NCD questions

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Anzgar

Anzgar

Member
Joined 2005
KLe said:

Hi Bgt
That's excellent :D My speakers are around 91/92db efficient :)
Are you using the LM4562 and AD8620 as preamps?

I have reading about Carlos's AD815 preamp and Greg Ball's SKpre. Both look very impressive. An issue with Carlos's pre is a small amount of DC offset. Everyone who builds it simply rave about how good it is :)

KL
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Where did you read about them? I would like to have a look at the circuit diagrams

:Popworm:
 
KLe

KLe

Banned
Joined 2005
Bgt said:
You mean preamps on the poweramps? Because my main pre is passive. The UCD's have 8620's on them and the NCD the LM6172 I believe. Will have a look at this preamp., Greg Balls SKpre, you mention. Missed this 1.
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Hi Bgt
Ahhh!
You might like to have a look at Burson Audio's discrete opamp, here http://www.bursonaudio.com/Burson_HDAM_Module.htm.
I believe that these are direct IC replacements and have been getting excellent reviews :)
I haven't used them myself as yet. So, at this time I know about them only by word of mouth ...

You can have a look at Greg's SKpre, here
http://www.diyhifi.org/amplifierguru/guru_008.htm
If your passive is a 10K pot, then, you could simply add the SKpre modules after it, and use a wall wart that outputs about 300mamps AC & 3.6VA to power them :att'n:

thanks
KL
 
KLe

KLe

Banned
Joined 2005
Anzgar said:
I have reading about Carlos's AD815 preamp ... Everyone who builds it simply rave about how good it is
Click to expand...
Where did you read about them? I would like to have a look at the circuit diagrams
Click to expand...
Hi Anzgar
How is your NCD1 sounding :)

You can have a look at Carlos's AD815 preamp on the Solid State forum or here http://www.diyhifi.org/forums/viewtopic.php?t=544 :)

Greg's is a kit, refer previous post :)

thanks
KL
 
Anzgar

Anzgar

Member
Joined 2005
KLe said:

How is your NCD1 sounding :)

KLe said:

You might like to have a look at Burson Audio's discrete opamp, here http://www.bursonaudio.com/Burson_HDAM_Module.htm.
I believe that these are direct IC replacements and have been getting excellent reviews :)
I haven't used them myself as yet. So, at this time I know about them only by word of mouth ...

KL
Click to expand...

My NCD1 sounds more close to perfect than anything I heard so far. I used to play on my hifi an hour or two now and then but since building NCD1 I have listened to my CDs about six hours a day :D Every disc sound better than ever; bass, treble, middle,timbre of instrumens,voices and orchestral sections....it's extremely correct - it's not laid back nor too aggressive although what first struck me was its dynamic ability.
The Burson discret op amp might be a good buy.I now use a pre amp built on an AD825 and an BUF 634 which sound very good but maybe that one would sound better or maybe the Micro pre amp as shown in the NCD1 cookbook.

:violin:
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soongsc

soongsc

Member
Joined 2005
Anzgar said:


My NCD1 sounds more close to perfect than anything I heard so far. I used to play on my hifi an hour or two now and then but since building NCD1 I have listened to my CDs about six hours a day :D Every disc sound better than ever; bass, treble, middle,timbre of instrumens,voices and orchestral sections....it's extremely correct - it's not laid back nor too aggressive although what first struck me was its dynamic ability.
The Burson discret op amp might be a good buy.I now use a pre amp built on an AD825 and an BUF 634 which sound very good but maybe that one would sound better or maybe the Micro pre amp as shown in the NCD1 cookbook.

:violin:
Click to expand...

Do you have them in the post filter or pre filter feedback mode? Are they running on the standard power or upgraded?
 
Anzgar

Anzgar

Member
Joined 2005
soongsc said:


Do you have them in the post filter or pre filter feedback mode? Are they running on the standard power or upgraded?
Click to expand...

I never tried the post filter feedback but use pre and standard psu 6wire with a separate 15V transformer.Mains transformer is a standard 500VA.
I play on a couple of planar loudspeakers,home built "La Folia" having 3,5 ohms resistans and very low sensitivity.Sometimes I connect a pair of MISSION "Argonaut" 4 ohms and 91 db sensitivity.No noice detectable with them.
 
