Definition needed: Having a "Pro Sound"

[rollo]

 Pro sound is accurate, thin, over detailed, crisp, bright, dynamic and boring. Two dimensional at best. Neutral to the source. NHT,  anyone ? This way the Engineer can color it up or freak it up is more like it.


charles

[Bob in St. Louis]

Interesting Charles, thank you for the reply. Oddly enough, more than half of your adjectives are appealing to me. 

My head has cleared up quite a bit since yesterday and can hear better as a result. Have begun to get a taste of my new sound. Starting to agree with you guys about the crisp, bright aspects. But that's the part I like, within reason, of course.
Was listening to Best of Basia this morning, and received an icepick to the temples at the 2:20 point in the song "Time and Tide". 
Oh damn...that sucked.
I've got three pair of Jantzen caps in values of 1.0uF, 2.2uF, and 3.3uF.
So I went right for the 3.3 value pair to put in series on the compression tweeter (handles 2,500Hz and up).
That's much better. Might go back down to the 2.2uF.

I suppose in Charles example, I'm playing the roles of the engineer coloring/freakin' it up. 

One more question for you guys:
I've got tubes downstream of the DCX that power everything from 80(ish) on up.
Would it be safe to say tube rolling is another area I could "make it better"?

Thanks a million fellas!!
Ya'all are great!
Bob

[bpape]

Could help a bit potentially.  Certainly doesn't hurt to try...

Bryan

[rollo]

Si senor.  RCA, Mullard, Tungsol, Amperex, Tele, and last Siemens in that order of richness. RCA being the richest sounding. For me the final dial in are the tubes used. Just changing the output tubes in the amp or the Preamp will alter the character from rich to bright[ God forbid] or somewhere in between. Many flavors to play with.
  Play away my friend.


charles

[richidoo]

For 12au7 I found Amperex were the richest, RCA 50s gray just a little rich, RCA clears about neutral, telefunken too far the other way. In the end I learned to despise the distortion and warmth of vintage tubes. YUK! I like clean robust and rich sound of modern Chinese tubes. SS is even better if it doesn't fuck up the high freqs, which is rare.

[Bob in St. Louis]

Presently using:
(4) Groove tube 12AT7
and
(4) Electron Tube EL34A Although, I've got a matched quad of Groove Tube GTE34LS {aka: 6CA7}.

But it's good to learn the definition of a "rich" sounding tube. Thanks for that fellas.

Bob

[richidoo]

Those E34Ls are

AWESOME!

Bill O'Connell has more from older batches before they went to crap. New ones are why I sold my Snappers.

AT7s are more difficult. Supposedly the current JJ is supposed to be the lowest distortion 12AT7 ever made. Read about it on AA or Agon forum. I'll try to send you the links. I used them, they sounded great, but started to pass wind after 3 months. I would let them rest for a couple months and put them back in to work god for another three months before noising up and needing another rest period. JJ quality is shit, but their tubes sound great when they work. They make your E34Ls too. It is a copy of General Electric version EL34 which was tweaked for more power by Mitch Margoles ( Manley designer extraordinaire) and built on original GE machines and raw materials by JJ.

[mgalusha]

Warning - thread hijack...

Bob, you can make a huge improvement to the DCX output stage for relatively little money and effort and retain the original board. Because of the way it's laid out, you can remove all the stock op-amps and coupling caps to be replaced with 1 high quality op-amp per channel and no caps in the signal path. Total cost is less than $50 for the parts if you can DIY.

The upside: much simpler and shorter signal path. No nasty electrolytic coupling caps, no 12 cent op-amps. Also, signal levels are adjusted to be more compatible with consumer gear. This helps improve the S/N ratio and allows the digital levels in the DCX to be higher, resulting in more resolution.

The downside: Impedance balanced output vs differential balanced output. This is only a problem if you are driving an amp that needs a differential signal. They exist but there are not that many of them. If you are running it into any sort of XLR/RCA converted this is a moot point. Note this applies to Jan Didden's analog board as well.

The other downside: The traces on the DCX boards are very fragile, great care must be used lest you trash your DCX. Trust me on this... 

An option, I have some spare I/O boards and could convert one for you. This would make it a drop in.

If you like I'll write up some instructions on what to change. I might even have some pictures as I have built one like this for Tyson over on AC.

