rudi said:t. that is last weeks design😀
maybe I have to revert back. 😀
Check your mail
Hi Rudi,
I'd already just etched those boards and then you posted me the latest one😀 told you your too fast for me😉 so this one is the one before the last one you mailed me
All my amps are packed away at the minute so I've not had any chance to try it at home.
So are you still having problems with the latest layout?
carlosfm said:
This are the first speaker that I have built and the only one that I kept(for stereo listining). The speaker have 4" woofers,dome tweeter in the front and cone tweeter in the back. In the listening position the speaker is about 83db and averaging 4ohm or less. The room is 10' high x 15 x 12.
Well anyway,I will have new speakers soon and go with Walter Jung preamp with Carlos' lm3886 power amp
Attachments
t. you are welcome. Damn nice looking pre. 
It's hard to keep up with Rudi. 😀 The man is in abundance with energy and ideas. 😀
It's hard to keep up with Rudi. 😀 The man is in abundance with energy and ideas. 😀safetyman said:t. you are welcome. Damn nice looking pre.
Cheers mate!
All I need now is a case😀 This is another thing we need in the UK, a company that can supply nice cases for our projects
I also can't make my mind up which of my volume controls to use, I may remove the 22k Attenuator from my passive pre or may use my spare 20k Noble but try the shunt mod
ALW Super reg, star gnd and snubbers
I tried two ideas this evening: Implementing a truer star ground set-up with Rudi's X-calibre amp and using a 0.47R+22uF snubber on the output of the ALW super reg.
The mods in combination seem to open the sound stage more, but what I like most is the enhanced detail across the freq band. Bass appears to be much tighter and clean 😎
My 2c.
Ryan
I tried two ideas this evening: Implementing a truer star ground set-up with Rudi's X-calibre amp and using a 0.47R+22uF snubber on the output of the ALW super reg.
The mods in combination seem to open the sound stage more, but what I like most is the enhanced detail across the freq band. Bass appears to be much tighter and clean 😎
My 2c.
Ryan
carlosfm said:
Huh... I've been cascoding jfets on my phono pre...
Glad to see your still keeping an eye on us Carlos😎
I'm still looking for a damn case
I keep getting moaned at for having pieces of wood with bits and pieces bolted to them🙄This is as far as intergrating my preamp together with its remote voule control has gone. Waiting to get some spare time and a wooden front panel for the gutted router unit my Dad is making for me.
Just wondering how i should go about the grounding scheme in this unit? Any ideas?
Have a star ground for input and output sockets and also the input and output from the ad815 board. Should this all then be tied to the safety ground or not?
Sorry basic question but just thinking out loud.
Phil
Just wondering how i should go about the grounding scheme in this unit? Any ideas?
Have a star ground for input and output sockets and also the input and output from the ad815 board. Should this all then be tied to the safety ground or not?
Sorry basic question but just thinking out loud.
Phil
Attachments
Local Source
t.
Take a look a Deltron for some fairly nice cast aluminium cases. I am stuffing the boards in the 8.7 x 5.8 x 4.2 inch one tonight. Might be posting pics tomorrow.
They are my faves for easy make cases, plus make my favorite connectors, locking mini DIN. You Brits are soo lucky.
George
t.
Take a look a Deltron for some fairly nice cast aluminium cases. I am stuffing the boards in the 8.7 x 5.8 x 4.2 inch one tonight. Might be posting pics tomorrow.
They are my faves for easy make cases, plus make my favorite connectors, locking mini DIN. You Brits are soo lucky.
George
Been playing around with the grounding of the pre and trying it on various positions. Now I know this is old tricks but I am just going down the road that millions did before me. And sometimes even the old folk need to be reminded of this
1-get the ground reference to star ground as close to the signal ground as possible - more clarity
2-if possible split power gnd and the signal gnd to star gnd
this way I got more clarity from the preamp
For the guys with Ref-C and the X-calibre. Remove the 1R resistor that connects the signal gnd to power gnd. connect a wire at the input gnd and take that down to star gnd. you cans still use the 1R if you want but it isn't required
1-get the ground reference to star ground as close to the signal ground as possible - more clarity
2-if possible split power gnd and the signal gnd to star gnd
this way I got more clarity from the preamp
For the guys with Ref-C and the X-calibre. Remove the 1R resistor that connects the signal gnd to power gnd. connect a wire at the input gnd and take that down to star gnd. you cans still use the 1R if you want but it isn't required
Re: Local Source
Thanks for that George, I've been having a browse around and came across these nice unusual looking cases too , what do you guys think? http://myweb.tiscali.co.uk/nuukspot/decdun/propods.html
Should be ideal for something like the AD815
Panelhead said:
Thanks for that George, I've been having a browse around and came across these nice unusual looking cases too , what do you guys think? http://myweb.tiscali.co.uk/nuukspot/decdun/propods.html
Should be ideal for something like the AD815
UNO - Single JFET preamp
Hi Carlos and Nuuk, I have a question for you guys:
What is the voltage drop across drain resistor (75 Ohm) with no signal on gate, ie. what is the current which flows through K170. I ask you this because I want to build UNO and can't decide which type of K170 to use (sorted by Idss - GR, BL, V). Considering the low value of drain and source resistors (75 and 2.2 Ohm) the JFET should be V type, but Carlos came up with the actual circuit and Nuuk built one and presented it on his site, so who would know better ?
Thanks !
Cheers all !
Hi Carlos and Nuuk, I have a question for you guys:
What is the voltage drop across drain resistor (75 Ohm) with no signal on gate, ie. what is the current which flows through K170. I ask you this because I want to build UNO and can't decide which type of K170 to use (sorted by Idss - GR, BL, V). Considering the low value of drain and source resistors (75 and 2.2 Ohm) the JFET should be V type, but Carlos came up with the actual circuit and Nuuk built one and presented it on his site, so who would know better ?
Thanks !
Cheers all !
Juma, please choose one of the following statements:
This question is far too simple for me to bother with it.
This question is far too technical for me to answer it.
Carlos - HELP!
This question is far too simple for me to bother with it.
This question is far too technical for me to answer it.
Carlos - HELP!
Sorry to be a pest, but is there a summary of the basics of this thread? I keep hearing that this is the preamp to be building, but I'm wary of starting something where I've got to go reading through 60 pages to find what to do next.
Garnett said:
There is nothing as yet.
The basic summary of stuff tried.
1 - Carlos's original circuit.
2 - Addition of a DC servo instead of Carlos's nulling circuit
3 - Dual regulated power supply instead of the single regulation as originally posted by Carlos
4 - Possibility of the Walt Jung circuit.
5 - Use of the ALW super regulator for power supply
I have left out the battery and the SMPS seeing that not much have been said about it.
so basically we have a Carlos's original schematic values left. But you can change that as well (going upto 1K is still ok for feedback) runs a bit cooler this way
so there is a multitude of flavors out there
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