The diyAudio First Watt M2x

IPS6/IPS7 first listening

Hello M2X-builders,


I stuffed the IPS7- boards.



Put the IPS6- and IPS7-boards into the amp and gave them a first listening. :D


First impression: they both sound really; really good! I think these boards are very 'unnoisy (compared to Mountainview)'. Seems this was one of the 'aims' of Mark? :confused:
I think this is the reason why Mark has chosen the Zetex ZTX558 as a CCS on the IPS6 - board? :rolleyes: And it shows me again what a good job the J113s can do...

I have to listen more to give a real statement on the sound. Although these are 'buffers' and they shouldn't 'sound'. But they do....

Well done Mark! Thanks!


Greets
Dirk :hphones:
 

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There are three constant current sources on the IPS6 schematic: Q1, Q3, and Q7.

Several factors were considered when choosing specific device types for each position, including the prevalence of counterfeit devices (if an unwise builder decides to save a dollar by purchasing transistors from eBay or Tayda instead of Mouser).

If you want to compare IPS6 to MountainViewIPS, let me call your attention to the bias networks at the lower left in each schematic diagram. MountainView has a double-regulated bias network: R1-D1 is the first regulator, and R2-LED1 is the second regulator. On the other hand, poor old IPS6 only has a single-regulated bias network: R1-IC1.

For those who prefer the sound of MountainView over the sound of IPS6, now you have a "reason" you can point to, triumphantly. Double regulated bias! Oh baby.

And for those who prefer the sound of IPS6 over the sound of MountainView: you'll just have to say "high output impedance transconductance amplifier driving transformer primary, gives excellent sonic results."


_
 

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Last edited:
Black Forest Buffer Proto

Just for my own curiosity, I played around with the BFB proto further today.

Firstly, what happens without load ?
Nothing.
Both square wave and frequency response is the same as 600R load.
The bandwidth is determined by the input RF filter, and not by the buffer itself.

How about DC drift ?
On cold start, DC was +1.2mV. After 2 minutes it was -1.0mV.
After 5 minutes, it was 0.0mV +/-0.3mV.
I used nominal-value resistors throughout without any trimming (1% metal film).
JFETs Idss are 3.53mA & 3.51mA.
Hfe for the BJTs were 222 & 200, not perfectly matched.

Maybe just luck. ;)


Cheers,
Patrick

.
 

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Further information ...
Maybe I'm exaggerating, because the noise can only be heard with the ear in the speaker, but I want to catch up with those who have silence in the speakers.
The amplifier connected to the preamplifier is ... quieter. Not much, but 100hz and 200hz have disappeared. 150hz remained at the same level.
Anyone have any ideas? pre%20cd%20off.jpg pre%20cd%20on.jpg
 
Hello M2X-builders,


I stuffed the IPS7- boards.



Put the IPS6- and IPS7-boards into the amp and gave them a first listening. :D


First impression: they both sound really; really good! I think these boards are very 'unnoisy (compared to Mountainview)'. Seems this was one of the 'aims' of Mark? :confused:
I think this is the reason why Mark has chosen the Zetex ZTX558 as a CCS on the IPS6 - board? :rolleyes: And it shows me again what a good job the J113s can do...

I have to listen more to give a real statement on the sound. Although these are 'buffers' and they shouldn't 'sound'. But they do....

Well done Mark! Thanks!


Greets
Dirk :hphones:

Do yourself a huge favor and ditch the OPA for an LM49720 in the IPS7.:D:D
As a unity gain buffer OPAs family seems very dark with overly exaggerated bass and poor imaging. Unless you have a vintage ribbon tweeter bookshelf speaker that needs freq response 'rebalancing' I would avoid.
 
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Joined 2006
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Listening to my just finished Cedarburg daughter cards. Wow! I have built several cards now, including both the other DIP OpAmp cards. This set is my favorite so far.

In my system, the correct balance of delicate, precise, and a touch of lush. Sounded great with Deadmau5, Nora En Pure, Steve Martin, Laurence Blatt, Dire Straights, Norah Jones, Nickel Creek, and still working on others. Bass was sharp, precise, and well weighted in the electronic tracks.

Monoblocks with Fairchild Mosfets. Daedalus Muse Studio speakers, in a very undersized room. (I measured 15 minutes to change both the daughter cards, and close back up)

Thanks for my new favorites Mark Johnson! Maybe it was just a fun exercise for you, they are magic in my system.

All that being said, I have extra cards (ordered the minimum 5, but they sent 7), and can offer a set of 2 and a set of 3 cards, in all their RED + ENIG glory, free for whoever wants them. I will cover postage to the continental USA.

Edit - its going to be hard dragging them out to clean the solder flux, I knew I should have cleaned them first...
 
Member
Joined 2019
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Listening to my just finished Cedarburg daughter cards. Wow! I have built several cards now, including both the other DIP OpAmp cards. This set is my favorite so far.

In my system, the correct balance of delicate, precise, and a touch of lush. Sounded great with Deadmau5, Nora En Pure, Steve Martin, Laurence Blatt, Dire Straights, Norah Jones, Nickel Creek, and still working on others. Bass was sharp, precise, and well weighted in the electronic tracks.

Monoblocks with Fairchild Mosfets. Daedalus Muse Studio speakers, in a very undersized room. (I measured 15 minutes to change both the daughter cards, and close back up)

Thanks for my new favorites Mark Johnson! Maybe it was just a fun exercise for you, they are magic in my system.

All that being said, I have extra cards (ordered the minimum 5, but they sent 7), and can offer a set of 2 and a set of 3 cards, in all their RED + ENIG glory, free for whoever wants them. I will cover postage to the continental USA.

Edit - its going to be hard dragging them out to clean the solder flux, I knew I should have cleaned them first...

Wow! I am running Ishikawa and it sounds really good. Maybe even great. Austin-unused, #7 just finished, #6 parts and boards in hand, Cedarburg boards in hand and parts in transit.

Guess I may as well cut to the chase and install Cedarburg next. I get the feeling Austin will never be heard. Poor little guys. Oh well....

Don
 
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Joined 2011
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There are lots of DIP-8 opamps sold by Analog Devices; those who wish to test the "house sound" hypothesis could try the AD817, AD744, AD843, and AD847. Either in the Tucson daughter card, or the IPS7 daughter card.

Tons of people here on diyAudio praise the AD825 to high heaven, even though it comes in an SOIC-8 (surface mount) package. Luckily, SparkFun will sell you a cheap adapter board LINK that lets you plug an AD825 into a DIP8 socket.