The NCore 400 was for me the least attractive of all amps I've listed... Very "clinical" and not natural sounding. FO was very good soundwise, but loads of instability and reliability issues. JOB225 and 1200AS2 also quite nice.
Same here. Great grip in the bass from the nc400 but slightly synthetic upper mid and treble.
That's probably what I perceive as harshness. The three of us seem to share the experience but use different words to describe it. (That's in part why I rely on measurements
).Tom
I got that configuration running tonight. To compensate for the 6 dB gain difference between the MOD86 and MOD686, I dialled the gain of the tweeter channels up by 6 dB.
The MOD86+686 is a very capable amplifier combination on the LXmini. It doesn't sound quite as clean and coherent as I remember the 4xMOD686, but it's also considerably lower cost. In addition, the MOD686 does contain a few new tricks, which drive up the performance even further and could explain some of the difference.
That said, the MOD86+686 does offer an improvement over the 4xMOD86. For example, I find the bass to be much better controlled by the MOD686, in particular at higher settings on the volume control. Also the harshness I perceived at higher volume settings with the 4xMOD86 is now gone. Maybe you really do need more than 40 W.
I'll still recommend 4xMOD86 for those who are on a limited budget or who prefer to build using leaded components only. Those who are looking for even higher performance should consider the MOD86-686 or 4xMOD686 for their LXmini.
Tom
Hi Tom.
I have got a question for the Power686 safety ground hook up. The older Power86 had a six pole connector which took the safety ground wire next to the four wires of the transformer secondaries. The Power686 has only a four pole connector and therefore no extra space to connect the safety ground.
Question: Do I squeeze in the safety ground together with the transformer center tap wires or do I connect the safety ground on the Power686 output side where is more space?
Thanks.
BR
I have got a question for the Power686 safety ground hook up. The older Power86 had a six pole connector which took the safety ground wire next to the four wires of the transformer secondaries. The Power686 has only a four pole connector and therefore no extra space to connect the safety ground.
Question: Do I squeeze in the safety ground together with the transformer center tap wires or do I connect the safety ground on the Power686 output side where is more space?
Thanks.
BR
nce.
That said, the MOD86+686 does offer an improvement over the 4xMOD86. For example, I find the bass to be much better controlled by the MOD686, in particular at higher settings on the volume control. Also the harshness I perceived at higher volume settings with the 4xMOD86 is now gone. Maybe you really do need more than 40 W.
Finding it difficult to resist Tom, but it will have to wait.
Others build and enjoy!
Thanks, I appreciate it.
One more please. Could you please confirm, the ISS doesn’t get connected to safety ground?
I've read the complete topic and I am really interested in this amp, but would like to read some comments from people who compared it to other well known amps. Anyone?
I have a pair of 500VA 27V Amplimo's lying around, is this too high voltage for the mod 686? They need to drive 4 ohm medium sensitive loudspeakers.
P.S. The use of opamps holds me back a bit too....
I have a pair of 500VA 27V Amplimo's lying around, is this too high voltage for the mod 686? They need to drive 4 ohm medium sensitive loudspeakers.
P.S. The use of opamps holds me back a bit too....
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I think Tom recommends 25V max out of the Transformer.
Can’t help you with your decision though. However I would rely on the multitude of objective measurements Tom provides and less on the subjective impressions of a few who have built the amp. Also what other like you might not.
The 286 is certainly wonderful as already discribed earlier and in another thread. But again that’s my taste. The 686 is under construction so no impressions to share yet.
Can’t help you with your decision though. However I would rely on the multitude of objective measurements Tom provides and less on the subjective impressions of a few who have built the amp. Also what other like you might not.
The 286 is certainly wonderful as already discribed earlier and in another thread. But again that’s my taste. The 686 is under construction so no impressions to share yet.
It's probably right on the edge. If the 2x27 VAC is unloaded, you're probably fine. If it's 2x27 VAC at full load, you might end up over-voltaging the LM3886es at idle. I'd build a supply, load it with 2x350 mA, apply 10% over the nominal mains voltage to the primary, and measure the supply output. If ±36 V or less, you're good.
