The traditional position for a volume control would be "R2". Use a 100K pot to ground, input comes from R1, wiper goes to Q3 and Q4. Since it's DC coupled, if the input signal happens to have any DC offset, changing the volume control can produce a scratchy sound.
You probably don't want to drive the output stage from an impedance that varies with volume control setting. So you probably don't want to install the pot between the secondary and the output stage.
Probably not. The attenuator would have a fixed output impedance, did not draw that in layout, but I see it will not work w/o an additional buffer between attenuator and output stage.
Odd, I note none of the soft low end or lack of detail.... I guess rooms, ancillaries, and speakers can change things up? 😎
Rooms, ancillaries, and speakers should not be the cause otherwise the deficiencies would occur also with my main amplifier which has very high level of detail (Parallel-86 from Neurochrome) compared to the M2. I guess the M2 is not the best match for my speakers (German Physics Unlimited MK2, 88dB sensivity, 4 Ohm).
Will try if the F6 (next build) is a better match.
gimme a break !!
" Amplification required
Minimum 90W/4 ohms "
and you're driving it with M2's 50W ?
while Neurochrome is 120W/4R
with proper spks , M2 is waaaaay away from "soft low , soft high"
" Amplification required
Minimum 90W/4 ohms "
and you're driving it with M2's 50W ?
while Neurochrome is 120W/4R
with proper spks , M2 is waaaaay away from "soft low , soft high"
Probably not. The attenuator would have a fixed output impedance, did not draw that in layout, but I see it will not work w/o an additional buffer between attenuator and output stage.
Rooms, ancillaries, and speakers should not be the cause otherwise the deficiencies would occur also with my main amplifier which has very high level of detail (Parallel-86 from Neurochrome) compared to the M2. I guess the M2 is not the best match for my speakers (German Physics Unlimited MK2, 88dB sensivity, 4 Ohm).
Will try if the F6 (next build) is a better match.
I think the F6 might be a better fit. I'm driving some not too efficient 3 ways with mine and it sounds great. My M2 also sounds great but is more picky who it plays with.
M2 is no nfb amp , it must be pickier
pair it with adequate Lautsprechers , that's Mana from Heaven
pair it with adequate Lautsprechers , that's Mana from Heaven
I think the F6 might be a better fit. I'm driving some not too efficient 3 ways with mine and it sounds great. My M2 also sounds great but is more picky who it plays with.
I have F6 and M2. My impression is M2 winner😛
gimme a break !!
" Amplification required
Minimum 90W/4 ohms "
and you're driving it with M2's 50W ?
while Neurochrome is 120W/4R
with proper spks , M2 is waaaaay away from "soft low , soft high"
Perhaps you are right, however power amplifier wattages recommended by speaker manufactures are most based upon maximum dB the speaker can produce. In a test report of my speakers it was stated that the GP Unlimited can take a lot of power even from amplifier monsters but work well also with small amplifiers which also deliver dynamics and presssure.
Today I hooked up a MyRefc which can deliver ~68Watt at 4 Ohm to GP MK2 speakers. Bass response is better as with M2, though overall sound not as clean as the M2. Instrument/voice localization is nearly M2 but not as good as when PAR-86 is connected to the speakers.
Will test the M2 with Tannoy DC8BS speakers soon and start to finish the F6 build.I think the F6 might be a better fit. I'm driving some not too efficient 3 ways with mine and it sounds great. My M2 also sounds great but is more picky who it plays with.
as I wrote - M2 is no-NFB amp and it's strength isn't primary in driving tougher loads
mate it with speakers based on proper 12" or 15" foundation , with no nasty behavior in impedance domain and it'll be in intended environment
for different ones , if FW stable is to choose from , choose amp with feedback , thus having lower output impedance and increased driving capability
mate it with speakers based on proper 12" or 15" foundation , with no nasty behavior in impedance domain and it'll be in intended environment
for different ones , if FW stable is to choose from , choose amp with feedback , thus having lower output impedance and increased driving capability
I have F6 and M2. My impression is M2 winner😛
Same here. I found F6 closer to F5. It does indeed have a lot of high end detail. I turned my F6 into Aleph J and never looked back.
For harder to drive speakers, a complementary output BA3 with 30 volt rails does fine duty.
Russellc
Quick question,I am finally getting around to installing the buffer in my M2 boards.I don't have a 100k (R2) on hand but have some 47k resistors.Would those be ok to install and if no why not.Thanks in advance for any input.
Thank you,I think you should get an award for all your valuable input on diyit's OK , change it later
it's there to define Rin of amp
Pass DIY Addict
Joined 2000
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After some more effort, my M2 now resides in a more stable and portable chassis. The chassis is almost entirely recycled and left-over parts. The sinks was a flea market find for $6, the top plate is one of my veneer test panels that I made when I built my FHXL speakers, and the front and back panels are scraps from the garage. The only new purchases for the chassis were the aluminum brackets at the rear to provide room to mount the mosfets appropriately on the sink and a handful of screws. The sinks appear to be a good size for this amp, they only see a 20c rise after more than an hour.
The chassis is 12" wide, 12" deep, and 8" tall. The bottom of the sinks are elevated about an inch above the tabletop by the front and rear panels. The bottom is open and the hole in the back panel provides air circulation through the chassis. The input jacks are temporarily on pigtails while I wait for proper ones to arrive - the current ones are too small in diameter (cheap crap from Chinese seller on e-bay). Not even the super-tight Monster cables can hold these jacks tightly. This is my second amp to use my modular power supply. F4 was my first and Aleph-J will be my next.
Now it's time to spend some time listening 😀
The chassis is 12" wide, 12" deep, and 8" tall. The bottom of the sinks are elevated about an inch above the tabletop by the front and rear panels. The bottom is open and the hole in the back panel provides air circulation through the chassis. The input jacks are temporarily on pigtails while I wait for proper ones to arrive - the current ones are too small in diameter (cheap crap from Chinese seller on e-bay). Not even the super-tight Monster cables can hold these jacks tightly. This is my second amp to use my modular power supply. F4 was my first and Aleph-J will be my next.
Now it's time to spend some time listening 😀
Attachments
Use two 47K in series.
Quick question,I am finally getting around to installing the buffer in my M2 boards.I don't have a 100k (R2) on hand but have some 47k resistors.Would those be ok to install and if no why not.Thanks in advance for any input.
Pass DIY Addict
Joined 2000
Paid Member
After some more effort, my M2 now resides in a more stable and portable chassis. ......
I like it very much
so cute
Pass DIY Addict
Joined 2000
Paid Member
so cute
Ha - perhaps I should have cut the "smile" into the front plate rather than the rear 😉 Paint it orange and it's ready for Halloween...
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