Note, the stock input stage sucks as well and unfortunately can't be "fixed" on the board. There are several options here. Gary Pimm's setup would work very well but good transformers are expensive. Another option is to use a SE to differential op-amp to generate the required signal for the DAC input. There is room in the case to install a small board with this and wire it to the existing I/O board. I have the schematic I drew for this somewhere if you like.

These are the cheap options and are a compromise. Jan Didden's kit is really good but fairly expensive. You do get analog level control though, allowing the digital signal to remain as high as possible, avoiding the dropping of bits.

If you're really after the best it can do, it just gets more expensive and fiddly from there. Clock, SRC, DAC chips, power supply changes. A fully tweaked DCX can sound really good but they are fussy and very labor intensive, which is why I don't build them any more. Modding an output board is pretty easy, wholesale upgrades are very involved.

Sorry for the hijack..

mike

[richidoo]

Continuing in the spirit of hijack, which is actually the original point so not a hijack....

Mike, what do the 1:1 transformers do? Convert SE/BAL?  Is there any buffering with equal windings?
Thanks

[Bob in St. Louis]

Mike, with all due respect Sir...You don't know the meaning of the phrase "thread hijack".
It's not within your being. Your words are pure wisdom and always relevant. Pure and simple.
Yes, you've piqued my interest.

The fella (you told me about) from Norway with the input board sent me an email this morning saying it was shipped today.
That will be my first DCX mod. After that's complete, I'll put it back in the system, (recover financially), and see what it does for the sound quality.

After that, I'm open to the next best path of upgrade. Although I do have a soldering pencil and very little fear, I do not have the ability to think for myself. I would need explicit instructions, complete with pictures, for any mods I perform.
That being said, if you are indeed willing to help me out, I'd be very grateful.
At this point in time, money is very much part of the equation so I would not be interested in having anybody build anything for me. I just can't afford it right now. But pictures, instructions and parts lists are MORE than welcome!

Your earlier comment about the Chipquik has not gone unnoticed. I will get some of that before I open the case.

Yea, I'm eager and excited!

My head has cleared up almost 100%. I'm beginning to form my own definition of "pro sound".
On some songs, it seems to be a slight improvement. However, there are some that have been rendered unlistenable as a result of the stock DCX. 

Bob

[Carlman]

My head has cleared up almost 100%. I'm beginning to form my own definition of "pro sound".
On some songs, it seems to be a slight improvement. However, there are some that have been rendered unlistenable as a result of the stock DCX. 

Bob

Work on getting rid of the distortion rather than shaping the sound and you will be rewarded!

[Bob in St. Louis]

Hmmmm....Yea. Agreed Carl. Good words indeed!
I'm about finished getting the OX/gain and all the various files saved for my various sources and "moods". Without measuring the room, I've gone about as far as I want to go with "serious" shaping.
You're correct. It's time to "clean it up".

Thanks!
Bob

[Bob in St. Louis]

I just read the thread Rich started about biasing tubes, and it got me thinking.....
On a Jolida 202a, if I turn the bias down a bit, would that "richen it up" a bit?

Sorry for the noob question.

Bob

[richidoo]

There's no way to know until you try. It will sound different, both below and above the nominal setting. You don't want to turn it up too high, but I don't think that too low will hurt anything. You do want to make sure that the difference between two tubes in a pair are not too far apart at any given time. So starting from zero, bring them up 5mA at a time till you get to your target.  If you are already at 30mA bias, that's the typical setting for el34 tubes. Read the data sheet and search the forums for recommended bias settings for your tubes. I ran my E34Ls a little cool because i did not want them to blow up as quick (bad batch). Hotter bias is farther into class A so it supposedly sounds good, but there are so many other factors, it may not sound better at all. The designer tweaks the circuit and bias altogether.   So many people own Jolida, you will find some recommendations. That particular tube is pretty robust and has extra cooling inside, and extra power handling. I would try 35mA, compare to 30mA and 25mA. That will give you a sense of what is happening, then you can research or ask the mfg if you can do anymore. The internal fuse on the B+ will limit how much overall bias you can apply. The more bias you apply, the shorter the tube will last.

[Bob in St. Louis]

Ok, good deal Rich.
I memory serves, the factory recommendation is like 40mv. But it's been a while since I've done it, I might be wrong.
Due to the way my rack is set up, it's a REAL P.I.T.A. to check/change my bias. That's why I was asking. Sounds like something I should give a try.

Good advise about not having too big a difference between two tubes in a pair. I didn't know that.

Thanks man,
Bob