(re)searching for a better preamp

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#362
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This thread has been dormant too long. Installed the dual chip circuit board in the chassis earlier this week. After a couple of days running and several power up and down cycles it is working really well.
Several items on the new board. Only using one chip side in each. The unused side is has a feedback resistor and 1K resisitor from NI input to ground. The offset nulling circuit is not connected to the unused side.
The power supply is in another box, there is a pair of 6800 ufd FM caps, with snubbers, then a pair of 1000 ufd ZL on each chip with snubbers. Finally 100 ufd ZA caps soldered straight to the power pins of the AD815's.


George
 

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#363
Sound

I may be dreaming, but it sounds even smoother and the one before that used one AD815. A couple of other things were changed, so it may not just be my imagination.
I have heard several 5,000.00 - 10,000.00 commercial linestages at my house. This simple circuit beats them. It is fleshier sounding, with deeper taunt bass. The highs are very extended. There seems to be more wrinkles in the soundstage. The low level artifacts and minute details are exposed more clearly.
Love this thing.


George
 

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#364
Re: Sound

Panelhead said:
I may be dreaming, but it sounds even smoother and the one before that used one AD815. A couple of other things were changed, so it may not just be my imagination.
I have heard several 5,000.00 - 10,000.00 commercial linestages at my house. This simple circuit beats them. It is fleshier sounding, with deeper taunt bass. The highs are very extended. There seems to be more wrinkles in the soundstage. The low level artifacts and minute details are exposed more clearly.
Love this thing.
George
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Hello George,

I too have heard many $$$$ commercial preamps, but this one seems to be on a league of it's own.
And then you wonder why I don't open my pre for a long time.
This may be the pre of your life.
It is not easy to improve on this, but as a principle I never say never, who knows.

The Jeff Rowland Coherence left my head spinning around, I had to do something with this chip.
I don't have access to that Jeff Rowland preamp anymore, it would be a nice test to compare it with my implementation.
The Jeff Rowland has too many parts IMO, and a Crystal chip for volume control, I feel that I've made better than that.
 
#367
filholder said:
Hi Carlos,

Which Crystal chip was it using, the CS3310?
Click to expand...

Yes.

filholder said:
I have etched my Ad815 board and will soon complete them, and i need something for remote volume.

...or this

http://eshop.diyclub.biz/index.php?cPath=85_186

Any ideas? Or would something like a motor alps blue velvet be better?

phil
Click to expand...

Both of those choices seem better than using a chip.
It looks like Peter Daniel is working on a similar thing, why no drop him a message?
I don't know if it will be remote controlled, though.
 
#368
Thanks for your replies guys, useful input as always.

Certainly going to try one of those options.

Things is I use my main and only system for eveything. I am not really into 20.1 channel home movie setups finding that for my small flat a decent stero setup work very well. Trouble is that then means the preamp has to have a remote. Try explaining to my missus why the tv volume isnt on the universal remote when her family phone from spain. This is an easy way to start the third world war.

Rudi cheeres for all your help, got my very first boards etched the otehr night and they look great. Very happy, work has been too busy (doing Gorillaz stuff for the grammys and brits). When i finaly get a few hours spare I will stick it all together. I am guessing it is better to stick the PSU together test that, then work onwards?

Thanks for all your help, the 18mm cap change was very good of you,

Cheers,

Phil
 
#371
The thing is here in the u.k. you basiclly need a DVB box, then a TV screen and i am sending the audio out into the HIFI. This also hs a TT, DAB tuner and a modified arcam alpha 5 on it.

You have no idea how many permations of get no audio or picture from the tv etc. my girlfriend has discovered. Really Its almost frightening. And this is with a fully programmed Universal remote to do the lot. Some times i just bow my head and weep!!!!!

Which ever way it needs a remote.

Phil
 
#372
Well Phil, if you want all the mods on the V3310 i can mail that to you. I am very happy with mine and it isn’t that expensive. But the discrete resistor version seems very appealing but at the time I thought it a touch expensive.

Test the PSU first then build the rest. And get the grounding right. :devilr: one of my friends had lots of problems with that 🙄
 
#373
I finally managed to get the AD815 up and running yesterday, Rudi kindly sent me the pcb files so I could get it etched.
Its the version using the servo for the nulling
I'll have another go at Carlos original nulling circuit, my first attempt it gave me a few problems but I'll have a look at it later, it would be nice to compare them just to see if the servo does have an influence on the sound

I've tried the the AD815 with three of my amps
My-RefC
UCD180
AvondaleNCC200
It works well with them all but seemed to work extremely well with the AvondaleNCC200, the sound is very impressive, the bass was explosve with some tracks:devilr:
The sound is also very clear and detailed🙂 I'm going to spend some more time listening to it today, it could also do with a few more hours running in but so far I'd say these are very good pre-amps, I've also got a highly modded super regged Air-Guitar pre to use as a reference, this is based on the Naim pre-amps.

A big thank you to Carlos and Rudi😎
 

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#375
jaudio said:
t.

That's excellent work:up:

Is your case work done?
Click to expand...

Cheers mate, its actually Rudi and Carlos who should get the credit

I'm actually searching for a case, infact I need one for Pedja's dac and a few other projects:bawling:

I also need a better volume control, I'm currently having to use my diy passive 22k Attenuator
 
#378
How does the setup compare to the Air-Guitar?

I am currently about 70% through building Rudi's setup, just interested since i have also been following the Air-Guitar threads over at pink fish media.

I ended up going with this one mainly because i now know a fair few of the characters on this board, and trust there opinions.

fil
 
#379
filholder said:
How does the setup compare to the Air-Guitar?

I am currently about 70% through building Rudi's setup, just interested since i have also been following the Air-Guitar threads over at pink fish media.

I ended up going with this one mainly because i now know a fair few of the characters on this board, and trust there opinions.

fil
Click to expand...

To be honest so far I prefer the AD815, the Air guitar is very very good although it does use all good qualty parts, ALW super regs,Vishay dale and caddock resistors, M-cap capacitors
The AD815 uses standard parts except for a few Oscons.
I found although the Air-guitar is very good it adds more of a character to the sound, the AD815 seems to have less of a character if that makes sense, personally I think a lot of this is down to the coupling caps, the AD815 has the advantage because it does not need them.
Either way both pre amps are very good, like everything else its all down to personal opinions😉
 
#380
BTW, Its worth trying to use Oscons for the 33uf caps, low esr caps are not normally recommended to be used on the output of voltage regs but they do seem to work well in this set up

Good luck with the Pre and let us know how you get on, just remember to give it a while to burn in and keep an eye on the chips temp, I've heatsinked mine
 
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