193L in a Modded DAC-AH..

[lucpes]

Just my 2c - most times, mains filtering using a cheap common-mode choke with 2 polypropylene capacitors forming a PI-filter (low value, say 0.047uf) helps a lot on digital and/or line-level applications.

 

[Puffin]

I am thinking of changing the op-amps in my Dac Ah. Are the stock ones fitted in the factory single or dual op-amps ?

 

[lucpes]

I am thinking of changing the op-amps in my Dac Ah. Are the stock ones fitted in the factory single or dual op-amps ?

Single opamp. At least in mine it's the OPA602, which has a similar sonic signature to the highly regarded OPA627. Taking into account the fact that OPA602 is better at driving capacitive loads than the OPA627 I would leave those in place as they are. Better change the output capacitors, that's where most of the sound quality is lost in the first place.

 

[singleended40]

By-pass the opamps

I have tried to replace the output caps with two 100K resistors. The sound was better than the stock unit but compared with bypassing the whole buffer stage(opamps) I think it is much better way since the more simple circuit makes the better sound.

 

[Puffin]

The stock op-amps in my dac are not BB's and are some obscure make and number.

 

[singleended40]

Modded Lite Dac Ah

The stock op-amps in my dac are not BB's and are some obscure make and number.

Hi Puffin,

I think you do not want to waste your money to purchase the BB Opamps 627BP (the best opamps sofar) and also two coupling caps and two resistors 100K @ output stage. Like I mentioned before the best way to mod is two(2) Auricaps 2.2uF/200V @ output stage by bypassing the buffer stage, two Auricaps 0.47uF/600V and Hammond choke 193L @PS and IEC. The sound in my system right now is getting better and better. Good luck.

Tan.

 

[Puffin]

Tan. Thanks for your reply. There was a long thread on the headfi forum about modding the DacAh. Is the modification you are talking about the "passive" mod whereby the active stage (the op-amps) are by-passed ?

 

[singleended40]

modded lite dac ah....

Puffin,

I have tried other headfi mod version and that version did not sound good enough to me as this mod version of JANDG in this page. You might email him some more details about it. JANDG is a nice and knowledgeable gentleman and will answer any questions right away.

I have modded my DAC AH with his version and had tried NOS caps as Gudeman, Sprague Vit. Q and Westcap caps. The oilers give you a nice soft musical sound but not as good as Auricaps as metallized polypropylene caps, which have more details, real open-up musical and more energetic -I mean strong punchy- sound (in the third day caps breaking-in usually 100 to 200 hours and a week 193L choke break-in too). I also replaced Furutech IEC and two Sprague Vitamin Q 0.0015uF/100VDC @ C1 and C2 where two blue square caps were.

Besides this is not a passive mod @PS (as I understand using battery) and I use a DIY PC. Trust me battery PS is very quiet but you can not listen your music continuously unless you are using a huge battery or an expensive Odyssey or Optima battery (range of USD$150-$300).

Good luck on your mod but you will absolutly satisfy with the result.

Tan

 

[nicoch58]

hello all, look this mod

http://www.audiodesignguide.com/Headphone_opamp/theHeadphone_opamp.html

 

[vvs_75]

DAC-AH 193L choke mode . C1 & C2 caps Q?

C1 & C2 are .001uf Mundorf silver supreme's & the outputs by-pass caps are 2.2uf 450v Auricaps.. There is 2-.47uf 600v Auricaps across mains, as well as a Hammond 193L, I did lots lof listeniing with differant configuration on the power & this I like & have no want to change.. Acyually haven't even touched the DAC in a long while because it just makes me happy now, with all types of music. J & G

Hi J & G!

I wante to order parts to make 193L mode to my DAC-Ah and I am wondering if you remember why you chose 0.001uF replacement for C1 & C2 caps?

I checked the schematic and the C1, C2 caps are 103nF which is about 0,103uF. Are there any sonic benefits of chosen 0.001uF capacitors?

Also I found that the H version of 193 choke have almost the same spec. except it can take 600VDC compare to 800VDC on 193L. But it�fs cheaper and twice smaller!

Can I use 193H choke? What do you think?

Thank you for you time! I am really appreciating you help!!!

 

[JandG]

truthfully, I am not sure on the .001uf, It could be .01 ..I have not popped the top in almost a year, I will check it out this weekend & let you know about c1-c2..I am not sure about using the H...probablly would be o.k...what the L does in theory is complex as expalined to me by a EE audio nut,, but I am not qualified to say if the H would be safe to use..I will get the input cap value's for you this weekend..This Dac is extremely good in this form...my tube amp is .33v sensitive for full output @ 100K..just so you know..1.5v & up sensitive..amps will struggle with the low Voltage of the by-passed output stage..so then apre or best bet would be one of the tube output stages posted around the net..hopefully you can run it as I do ,,simple & I feel better,,clean, clean////

 

[vvs_75]

Thank you for the prompt respond!

Also your 193L choke is connected directly to the IEC so it always powered. May be it's better for me if I put it after the switch in parallel with 0.47 caps thus the choke can be switched off with the rest of the circuit.

Thanks!
Vad

 

[pulidzz]

WOW $2 mod!!!

I just finished doing the passive mod on the DAC ah. I used two 2.2µF 50V 20% Nonpolarized Electrolytic Capacitor 9,000Hz from radioshack (worth 99 cents each).

This mod really works. My stock dac ah was using a pair of EL2044 op amp. I am not familiar with the said op amp and I cant Google anything about it. Anyway I don't like the stock sound. The highs sounds distant and rolled off, the mids kinda too in front of the sound stage and sounds muffled and congested at times, the bass is punchy but sounds like its rolling off too early. Something just doesnt sound right when listening to the sound of an electric guitar on rock recordings. With the Radioshack caps, I can hear improvements already (I cant wait to some 1% tolerance Dayton caps in this mod). Thanks JandG for the help!

BTW, can anyone tell me what's the positive and negative wires of the Auricap and Dayton caps? I just dont want to solder them incorrectly. Again, thanks!

 

[JandG]

With Auricap it is signal into Black lead & out Red lead, but doesn't really matter as far as damage to anything. try eaither way it does not matter. Also w/ the Dayton, you can put it in there anyway you want to, & will work fine.

 

[jeffdavison]

update on promised info?

JanfG.

Have you ever gotten around to popping the cover of your Dac AH to see what the values of the Mundorfs are in the C1 and C2 position? Mundorf doesn't make a .001 capacitor.
Also, where did this mod originate? What is the purpose and function of changing out these caps? Why specifically Mundorf Silvers? Can you tell me if any other good capacitor (Hovland, MIT, Vcap etc) would be acceptable in place?

Thnaks

JD

 

[kennykong]

hi, im new to DIYAUDIO and a beginner! Im very very interested in the LITE DAC MOD posted and i will definitely gonna try on my dac ASAP! Just to confirm, does this mod sttill need OPAMP to work? I have seen mods that no longer need op amps anymore! And whats the difference? Thanks alot for clearing my doubts!

 

[kennykong]

and how you guys determine the value of coupling caps? thanks!

 

[JandG]

Jeffdavison,
The M-cap silver supremes are a pair of 0.01uf caps. I just poped the top & looked, sorry for the wait.
Joe

 

[kennykong]

hi janG, i just followed your recomendation and hooked up Auricaps and a choke , and the sound is much better than op amp! thanks alot for sharring. I havent replaced C1 and C2 yet. and i plan to replace caps near Toslink too, since im using optical. You think it will make much difference? Thanks.

 

[kennykong]

btw, have u tried modding using tube output?