Hi Tom.
I finished my amp over the weekend. Firstly a massive thank you to you for designing this fantastic amplifier and making it available as a project for the DIY community, and an additional thank you to you and the others in this thread who advised me during my build.
I'd like to give something back, a review of the amp which I'm happy for you to quote all you like.
Firstly a quick background.
I've been a music obsessive for as long as I can remember. I DJ'd & produced techno for nearly 20 years. When I moved away from that I found my self writing modern classical music which is what I do now as a hobby. I'm a professionally trained sound engineer, I also have a good ear for mastering. I feel I've come full circle on music technology and by extension consumer audio. I have built many analogue studio pre's, EQ's, analogue summing units & compressors, not to mention analogue modular synthesizers. All because of the hype that they sound better. But when it comes down to it, none of it made the process of creating music any easier or made my music sound noticeably "better", so I sold nearly all of it and I'm writing modern classical music with a stripped back completely digital set up.
To bring this back to consumer audio I made a focus of just wanting the purest signal path possible, the things that appeal to me are accuracy and transparency which is how I came across your amp in the first place, put simply, i like to hear what they heard in the studio.
My set up for listening is a laptop with an ODAC RevB (a DAC made by a guy who i think you'll appreciate) he took a no nonsense approach and kept his design all about accuracy (amazing DAC for less than £100)
My speakers are Tannoy DC6T (not super expensive but absolutely fantastic floor standing tower speakers)
For comparison my existing amps we're a pair of SONY TA-N55es each running in bridged mono mode.
The first thing I noticed with the Mod86 are the transients. Don't get me wrong, my Sony's are natural and accurate, but clearly the Mod86 is faster and that's evident in it's output. I'm not going to comment on whats "better" but all I can say is that i prefer fast transients. It sounds truer to me, and that's what I strive for in my set up.
The next thing that became apparent to me is the nice balance between "focus" and "invisibility". To explain "invisibility" it's more a characteristic of speakers rather than amps, but it's basically that sense that some speakers disappear in the room, you cant quite pin point where the sound is coming from. In my book that's a desirable quality of a speaker. While my speakers don't completely disappear here they certainly feel like the sound is transmitting from a wider area when using the mod86, yet the focus to where I'm sat is still very central and cohesive.
So after I'd listened to a few tracks I'm most familiar with (a mixture of Folk, Rock and Classical) I started to notice how revealing the mod86 is, the best way to describe this is comparing to the Shure in ear monitors that I use everyday (again, something I bought because all the reviews say how natural and accurate Shure IEM's are - and I can say I'd never go back to anything else now) There's an intimacy that I've only ever experienced on good headphones, that the Mod86 can also reproduce. I can pick out the texture of rough fingers on an acoustic string and the extended plate reverbs that my studio ears are trained to zoom in on, the mod86 absolutely nails that.
This next one is hard to describe in technical terms without straying into those subjective superlatives often used by "audiophiles" to justify their £8,000 speaker cable and power chord, but I'll try... So as I listen to music with very powerful vocal performances (Frightened Rabbit - Quietly Now! Liver! Lung! Fr!) it encourages me to turn it up. The Mod86 feels like its increasing potential of the speakers, almost as if the speaker is growing as the vocalist pushes harder and harder, it gives an ever growing "height" to sound without ever distorting at the most intense parts of the vocal (unless there's some distortion in the recording.) This goes to the point where I can pick up the dynamic compression (I'm not talking about digital bit rate compression here) on lead vocals on a small number of songs, but this isn't a criticism of the amp, it's just relaying exactly whats on the recording. I guess to summarise, the sound is unbound, like sonic limits are miles away from being reached, especially in that mid range where lead instruments and vocals sit.
I'm writing this as I'm on my 3rd listening session with the amp, currently playing a wav version of REM - Automatic For The People album, I can't find any negatives with the Mod86, I keep turning it up every few songs, the only downside here is once I get above a certain volume I hit the physical limitations of my room. As I'm accustomed to acoustically treated studios with low RT60's my reflective living room cant compare, and the Mod86 exposes that so well.
Unfortunately for my Sony's, they've been unplugged, so that says it all really. The Mod86 outperforms a pair of very capable mono amps.
I can say with complete honesty I get the same sense of being impressed by the Mod86's sound, as I do when I hear my mates Linn set up which cost more than £6,000. If that's not an endorsement for an amp that costs less than £300 to build I don't know what is.
I have a feeling the Mod86 will be the centrepiece of my home set up for a very long time.
Sorry if that's too long but there it is!
Tom
I finished my amp over the weekend. Firstly a massive thank you to you for designing this fantastic amplifier and making it available as a project for the DIY community, and an additional thank you to you and the others in this thread who advised me during my build.
I'd like to give something back, a review of the amp which I'm happy for you to quote all you like.
Firstly a quick background.
