You don't need R1 & R2, then just for setting the regulation for LM317. No need to jumper. Just use the input & output hole for the new out board regulator. You can use the Adj. hole for the new regulator grounding point. Remember to disconnect the track (dac board) from Big lyic caps to the regulator if your new regulator has its own power caps and rectification like Rysen said..
Thanks for your help on this Bill. I've just connected an LED across the solder blobs under the board for one of the red LEDs but it's not oworking. Sorry to ask such basic question but what voltage LED should I use? I suspect the one I've used is 12V.
If it is a "12V" LED, it has a built in resistor and is not sutable for this circuit.
In general, LED have forward voltage drops between 1 and 3 volts depending on color and process technology. If you look it up, there is a polarity standard that matched the internal construction.
Here is the first hit I got Shedding Light on LEDs
or Light-emitting diode - Wikipedia, the free encyclopedia
Doug
Dear All
I recently bought a Gigawork dac with upsampler, since I believe this kit has potential I searched the web and finally ended up into this thread. Very interesting stuffs.
I tried to go over all post but it is almost impossible to keep track of all mods that have been proposed here. Please, forgive me if I am asking for something that have been already discussed before.
I would like to try to add a signal transformer on the output as extensively suggested here. It seems that there have been a lot of experimenting. Based on what I read it seems that there are three top alternatives: Lundhal LL1690, UTC HA-108 and Tamura. I am now considering to buy one of those trafos.
I would like to understand the differences between them, the latter may have been discussed in previous posts, in that case I must have missed it.
Best Wishes
Keph
I recently bought a Gigawork dac with upsampler, since I believe this kit has potential I searched the web and finally ended up into this thread. Very interesting stuffs.
I tried to go over all post but it is almost impossible to keep track of all mods that have been proposed here. Please, forgive me if I am asking for something that have been already discussed before.
I would like to try to add a signal transformer on the output as extensively suggested here. It seems that there have been a lot of experimenting. Based on what I read it seems that there are three top alternatives: Lundhal LL1690, UTC HA-108 and Tamura. I am now considering to buy one of those trafos.
I would like to understand the differences between them, the latter may have been discussed in previous posts, in that case I must have missed it.
Best Wishes
Keph
Hmm, I've seen many more posts about the UTC A-20s than the HA-108. But honestly I think the consensus would be that they all perform admirably with minor differences - but then it all depends on what filters you use as well on the primaries, etc. I'm sure. It's a rabbit hole. In terms of sheer word count, the LLundahl and the UTC A-20 get the most kudos.
Another transformer discussed is the jensen JT-11P-1 which I installed on my DAC. I used the primary and secondary filters as per jensen documents AS089 and AS093. I am very happy with them.
Same here.
If bass is your thing the A-20s won't disappoint.
If you're on a tight budget Edcor's are dirt cheap
If money is not an object you can check out the Lundahl LL1690.
Some Tamuras are nice but could be hard to come by.
Is the UTC much better than Lundahl LL1690 in the bass region? On a scale from 0 to 10, how would you quantify the difference.
And what about other paramaters (dynamic, midrange, highs, depth etc)?
Best
Kehp
I can vouch for the A-20's they are very good in the whole musical range not just bass. However they are becoming hard to find in good condition. There's probably not many people who have heard both the Lundahl's and the A-20's comparatively.
Also worth considering:
Lundahl LL1527 have some praise here and are cheaper than the LL1690
Cinemag CMOQ-2H - Supposed to be very good indeed.
Also worth considering:
Lundahl LL1527 have some praise here and are cheaper than the LL1690
Cinemag CMOQ-2H - Supposed to be very good indeed.
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what I should be careful about to make sure they are in good conditions. I have seen some on the iternet but I couldn't say whether thy are in good conditions.
Keph
Hi Keph
Try and find a supplier with NOS (New Old Stock) transformers that are unused. Alternatively source some used but tested and matched pair.
This supplier has some good audio transformers. You want 1:1 (600:600 ohm) ratio.
Audio & Interstage Transformers - Hermetically Sealed - Low Impedance
The way I feel about this DAC is that at the end of the day it is a 'budget' kit. We are trying to squeeze the most and highest quality performance for as little as possible - directly proportional to the cost of the DAC. If you spend £400 on Transformers you might as well buy a very high end kit such as the Buffalo or other expensive ebay kits or even one of the excellent custom kits avaliable on this forum.
However you pays your money, it's only my opinion. No offence intended Keph.
Rich
Try and find a supplier with NOS (New Old Stock) transformers that are unused. Alternatively source some used but tested and matched pair.
This supplier has some good audio transformers. You want 1:1 (600:600 ohm) ratio.
Audio & Interstage Transformers - Hermetically Sealed - Low Impedance
The way I feel about this DAC is that at the end of the day it is a 'budget' kit. We are trying to squeeze the most and highest quality performance for as little as possible - directly proportional to the cost of the DAC. If you spend £400 on Transformers you might as well buy a very high end kit such as the Buffalo or other expensive ebay kits or even one of the excellent custom kits avaliable on this forum.
However you pays your money, it's only my opinion. No offence intended Keph.
Rich
I personally haven't had the chance to compare the LL1690 with the A-20 but from what others have stated I would say the LL1690 and the JT-11P-1(which I own) have better balance than the A-20s and still provide plenty of bass.
I think the A-20s are OK if you can get them for a decent price like I did but the bass may prove to be a bit much in certain systems. It's a question of taste - I sold mine.
I haven't heard the LL1527s but I believe Linn is using the LL1527XX in their top of the line servers. I had a chance to listen to one of those at the Montréal audio show last month and it sounded very nice. I also tried Cinemag CMOB-2L with 50/50 cores. I found them way too dark for my tastes however I'm confident that would not be the case with some of their other models particularly those with 80% nickel cores.
I think the A-20s are OK if you can get them for a decent price like I did but the bass may prove to be a bit much in certain systems. It's a question of taste - I sold mine.
I haven't heard the LL1527s but I believe Linn is using the LL1527XX in their top of the line servers. I had a chance to listen to one of those at the Montréal audio show last month and it sounded very nice. I also tried Cinemag CMOB-2L with 50/50 cores. I found them way too dark for my tastes however I'm confident that would not be the case with some of their other models particularly those with 80% nickel cores.
yes you are right, vintage stuffs is often nice but it's always risky to buy unless you can test before to buy.
Surfing further the web I came across the K&K Audio website and in there is a projects section, I found this link:
Kevin's CS4397-based DAC
This guy uses the LL7902, know being not expert in transformers I ask myself what's the difference with the LL1690
Cheers
Keph
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But the big caveat is that everything else in the chain has their influence. What may sound dark/bassy/detailed, etc. on one system may sound neutral/bright/bassy/warm, etc on another due to the speakers, amp, preamp, etc and vice versa and so on... right?