[Luckbad]

How often do you turn the DAC60 off? That seems like a slight internal contradiction with this type of DAC to me. R-2R chips are said to do best if left powered on for days at a time, while tubes generally need a rest. Or am I overthinking things?

 

[rb2013]

  How often do you turn the DAC60 off? That seems like a slight internal contradiction with this type of DAC to me. R-2R chips are said to do best if left powered on for days at a time, while tubes generally need a rest. Or am I overthinking things?

I run mine 24/7 - yes the R2R chips like to be warmed up to sound best.  Tubes generally will last a bit longer if turned off then on - the issue is on power up they get stressed - so that reduces their life.
 
Tubes only need 10-15 to warm up.

 

[Luckbad]

I'm using 5000-10000 hour type tubes right now. Designed to be used in critical military applications. Maybe it's okay to leave it on.

 

[rb2013]

I'm using 5000-10000 hour type tubes right now. Designed to be used in critical military applications. Maybe it's okay to leave it on.

The Russian '75 HGs 6N23P I use are rated for 10,000.  BU thave been running for over a yr and still test good.  The DAC60 does not stress the tube (unless you do the I/V resistor mod!) so they should last longer then normal.

 

[zaccio]

Yes the Russian 6N23P are also military tube and very strong. They work in my DAC60 and Project PRE BOX RS (also 2x 6N23P) On-off 2x per day since more than 1 year without any issues. With my previous mhdt Havana my NOS Bendix 2c51 broke after only 8 month. I replaced with WE 396A (very nice tube).

 

[rb2013]

  Yes the Russian 6N23P are also military tube and very strong. They work in my DAC60 and Project PRE BOX RS (also 2x 6N23P) On-off 2x per day since more than 1 year without any issues. With my previous mhdt Havana my NOS Bendix 2c51 broke after only 8 month. I replaced with WE 396A (very nice tube).

Yes I like the WE 396A - I used them in my Exemplar Audio pre-amp years ago.
 
Came on this and posted to a different thread - interesting:
 

  From NOS General Electric 5670 tube/valve

The 6922 tube/valve is one of the most famous ‘dual triode’ designs and is ubiquitous. It has and is still, used in many tube/valve audio products from CD players to headphone amplifiers.
First introduced by Western Electric in 1946 with the WE396A, from the 1950s onwards (and for the next 30 years thereafter) General Electric (and several other tube/valve manufacturers) followed Western Electric with their own premium version of 6922. This range had controlled warm-up and tight specifications on grid-current, noise and microphony. The result, significantly smoother and more organic sound qualities.
While the 9-pin design was used, the electrical pin outs changed. As such, the GE5670 was not a straight ‘drop-in’ substitute for the 6922. So the GE5670 remain unloved and unused until……2014
From Machine-fabricated adapter with noise filtration

…2014, when iFi brought out the iTUBE tube buffer/pre-amplifier. From our research of the tube inventories around the globe, we found the GE5670 to be in supply and with surprisingly good sound. While the iTUBE was designed from day one with the GE5670 in mind, we found that customers really liked the GE5670 in the iTUBE but they wanted more…yet because of the different electrical pin configuration, the GE5670 was a no go.
The iFi solution was to machine-fabricate a special ceramic adapter with a miniature capacitor circuit to bring heater supply circuit noise (a common issue) sharply down.
Enter the NOS 6922 matched pair

Factory installed, the GE5670 + Adapter work as one (they cannot and should not be separated under any circumstances). Serendipity struck as the shorter GE5670 plus the taller adapter equated to virtually the same height (tolerance within ~1mm from tube to tube).
Therefore, there should be no physical limitations to installing the NOS 6922 tube set in any 6922 audio component.*
Special rejuvenation process

General Electric manufactured the GE5670 from the 1950s through to the 1980s. Hence each valve is at least 30 years old or more. This extensive length of time in storage means one should adopt a special temperature and time-controlled oven ‘baking’ procedure to gently ‘rejuvenate’ each and every valve.
If they were just powered up after such a long time in storage, it would certainly weaken their internal architecture and shorten the life span.
With iFi’s special rejuvenation process, we gradually bring the GE5670 back to life to continue the NOS military level of performance.
Hand-selected and computer-matched

