is connected in parallel with the THAT Driver.
Any issues with this?
Cheers, Curtis
In my case, I want to add a balanced connection to go to my Mod-86 amp, but I want to retain the single-ended output to connect to a second device (preamp).
The source output impedance would be 100 ohm. The input impedance for single-ended preamp would be 10k, and the input impedance of the THAT Driver is 100k. I am thinking that the source would see ~9k if the preamp is connected in parallel with the THAT Driver.
Any issues with this?
Cheers, Curtis
I'm confused. The Modulus-86 has a differential/balanced input. If your source is also differential all you have to do is to connect the source to the amp and be done.
The THAT Driver takes a single ended source as input and provides a differential output. Think RCA -> XLR.
The THAT Receiver taxes a differential input and provides a single ended output. Think XLR -> RCA.
Single ended is the same as unbalanced.
Differential is the same as balanced.
Hope this helps.
Tom
The THAT Driver takes a single ended source as input and provides a differential output. Think RCA -> XLR.
The THAT Receiver taxes a differential input and provides a single ended output. Think XLR -> RCA.
Single ended is the same as unbalanced.
Differential is the same as balanced.
Hope this helps.
Tom
The source does not have differential output. It only has one set of single-ended outputs. I want to create a set of single-ended outputs and a set of differential outputs.
The way that I read the THAT Driver description suggests that it replaces the single-ended source: SE output -> THAT Driver input. However, I want to install the THAT Driver parallel to the single-ended outputs.
I have attached a sketch that will hopefully clarify things.
Cheers, Curtis
Attachments
Hi Tom,
I just finished my first amp project, circuitbasic´s LM3886 in monoblock arrangement (A Complete Guide to Design and Build a Hi-Fi LM3886 Amplifier - Circuit Basics ), when I came across your Mod86 / 286 and its excellent specs. As I am not entirely convinced of the sound of my first effort I wanted to start a second project with your boards. Speakers are KEF R700 (8ohm, 87db/W).
Although I have read through a lot of this thread as well as the vendor thread, I have a few questions, before I order your boards. Please bear with me as I am quite new to the diy audio Hobby and some of the questions are most likely trivial to experts.
a) Should I change something to reuse the existing powersupply from my first project? (2x22v, 2x160va monoblocks, ca. 32kuF per channel,
Schematic:
https://www.dropbox.com/s/ub99hss8k1v31mv/Power%20Supply%20Schematic.pdf?dl=0 )
PCB:
https://www.dropbox.com/s/ddib88oewectx9j/Power_Supply-8452cd280c604632bc4d8c790e0f35be.png?dl=0
I think it should be ok, as the your amps have this great PSRR, but I am unsure especially about the star ground arrangement and the ground loop breaker.
b) Should I use the bi-amping feature for the KEFs and possibly get two 286 or even four 86 boards? Would the 2x160va still be ok? I guess, as with the 87db/W and ca. 2.7m listener distance I still get plenty of SPL. What do you think?
Thank you so much.
Best regards,
SH
I just finished my first amp project, circuitbasic´s LM3886 in monoblock arrangement (A Complete Guide to Design and Build a Hi-Fi LM3886 Amplifier - Circuit Basics ), when I came across your Mod86 / 286 and its excellent specs. As I am not entirely convinced of the sound of my first effort I wanted to start a second project with your boards. Speakers are KEF R700 (8ohm, 87db/W).
Although I have read through a lot of this thread as well as the vendor thread, I have a few questions, before I order your boards. Please bear with me as I am quite new to the diy audio Hobby and some of the questions are most likely trivial to experts.
a) Should I change something to reuse the existing powersupply from my first project? (2x22v, 2x160va monoblocks, ca. 32kuF per channel,
Schematic:
https://www.dropbox.com/s/ub99hss8k1v31mv/Power%20Supply%20Schematic.pdf?dl=0 )
PCB:
https://www.dropbox.com/s/ddib88oewectx9j/Power_Supply-8452cd280c604632bc4d8c790e0f35be.png?dl=0
I think it should be ok, as the your amps have this great PSRR, but I am unsure especially about the star ground arrangement and the ground loop breaker.
b) Should I use the bi-amping feature for the KEFs and possibly get two 286 or even four 86 boards? Would the 2x160va still be ok? I guess, as with the 87db/W and ca. 2.7m listener distance I still get plenty of SPL. What do you think?
Thank you so much.
Best regards,
SH
SH,
Nice speaker by the way with some very fine measurements(!) and very nice vertical and horizontal dispersion, as well as directivity control, see here:
https://www.stereophile.com/content/kef-r700-loudspeaker-measurements
The impedance minima is about 3.2 ohms at about 145 Hz. Phase seems electrically benign as well. Efficiency is about 87-89dB at 2.83V.
