Have you tried without transformers at all ? I have tried the Cinemags , and the Sowters, and prefer none of them.
The Cinemags is not so clear and dynamic as the Sowters.
Before my dac get the last upgrades from Iancanada, i used the Sowter trafos that doede douma sell, and was very happy. I liked the punch theese creates, and still do, but no transformers today.
The Cinemags is not so clear and dynamic as the Sowters.
Before my dac get the last upgrades from Iancanada, i used the Sowter trafos that doede douma sell, and was very happy. I liked the punch theese creates, and still do, but no transformers today.
Thanks for your reply. No, I have only tried the DDDAC with transformers. May I ask why you prefer a transformerless solution? Do you still have the Sowter transformers that Doede Douma sells? I might be interested in buying them.
Yes, I have the doede Sowters. My setup has a lot of power. The Sowters has 1:2 output, and therefore much gain. We have all different setups and taste, so maybe Sowter is for you.
Hello,
For those people living in France and using a DDDAC with 4 boards.
There are some Lundahl LL2771 3H 1A on ebay by someone living in Bordeaux. He only wants to sell them in France otherwise i would have bought them.
If you wire the two coils in parallel ( it will reduce total DCR to 2,8 ohm ) you could also use them in some Hiraga or Nelson Pass power amp designs.
Greetings, eduard
For those people living in France and using a DDDAC with 4 boards.
There are some Lundahl LL2771 3H 1A on ebay by someone living in Bordeaux. He only wants to sell them in France otherwise i would have bought them.
If you wire the two coils in parallel ( it will reduce total DCR to 2,8 ohm ) you could also use them in some Hiraga or Nelson Pass power amp designs.
Greetings, eduard
Attachments
From the datas LL2771 is power supply choke?
It is not designed to use as signal transformer.
Yes it could be used as transformer - but it is the power supply choke.
And yhe inductance of 3Hy is given for the coils in series.
So the individual coil is 1.5Hy.
Maybe it is not suficient for the good LF BW?
Please try to clculate Fo within the source internal resistance value.
That will be the output impedance od DAC or paralleled DACs...
cheers
It is not designed to use as signal transformer.
Yes it could be used as transformer - but it is the power supply choke.
And yhe inductance of 3Hy is given for the coils in series.
So the individual coil is 1.5Hy.
Maybe it is not suficient for the good LF BW?
Please try to clculate Fo within the source internal resistance value.
That will be the output impedance od DAC or paralleled DACs...
cheers
Hello,
Sure it is a power supply choke!
I use it myself too for a choke input power supply for the dddac
Also use it for Roon Nucleus power supply, for Virtue sensation m901 integrated amp and for raspberry pi3 power supply.
My friend uses it in Hiraga 20 watt power amp CLC power supply.
Greetings,Eduard
Sure it is a power supply choke!
I use it myself too for a choke input power supply for the dddac
Also use it for Roon Nucleus power supply, for Virtue sensation m901 integrated amp and for raspberry pi3 power supply.
My friend uses it in Hiraga 20 watt power amp CLC power supply.
Greetings,Eduard
In that case - ecellent 🙂 use as in the + branch and in the ground line too, as in the last recommendation note picture in PDF?
ofcourse - it is overkill for dac supply...
I mismatched somehow that is aim to use as the line transformer - sorry 🙁
cheers
I used the Sowters for many years. However, I honestly never needed the voltage gain. I am now using some high quality caps for AC coupling of the balanced (!) DAC output to the preamp, and I am not looking back.
Just for information for the DDDAC Fans. I just posted an article of my Moving Coil Pre Preamplifier.
to the article on my blog site
to the article on my blog site
Hello.
I went from big transformer and not so big choke ( ll2733) to a smaller transformer and a bigger, much bigger choke. From 525 mH to 3000mH. Dcr is of course higher but current draw from Dddac is rock steady because of Tent shunts so i dont think it is a big issue. But you will need a transformer with a much higher ac . With 4 boards close to 30 volt ac for choke input wired as pictured on the bottom of the Lundahl pdf. Greetings Eduard
I went from big transformer and not so big choke ( ll2733) to a smaller transformer and a bigger, much bigger choke. From 525 mH to 3000mH. Dcr is of course higher but current draw from Dddac is rock steady because of Tent shunts so i dont think it is a big issue. But you will need a transformer with a much higher ac . With 4 boards close to 30 volt ac for choke input wired as pictured on the bottom of the Lundahl pdf. Greetings Eduard
Lots of parts in parallel! Typical Doede 🙂
I wonder if 10x input JFETs don't present (too) much gate capacitance for the MC cartridge, though.
Why not use a single low-noise Toshiba SJ74/SK170 JFETs instead to get low noise?
LOL, yes parallel worked for me always 😉 Without going in all the background calculations for the topology I wanted, these were best fit. Ciss is 10pF so adds up to 100pF even if it was 1nF, together with a load of let’s say 100 Ohm for the MC cartridge, we are still looking at MHz range of influence. For MM input capacitance would matter, not for MC generally spoken. The fact the are B and C versions, made the design pretty straight forward. That is, in terms of the CCS on top of the VCCS.
Anyway, we could continue the discussion (thanks for feedback) on the analog source section, where I opened a thread for this, hoping to get some discussion going
Hello all, I've been using 12VDC super regulators in place of 7810s on the analog side of PCM1794 chips (I have one single dddac board and blue motherboard) with external psu with no issues so far and good results.
A couple of questions:
- would it be better to lower their output to the tent shunt inputs to 10VDC and is 10VDC optimal or... ?
A couple of questions:
- would it be better to lower their output to the tent shunt inputs to 10VDC and is 10VDC optimal or... ?
I have some V4.4 boards. What version are the current boards and are there any significant differences compared to V4.4?