Hi
I will take one step at the time,,,so i am starting with the supply
waiting for component for the Salas DCSTB ,have also ordered 2 pieces 18v 80va trafo from Poland
latest thing i tried was to use Copper cable instead of my normally clean silver cable from pre to amp
it gave more difference to the sound of what i have expected,,,from a little thin but very good and clean top,with the silver,,,,to a more bold and warm sound from the copper
must wait and see when the supply are finish
have also ordered other opamp,,,
will the sound from the opamp in the servo , be more or less the same sound if the opamp are used in a normally way
then i will think the opa2134 will be the wrong choice ,,it is a boring sounded opamp
newer heard the TLE2072.. must try
Best Bjarne
I will take one step at the time,,,so i am starting with the supply
waiting for component for the Salas DCSTB ,have also ordered 2 pieces 18v 80va trafo from Poland
latest thing i tried was to use Copper cable instead of my normally clean silver cable from pre to amp
it gave more difference to the sound of what i have expected,,,from a little thin but very good and clean top,with the silver,,,,to a more bold and warm sound from the copper
must wait and see when the supply are finish
have also ordered other opamp,,,
will the sound from the opamp in the servo , be more or less the same sound if the opamp are used in a normally way
then i will think the opa2134 will be the wrong choice ,,it is a boring sounded opamp
newer heard the TLE2072.. must try
Best Bjarne
Changing supplies one after another will shift your tuning base and may upset your up to now tuning ways. Plus a couple of days power-on time is needed for any first time used electrolytic to chemically come up in full. On the other hand its a learning compass, when not hasty to finish, and opens up further your personal research window of best subjective synergy possibilities within a specific audio system.
The servo drives a 10K resistor that goes to the feedback point. And through that it dynamically DC shifts the output in a counter offset manner. Whatever little imprint of its transfer function and own noise it can add there is surely less audible than capacitor coupling this preamp, I have compared that. The chips don't work in their usual experienced manner there but as an integrator. In the concept of your system synergy you may find rolling them both different than expected and rewarding as yet another detail tuning element in your arsenal. At least its a very easy evaluation to perform. No disassembly no soldering rework no expensive parts. I would suggest you try the 2134 too without prejudice.
The servo drives a 10K resistor that goes to the feedback point. And through that it dynamically DC shifts the output in a counter offset manner. Whatever little imprint of its transfer function and own noise it can add there is surely less audible than capacitor coupling this preamp, I have compared that. The chips don't work in their usual experienced manner there but as an integrator. In the concept of your system synergy you may find rolling them both different than expected and rewarding as yet another detail tuning element in your arsenal. At least its a very easy evaluation to perform. No disassembly no soldering rework no expensive parts. I would suggest you try the 2134 too without prejudice.
You will dial in the preamplifier to your system exactly as you prefer in the end, no doubt. That's the magic of doing it yourself. Especially when tuning in a big speaker big sounding system environment like yours takes more patience. As for cables its a highly controversial subject unless there are pF and nH influential differences at play there, but you are not doing lab research, so have fun. Its a hobby and fun is the core purpose of any hobby after all.
Yes cable are hard to explain ,,,but my cable is diy ,so the price is not insane ..only my speaker cable is not diy,,price about 2000usd,,new price i gave only 500usd used, so it was cheap
just make pass aleph 1.7 diy pre ready for my brother,,it plays good,,but it is not a Salas pre
i like to have many good hours, to make the Salas pre sound in the right way
just make pass aleph 1.7 diy pre ready for my brother,,it plays good,,but it is not a Salas pre
i like to have many good hours, to make the Salas pre sound in the right way
As long as you pay little and you go for different geometry and different shielding cable constructions to try, some parameters like RFI or rise time may get influenced to a degree and to no financial hurt. As for the whole pre itself in the course of changing your pots and psus and chips you should feel your winning subjective mix in your own system right away when you hit it.
Most all items are delivered now (except the final heatsink).
I was so impatient that I bought heatsink (not really the right one) in a local store because I wanted to test my build.
Everything works, offset is fine and the DCG3 sounds good. I just have to test a little bit more and decide wether I should increase the gain about 6db. Could be a little bit more of power for my DT1990 Pro.
I was so impatient that I bought heatsink (not really the right one) in a local store because I wanted to test my build.
Everything works, offset is fine and the DCG3 sounds good. I just have to test a little bit more and decide wether I should increase the gain about 6db. Could be a little bit more of power for my DT1990 Pro.
Attachments
My source is a soekris dam1021 using the raw output, controlled by audiozen OLED Kit. Due to the kit output ist limited to 0db. When using the soekris normal pot +10 db are possible.
I‘ll try 1.5k for R6 to get 4x gain or is 2.2k possible to get 5x gain without clipping in frontend of DCG3?
I‘ll try 1.5k for R6 to get 4x gain or is 2.2k possible to get 5x gain without clipping in frontend of DCG3?
Regarding the Soekris' analog output, you'd better plan your gain structure assuming that it outputs 1V RMS, since a bunch of the better custom filters include some volume reduction to protect against inter-sample peaks that might result in clipping.
Also, that +10db output option is practically useless since we're talking about digital gain. The resistor ladder is limited to outputting 1.4V RMS max (~1V RMS with the better filters).
Sorry for the OT..
The dam has 1.4V max at 0dBFS ? The preamp's input won't clip with that high signal but you have to remember you roughly got +/-17V rails. So a 34V envelope. Your input RMS max times gain tells you your output RMS. Your output RMS*2.83 must not exceed the peak to peak envelope your rails allow. Plan accordingly.