How many opamps do you think the signal has been through before it reaches the input of the Modulus-686?
Opamps provide a convenient way of getting very high loop gain. You're not likely to ever be able to reproduce the results of the Modulus-686 in a discrete design.
+1
Tom
If money is your primary concern, I'm not likely to be able to help. The MOD686 will set you back a little over $300 per channel if you go the DIY route. So you're in for at least $600+. That's if you have heat sinks, power supply, etc.
Now, if you're willing to spend real money, you could build a very nice amp, that would have some resale appeal should you decide you prefer an amp that colours the sound.
An alternative would be to wait for the listening impressions from Burning Amp to come out (or attend the event in person on September 30th in San Francisco - Ft. Mason). Of course, none of these impressions will tell you how you will feel when you hear the amp, but at least they might shed some light on how that particular listener felt when they heard it.
Best of luck with your endeavour.
Tom
Tom,
Money isn't my primary concern, however I need to be honest, I've owned lots of amps the last couple of years and all of them were told to be among the best amp available. Some of them were really, really good, but I am still looking for something better (for my taste). I do know what it will cost to build double mono version of the mod 686. I do have casings with decent heat sinks for testing, I do have 8 pcs. of nice Kemet 35.000 uf 100V caps, I do have bridge rectifiers, etc. What I don't have are suitable transformers... I have to make a choise whether I buy a pair of suitable transformers (600 or 800VA) or go the Mean Well road. Is the Mean Well 400 Watt version (the one you recommend) suitable to deliver full power of the amp into 4 ohms? Isn't a regulated PS less dynamic compared to a non-regulated one?
A bit more about my preferences, I don't like amps with lots of coloration. I do like valve amps a lot, but mainly for their amazing soundstage ability and posability to show micro details and "open" sound. However I don't like the coloration and I don't like the hassle with tubes.
So I am with you if you say an amp shouldn't color the sound, however it should show ALL the color what is in the input signal! It should not mask a lot of the natural colors within the music.... That's the most important task in my opinion. I hope your amp can deliver this. About the resale apeal, don't think I can sell it in our country... Will be hard, that's for sure....
Money isn't my primary concern, however I need to be honest, I've owned lots of amps the last couple of years and all of them were told to be among the best amp available. Some of them were really, really good, but I am still looking for something better (for my taste). I do know what it will cost to build double mono version of the mod 686. I do have casings with decent heat sinks for testing, I do have 8 pcs. of nice Kemet 35.000 uf 100V caps, I do have bridge rectifiers, etc. What I don't have are suitable transformers... I have to make a choise whether I buy a pair of suitable transformers (600 or 800VA) or go the Mean Well road. Is the Mean Well 400 Watt version (the one you recommend) suitable to deliver full power of the amp into 4 ohms? Isn't a regulated PS less dynamic compared to a non-regulated one?
A bit more about my preferences, I don't like amps with lots of coloration. I do like valve amps a lot, but mainly for their amazing soundstage ability and posability to show micro details and "open" sound. However I don't like the coloration and I don't like the hassle with tubes.
So I am with you if you say an amp shouldn't color the sound, however it should show ALL the color what is in the input signal! It should not mask a lot of the natural colors within the music.... That's the most important task in my opinion. I hope your amp can deliver this. About the resale apeal, don't think I can sell it in our country... Will be hard, that's for sure....
Mark
You don't need to worry about resale values because you won't want to sell it
A few months back the sales manager for Wilson Benesch came to my house to demo some of their speakers and he heard my Neurochrome amps driving them. He was very impressed. They are also the UK distributors for CH Precision amps and they often use them at shows to demo their speakers. Those amps cost a shed load of money (as we say in these parts). That may not impress you, but it put a smile on my face. FWIW . . . .
You don't need to worry about resale values because you won't want to sell it
A few months back the sales manager for Wilson Benesch came to my house to demo some of their speakers and he heard my Neurochrome amps driving them. He was very impressed. They are also the UK distributors for CH Precision amps and they often use them at shows to demo their speakers. Those amps cost a shed load of money (as we say in these parts). That may not impress you, but it put a smile on my face. FWIW . . . .