For that reason I would recommend (2) Modulus 286 boards, each built up to be used as a parallel amplifier, such that you can get 100 watts/4 ohms per channel (for a stereo build) from a +/- 36V supply. There are switching supplies that can do +/- 35V (Connex SMPS300RE) or you can go with a linear supply using Tom's Power-86 boards rather easily and an appropriately sized transformer (~400VA), to reach a bit higher at +/- 36V. The power output differences between +/- 36V and +/- 35V are really negligible but the switching supply is a bit easier to use as it is already a built unit.
You can try biamping in the future but I would first get your feet wet with a good parallel build that is suited for your excellently designed loudspeaker. And you might be happy enough to just stop right there!
Best,
Anand.
Nice speaker by the way with some very fine measurements(!) and very nice vertical and horizontal dispersion, as well as directivity control, see here:
https://www.stereophile.com/content/kef-r700-loudspeaker-measurements
The impedance minima is about 3.2 ohms at about 145 Hz. Phase seems electrically benign as well. Efficiency is about 87-89dB at 2.83V.
For that reason I would recommend (2) Modulus 286 boards, each built up to be used as a parallel amplifier, such that you can get 100 watts/4 ohms per channel (for a stereo build) from a +/- 36V supply. There are switching supplies that can do +/- 35V (Connex SMPS300RE) or you can go with a linear supply using Tom's Power-86 boards rather easily and an appropriately sized transformer (~400VA), to reach a bit higher at +/- 36V. The power output differences between +/- 36V and +/- 35V are really negligible but the switching supply is a bit easier to use as it is already a built unit.
You can try biamping in the future but I would first get your feet wet with a good parallel build that is suited for your excellently designed loudspeaker. And you might be happy enough to just stop right there!
Best,
Anand.
Last edited:
Hi Anand
Thank you very much for the input.
I was almost afraid I had to go for the Mod286s and could not reuse the 2 160va transformers incl powersupply from my previous project. Could you elaborate some more on your reasoning to go for the 100w / 4ohm (60w / Ohms)? From the online SPL calcs I had figured I would get over 90dB with the Mod86 at 40w / 8ohms. Are there not enough dynamic reserves in your opinion?
Thanks a lot
SH
Thank you very much for the input.
I was almost afraid I had to go for the Mod286s and could not reuse the 2 160va transformers incl powersupply from my previous project. Could you elaborate some more on your reasoning to go for the 100w / 4ohm (60w / Ohms)? From the online SPL calcs I had figured I would get over 90dB with the Mod86 at 40w / 8ohms. Are there not enough dynamic reserves in your opinion?
Thanks a lot
SH
SH,
Actually, that's okay. If you want, start off with just (1) Modulus 286 board and use it to get 65w/4 ohms. If you find that you are playing at higher levels then you can easily modify to use (2) Modulus 286 boards with some smart planning of chassis and power supply.
I play music rather loud, sometimes up to 100dB peaks at the listening position and with that thought, I had recommended (2) Modulus 286 boards wired in parallel.
Either way, you've come to the right place!
If SMD soldering is too much for you, Tom can do it, or you can just go for the Mod 86 thru hole design, just keep in mind you might have to limit your peak SPL levels.
I also don't have have the budgetary restrictions others have and at the prices Tom sells his boards for, the design is extremely well thought out, the instructions are beyond par and the service is exemplary. If you want a solid state reference amp, you've come to right place.
Best,
Anand.
Actually, that's okay. If you want, start off with just (1) Modulus 286 board and use it to get 65w/4 ohms. If you find that you are playing at higher levels then you can easily modify to use (2) Modulus 286 boards with some smart planning of chassis and power supply.
I play music rather loud, sometimes up to 100dB peaks at the listening position and with that thought, I had recommended (2) Modulus 286 boards wired in parallel.
Either way, you've come to the right place!
If SMD soldering is too much for you, Tom can do it, or you can just go for the Mod 86 thru hole design, just keep in mind you might have to limit your peak SPL levels.
I also don't have have the budgetary restrictions others have and at the prices Tom sells his boards for, the design is extremely well thought out, the instructions are beyond par and the service is exemplary. If you want a solid state reference amp, you've come to right place.
Best,
Anand.
I'm generally not one to toot his own horn, but I thought I'd brag just for a moment and mention that I have already (almost) finished my build of four channels of the Mod 86, from rev1.01 boards that I bought in December, 2014.
Had a couple of small problems with the BOM and Mouser (no 1N4148s, and only half as many C7-8 caps as needed) but getting the boards stuffed was kind of satisfying. Now wondering whether to use my Deluxe 4U chassis (would need some additional holes in the back panel to convert to 4-channel use) and a linear supply with Antek transformers, or to use a more compact box and an SMPS500R.
This thread has been great. Just what I needed to nag me into getting this project going.
