Rnn resistors
In Post #2 and in the down loaded build notes it is stated:
"ii. All resistors Rnn except 3W parts R13 and R14."
Mauser has "RN" but not RNN. Will that series work, and if so what wattage, and PPM are recommended?
I'm guessing that these values are fairly consistent with Nelsons designs.
I have a small stash of Toshiba Jfet matched pairs. So it would seem logical to build those Ishikawa boards (keeping the Jfet legs long) . With the scheme of this amp, I'm going to build one of the other sets. Starting out I will be driving some full range speakers with a Mesmerize pre. Down the road, more than likely I will be using it to drive some two or three way speakers maybe by-amped with an F5T for the bottom end.
I have small listening rooms, the largest is 180sqft. So I'm not needing to drive them much over 90dB, 80dB seems to be the WAF limit, haha.
So here we go "Which of the other boards should I build?"
I'm not yet confident with my soldering skills to attempt the SMD Norwood boards. But is not out of the realm of possibilities in the future.
In Post #2 and in the down loaded build notes it is stated:
"ii. All resistors Rnn except 3W parts R13 and R14."
Mauser has "RN" but not RNN. Will that series work, and if so what wattage, and PPM are recommended?
I'm guessing that these values are fairly consistent with Nelsons designs.
I have a small stash of Toshiba Jfet matched pairs. So it would seem logical to build those Ishikawa boards (keeping the Jfet legs long) . With the scheme of this amp, I'm going to build one of the other sets. Starting out I will be driving some full range speakers with a Mesmerize pre. Down the road, more than likely I will be using it to drive some two or three way speakers maybe by-amped with an F5T for the bottom end.
I have small listening rooms, the largest is 180sqft. So I'm not needing to drive them much over 90dB, 80dB seems to be the WAF limit, haha.
So here we go "Which of the other boards should I build?"
I'm not yet confident with my soldering skills to attempt the SMD Norwood boards. But is not out of the realm of possibilities in the future.
RN55 series are perfect. They are 1/4w resistors that say 1/8 or 1/10w on the data sheet, as they are mil-spec and 100% derated. Don't worry about PPM.
Build Tucson and/or Mountain View.
Build Tucson and/or Mountain View.
"Rnn" is trying to convey "all resistors whose name consists of the letter R followed by one or two numerical digits" ... except R13 and R14 which are 3 Watt resistors.
A more verbose translation might be:
A more verbose translation might be:
i. The first thing to do is stuff and solder diodes D1 , D2 , and D3
ii. The second thing to do is stuff and solder the normal sized resistors named R1 thru R12. However in this step do not stuff and solder the resistors named R13 and R14 (which are great big 3 Watt parts), those will be dealt with later. If you use a resistor lead forming tool (like the Sparkfun TOL‐13114), you will quickly discover that the normal sized resistors need their leads bent to 0.50 inch pitch (12.5 mm).
iii. The third thing to do is stuff and solder C1, and (if you so choose!) C0.
iv. The fourth thing to do is stuff and solder Q5, Q6, Q7
v. The fifth thing to do is stuff and solder resistors R13 and R14 (which are big 3 Watt parts)
vi. The sixth thing to is stuff and solder the Edcor transformer. Gently try both orientations, use the one that fits very easily. Tape down with a lot of masking tape before soldering.
vii. The seventh thing to do is stuff and solder C2, RV1, C3, and CB3
viii. The eighth thing to do is stuff and solder the six 1/4 inch blade connectors (VPOS, VNEG, OUTPUT, 3xGND)
ii. The second thing to do is stuff and solder the normal sized resistors named R1 thru R12. However in this step do not stuff and solder the resistors named R13 and R14 (which are great big 3 Watt parts), those will be dealt with later. If you use a resistor lead forming tool (like the Sparkfun TOL‐13114), you will quickly discover that the normal sized resistors need their leads bent to 0.50 inch pitch (12.5 mm).
iii. The third thing to do is stuff and solder C1, and (if you so choose!) C0.
iv. The fourth thing to do is stuff and solder Q5, Q6, Q7
v. The fifth thing to do is stuff and solder resistors R13 and R14 (which are big 3 Watt parts)
vi. The sixth thing to is stuff and solder the Edcor transformer. Gently try both orientations, use the one that fits very easily. Tape down with a lot of masking tape before soldering.
vii. The seventh thing to do is stuff and solder C2, RV1, C3, and CB3
viii. The eighth thing to do is stuff and solder the six 1/4 inch blade connectors (VPOS, VNEG, OUTPUT, 3xGND)
6L6 and Mark, a Big thanks!
That clears it up for me. Maybe I should save the Toshiba Jfets for a different project, and build the Mountain view and Tucson boards.