At iFi, given the AMR background, we are literally besotted about tubes/valves. Therefore, we hand-select each and inspect every valve, to ensure their internal structure has not been compromised by the long storage. We then burn them in for 48 hours before finally matching them by computer.
This ensures that each and every pair is perfectly matched and prepared for hours of usage.
User Note* In rare circumstances, the iFi GE5670 tube set may not be a suitable replacement for the 6922 valve. No damage should result but when replacing the valve, as always, check that this does not void your product warranty. AMR/iFi is not responsible for any damage/injury caused.
If in doubt, consult your product manufacturer prior to change the tubes/valves.
 
Anybody try these iFi's?
 
http://ifi-audio.com/portfolio-view/accessory-nos-6922-2/

 

[Luckbad]

Umm... $100 for two of the cheapest and most common decent 5670 tubes you can buy? No thanks.

You could easily buy 20 of those tubes for the price. Unless the oven-baked process increases the lifespan by more than 10x, you're losing money.

Or you could get 5-6 of the GE 5670 Five Star which will last even longer and sound better.

 

[rb2013]

Umm... $100 for two of the cheapest and most common decent 5670 tubes you can buy? No thanks.

You could easily buy 20 of those tubes for the price. Unless the oven-baked process increases the lifespan by more than 10x, you're losing money.

Or you could get 5-6 of the GE 5670 Five Star which will last even longer and sound better.

Well I guess it's mostly for the special adapter/filters.  Too bad they can't be separated.   I have some vintage WE396A I would love to try.
 
You can't use these tubes in place of a 6922 directly.

 

[Luckbad]

Oh I see! Email Jeremy at Garage1217 and ask if he can make you an adapter. Or sell me a couple of your WE396A.

 

[rb2013]

Sure I will sell you my WE396A's Here's a picture of them - I bought NIB and never used them as I sold the pre-amp shortly after getting it - PM me if you are interested:
 

 
I found these adapters on Ebay - http://www.ebay.com/itm/2pc-Gold-plated-5670-6n3-WE396A-TO-ECC88-6922-6DJ8-tube-adapter-for-you-amp-/191636111735?hash=ite

 

[rb2013]

After much experimenation I have found the Regen and the PUC2 Lite DDC a fantastic combination!  The PUC2 needs USB power and using a TeraDak X1 (with a Cerious Tech power cord) fed through the Regen is simply outstanding.
 
I have ordered an iFi DC iPurifier to run between the Regen and the TeraDak (set to 7.5VDC) linear power supply.  This should clean up the power even further.
http://ifi-audio.com/portfolio-view/accessory-dcipurifier/
 
And also an iPurifier2 to try between the Regen and the PUC2 lite.  Just to see:
http://ifi-audio.com/portfolio-view/accessory-dcipurifier/

 

[AudioMan2013]

How are the iFi iPower power supplies?  I was thinking about replacing the battery powered clock on the dac to a 9v power supply.

 

[rb2013]

  How are the iFi iPower power supplies?  I was thinking about replacing the battery powered clock on the dac to a 9v power supply.

I like them - using a iFi iPower 9VDc on my Wyrd Remedy feeding the DAC60 - I like the sound a bit better then the more expensive TeraDak DC-30W.
 
I wish they made a 7VDC for my Regen.

 

[Drastic]

Very long time lurker here at head-fi. This thread made me finally come out of the shadows. I was almost set on getting the audio-gd dac 19 10th anniversary dac. I stumbled on this thread in search of an R2R dac. Now I am considering getting this and possibly attempting some of the mods. The tubes will be upgraded for sure. Just wanted to chime in and thank everyone including rb2013 for all the detailed info. With upgrades for me this has the potential to be a end game dac.

 

[Luckbad]

Anyone who needs a 5670 to 6922 adapter, I bought the inverse adapter from this person and it's solid quality, at least to try things out:
 
http://www.ebay.com/itm/191636111735
 
I bought the other direction because my main DAC is an MHDT Labs Atlantis and I wanted to try out 6N2P tubes in it, and it takes 5670 tubes.