(re)searching for a better preamp

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#381
I have currently put in the Rubycon ZA, i bought some oscons but by mistake they were only rated for 20v by mistake and maybe that is a bit low.

All the rest are panasonic FC just cos i like them and they are pretty cheap from farnell.

I also bought oscon for the surface mount eletrolitics on the AD815 daughter board.

Thanks for the advice about it vs. the air guitar, sounds very re-assuring. I try not to listening to anything properly for a day or 2, i rember my gainclone sounding pretty flat for the first couple of days, then sounded great after burn in.

I have a couple of old heatsink i am going to experiment with.

Thanks for the advice.

Fil
 
#383
Hi Phil

you can buy the remote setup from DIYclub in Hong Kong. I then modded it with a BB PGA2311 from Ti. (direct replacement)
http://eshop.diyclub.biz/product_info.php?cPath=85_187&products_id=196

get a mate to buy one aswell to share the shipping cost. the basic unit is $48 US and the shipping is $22 US. Maybe T will club-in just to add to his collection

btw. I am also using the 20v Oscons and they seem to be OK

cheers
Rudi
 
#385
Great news-Power supply mods enhance the AD815's performance

Hello all,

Several posts ago, someone asked about the benefit of dual regulation for the AD815. I replied that I tried it with much success on a NAIM pre-amp, but that the AD815 PSRR was high so perhaps there was no point.

Well, I simply added a second reg to the 317 and 337 and WOW, what a difference it makes!

The most obvious benefits are in the highs that become even extended, with such an incredible sense of timing. Bass also benefits substantially, appearing to clean up even further, yet maintaining the already phenomenal extension.

Overall a fantastic and simple mod. Would be interested to hear from anyone else trying this.

My scheme: 10,000uF to LM317 (with 47uF on ADJ pin) to 4,700uF to LM317 (with 47uF on ADJ pin) to 25uF (tantalum cap) to AD815. Same for LM337.

Ryan
 
#386
Right Rudi,

Didnt know it was a race 😀 .
I guess the fact it was the first time i had etched a pcb, and the fact that my delivery from the component suppier were late and i had order a coup[le of things wrong. Mainly the connectors to stack the pcb on top of each other were 2mm rather than 2.5mm pitch so,I am trying to do it via solid copper wire but its pretty tough!!

Also my accounts and missus have got in the way.

I love this stuff but cant always spend much time on it.

Poco a Poco

Fil
 
#387
filholder said:

Didnt know it was a race 😀 .
Click to expand...

So I guess I shouldn't tell you that i am working on a board following Dr.H's ideas. :devilr:

yes i know how it goes. the first time it took me longer. about a week. but i designed the board around stuff i could get hold of. i think that makes it a bit easier. :angel:

well good luck. you will love it once it is up and running 😎
 
#388
Yeah cant wait to hear it , maybe as early as tonight, only have the smd resistors and caps on the daughter board to go.

I am very interested to hear how the dual reg version works, i have spare Ad815's since i thought that might happen!!

Post you results when its ready i might have a go at that as well. Compared to the case work and remote setup for the new preamp the actual preamp boards will be a small percentage of the total time spent, soi dont mind testing a few.

Phil
 
#390
Very true Nuuk

Things is when you have to order stuff from Farnell etc. it sort of makes sense to go slow.If you rush and blow something up then its gonna be another couple of days before you get another chance.

Anyway the PSU was tested yesterday and was perefect, so i can get the rest done in no time.

Be listening tonight i recon,i was soldering till 3 last night whilst trying to do my monthly accounts. Thanksfully today has been slow at work!!!

Phil
 
#391
Yes, joking aside, it doesn't pay to rush these jobs unless you have money to throw away!

I rushed a job over Christmas and landed up replacing a load of parts for a power supply. I hope that I have learned my lesson this time! 😉

I am amazed at the speed some guys can work at though. I have seen an idea put forward on these forums and somebody has built a complete circuit within a couple of hours. I guess it depends if you work with electronics for a living or pick up a soldering iron only as a hobby. And also if you understand electronics you can go a bit faster than those of us who have to check back with the circuit diagram each time we solder in a component! :att'n:
 
#392
From experience, the first one is the tough one. Then if your circuit works and the PCB is easy enough to etch and you have all the parts on hand then it goes quickly.

Design is the other important issue. I will rather spend my time designing to eliminate possible problems than trying to sort them out afterwards.

look at my implementation of the AD815. to build this is very easy. it just looks complicated because of the double boards.
 
#397
Re: Great news-Power supply mods enhance the AD815's performance

Dr.H said:
Hello all,

Several posts ago, someone asked about the benefit of dual regulation for the AD815. I replied that I tried it with much success on a NAIM pre-amp, but that the AD815 PSRR was high so perhaps there was no point.

Well, I simply added a second reg to the 317 and 337 and WOW, what a difference it makes!

The most obvious benefits are in the highs that become even extended, with such an incredible sense of timing. Bass also benefits substantially, appearing to clean up even further, yet maintaining the already phenomenal extension.

Overall a fantastic and simple mod. Would be interested to hear from anyone else trying this.

My scheme: 10,000uF to LM317 (with 47uF on ADJ pin) to 4,700uF to LM317 (with 47uF on ADJ pin) to 25uF (tantalum cap) to AD815. Same for LM337.

Ryan
Click to expand...

Curious... that's not my experience, with other op-amps.
But the AD815 is a different animal, no doubt.
And btw it doesn't have a brilliant PSRR, that's why at the time I've built an RCRC PSU (that's before the LM317/337 regs), which I usually prefer to double regulation.
I didn't try double regulation with the AD815.
 
#399
t. said:
Hey, now I'm tempted to try my pair of ALW super regs on this thing :devilr: they are easy enough to fit
Click to expand...

Do that.
I also have a super reg, may try it.
But as I have a Teac VRDS10 on the works, and a phono preamp to finish, I would apreciate if you take try it first and report. 😀

There's a lot of porential on this chip, I think you have already found out.

Btw I've spent the last couple of days (nights) working on my old Pioneer tuner and I can say now that I really enjoy it.
Another high-end source on my system. 😎
 
#400
Nuuk said:
Carlos, I was wondering where you had gone to
Click to expand...

There has been a little misunderstanding with a post of mine, which should have been taken as a joke (and that's what it was), so I've been parked at the Sin Bin for two days.
Seems like I have to moderate my sense of humour, or adopt the american way.
The british humour on my post was misunderstood.

Nuuk said:
I hope to try the AD815 pre sometime with my double regulated PSU! :att'n:
Click to expand...

Prepare yourself... the music will invade you. 😎
 
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