I have to finish the F5T first! Parts are on hand.
Thanks again for all the awesome work you guys do. I'd still listening to crappy powered speakers. But now I have a new hobby, haha.
That clears it up for me. Maybe I should save the Toshiba Jfets for a different project, and build the Mountain view and Tucson boards.
I have to finish the F5T first! Parts are on hand.
Thanks again for all the awesome work you guys do. I'd still listening to crappy powered speakers. But now I have a new hobby, haha.
When soldering the Jfets in, leave them up as high as you can...that way you can always clip them and use for another project!
M2X experience
Hello M2X builders,
I have posted some photos and information about my M2X-build in the
'pictures of your pass diy amplifier' - thread.
I want to describe my more technical impressions here.
I had a problem with my loudspeaker offset. When I was turning down RV1
to 0 ohm I had an offset on the output around - 44mV to - 50mV.
I followed the 'blasphemous heresy'-way of 6L6 and changed R6 to 37.4 kohm
and RV1 to a 20kohm trimpot. Then it was easy to adjust the M2X.
Some pics taken in short time (all few seconds). It is fluctuating a little bit.
But that is normal.
Greetings
Dirk
Hello M2X builders,
I have posted some photos and information about my M2X-build in the
'pictures of your pass diy amplifier' - thread.
I want to describe my more technical impressions here.
I had a problem with my loudspeaker offset. When I was turning down RV1
to 0 ohm I had an offset on the output around - 44mV to - 50mV.
I followed the 'blasphemous heresy'-way of 6L6 and changed R6 to 37.4 kohm
and RV1 to a 20kohm trimpot. Then it was easy to adjust the M2X.
Some pics taken in short time (all few seconds). It is fluctuating a little bit.
But that is normal.
Greetings
Dirk
Attachments
M2X experience
I made an switchable input for the inputboards. Then I tested the loudspeaker
offset with the different boards (at the moment AUSTIN / NORWOOD /
MOUNTAIN VIEW).
AUSTIN and MOUNTAIN VIEW behaved very similar (extremely low offset /
most often below 1mV).
NORWOOD let my offset run away. It run very fast to more than 150mV at
the speaker outputs. So I did an emergency shutdown. No smoke. All is o.K..
But I have to check for the reason.
Hallelujah!
Dirk
I made an switchable input for the inputboards. Then I tested the loudspeaker
offset with the different boards (at the moment AUSTIN / NORWOOD /
MOUNTAIN VIEW).
AUSTIN and MOUNTAIN VIEW behaved very similar (extremely low offset /
most often below 1mV).
NORWOOD let my offset run away. It run very fast to more than 150mV at
the speaker outputs. So I did an emergency shutdown. No smoke. All is o.K..
But I have to check for the reason.
Hallelujah!
Dirk
Attachments
Stuff the compensation cap ( Ccomp1 ) on Norwood's input opamp! It will not work properly without it, the AD744 is an externally compensated opamp.
M2X experience
My test setup for the first round of listening:
PRIMARE CD - player and
MUSICSERVER (all in flac)
Preamp: PASS BA-3
Amp: M2X
Loudspeaker: self construction - 2 -way d'appolito
tweeter: 30mm silk dome
bass/mid: 6inch with phase plug (2 each)
passive crossover with lots of MUNDORF-parts
first impressions are very promising! Nothing to complain about yet.
Will take some time to listen and to write all down.
I'll be back!
Thanks to Mark Johnson, 6L6, Nelson Pass and everybody else who
was involved.
Dirk
My test setup for the first round of listening:
PRIMARE CD - player and
MUSICSERVER (all in flac)
Preamp: PASS BA-3
Amp: M2X
Loudspeaker: self construction - 2 -way d'appolito
tweeter: 30mm silk dome
bass/mid: 6inch with phase plug (2 each)
passive crossover with lots of MUNDORF-parts
first impressions are very promising! Nothing to complain about yet.
Will take some time to listen and to write all down.
I'll be back!
Thanks to Mark Johnson, 6L6, Nelson Pass and everybody else who
was involved.
Dirk
Attachments
The R6, RV1 change to 37.4 k, 20k if DC offset can not be zeroed using original values….can I do something up front to verity if I need original or modified values?
Has it something to do with matching the output FETs as a pair?
Is there a post # which is good to read?
Has it something to do with matching the output FETs as a pair?
Is there a post # which is good to read?
If everything is assembled correctly, the green nonpolar electrolytic capacitors on the input daughter cards {visible in the photo of post #1329}, guarantee that every daughter card has the same impact upon offset voltage. And that impact is: zero. There is no circuit pathway for the daughter card to have any effect; the DC blocking capacitor prevents this. Swapping daughter cards should have no effect upon offset at the speaker termianls.