KLe

KLe

Banned
Joined 2005
Bgt said:
Nice stuff:D Very tempting to try.
I have to build a small active pre for somebody anyway but with tone controls:xeye: Just want to try the LM4562.
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Lars Clausen said:
I ordered LM4562 chips some time ago, and this friday i got a big package with a bunch of .... LM4652 :xeye:

So it will be around Christmas before i get to play with this chip, and i am very curious to find out how it will perform and sound in a ClassD amplifier.
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Anzgar said:
My NCD1 sounds more close to perfect than anything I heard so far. I used to play on my hifi an hour or two now and then but since building NCD1 I have listened to my CDs about six hours a day :D Every disc sound better than ever; bass, treble, middle,timbre of instrumens,voices and orchestral sections....it's extremely correct - it's not laid back nor too aggressive although what first struck me was its dynamic ability.
The Burson discret op amp might be a good buy.I now use a pre amp built on an AD825 and an BUF 634 which sound very good but maybe that one would sound better or maybe the Micro pre amp as shown in the NCD1 cookbook.
Click to expand...

Hi Bgt
I think so, I will let you know ... its good to have options, isn't it :D

Hi Lars
Good to hear from you and hope everything is going well :D Nice to have the thread moving again. All I have been seeing is UCD. So, nice to see a some NCD news :D

Hi Anzgar
That's simply excellent ... If your enjoying the AD825/BUF634 pre, why change. Enjoying the music is what it is all about and you are, very much so :D

thanks
KL
 
C

cdl

Member
Joined 2003
KLe said:
Hi All
Have many others built the NCD1's other than Bgt and Anzgar :)

thanks
KL
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I have built one too, it was up and running some three weeks ago. I tested it with "disposable" speakers for a day or two. As I've been travelling since, I haven't had a chance to test it with proper speakers, so I can't really comment on the sound quality yet. I will post my experiences once it's playing in my proper system... so that's in a few weeks.

I can however note that there is a controlled, but distinct "pop" when the speakers get activated; but (as Lars promised) no turn-off sound (it tries to keeps playing even after the power is cut off though). I've measured up to 80 mV or so DC offset on one module, up to 110mV on the other. Seems to depend on the load resistance, temperature etc. Without resistive load (cap in series with the voice coil), DC offset went real high - but fortunately I'm not biamping, so I won't have problems with that.
I hope DC offset and turn-on pop will be less on my proper speakers that are only 4 ohm (and perhaps not quite as capacitive). A little bit of the offset may also come from my MP3 player which I used for testing); but there's offset even with shorted + inputs (nothing connected to - input).

/cdl
 
B

Bgt

Member
Joined 2005
grotel.nl
after replacing the opamp. LM6172 with the LM4562 I can only say............it sounds cleaner, more detailed, mid and highs. It is marginal but its there.
With the UCD400AD's the difference is more than marginal. Now you see how borring the sound of the 8620 is. Its flat.
I am waiting for more chips. to try and my DAC should now also be changed, I mean the analog bit. It consists of OPA627's and AD8610's now. They have to go to the dustbin. How I love progress:D and changes in electronics.
Oh, and offset is no issue, with speakers connected I'll get some 20-60mv.
 
G

ghemink

Member
Joined 2004
Bgt said:
after replacing the opamp. LM6172 with the LM4562 I can only say............it sounds cleaner, more detailed, mid and highs. It is marginal but its there.
With the UCD400AD's the difference is more than marginal. Now you see how borring the sound of the 8620 is. Its flat.
I am waiting for more chips. to try and my DAC should now also be changed, I mean the analog bit. It consists of OPA627's and AD8610's now. They have to go to the dustbin. How I love progress:D and changes in electronics.
Oh, and offset is no issue, with speakers connected I'll get some 20-60mv.
Click to expand...


Hello Bert,

Thanks for the update. How do the UcD400 amps compare with the NCD when the UcD is modded with LM4562?

Best regards

Gertjan
 
E

edge540

Member
Joined 2005
How are the highs for you?
For the moment, after 40h, they are a bit hard. My charlize is more smooth. Is it because they are not breaking in?
The bass are :bigeyes: . Impressive!!! The dynamic is excellent. They are quiet with the gnd as indicated in the cook book.

For the moment, in conclusion, if the highs too hard is solving, they will be one of the most impressive amps i've heard.
 
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