[gfontes]

Pat, Where did you buy the tube buffer. There are several for sale on E-bay.

There also is a version w/a single 6DJ8 vs. the version (which I think you have) w/the two 6J1's. Do you, or anybody, know the difference besides the tube complement? I'm kinda hesitant to add anything into the signal chain but this sounds worth listening to.

Thanks

 

[tubes]

There's very little info out there comparing the 1 tube unit vs the 2 tube unit. I did find a comment that "the 1 tube unit is the latest and it is quieter than the 2 tube unit". Take this for it's worth, I can't find anything to confirm it.

 

[PatOMalley]

This is the ebay seller i got the Yaqin from: eBay Store - Canadian HiFi Online: Cables, Amplifiers Preamplifiers, Tube Buffer

Remove the input tubes. More air but some topend edge and breakup. Not a lot but enough to make piano seem crackled. Replaced the output tubes /w cryo'd 1uF Obbligatos from Bill. Thanks, Bill. And just asa described they have extension that holds together. Incredible.

But don't take the input caps out unless you change the output caps.

Tight fit. I got a nice pop when I touched the power rail. No smoke. All OK.

All this talk about the Yaqin buffer seems to have diverted attention from the DC-30W, which is unfortunate because dynamics and pace are far increased with it. The Yaqin provides HiFi. The DC power supply moves the DAC more along the vinyl sound, which was my original purpose for getting it. I feel like the power supply is running linear with the core sound. The Buffer is _doing_ something more than just coupling, which the CineMags were doing with aplomb. But the buffer does not do a great job stock - you have to change at least the output caps. Changing the input, as well, takes it to that next level.

Having heard the DC-30W I think you need both the power supply and whatever you choose to add at output.

It's getting so good it's creepy.

 

[PatOMalley]

I asked Michael why the 12v tap was not wired to the PSU board.

He tells me "Originally the yellow and blue wires are all wired to the PCB. The yellow wire is 12 V AC output and the blue wire is 9V AC output.
Because the voltage difference before and after regulation is large, the heat from the regulator is large dramatically. Especially for this high current output, the case is very very hot. Therefore, we only use the blue wire 9V AC for the PS.

Because of this R-core single routing, there is no difference between these two wiring methods.

...

The 2 voltage outputs were pulled serially from the same core. "

 

[hifi2001]

Quote:

Originally Posted by PatOMalley /img/forum/go_quote.gif I asked Michael why the 12v tap was not wired to the PSU board. He tells me "Originally the yellow and blue wires are all wired to the PCB. The yellow wire is 12 V AC output and the blue wire is 9V AC output. Because the voltage difference before and after regulation is large, the heat from the regulator is large dramatically. Especially for this high current output, the case is very very hot. Therefore, we only use the blue wire 9V AC for the PS. Because of this R-core single routing, there is no difference between these two wiring methods. ... The 2 voltage outputs were pulled serially from the same core. "

Thanks for the inside information Pat

Now, are you still using both 7.5 and 5 VDC or just 7.5VDC to the DAC?

Norm

 

[PatOMalley]

Norm,

Just wanted to put that out there in case someone buys the PSU, opens it up, and says 'what's up'.

I did not rewire it. Michael indicated there would be no benefit and unless someone more experienced than myself kicks in on how to mod the thing beneficially I am leaving it as is.

I am not an engineer, just a nag.

Were you thniking of changing it?

-Pat

Quote:

Originally Posted by hifi2001 /img/forum/go_quote.gif Thanks for the inside information Pat Now, are you still using both 7.5 and 5 VDC or just 7.5VDC to the DAC? Norm

 

[hifi2001]

Quote:

Originally Posted by PatOMalley /img/forum/go_quote.gif Norm, Were you thniking of changing it? -Pat

Hey Pat,

No. I don't have any plans to use that untapped 12VAC at the moment. But it is good to know that it is there... I don't have anything at the moment that can use it.

So, are you using only the 7.5VDC on the DAC? Or 5VDC as well which in this case you need to remove the onboard regulator.

Norm

 

[PatOMalley]

Quote:

Originally Posted by hifi2001 /img/forum/go_quote.gif Hey Pat, So, are you using only the 7.5VDC on the DAC? Or 5VDC as well which in this case you need to remove the onboard regulator. Norm

Both.
I removed both regulators and connected as shown below:

 

[driguy]

I have over 170 hours on the DC-30 so I think that most if not all of the changes from break-in are done. First off; the case on the unit is IMO much better than the original one on the DAC. It also runs very cool to the touch with no sense of vibration at all. Most here on this forum do not know me but I am a friend of Bill Allen whom most of you know from this forum. I do not listen to headphones so my observations must be taken it that context.
I have built or modified most of my gear so I have a good sense of what modifications can do. Power supplies are critical to all equipment IME. I have upgraded Audio Note kit gear (M3 preamp and Signature DAC), my 300b amps (DIY HiFi) and my current 26 tube based preamp. Without exception the power supply improvements are easy to hear. The Teradak is no different.
The improvements that I hear with this power supply are nothing short of impressive. The sense of realism, ease, increased soundstage, lack of edginess, 3D imaging, tighter and more realistic bass all contribute to an overall global improvement that for such relatively small change in my system is hard to believe at times. The power supply to me is a "no brainer" as far as upgrades to your system. It has the ability to actually make the recordings sound different in a very good way. Hate to use an audiophile cliche especially in my first post but it can make you hear things "that you haven't heard before".
For point of reference I have made the following upgrades to the DAC:
1. Sampling frequency mod
2. Silver wire from the board to the caps and then to the coax out
3. Dueland 4.7 uF caps on the output
4. Caddock I/V resistors
5. Blackgate caps on the DAC chips
6. I mounted everything in a new chassis that I had from a chip amp project
7. Upgraded the RCA outputs to Audio Note OEM because I had them around
For point of reference the rest of my system consists of:
Modified DIY HiFi 300b amps; CCS for driver stage, paralleled driver tube, V-Cap coupling caps, Jack Elliano Partial Silver output transformers and power supply transformers, solid silver wiring and Mundorf M Tube caps in the power supply, etc.
26 tube preamp
D'Apollito Bastanis wideband drivers w/ subs
Flat silver speaker wire (DIY)
VH Audio solid silver DIY interconnects and power cable
Bastanis power cable
My listening is focused on Jazz and 60's through 90's rock. My priorities for my system are realistic dynamics, believable soundstage, proper tone and timbre and a lack of grain and harshness in the treble region as this seems to take away pleasure faster than anything else.
I would also like to take the time to thank all of the posters here for their time and efforts to keep the hobby close to it's roots, i.e. having fun listening to music.
Regards to all, Tony

