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Official M2 schematic
Official M2 schematic
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Old 13th June 2018, 07:13 PM   #2741
1543 is offline 1543  Germany
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Official M2 schematic
Quote:
Originally Posted by Mark Johnson View Post
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.

Quote:
Originally Posted by Russellc View Post
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.
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Old 13th June 2018, 09:18 PM   #2742
Zen Mod is offline Zen Mod  Serbia
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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"
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Old 13th June 2018, 09:43 PM   #2743
PJN is offline PJN  United States
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Quote:
Originally Posted by 1543 View Post
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.
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Old 13th June 2018, 09:48 PM   #2744
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M2 is no nfb amp , it must be pickier

pair it with adequate Lautsprechers , that's Mana from Heaven
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Old 13th June 2018, 09:51 PM   #2745
El Reino is online now El Reino  Finland
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Quote:
Originally Posted by PJN View Post
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
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Old 14th June 2018, 09:39 AM   #2746
1543 is offline 1543  Germany
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Quote:
Originally Posted by Zen Mod View Post
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.


Quote:
Originally Posted by PJN View Post
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.
Will test the M2 with Tannoy DC8BS speakers soon and start to finish the F6 build.
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Old 14th June 2018, 09:51 AM   #2747
Zen Mod is offline Zen Mod  Serbia
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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
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Old 14th June 2018, 12:07 PM   #2748
Russellc is offline Russellc  United States
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Quote:
Originally Posted by El Reino View Post
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
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Old 14th June 2018, 05:56 PM   #2749
oreo382 is offline oreo382  Canada
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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.
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Old 14th June 2018, 06:40 PM   #2750
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it's OK , change it later

it's there to define Rin of amp
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