lampizator dac

[Professor smith]

http://www.lampizator.eu/LAMPIZATOR/...Lampizator.doc
page 16

I am looking to try this out. What do you think of the circuit? How do I know which DACS will need filtering?


thanks

[Zen Mod]

asking for extensive electronic training - on line ?

[rikkert1978]

There are several dacs that don`t really need filtering, mostly the newer types of dacs I think.

I have build both the sony 227 esd with lampizator, and the behringer dac with lampizator, and I did not use filtering in both.
The behringer dac sounds really good in my system, and compared to the tda1541 used in the sony 227 esd, it sounds more relaxed in terms of listening fatigue.
I think it has something to do with the dac in the behringer has very low distortion, and even that is way out of the normal audio band.

Some caution though on building the lampizators, is that you cannot blindly copy all the scematics, as I found out, some are not correct for some aplications.
For example the behringer dac lampizator has so much gain, that my amp would clip allot. The solution was to not build it as the schematic (anode follower) but as a cathode follower, which basicly gives 1:1 gain.

You can always build it first without a filter. For me, with my behringer scr24/96 with lampizator, I use no filter and am not going to use one, it sounds fine without.

[tussi68]

I also did the Behringer lampizator and have problem with too much gain.
I used the anode follower as described from Mr. Lamoizator and wonder if it is possible to use resistor on the + out from DAC in series with the condensator to lower the output ?
What would in this case be a good value for resistor ?
If it does not work with this resistor, do you have a schematic or a sketch to built a cathode follower ?
BR
Helge Haga

[ClefChef]

Originally Posted by tussi68

I also did the Behringer lampizator and have problem with too much gain.
I used the anode follower as described from Mr. Lamoizator and wonder if it is possible to use resistor on the + out from DAC in series with the condensator to lower the output ?
What would in this case be a good value for resistor ?
If it does not work with this resistor, do you have a schematic or a sketch to built a cathode follower ?
BR
Helge Haga

I tried attenuating the input with resistors, from 33k to 47k and the triode was still distorting. Finally I switched to cathode follower and everything seems to be good now.
The anode follower has too much gain for Vout DAC's...

[PlasticIsGood]

Originally Posted by tussi68

I also did the Behringer lampizator and have problem with too much gain.
I used the anode follower as described from Mr. Lamoizator and wonder if it is possible to use resistor on the + out from DAC in series with the condensator to lower the output ?
What would in this case be a good value for resistor ?
If it does not work with this resistor, do you have a schematic or a sketch to built a cathode follower ?
BR
Helge Haga

Interesting. Looked at that site quite recently...hard to avoid because he's become quite a celebrity...and wondered what that anode follower was for.


If the output from the triode is intended as a line out, then the gain is too high and so is the output impedance. If there's no need for gain, a cathode follower is commonly used as a buffer with a low(ish) output impedance.


Not keen on cathode followers, I would use an anode follower and an output transformer. Expensive and heavy, and needs space, but it allows a lot of flexibilty in the trade-off between amplification and output impedance.

Unnecessary amplification adds distortion, so your idea of attenuating the signal falls down there too, I'm afraid.

Ian

[ClefChef]

Behringer AKM DAC is a balanced signal voltage output DAC, I would suggest using something like Broskie Cathode Follower that would take advantage of that balanced signal.
Most Lampizator single tube designs look somewhat questionable, makes me wonder if he does actually produce the schematics he posts on his site. His anode follower layout drawing for Behringer dac is plain wrong by the way - Right signal inputs go straight to the ground...