I've been a music obsessive for as long as I can remember. I DJ'd & produced techno for nearly 20 years. When I moved away from that I found my self writing modern classical music which is what I do now as a hobby. I'm a professionally trained sound engineer, I also have a good ear for mastering. I feel I've come full circle on music technology and by extension consumer audio. I have built many analogue studio pre's, EQ's, analogue summing units & compressors, not to mention analogue modular synthesizers. All because of the hype that they sound better. But when it comes down to it, none of it made the process of creating music any easier or made my music sound noticeably "better", so I sold nearly all of it and I'm writing modern classical music with a stripped back completely digital set up.
To bring this back to consumer audio I made a focus of just wanting the purest signal path possible, the things that appeal to me are accuracy and transparency which is how I came across your amp in the first place, put simply, i like to hear what they heard in the studio.
My set up for listening is a laptop with an ODAC RevB (a DAC made by a guy who i think you'll appreciate) he took a no nonsense approach and kept his design all about accuracy (amazing DAC for less than £100)
My speakers are Tannoy DC6T (not super expensive but absolutely fantastic floor standing tower speakers)
For comparison my existing amps we're a pair of SONY TA-N55es each running in bridged mono mode.
The first thing I noticed with the Mod86 are the transients. Don't get me wrong, my Sony's are natural and accurate, but clearly the Mod86 is faster and that's evident in it's output. I'm not going to comment on whats "better" but all I can say is that i prefer fast transients. It sounds truer to me, and that's what I strive for in my set up.
The next thing that became apparent to me is the nice balance between "focus" and "invisibility". To explain "invisibility" it's more a characteristic of speakers rather than amps, but it's basically that sense that some speakers disappear in the room, you cant quite pin point where the sound is coming from. In my book that's a desirable quality of a speaker. While my speakers don't completely disappear here they certainly feel like the sound is transmitting from a wider area when using the mod86, yet the focus to where I'm sat is still very central and cohesive.
So after I'd listened to a few tracks I'm most familiar with (a mixture of Folk, Rock and Classical) I started to notice how revealing the mod86 is, the best way to describe this is comparing to the Shure in ear monitors that I use everyday (again, something I bought because all the reviews say how natural and accurate Shure IEM's are - and I can say I'd never go back to anything else now) There's an intimacy that I've only ever experienced on good headphones, that the Mod86 can also reproduce. I can pick out the texture of rough fingers on an acoustic string and the extended plate reverbs that my studio ears are trained to zoom in on, the mod86 absolutely nails that.
This next one is hard to describe in technical terms without straying into those subjective superlatives often used by "audiophiles" to justify their £8,000 speaker cable and power chord, but I'll try... So as I listen to music with very powerful vocal performances (Frightened Rabbit - Quietly Now! Liver! Lung! Fr!) it encourages me to turn it up. The Mod86 feels like its increasing potential of the speakers, almost as if the speaker is growing as the vocalist pushes harder and harder, it gives an ever growing "height" to sound without ever distorting at the most intense parts of the vocal (unless there's some distortion in the recording.) This goes to the point where I can pick up the dynamic compression (I'm not talking about digital bit rate compression here) on lead vocals on a small number of songs, but this isn't a criticism of the amp, it's just relaying exactly whats on the recording. I guess to summarise, the sound is unbound, like sonic limits are miles away from being reached, especially in that mid range where lead instruments and vocals sit.
I'm writing this as I'm on my 3rd listening session with the amp, currently playing a wav version of REM - Automatic For The People album, I can't find any negatives with the Mod86, I keep turning it up every few songs, the only downside here is once I get above a certain volume I hit the physical limitations of my room. As I'm accustomed to acoustically treated studios with low RT60's my reflective living room cant compare, and the Mod86 exposes that so well.
Unfortunately for my Sony's, they've been unplugged, so that says it all really. The Mod86 outperforms a pair of very capable mono amps.
I can say with complete honesty I get the same sense of being impressed by the Mod86's sound, as I do when I hear my mates Linn set up which cost more than £6,000. If that's not an endorsement for an amp that costs less than £300 to build I don't know what is.
I have a feeling the Mod86 will be the centrepiece of my home set up for a very long time.
Sorry if that's too long but there it is!
Tom
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Sweet. Thank you. I'm glad to have been of help.
Thank you for taking the time to write. I really appreciate it. I'm glad you like the amp. Having the amp just 'be' and not be the show is how many experience the Modulus amps.
Yeah... Based on the feedback I get, I gather that the Modulus-86 tends to cause other amps to collect dust - including some marquee name brands.
Tom
Thank you! The controlled directivity was definitely one of the things I was after. One of these days, I'll bother to bi-amp them. I know a guy who makes amps...
Tom
That'd be Firebottle then! He didn't tell me he'd got them working already damn cheek
Tom might remember I blew up a 86 board when I switched to monoblocks and decided I should keep well clear of electronics. Glad they've been made good again.
It is. Hes done a typically top jobThat'd be Firebottle then! He didn't tell me he'd got them working already damn cheek
Tom might remember I blew up a 86 board when I switched to monoblocks and decided I should keep well clear of electronics. Glad they've been made good again.
Yes that's mine. Used to be on here as Firebottle but that was a few years ago.
Well pleased with the performance (Thanks Ian
)One thing I have noticed on my amp tom, I do hear a physical hum from the amp (the chassis, not through the speakers).