It leads me to wonder whether perhaps your Norwood boards might contain some kind of mistake, such as a poor soldering joint, two components accidentally interchanged, a component accidentally installed backwards, or something like that.
_
Attachments
Max - not a lot to do beforehand to see if you'll need the additional adjustment, but I see no logical reason to not make the change as suggested by Mark.
Post #3 has the specific information, the "Blasphemous Heresy" comment is merely humor, as it's a change to Nelson's original circuit, however small.
If you haven't yet read all the linked documents in posts #1, 2, 3 & 4 I suggest you do, it's very interesting stuff as well as has essentially all the information you'll need to understand the amp and the various daughterboards.
Post #3 has the specific information, the "Blasphemous Heresy" comment is merely humor, as it's a change to Nelson's original circuit, however small.
If you haven't yet read all the linked documents in posts #1, 2, 3 & 4 I suggest you do, it's very interesting stuff as well as has essentially all the information you'll need to understand the amp and the various daughterboards.
Thank you! …..seems it should be a permanent change…..
First I will build a dual mono +-25 VDC supply that can be reused for other power amp projects. Will try the universal PSU PCBs (purchased some at black Friday)…..I have 20 of these diodes in stock and think they can work and can supply M2X with enough current:
https://docs-emea.rs-online.com/webdocs/149f/0900766b8149fd48.pdf
Have to study the PCB layout so I connect the diodes correctly………..
Yesterday I got 2 x 500VA toriods with 2x18 V output each…...2x18 V seems to be the magic number…...with Firstwatt power amps…..
First I will build a dual mono +-25 VDC supply that can be reused for other power amp projects. Will try the universal PSU PCBs (purchased some at black Friday)…..I have 20 of these diodes in stock and think they can work and can supply M2X with enough current:
https://docs-emea.rs-online.com/webdocs/149f/0900766b8149fd48.pdf
Have to study the PCB layout so I connect the diodes correctly………..
Yesterday I got 2 x 500VA toriods with 2x18 V output each…...2x18 V seems to be the magic number…...with Firstwatt power amps…..
answer to Mark Johnson #1333
Hello Mark Johnson,
I only wanted to describe what happened. Your boards and the build guide is absolutely perfect!
If anybody is not perfect - than me myself.
I added the missing Ccap last night on both boards. I also rechecked the whole
board for shorts and so on. But it was very late.
I will do a check again of the Norwood.
The amp sounds wonderful!
Thanks for your patience and understanding!
Greets
Dirk
Hello Mark Johnson,
I only wanted to describe what happened. Your boards and the build guide is absolutely perfect!
If anybody is not perfect - than me myself.
I added the missing Ccap last night on both boards. I also rechecked the whole
board for shorts and so on. But it was very late.
I will do a check again of the Norwood.
The amp sounds wonderful!
Thanks for your patience and understanding!
Greets
Dirk
GB thread for the Melbourne is here:
https://www.diyaudio.com/forums/group-buys/333653-melbourne-daughterboard-m2x.html#post5690033
M2X experience
Hello members,
after a few hours of listening and many kinds of music (through rock-history - can't write down all),
some Jazz:
Marcus Miller: Afrodeezia - Papa was a rolling stone
Flim + the BB's: Tricycle - Tricycle
Siggi Schwab+Percussion Academia: Rondo a tre - Kassensturz
some classic:
Karl Richter: J.S.Bach - Toccata and Fuge
I can say, that I have a slight tendency to prefer the
MOUNTAIN VIEW board over the AUSTIN board.
But they both sound very very good!
Very detailed information, good dynamics, female and male voices sound
very natural, good bass and bass control. Good room information.
Only little minus for MOUNTAIN VIEW - more audible hum if music is off
Only first impressions. Yours can be different.
Good night!
Dirk
Hello members,
after a few hours of listening and many kinds of music (through rock-history - can't write down all),
some Jazz:
Marcus Miller: Afrodeezia - Papa was a rolling stone
Flim + the BB's: Tricycle - Tricycle
Siggi Schwab+Percussion Academia: Rondo a tre - Kassensturz
some classic:
Karl Richter: J.S.Bach - Toccata and Fuge
I can say, that I have a slight tendency to prefer the
MOUNTAIN VIEW board over the AUSTIN board.
But they both sound very very good!
Very detailed information, good dynamics, female and male voices sound
very natural, good bass and bass control. Good room information.
Only little minus for MOUNTAIN VIEW - more audible hum if music is off
Only first impressions. Yours can be different.
Good night!
Dirk
