You will use higher voltage for 50ohm load???
Then you will have drain resistance around 10-11ohms...
I will test a 50ohm load also...
great you like the sound with the thick film resistor..
when you will have some times with the SIt try to change the 2 computer grade power Caps with Evox Rifa or any lower esr aluminium caps..
what values did you try/use/prefer ?
I'm still messing with the basic cct
Thinking the 4 pole 33000uf Mundorf M-lytic HC+ might be a good alternative
Mundorf M-lytic HC+ Capacitors homepage
i use one RIFA PEH200 22000UF and 47000uF 63V on each side.
the mundorf mlytic have the same spec and are smaller to fit , i like both even as output cap
Interesting juanitox ,where did you manage to get the PEH200's ?
The PEH169 also looks good
Bypassed Source Res??
Hi Juanitox!
I tried the solution with the bypassed Source resistor - where I used a 10volt/0.22 Farad Nec capacitor. At the same time I changed the 47 ohm Gate resistor to a Amtrans(earlier it was Metal Film). And the soundstage grew somewhat bigger and a little more clear - BUT the voices and the music grew much too sharp, edgy and tonally very unpleasant. Nearly as sharp as when I tried a relatively middlepriced loudspeaker-cable.
I also use Amtrans in the signal-chain on my B1 Buffer. And I use Allen Bradley on the Sowther Trafo on the Direct SC3248Dac.
When I removed the Nec bypassed Cap, the edgyness disappeared and my Alp12P was back to that fine state of very transparent displaying of the musical content of everything I throw at the chain - and without my ears/wife being bothered with sharp sound and music.
So my experience is opposite to you - with my chain of electronics - Dac w/trafo and Carbon Resistor - B1 Buffer w/Carbon Res - LÀmp w/Carbon Res, AND no Bypassed Source Resistor. Clear and distinct sound with no edginess, and Solid State.
But to this I will add: I think I found a good speaker to make the Alp`s sing beatiful!
Best
Olav
in fact with a SS preamp i prefer bypassed source resistor version and with a tube preamp with output coupling cap i can go with battery on source which i prefer to LM317 bias module.. but anyway this sit is a keeper .
potting the 193V is a cheap but fine upgrade
Hi Juanitox!
I tried the solution with the bypassed Source resistor - where I used a 10volt/0.22 Farad Nec capacitor. At the same time I changed the 47 ohm Gate resistor to a Amtrans(earlier it was Metal Film). And the soundstage grew somewhat bigger and a little more clear - BUT the voices and the music grew much too sharp, edgy and tonally very unpleasant. Nearly as sharp as when I tried a relatively middlepriced loudspeaker-cable.
I also use Amtrans in the signal-chain on my B1 Buffer. And I use Allen Bradley on the Sowther Trafo on the Direct SC3248Dac.
When I removed the Nec bypassed Cap, the edgyness disappeared and my Alp12P was back to that fine state of very transparent displaying of the musical content of everything I throw at the chain - and without my ears/wife being bothered with sharp sound and music.
So my experience is opposite to you - with my chain of electronics - Dac w/trafo and Carbon Resistor - B1 Buffer w/Carbon Res - LÀmp w/Carbon Res, AND no Bypassed Source Resistor. Clear and distinct sound with no edginess, and Solid State.
But to this I will add: I think I found a good speaker to make the Alp`s sing beatiful!
Best
Olav
Attachments
Some missing words in post...
Hi all!
Some statement that was wrong in my last post - the last line should read: I think I found a really Good SpeakerCable to make the Alp12P sing beautiful with the L`Sit Amp!
And I have made the cable run straight to the driver - with no BindingPosts on the back of the speakers.
Best
Olav
Hi all!
Some statement that was wrong in my last post - the last line should read: I think I found a really Good SpeakerCable to make the Alp12P sing beautiful with the L`Sit Amp!
And I have made the cable run straight to the driver - with no BindingPosts on the back of the speakers.
Best
Olav
hi olav, i have now a 26 DHT preamp with output cap and now use a 4V cell battery as Bias with my sitamp ... but from the time i used a bypass cap and douce resistor i didn't notice any hardness in the sounds but i was using a 47000uf mundorf mlytics in this place..
anyway you have a fantastic looking wooden case for your sitamp !!!
cheers
rohan
anyway you have a fantastic looking wooden case for your sitamp !!!
cheers
rohan
Yes Vdi_nenna and juanitox...
Hi both builders of fine audio gear....
I used the Nanotech(silver/gold layered) diy cable-kit from Jaguar-design, and it gave a very audible and warm displaying of the music when I changed from some self-made silvery/copper(also good) - bought from EBay! the silver could also sound some cold at times!
Yes Juanitox - my boxès for the SIT was nearly as ordered(they were made for 3 liter wine-box), and I fixed and strightened them somewhat so they could stand the 400 watt trafo + some electronic and such! Ended up stuffed - and I don`t want to show the inside - even if it is fairly orderly and safe - it is STUFFED. Some Heat-sink also.....
I think I will build a new pre-amp, so I have not moved the Nec-cap fully out(disconnected) - and will make a LDR - based pre-amp from Tortuga(probably) in the autumn. So I will try it again.
But the sound is again harmonius and revealing AND without the roughness that the Caps was displaying(or maybe they should have some more run-in time????)
But the sound with Carbon is my preferance on The Sowther Dac-The B1 an The L`Sit!
Best
Olav
Olav
Hi both builders of fine audio gear....
I used the Nanotech(silver/gold layered) diy cable-kit from Jaguar-design, and it gave a very audible and warm displaying of the music when I changed from some self-made silvery/copper(also good) - bought from EBay! the silver could also sound some cold at times!
Yes Juanitox - my boxès for the SIT was nearly as ordered(they were made for 3 liter wine-box), and I fixed and strightened them somewhat so they could stand the 400 watt trafo + some electronic and such! Ended up stuffed - and I don`t want to show the inside - even if it is fairly orderly and safe - it is STUFFED. Some Heat-sink also.....
I think I will build a new pre-amp, so I have not moved the Nec-cap fully out(disconnected) - and will make a LDR - based pre-amp from Tortuga(probably) in the autumn. So I will try it again.
But the sound is again harmonius and revealing AND without the roughness that the Caps was displaying(or maybe they should have some more run-in time????)
But the sound with Carbon is my preferance on The Sowther Dac-The B1 an The L`Sit!
Best
Olav
Olav
these are "memory caps" , so - having sissy current capabilities , absolutely inadequate for task