If i press firmly on the chassis it dampens it, so it's definitely mechanical vibration.
I've been round the amp and tightened all the screws and really firmly tightened the torroidal traffo but I can still hear it.
Any ideas what causes this or how to remedy it?
If i press firmly on the chassis it dampens it, so it's definitely mechanical vibration.
I've been round the amp and tightened all the screws and really firmly tightened the torroidal traffo but I can still hear it.
Any ideas what causes this or how to remedy it?
Itll be the traffo, dont tighten it down to much and make sure you have rubber pads top and bottom. Mine is actually bolted to a perspex disc which is glued onto a 10mm neoprene pad with 3m contact adhesive. So I cant invert them safely but theres no physical connection being traffo and chassis. 400va toroidy traffo is mono block bridged mod86p.
I use the hammond traffo, it came with top and bottom rubber pads in the mounting kit.
Thinking about it I think the casing of my IEC inlet socket may be close to the traffo and this is also probably close to the top of the chassis (its tightly packed as i mistakenly bought the smaller chassis)
I'll try putting some rubber between the traffo and the casing of the IEC socket, and the top of the IEC socket and the top of the case.
That makes sens why it would stop when i press down on top of the case, its dampening the vibrations.
DC causing toroid hum and vibration
There also may be DC on the AC line. Toroids are sensitive to it, and depending upon their design, construction and the amount of DC, they can hum quite badly. I believe that the Elliot sound website has a long article on this as well as design information for constructing a DC blocker. The need for over-rating the blocking capacitors must be followed to ensure safety. It may also be a good idea to encase the DC blocker in it's own robust enclosure within the amp chassis.
There also may be DC on the AC line. Toroids are sensitive to it, and depending upon their design, construction and the amount of DC, they can hum quite badly. I believe that the Elliot sound website has a long article on this as well as design information for constructing a DC blocker. The need for over-rating the blocking capacitors must be followed to ensure safety. It may also be a good idea to encase the DC blocker in it's own robust enclosure within the amp chassis.
I have a plywood case with aluminium rear panel. My traffo used to cause a hum which was reduced by pressing the top panel. My solution was to fit double sided tape with the film left on one side acting as a soft gasket, under the lid.
I have a mains DC blocker and balanced transformer supplying my rig.
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I'd be surprised if the Hammond toroidal transformers hum by design. That's not to say that it's impossible, just that I find it somewhat unlikely.
If it does hum, I'd try the DC blocker first.
Most mounting kits are designed to be reasonably low profile. Some have an enamelled top washer and recessed nut to make sure that incidental contact between the mounting kit and the inside of the top chassis panel doesn't result in a shorted turn around the transformer. You can, of course, back that up with a piece of plastic, rubber, FR-4 fibreglass, etc. You still want some gap between the mounting kit and the insides of the top panel. At least enough to prevent a shorted turn if someone puts a stack of books on the chassis. 3-5 mm is probably plenty for most chassis.
Nothing should be allowed to rub against the transformer. You don't want stuff to chew into the insulation on the windings and short things out.
Tom
One idea: Saw off a short length of 1.5x1.5 angle aluminum, and use it as a heat sink until the real one shows up. You may have to make some adjustments to make it fit properly, but it will be a decent stop gap.
Another idea is to just tack in an ordinary chassis mount rectifier with pig tails, for the time being, and mount it to the chassis or a metal plate.
A final suggestion is to use the rectifier with no heat sink, and just go easy on the volume control. It will only really get hot if you are pushing a lot of power. For example if you have 10 watts average power with an 8 ohm speaker, that's only 1.11A average through each pair of diodes, multiply that by the 0.6V diode drop and times two pairs, you have only 1.3W lost in the bridge. Frankly if you are just using the amp with moderate volume music and not pushing it with continuous power testing I think you don't really even need the heatsink. 10W of average power is louder than most people ever normally listen.
Make sure to back order it though, it looks cool, and it lives up to neurochrome's slogan, because with that heat sink the rectifier will last virtually forever with any kind of use.
Another idea is to just tack in an ordinary chassis mount rectifier with pig tails, for the time being, and mount it to the chassis or a metal plate.
A final suggestion is to use the rectifier with no heat sink, and just go easy on the volume control. It will only really get hot if you are pushing a lot of power. For example if you have 10 watts average power with an 8 ohm speaker, that's only 1.11A average through each pair of diodes, multiply that by the 0.6V diode drop and times two pairs, you have only 1.3W lost in the bridge. Frankly if you are just using the amp with moderate volume music and not pushing it with continuous power testing I think you don't really even need the heatsink. 10W of average power is louder than most people ever normally listen.
Make sure to back order it though, it looks cool, and it lives up to neurochrome's slogan, because with that heat sink the rectifier will last virtually forever with any kind of use.
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IMO, that's the best solution.
Alternatively - as I swear I typed this morning - fashion a heat sink from a piece of scrap aluminum and use the mounting holes on the board to secure it. You can pretty easily bend aluminum sheet in a vise to form a 'foot'. Then drill mounting holes in the 'foot'.
Tom