Question for our tube amp builders....

[Jim Naseum]

The money you save will be an inconsequential fraction of the whole cost. XLR Connectors? That are about $2 more than RCA.

[tube fanatic]

Or maybe not. I guess no one has any technical advise about the OPs interesting inquiry, then. 

Jo, this was addressed to some degree in posts #14 and 18 in the "Ultimate Gem" thread.  Richard, as to using XLR, it would require either an input transformer to create a balanced to unbalanced network, or a differential/balanced driver arrangement.  Either way, it is not going to be full differential all the way through.

 

Maynard

[Coytee]

I don't know what a full differential design means nor what it's true benefits are.  I "think" I know enough to say that it's "good"???

 

If you add an input transformer, is that going to contort the sound a bit? (for the purist at heart person)

[Jim Naseum]

 

Or maybe not. I guess no one has any technical advise about the OPs interesting inquiry, then. 

Jo, this was addressed to some degree in posts #14 and 18 in the "Ultimate Gem" thread.  Richard, as to using XLR, it would require either an input transformer to create a balanced to unbalanced network, or a differential/balanced driver arrangement.  Either way, it is not going to be full differential all the way through.

 

Maynard

 

 

OIC.

 

He mentioned XLR connectors. I didn't think he would mean balanced input on a tube amp. Got it.

[Jim Naseum]

I don't know what a full differential design means nor what it's true benefits are.  I "think" I know enough to say that it's "good"???

 

If you add an input transformer, is that going to contort the sound a bit? (for the purist at heart person)

 

The only advantage of a balanced line is reducing the noise that is picked up on the cable connecting two devices. Often, this is done for long runs, like 50 feet, where noise can be an issue. 

 

If there is no noise issue, adding an input transformer means adding a LOT of cost. Good ones are very dear. Crappy ones will ruin the sound.

[mike stehr]

I've had several SET amps and a pair of SE-OTL amps.

 

Though I liked the quality of the sound, I was terribly frustrated with the lower output.....I simply wanted more of what it gave.

 

That is in part what has me curious.

 

If a SET-300B gave me good sound but not enough, could a 300B designed for a more narrow output, provide more of it?

 

Also, since I'm using an active, it would be nice to have XLR inputs.

 

No, it will be the same. It's just that the tube amplifier will only play the frequencies the active crossover allows.

It will be easier on the amplifier with regard to not having to play bass from 300-500Hz down.

 

Beyond that, I think you would end up in the same boat, wanting more power...Maybe a big push-pull tube amp from 300-500Hz up?

 

Don't you bi-amp with a pair of Crown K2s, with the EV active x-over? I think using bi-amplification with two similar amplifiers is a good idea...and the K2 ain't no slouch amplifier.

 

Are you wanting a little sweeter midrange/top-end with the Jubilees? What improvement may you be seeking?

 

Maybe ponder about using the Nelson Pass FirstWatt amplifiers. ChrisA likes his FirstWatt amplifier with his Jubs.

[Coytee]

Don't you bi-amp with a pair of Crown K2s, with the EV active x-over? I think using bi-amplification with two similar amplifiers is a good idea...and the K2 ain't no slouch amplifier.

 

 

Yep, pair of K2's.  I agree they're no slouches.  I am in no particular train of thought of wanting/needing any amp nor (amp) improvement.  (what I'd like to do next with her permission is to do some room treatments).

 

I just wondered about the question at hand (could the narrowing of the output allow for more) as I'm a curious type.

[Jim Naseum]

Using an SS amp for the low ranges and a tubed amp for the high range has a built in problem of voicing. For an octave or more around the crossover frequency both amps will be playing the same material. The two amps have radically different distortion characteristics, or signatures.

Since the crossover point often occurs in the midrange, vocals will take on an unpredictable quality. Perhaps very poor.

It's hard to see any advantage of any kind by adding a tube to this kind of existing system. Kind of like adding an external hard drive to a tablet. Yes, it can be done, but why?

Sent from my SM-T330NU using Tapatalk

[SWL]

I used to do this years ago and sincerely thought I was doing something special. I mean it sounded real good and hey, I had the best of both worlds right? Well, I switched back eventually and ran everything 'normal'......over a period of time I went back to the passive bi-amp deal with the tubes on top and solid state on the bottom and it sounded like a mess. The center image was just 'not right' and yeah, I could hear the nice tooby goodness in the mids-highs but it was somehow out of focus. 'Fools bi-amping'.....yes, I kinda felt like a fool.

[Jim Naseum]

I would apply the old truism that "the sum of the parts can be less than, equal to, or greater than the whole." 

[horatio2]

To SWL's comment about having done the biamp with solid state bottom and tube top and the long and storied road- been, there, done that, too and I can agree with a lot of your sentiment.

 

But, I have to say, keeping at it can bring its rewards.  I use a SET into an Altec 288 on an old school 1st gen EV CD horn, and a fat mosfet amp for the bass horn, and I really never got a satisfactory result (had been using a Rane AC23) until I went digital on the crossover, and got those niggling hum problems with the tube amp sorted.  The digital crossover move enabled time alignment, which, along with the CD horns, brought the image sharply into focus, and also enabled me to sidestep another shortcoming, that of the upper end bass horn response.  I use the Le Cleach approach, and cross the bottom at 300 Hz.  That woodiness at the top end of the bass horn is largely gone.  I would NEVER go back to the original having reached the point of having this dialed in.  Before getting it dialed in...sure, I kept those type A's close at hand, as I looked into the mirror asking myself if I really was all that smart to begin with. 

 

But, this is a pretty complicated system to run, now, as it must be carefully power sequenced on and off.  And I recently made the jump to a full digital front end, using an RPi2 running the full digital HiFiBerry Digi into the MiniDSP, delaying analog until hitting those amps.  This is pretty nice, but again, more complicated to operate than simply walking up the stereo and pushing some buttons.

 

On the whole, though, moving smartly in the right direction.  Don't discount what can be done with the biamp, just recognize there's going to be some fooling about (a lot) to get it right.