Mic Pre

[moamps]

I think a few behringer tube products ran 24 or 36 volts ht , and reduced heaters on 12ax7's , it adds the tube processed signal in parralel with the op amps which do all the work ,

Here are some data I have:
Behringer MIC200 - B+=48V, Vf=5V, ECC83, systems in parallel
                      T1951,2,3 - B+=48V, Vf=24V stab., 2xECC83, all systems in series

 

[Tubetec]

Valve window technology I call it , like you said John sound matters little ,its the knowing you have a valve in the circuit that counts , kinda like the placebo effect really .

Im still looking for an 8 channel  Behringer tube 'magician' to gut and rebuild with proper ht and transformers .

 

[clintrubber]

I think a few behringer tube products ran 24 or 36 volts ht , and reduced heaters on 12ax7's , it adds the tube processed signal in parralel with the op amps which do all the work ,

FWIW, recall even having seen a Beh. patent application for this, with some handdrawn schematics.

 

[clintrubber]

OK, this thread at 3 pages already, let's have a view of the schematic now that started all this.
Analag, the floor is yours 

 

[Ricardus]

OK, this thread at 3 pages already, let's have a view of the schematic now that started all this.
Analag, the floor is yours 

Right?

It's it's the world's longest tease, or we're being trolled! 

 

[clintrubber]

It's it's the world's longest tease, or we're being trolled! 

... history repeating ... 

 

[JohnRoberts]

Right?

It's it's the world's longest tease, or we're being trolled! 

It's the brewery... which do you think is more likely?  :

JR

 

[ruffrecords]

Analag likes to kick the tyres and listen to what hisses.

Cheers

Ian

 

[iomegaman]

Analag likes to kick the tyres and listen to what hisses.

Cheers

Ian

I live in a very old apartment building...I have access to the basement...building built in 1905...Tucson, was a hospital among other things...recently went down into the basement...turned on the fluorescent light at the top of the stairs and started down...got to the bottom curve and heard what my ears thought to be the sound of either a rattle-snake warning me "come no closer" or a Palo Verde beetle (large 2"-6" seasonal beetles we have here) trapped in a dryer vent pipe...either one could be true only one can HISS....the one that hisses can cause serious damage if the fangs find you, the beetle is just looking for love...

Freaked me out...cautious I inspected every element under the wooden staircase with a pole...nothing...no snake no beetle...

Turns out the fluorescent light can perfectly imitate one of our ancestral predators if the ballast is going out...

Still...it is the desert and we just rent it from the fangs, the heat and from the spikey shrubs that have dominated this region for longer than us...caution is better than emergency visits.

 

[fazer]

“Snakes....I hate snakes”

 

[analag]

I started simulating this then scraped the idea and went forward.  It probably would be a great sounding pre, but I prefer the sound of tubes with SS either in the cathode or plate circuit.  that way I can get good sound out of worn out and or cheap crap tubes like what we see on the market today

 

[analag]

I have built this in various forms and settled on one that I liked, but i started with this idea

 

[analag]

The work never ends, silicon is starting to please me

 

[shabtek]

where did you buy the pcbs?

 

[gyraf]

.. I prefer the sound of tubes with SS either in the cathode or plate circuit.  that way I can get good sound out of worn out and or cheap crap tubes like what we see on the market today

Yes. because you're not hearing the tubes then. But if main focus is simulation games, then why bother?

They're being reduced to support hardware, but you're right - in this case you may as well plug in any tube you find, not being distracted by it's quality.

I've tried countless variations of this sort, and not a single one of my test pilots has ever liked such a mixed circuit over a clean one. It's all a matter of taste really - such architecture is just not in high regard around here..

Jakob E.

 

[analag]

where did you buy the pcbs?

eBay, via China. Bought as bunch of PCB's and built a couple sets

 

[analag]

Yes. because you're not hearing the tubes then. But if main focus is simulation games, then why bother?

They're being reduced to support hardware, but you're right - in this case you may as well plug in any tube you find, not being distracted by it's quality.

I've tried countless variations of this sort, and not a single one of my test pilots has ever liked such a mixed circuit over a clean one. It's all a matter of taste really - such architecture is just not in high regard around here..

Jakob E.

Really? The characteristic of the tube will shine through regardless. The SS is simply functioning as a high value resistor with a large B- or B+. But if you believe it's all simulation games well, that is your opinion. Like I said I have the fully functioning units in my studio.  I'm not looking for a tube sound, I'm looking for "sound" get it? As a manufacturer you have to satisfy a group of people you're trying to extract money from. Me? I'm just satisfying my soul. I started designing and building tube gear at the tender age of 12 and 43yrs later I know what tubes sound like. Do not confuse me with the "Johnny come lately" crowd.

 

[abbey road d enfer]

The SS is simply functioning as a high value resistor with a large B- or B+.

That's not what I see. The 1st triode's anode meets the source of the 1st MOSFET, so it looks to me like a quite low Z.
The second triode is cascoded, so again the anode load is very low. Correct me if I'm mistaken.

 

[Winston OBoogie]

That's not what I see. The 1st triode's anode meets the source of the 1st MOSFET, so it looks to me like a quite low Z.
The second triode is cascoded, so again the anode load is very low. Correct me if I'm mistaken.

I see the same as you Abbey. 
Also, the first schem based on the REDD, you've got voltage from the input cathode on your output transformer. 
Maybe that's what you wanted?

 

[moamps]

I've tried countless variations of this sort, and not a single one of my test pilots has ever liked such a mixed circuit over a clean one.

May I ask does "mixed circuit" mean mixed technologies like tubes with FETs, Mosfets and BJTs or mixed topologies at all like using cascodes, active loads, current sources in a standard circuit like CF, common cathode amp, etc?