Experience with this DIY DAC ?

What is your configuration with the JT-11P-1 ?

Just DAC to trafo and out to RCA. No C's or R's yet.
After that a tube preamp (6N1P) with a pot in front of 100k.
(Actualy a 39k series-resistor with the 100k pot after that from resistor to ground with the wiper connected to the resitor too. So no contacts in series!)
An other thing: The Jensen was a little light in the bass in the beginning, but after a couple of days, the bass is really strong.
 
Hello Michel

Already received your parts from Jensen ?
May be, you can omit the primary filter
And about secondary, it's just an "anti-resonnance", but if you have a load from your amplifier ~10k, you can omit also...
Depending on your taste, you can add after some listenings ...
Working for you about filtering 5v power ...

Richard
 
Be careful using those trafos without the secondary filter or a decent load(10k or less), they have tremendous bandwidth and the ultrasonics could roast your amp and tweeters. If you saw what I saw on the scope you wouldn't try them without, unless you have a tube rig.
The impedance is so high the dac chip doesn't even know the trafos are there, the chips should be happy as clams.
McCrackers, let me know how they stack up, I'm assuming you are still using upsampling.
 
Thanks for the replies.
I was planning on using them on my upsampling board. I have the above mentioned R&Cs on hand and should, hopefully, be getting the Jensens by the end of next week. I have a brand new amp so you can be sure that I won't be risking it without filter - especially with what Bill just wrote. :scared:
 
Is this all you hear or is there some music too?

If there is no music then there must be a wrong connection.
Could you send a picture of it?

Im getting music, its funny the buzz was just audible when there was a gap between songs or if volume was pushed up, but I left it on over night and now the buzz is much worse as in drowning out the music.
The traffos are not bolted to the frame just lying down for the moment.
 
I received the UTC HA-108 today

They are big and heavy transformers

I listened them for a short period of time and I can tell that the bass is terrific and listening piano reveals probably the best mids I never heard

More on that later

Last night I took the three dacs with different transformers to one of my friend's system ($$$$$) and we done some testing.

As soon as I will finish to compare the UTC to others, I'll give you the results (shootout)

So the shootout was partially done in two different systems with 4 peoples.

Here are the UTC monsters

message for Legarem
you explain how to connect the pins of the transformer UTC Ha-108.
thanks :D
 
As always, miss the obvious, lesson learned

Recall that I had problem with my dac that simply distorted. The severity varied from different opamps, but none was bug free. Of course, the SQ was never even close to what I read from this thread.

To make a long story short, I measured everything that were suggested with one exception, the opamp voltage, because opamp can operate from a wide range of voltage. It couldn't be way off.

It turned out the -ve voltage was way too low - measured only -3.34VDC!! The ne5534 needs a minimum of -5V, and the opa2134 needs -2.5V. No wonder why the opa2134 sounded less severe than the NE5532. It was clipping on the -ve rail all the time!!

If I did 1 of 2 things first, I could have reduce my stress level of the last 2 weeks with this dac:
1. Gone transformer right from the beginning (my bad, never spent time to
take the Edcors out from the Buffalo 24), or
2. Measured the opamp power supply

Lesson learned, even the most obvious need double checked when it comes to trouble shooting :eek:
 
Hi
I search on eBay for a DAC and I see that this DAC for a few dollars more you can receive it with CS43122, anyone try it? (I have the version without USB input) It works better then CS4398, I see also available a PCM1793 but this converter I think is not superior to CS4398.
If some one have information about this upgrade please inform us.
I would like also to know how big is the signal level in V rms at 1 kHz with output transformers.
Thanks
 
Well I wired up my newly arrived Monacors today and it looks like one is a duff.

Output is fine from both DAC channels through the functioning tranny and I even swapped the RCAs to eliminate them.

What are the chances of a duff transformer? Am I missing something?

Andy

You can check the bad one with an ohmeter. If they are 600ohms they will read about 30-60ohms DC resistance.
 
Hi
I search on eBay for a DAC and I see that this DAC for a few dollars more you can receive it with CS43122, anyone try it? (I have the version without USB input) It works better then CS4398, I see also available a PCM1793 but this converter I think is not superior to CS4398.
If some one have information about this upgrade please inform us.
I would like also to know how big is the signal level in V rms at 1 kHz with output transformers.
Thanks

The signal level depends on which DAC chip you have and what trafos you are using. 2VRMS from a 4398 through a 1-1 trafo gets you 2VRMS, 4397 is less, use a 1-2 trafo you get more. I don't know anything about the 43122. You can also use a PCM1796 if I'm not mistaken. I use upsampling and I love it, very organic.

Best, Bill
 
Jensens arrived today(already) First listening impressions: It's a bit late to crank up the volume so I'll have to wait 'til tomorrow to better evaluate them but I think it's safe to say that the trafo hunt is over. Like GerardA said - I can't see it getting any better than this.

One small disappointment is that, like the Tamuras, I'm still getting some hum. I thought the fact that these are shielded would solve the problem - but no. For some reason it's slightly worse with the DAC's power turned off. Black/white trafo wires are not connected to anything for now.
Any suggestions?

Also - I though I had some 13Ks on hand for the secondaries but I could only dig up some 12Ks.
Is it safe to leave it as is or should I add a 1K in series?