Power tube buffer

[Stee]

as you know
the accurate sound of the Valves does not give a deep bass, never
this Balanced buffer does not lose quality of your acoustic scene
and Complete the soul finally adding a body to music

 

[DF96]

Valves work fine down to DC, but transformers do not. Nothing you add after the transformer can change this.

 

[DualTriode]

as you know
the accurate sound of the Valves does not give a deep bass, never
this Balanced buffer does not lose quality of your acoustic scene
and Complete the soul finally adding a body to music

Please tell me more.
What is the input impedance of the transistor buffer?
Is the transformer a typical tube output transformer, or is it a matching transformer between stages? If it is a transformer at the output of a tube power stage with limited bass output that is what your buffer will have, limited bass.
Where does the idea that tubes plus output transformer lacks a deep bass come from? Depending on the transformer 25 Hz to 20K Hz bandwidth is not uncommon (also not cheap).
DT
All just for fun!

 

[Wavebourn]

It reminds me some popular in 1970'th power amps-plugins that had PS, output transistors, and trifilar input transformers. Such an amp driven by a boombox sounded very loud. But did it sound clean?

 

[Michael Koster]

It reminds me some popular in 1970'th power amps-plugins that had PS, output transistors, and trifilar input transformers. Such an amp driven by a boombox sounded very loud. But did it sound clean?

I remember "Mindblowers" by Tenna; 6x9 speakers with special voice coils and similar buffer circuits (I used to install car stereo...), about 80 watts out of a 12V supply... Mounted in the rear window of a TransAm or Mustang they would definitely cause hearing damage. Lots of bass for sure!

 

[Stee]

Load change source performance

the really transformer's 25 Hz to 20K Hz bandwidth depends of your load
also of your power level
specific data and parameters often make us lose the overview
best adjustement is move 10KOhm values to have Ic 2A @ 8 Ohm load (3A@6Ohm)
so need a very big dissipator for each channel

 

[Michael Koster]

Yes, that's how we sold Mindblowers. We explained to people that their existing car stereo will sound better because it's not driving speakers, just the "easy load to drive" input of the Mindblowers, and the Mindblowers are doing all the work!

 

[Stee]

the missing link in the chain

in structural projects, there are two safety factors, static is third of dynamic.
in short I am arguing that the TUBES output transformers are undersized 3 times.

I tried to shunt the secondary in parallel instead series (4 and 8 Ohm to 2 Ohm)
...improves but not enough.

advantage of the buffer is to isolate the reactive power back from the speakers on the negative feedback of tube.

you do not have large heat sinks may adopt a bias AB1 (0.5 A)
in this case it is better to use identical components with gain (gain means speed)

I found the same gain (Hfe 100) with A1302 and C5200
two generations who marry perfectly

 

[Wavebourn]

Which tube do you smoke today, Stee?

 

[Yvesm]

in structural projects, there are two safety factors, static is third of dynamic.
in short I am arguing that the TUBES output transformers are undersized 3 times.

Why not simply using larger ones

Yves.

 

[DF96]

If you reduce the load on the OPT, as you appear to do, then the result will be to raise the LF roll-off frequency, although negative feedback within the main amp will offset this. You may also get a higher output impedance, as seen by the speaker, as a plain emitter-follower might not be as good as global NFB for this purpose. A higher output impedance could give extra bass boom around the bass resonance, but less below it. I believe this is sometimes called "one note bass" - you could make your hi-fi sound like a cheap ghetto blaster!

So you end up with less bass overall, but more at one particular frequency. To uncritical ears this might sound like an improvement.

 

[Stee]

better impedance matching

may be my uncritical ears this might sound like an improvement
you can try in your transformers - it's easy
Why not simply using larger ones?
because you lose power
also need adjust NFB resistor to half value

 

[Yvesm]

. . .
Why not simply using larger ones?
because you lose power
. . .

Duh