Had a couple of small problems with the BOM and Mouser (no 1N4148s, and only half as many C7-8 caps as needed) but getting the boards stuffed was kind of satisfying. Now wondering whether to use my Deluxe 4U chassis (would need some additional holes in the back panel to convert to 4-channel use) and a linear supply with Antek transformers, or to use a more compact box and an SMPS500R.
This thread has been great. Just what I needed to nag me into getting this project going.
tubesguy,
The Deluxe 4U (from diyAudio store?) is beautiful, but probably overkill in size for what is needed in terms of thermal performance. IIRC Mr. Christiansen has his 4 x Mod-86 module nicely fitted inside a 2U chassis with a Power-86 and 300VA Antek shielded transformer.
Maybe Tom can confirm?
I have my Mod-86 (2 channel) running with a SMPS300RE.
And congrats on getting the boards populated, and hope you start enjoying the music soon. I'm listening to my Modulus-86 as I type...
The Deluxe 4U (from diyAudio store?) is beautiful, but probably overkill in size for what is needed in terms of thermal performance.
IIRC Mr. Christiansen has his 4 x Mod-86 module nicely fitted inside a 2U chassis with a Power-86 and 300VA Antek shielded transformer. Maybe Tom can confirm?
I have my Mod-86 (2 channel) running with a SMPS300RE.
And congrats on getting the boards populated, and hope you start enjoying the music soon. I'm listening to my Modulus-86 as I type...
SH,
Actually, that's okay. If you want, start off with just (1) Modulus 286 board and use it to get 65w/4 ohms. If you find that you are playing at higher levels then you can easily modify to use (2) Modulus 286 boards with some smart planning of chassis and power supply.
I play music rather loud, sometimes up to 100dB peaks at the listening position and with that thought, I had recommended (2) Modulus 286 boards wired in parallel.
Either way, you've come to the right place!
If SMD soldering is too much for you, Tom can do it, or you can just go for the Mod 86 thru hole design, just keep in mind you might have to limit your peak SPL levels.
I also don't have have the budgetary restrictions others have and at the prices Tom sells his boards for, the design is extremely well thought out, the instructions are beyond par and the service is exemplary. If you want a solid state reference amp, you've come to right place.
Best,
Anand.
Thanks Anand for sharing your thoughts. I certainly want a amp which utilizes the KEFs capabilities and I am not starting to skimp now. Also I agree the prices seem to be fair for the value one gets.
The Mod86 seems to measure a little better than the 286. In order to decide on the wattage I might just finish my first 3886 project to the point where I dare to hook it up to the KEFs.
Regarding the 286 and their SMD parts, I have to say that I never soldered SMD in larger quantities but I would consider myself well experienced in soldering. Therefore I might just get some SMDs to practice before I start burning holes in those 286 boards. Any hints?
From your webpage I noticed that you also have quite nice equipment. Any recommendations on a good dac with balanced outputs to go along with the Mods?
Thx and always good listening
SH
SH,
Nowadays there are numerous dacs that perform well. That being said one has to be careful to not over invest as digital audio like computers is a rapidly evolving technology (i.e. I can afford a Chord Dave, and it is a tremendous performer but its resale will be 50% in a year or two). You will get numerous opinions on what is best. Of course I like the Auralic Vega but there are indeed other options. You might consider the Mytek Brooklyn and if you want DIY then AMB's Gamma 3 has garnered nice reviews. The Vega, Brooklyn and Gamma 3 all measure well. I'm holding onto my Vega for a while and I'm hoping Neurochrome Audio will consider designing a dac in the future...but don't hassle Tom as he has a few other projects on his plate prior to tackling digital.
Regarding the Modulus 86 vs. 286, I would not get overly concerned with the small differences in measurements.
I don't have any recommendations for simple SMD projects I'm afraid as all my projects are for a purpose. That being said I'm sure there are some inexpensive SMD kits perhaps from EBay just for practice.
Best,
Anand.
Nowadays there are numerous dacs that perform well. That being said one has to be careful to not over invest as digital audio like computers is a rapidly evolving technology (i.e. I can afford a Chord Dave, and it is a tremendous performer but its resale will be 50% in a year or two). You will get numerous opinions on what is best. Of course I like the Auralic Vega but there are indeed other options. You might consider the Mytek Brooklyn and if you want DIY then AMB's Gamma 3 has garnered nice reviews. The Vega, Brooklyn and Gamma 3 all measure well. I'm holding onto my Vega for a while and I'm hoping Neurochrome Audio will consider designing a dac in the future...but don't hassle Tom as he has a few other projects on his plate prior to tackling digital.
Regarding the Modulus 86 vs. 286, I would not get overly concerned with the small differences in measurements.
I don't have any recommendations for simple SMD projects I'm afraid as all my projects are for a purpose. That being said I'm sure there are some inexpensive SMD kits perhaps from EBay just for practice.
Best,
Anand.