Same to me , I did listen with the M2 for I think a couple of months continuously . Fantastic .
I would like to add. If I had conventional speakers instead of horns I might prefer the F6 over the M2. Both are great amps but with different goals when designed. The M2 sounds much more like a SET amp than the F6 to me with my speakers. As Nelson has stated about the new F7, he went after the sound of "The Beast of a Thousand Jfets" rather than the SET sound. Different strokes for different folks.
Hey Zen, I decided to reread this thread from the start and I see in post #17 where you describe what to do about offset if it is negative or positive and will not adjust out.
however , upon completing the amp , if output offset stubbornly stays negative , decrease R6 ; if it stays positive , decrease R7 ; I believe I needed 39K for one , but can't remember which ; even though I used FQP/FQN parts
Mine would not zero but was negative some and would not go positive before running out of adjustment. The value I deemed as insignificant and hooked it up anyway to my test speakers. No pops or noises turning on or off so I may just leave it alone but I now know how to remedy this if I want to now.
however , upon completing the amp , if output offset stubbornly stays negative , decrease R6 ; if it stays positive , decrease R7 ; I believe I needed 39K for one , but can't remember which ; even though I used FQP/FQN parts
Mine would not zero but was negative some and would not go positive before running out of adjustment. The value I deemed as insignificant and hooked it up anyway to my test speakers. No pops or noises turning on or off so I may just leave it alone but I now know how to remedy this if I want to now.
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It will be a few days, power supply boards, and also some outputs utilizing Harris devices for one of them, said to provide more mellow sound.
I ask as Teabag has told me he thought bass a little "flabby" BUT this is on office system with mid 80's efficiency. It was just a quick note and didnt sound like he was disappointed or anything....I'm sure there will be more comments as these group buys, both Teas and Grims are built.
I know I will be gabbing on once done!
Russellc
It will be a few days, power supply boards, and also some outputs utilizing Harris devices for one of them, said to provide more mellow sound.
I ask as Teabag has told me he thought bass a little "flabby" BUT this is on office system with mid 80's efficiency. It was just a quick note and didnt sound like he was disappointed or anything....I'm sure there will be more comments as these group buys, both Teas and Grims are built.
I know I will be gabbing on once done!
Russellc
No I was not disappointed, and was not expecting the amp to shine here with inefficient 5 1/2 bass drivers. (And inexpensive speakers to boot) It's just the proximity of office to workshop!
The Bass at all registers was plenty there, but not as say controlled as possible. I expect with feedback it would be so, at the cost of something else. But I was clearly using speakers that were not really recommended for normal FW amp, and it was still fairly glorious. On acoustic material and vocals it was really nice.
Good examples of this are Sara K. "All Your Love" (from Water Falls) and Niamh Parsons "My Lagan Love" from Hearts Desire. The music is good, and if you man enough to admit being emotional about it, these tunes just might move you!
When I pushed say Daft Punks TRON soundtrack "The Grid" or M83s Oblivion soundtrack, you will notice it will not control small monitor speakers bass the same way as a higher feedback version will I imagine. Even these buggers are bi-amp capable so I may go that route later on, but it did not bother me in the least.
Your mileage may certainly vary.
Russellc, I thought you would be firing yours up this weekend. I find no fault in the bass at all with my LaScala's which are horn loaded. LaScala's start dropping off pretty early so the extreme lows some look for is not something I try to achieve. I want sharp clean quick bass and this amp sounds mighty good to me. As to the lower octaves some others will have to comment on that. The mids are mainly what I am looking for in an amp and this is where this amp shines for me. It has the SET sound or at least the 4 SET's I own.
mine goes damn good down , considering that I have 15" Tann from all way down (to up ) , with Beyma 15" helper (OB , referenced few posts up)
so that being 8R nominal , in parallel with 10R nominal (Beyma 8R + 2R35 resistor in series )
either music or heavy movie effects , I can't hear power compression anywhere
though , my M2 is dual mono , properly wired , 250VA Donut with 4x33mF per channel
so that being 8R nominal , in parallel with 10R nominal (Beyma 8R + 2R35 resistor in series )
either music or heavy movie effects , I can't hear power compression anywhere
though , my M2 is dual mono , properly wired , 250VA Donut with 4x33mF per channel
Help with grimberg boards. I am trying to physical locate R6 resistor on the grimberg boards. I have mine stuffed and installed and I want to parallel a 230K ohm resistor across R6 to achieve the 39K that Zen recommends without removing the boards doing this from the top side. With the resistors installed I cannot see the signs. Help would be appreciated. It is impossible for me to read the color codes accurately, I tried. The location of R7 may possible be needed as well. What I am trying to do is zero the offset. Mine is like .82 millivolts which is not giving a problem but like Zen said I may sleep better with the DC at zero.
0.82mV ?
if that's not typo .......... you'll never be an engineer
0.82mV is damn zero , if you ask me
8.2mV is perfectly close to zero
82mV is at least 50mV above acceptable
all that speaking for strict temp. equilibrium conditions , not before that
even if M2 is damn good in that department , from cold to hot - both for offset and bias stability
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Got mine
Many thanks for the nice boards!
You are welcome! I hope you start building your M2 clone soon.
0.82mV ?
if that's not typo .......... you'll never be an engineer
0.82mV is damn zero , if you ask me
8.2mV is perfectly close to zero
82mV is at least 50mV above acceptable
all that speaking for strict temp. equilibrium conditions , not before that
even if M2 is damn good in that department , from cold to hot - both for offset and bias stability
You are correct, I made a typo, it is -82mv and I did consider it acceptable. I did parallel a 230K across R6 and the offset went too far positive. I was thinking of maybe a 45K R6 but after what you have just said I am just going to be happy the way it is. My understanding of DC offset is that too much causes pops on turn on and off because it makes the speaker compensate for the DC present. I have absolutely no noise starting up or turning off. I am still impressed with the sound of this amplifier.
You are also correct, I will never be an engineer or even a designer of circuits at this stage of my life. I am happy to be a solder slinger and try and learn a little from the more knowledgeable guys present on this forum.