 

[PatOMalley]

Tony,

So were the changes across the 175 hours peak at some point? The reason I ask is that I make so many changes, and the thing keeps sounding better, that I probably can't be sure where to place the blame for all the sound improvements with ultimate surety.

But the description of ease and timbre I can relate to regarding the PSU.
The 3D imaging came on after a mod to the Yaqin tube buffer, more so this holographic effect. I probably should have given more time between mods so I could track changes better... but that is a piece of advice that I will probably never take.

Do you have any pictures? Those Dueland caps must be big as trash cans.

 

[Bill Allen]

I have been running in my DC-30 power supply over the past 10 days without any other system mods and the sound continues to get better. Scary better! This upgrade is completely different than all the other mods I performed. While the DC-30 has improved the sound along the lines that Pat and Tony describe. For me, it isn't so much hearing things I never heard before, but a total change to familiar recordings. I use computer audio and at first I thought I was selecting alternate takes by mistake. When I realized these where my favorite music files I almost crapped my pants. Wow, a bonafide "Depends" moment! This is way beyond "things" you haven't heard before ..........

You have to get yourself one of these things! ................ Period!

Ditto that remark for The Amarra Music Software Player. If you own an Apple Computer and rip your music files with .wav or .aiff files this is a must hear. You can download a demo for free here. Amarra Computer Music Player (If you have any questions or would like to purchase Amarra please PM me. Let’s keep this thread about the mods).

Tomorrow I expect delivery of my Empirical Audio Off Ramp 3 with the newest Audiocom Ultraclock installed. The Off Ramp has both Coax and I2S digital out. While I'll start with Coax into the Valab, the next step is to hook I2S directly into the small Valab DAC board. The plan is to power the DAC board with the 7.7 VDC of the DC-30 and tweaking the now unused 5 VDC up to 12 VDC for some clean feed to the Off Ramp 3. I intend to mount the tiny DAC board inside the Off Ramp 3 using its top cover as the heatsink. My JCC (Jupiter Cap Condo) will now live on top of the Off Ramp 3. Less is more my friends.

With the modded Valab DAC, TeraDak DC-30 power supply, and finally Amarra in my system, I can honestly say I am hearing sonic realism I never thought was possible from 44.1 16 bit music files. With the addition of Off Ramp 3 with Ultraclock and I2S direct hookup to the DAC chips, I suspect perfect sound forever may finally become a reality at my crib.

Damn this is so fun it's scary!!!

 

[r8833]

nice tweak for those who didn't swap out the 8 smd dac chips.

I bypassed the smd caps with vishay-roderstein MKP-1837 caps and the sound is much more airy and transparent..cheap to try


http://www.partsconnexion.com/capaci...lm_visrod.html

also bypassed the 4.7 cap with these too


Rich

 

[C.L]

Thanks for the review

 

[Bill Allen]

Rich,

Interesting tweak with the MKP-1837 bypass caps, do you have a picture?

In the past I recommended replacing the 8 stock DAC chip bypass caps with 47uf Blackgate FK's. The idea here was speed and a big fat reserve of power sitting directly on top of each individual DAC chip. To me, this was the biggest most important upgrade before the DC-30 came along. I now wonder if the DC-30 can maintain the constant current to the DAC chips and if the MKP-1837's can increase the speed ... without resorting to the Blackgates?

I bought an extra DC-30 for my Control DAC which I have now sold to my friend Jonathan. The only mods to the Control DAC was a complete Cryo treatment and adding the 220uf Blackgate to the DAC chip regulator. (This was a livable solution for Jonathan but no where near the sound of my fully modded Valab). Next I will add the DC-30 to the Control DAC which deactivate's both voltage regulators and also the 220uf Blackgate. The rubber should hit the road for you stock Valab DAC owners.

What does the DC-30 do for a stock DAC?
Are the Blackgate FK's still required?
Can we get away with simply adding the MKP's?
Can one truely live with the stock coupling caps.

All this and more though the month of August.

Stay Tuned!

 

[Bill Allen]

Just to get the ball rolling and answer Pat's question about break-in on the DC-30 power supply, I decided to pop in my unplayed DC-30.

Well, it sounds good................... But....................

Its sounds a bit louder and everything is much more 2D compared to my DC-30 with 250 hours on it. Obviously the DC-30 has an extended break-in in cycle. Pat it's safe to say that you're not "there" yet!

Question, is even 250 hours enough?

I have a rule of 400 hours before I declare something ready for prime time, and I to ... am not there yet.

Stay tuned!