Tubed CCDA I/V Amp for TDA1541(A)

[Radioman62]

Protection diode

Hi ide2003
The diode is there as a protection for the second section before both triode sections of the tubes have been warmed up and all voltages has settled .

It will do nothing under normal work but it will pass trough any large positive voltage on the grid of the second triode section to the cathode, if that should occur under upstart. You don't want positive going grid. Not good for tubes.

It's not critical at all which diode you use. Anything taking some more current then 1N4148 will do.

I see I also forgot to put that diode in the last updated schematic. I will update it promptly.

So, now It's updated on page 2 post#18. Refresh your browsers. This time it became 1N4004. Doesn't matter because it's not in the circuit at all under normal condition.

 

[ide2003]

Hi Radioman, thanks for your reply and explanation...whew..but please check it is your CCDA under counstruction

 

[Radioman62]

Hi ide2003

Nice to see someone try it out. But I hope you got it about using ECC83 and equivalents. Latest update on that is on my homepage. I also didn't investigate the sweet spot for loading when using that tube (the trimreistor after the output capacitor) You don't need it anyhow, it's just for getting the most out. Some people maybe not like the sound to be to clean. A little "tube coloration" with a nice -60dB second harmonic THD could be sweet sounding My ECC83 testings had some texture that now is gone with the crystal clear E88CC setup.

So in your case, stick to the paper sketch on the startpage but the "second approach" without PSF and choose the I/V resistor that suits your DAC. The filter I recommend in my own, "final", schematic you could use as an addon if you like.

I guess I have to structure up my homepage later on. To keep things separated more. The DAC I modify, The CCDA project and the testpage.
If I only had more time and if I only could be doing this full time ... That would have been great.

 

[ide2003]

Hi Radioman, yup, I have here ECC83, this should be compatible with 12AX7 isn't? it is also my goal to have a not so tubey sound, since this CDP going to LM1875 .

Right now, the I/V R is around 100ohm (with a trimpot), no filter yet, still not finalized, difficult to judge the sound with such low Vout..guess have to wait till the tubes are there ..thanks again Radioman for your help & nice informative website..I'll update this project..

 

[ide2003]

hi all, yesterday evening, the CCDA on denon finally sings..very well that is, first impression : I like the fresh mids-high and meaningful bass..here are the pics..Radioman..wish you was here in my garage then ..thank you very much. I'm now AB-ing both SRPP TDA1541 and CCDA PCM56 on my main system

 

[Radioman62]

Hi ide2003
Looks really nice. Seems you have the garage on your own. Thats a good thing.

The setup with the plexi design looks really cool

 

[samoloko]

I like to know what are results from comparing Radioman cda tube stage with op amps outputs and other alteratives

 

[ide2003]

hi all & Ove, sorry for very late reply..I did comparison-SRPP on Sony and CCDA on Denon..and samoloko..guess what? I've changed the SRPP to CCDA on my sony..just my personal taste..distorsion seems very low, I can hear piano damper sounds now from seating position (Inger Marie Gundersen-By My Self - track 13).

comparing with LM4562 seems interesting, but for me..its CCDA, sorry mr. Fikus, its just so hard to find sweet spot with 6N2P-SRPP

btw. Ove, that garage is now my DIY 'room'..no car

 

[codon]

HI Radioman62 I did try the ccda way,but the bass seem not punch like the SRPP way,so any way could you show me to make the bass stronger? I use 1 TDA1541 DAC.Thanks.

 

[marconi118]

6N2P

can you use this setup with the 6N2P tube?

any resistor value to change?

 

[ide2003]

it can, mine is 6n2p, run them at 1.3mA, forgot the actual Rk values though, I've put trimpot there , I think its similar to Ove's first scheme

 

[viki_v2]

Hello Sir,
I am interested in doing this project, kindly share details.

 

[ide2003]

Hi viki, I have changed my tube to 6N2P-EV, so if your tubes are the same it's ok, will post R values here. check out Ove's site as well. What CDP you planned to mod?

 

[viki_v2]

Hi viki, I have changed my tube to 6N2P-EV, so if your tubes are the same it's ok, will post R values here. check out Ove's site as well. What CDP you planned to mod?

I dont have any CDP as yet, But plan to purchase any used one .

 

[ide2003]

ok viki, just post here when you got your CDP. Mind you though, this CCDA does have quite a bit of gain. So look for CDP with current out DAC. I have good experience with Denon DCD5xx, look for CDP with PCM56, PCM61, PCM63 Dac, or of course TDA1541, TDA1543, AD1865 etc.

 

[Trident]

Hi Radioman62,

I´m building the analogmetric TDA1541A DAC, and i would ride the same circuit: Fast switching between OP amps or tubes

You can send me the PCB layout?

Greetings from Spain

 

[Radioman62]

Hello Trident
The prototype PCB layout had errors which I had to manually fix.
I will not update it and I havent even finished the project all trough yet.
I will tell you all redaers here when I have a working unit alltogether.

But there will never be any PCB layouts from my project here. Sorry. I don't have the time and in my age you begin to fade away when it comes to manage the tempo in life ;-)
To many things around me and to little time. Life is to short etc.

Happy building and a great hobby it is.

 

[Trident]

Hello, Radioman 62

Thanks for your reply, expected on the other hand, has given me encouragement to start my own project ...

Employ the first stage I/V with OPA627, correcting previously operating input voltage from the TDA1541A to null offset, and then correcting the output of the operational equally to null offset, attacking an NOS 6N1EB valve with very low noise and distortion directly without the use of coupling capacitor.
I am preparing the PCB layout for it.

I think replace the TDA1541A mounted for other TDA1541A S2 (double crown), purchased from a reputable supplier in the Netherlands, from a former player.

I will try to document my progress...

I share your thoughts on the brevity of life. Many times I've had, and I feel like time slips away every day of my life ...

But sometimes these projects in which we find ourselves make our lives are a little more full ... I like the idea of going a little further (Plus Ultra).
In old maps when the known ending was coming down .... "find dragons beyond," I like that idea
_______________________________________________________________________________________

Your project will be as good as the worst component mounted.

 

[niamex]

Hello, Radioman 62

Thanks for your reply, expected on the other hand, has given me encouragement to start my own project ...

Employ the first stage I/V with OPA627, correcting previously operating input voltage from the TDA1541A to null offset, and then correcting the output of the operational equally to null offset, attacking an NOS 6N1EB valve with very low noise and distortion directly without the use of coupling capacitor.
I am preparing the PCB layout for it.

Hi Trident,
Will you please share developments of the project ?
Thanks,

 

[Trident]

Hello, I will try to post pictures of the progress of my project.


This is the main PCB on which the project start, is of good quality, and not contains any design errors.