C-19 OP Amps

[wkhanna]

After years of pure joy with my Tom/Anders modified C-19 I have begun further pursuit of end-game performance from this marvel of audio equipment.

First was my installation of musician-grade Portuguese cork between the chassis & transformer.
Next was encapsulating the transformer in mu-metal http://en.wikipedia.org/wiki/Mu-metal along with the installation of PEARL tube coolers.

The next step is taking advantage of the sockets Tom installed to try some new op amps .
After some time investigating available options I have decided to give the Burson Discrete http://www.partsconnexion.com/opamp_burson.html units a try.

My question (hello Tom) is which op amps to replace for the pre section?
Are they single or dual?

[schwarcw]

Hey Bill!

Tell us about those tube dampers!

[Kingman]

I've never seen shit like that...hell, I've never even HEARD of shit like that!     

[bearjew]

I've never seen shit like that...hell, I've never even HEARD of shit like that!     

Kingman, you really are living proof that ignorance is bliss

[Kingman]

I've never seen shit like that...hell, I've never even HEARD of shit like that!     

Kingman, you really are living proof that ignorance is bliss

I bet 1 in 500 have heard of that metal stuff around the tubes...I got tube dampeners like the rubbers on there so I have an idea of their purpose...

[MacGeek]

Well, what kind of difference did it make?  Tell us how it sounds.

[Sir Thrift-a-Lot]

The tube coolers are common fare, but what exactly makes a piece of cork "musician-grade" (he asked hesitantly, awaiting the pummeling that is sure to follow).

[OldiesButGoodies]

the c19 uses dual op amps, I think.  better check w tom or someone in the carveraudio forum.  those burson supremes look awesome.  no idea if they sound better but they sure look badass.

[wkhanna]

The PEARL tube coolers are excellent heat sinks. Now the pre-section tubes are low power & the C-19 uses 'soft-start' so there is not as great an issue with heat degradation, but these are OS Mulards (from Tom) that I want to last as long as possible.
Interesting reading on tubes & the effects of heat here, for those interested. http://www.partsconnexion.com/PDF/pearl_tc.pdf

The PEARL's also act as dampers, which affects vibration & 'micro-dynamics' which low-power signal-level tubes demonstrate. Minimizing any vibration is a good thing in audio. More so for signal-level.

My friend Dan & I both noticed increased detail, imaging and a sense that the instruments had a more three dimensional quality. They were slightly, but noticeably more focused & yet removed from the speaker, more established in their own place in the air. Also, there was a V slight roll-off in the very upper end of the frequency, which worked well for my system.

Regarding the cork: Portuguese cork is the best in world (due to its climate).
Musician-grade is simply a grade rating for natural cork. It is the same stuff used for musical instruments like clarinets, saxes & other woodwind instruments.

Again, the reason for using cork is vibration control.
I have used it in all my gear for transformers & IC boards.
Dan & I have found it increases blackness (it makes passages with no sound quieter) & adds detail to subtitle elements like the shimmer of top-hats & cymbals & increases decay. You will notice it on well recorded piano immediately.

The mu-metal is amazing.
By far the most cost effective upgrade I have yet come across.
I put it on all my gear, digital, amps pre, everything.

Many super hi-end units use it to isolate nasty stuff coming off of high-power elements that contaminate sensitive components like chips, caps & resistors.
Nothing new, but seldom implemented on mid-level gear.
Other companies will totally isolate the high-power sections in separate chassis.
Put in the mu-metal yourself gets you a little closer to the last 2% of what is achievable.

Dan & found it gives much tighter, musical sounding bass, better detail, imaging & separation.
One of the first things you will notice is how the sound stage goes way back behind the speaker.

[Sir Thrift-a-Lot]

Regarding the cork: Portuguese cork is the best in world (due to its climate).
Musician-grade is simply a grade rating for natural cork. It is the same stuff used for musical instruments like clarinets, saxes & other woodwind instruments.

Thank you, that makes sense to me.

[schwarcw]

Bill,

Great write up and interesting information.  I have never heard of the mu metal before.  I've used the tube dampers and have definitely heard the impact.  A very inexpensive tweak.  I think the best results that I have heard have been on the dampers on the signal or preamp tubes.  I have not tried dampers on power tubes, but I may give that a shot on my small EL84 integrated amps.

[Rockman Rock]

IIRC the LME49720 is a great op amp that can be used in there. Is that what you had in there?

The Bursons are great. I used the Bursons in a Music Hall 25.3 DAC I modded.

Carl, you have the LME49720 in the Twisted Pear Legato v3.1 I/V output in your DAC, specifically the SE and headphone out. Your balanced out is discrete output, no op amps there.

[Rockman Rock]

The Bursons are great. I used the discrete Burson op amps in a Music Hall 25.3 DAC I extensively modded. Your power supply needs to be up to the Bursons. IIRC the Bursons imposed a 700% increase in mA over the stock op amps. I upgraded the op amp supply with Belleson Super regulator with larger heat sinks. It is based on the Jung regulator and was a drop in swap for TO-220 regs. Burson has a new design discrete op amp now so unsure of mA specs.

[schwarcw]

Rockman, you do some great work!

I know that Music Hall DAC.  IIRC somebody put the opamps in backwards with not so good results.  I'm just glad it wasn't me.

[Rockman Rock]

Rockman, you do some great work!

I know that Music Hall DAC.  IIRC somebody put the opamps in backwards with not so good results.  I'm just glad it wasn't me.

Thanks Carl! I didn't either. The fellow I sold it to let somoene borrow it. He got it back and stuck one in backwards. I had them puppies marked for proper orientation too.

Fortunately the DAC still works. The new owner purchased the new design Burson op amps. I have one of the Burson survivors to try in my Legato I/V board.