Is there any technical reason (aside from maybe too much gain) as to why an OTL tube headphone amplifier cannot work equally as well as a stereo preamplifier? The amplifier in question has a 22.1 kOhms input impedance which, while lowish, should be plenty high enough in this case. This OTL preamp uses 6H30 output tubes. I suppose the concerns *could* be running the signal through a capacitor (I'm assuming this is a cathode follower) and perhaps the circuit uses a prodigious amount of negative feedback, although honestly neither concerns me technically ...
I had originally planned to use my otl HPA as a front end for a 2a3 power section.
In my case (12bh7a and ecc99) has enough oomph but needs voltage swing to drive them that would be missing without changes.
I suppose the question is what do you want to drive? Line out? Or direct to power section.
I suppose if you have high impedance headphones with a large voltage swing makes it easier.
In my case (12bh7a and ecc99) has enough oomph but needs voltage swing to drive them that would be missing without changes.
I suppose the question is what do you want to drive? Line out? Or direct to power section.
I suppose if you have high impedance headphones with a large voltage swing makes it easier.
My Edelweiss-3 Preamp Plus has "Plus" in the name because despite it is clean and transparent premp, it can supply 20 mA current to drive headphones. I assume, if your headphone amp is clean, with higher load impedance it may be even cleaner, so yes, it can be used as a preamp.
The OTL headphone amp might be able to put out enough signal to damage the input stage of a power amp. I would place overvoltage protection on the amplifier inputs, just in case of an 'accident'.
NickKUK wrote:
"In my case (12bh7a and ecc99) has enough oomph".
What does "oomph" mean? Tried to figure it out but failed.
Sorry for my stupidity in this matter.
Please explain, thanks,
Joe.
"In my case (12bh7a and ecc99) has enough oomph".
What does "oomph" mean? Tried to figure it out but failed.
Sorry for my stupidity in this matter.
Please explain, thanks,
Joe.
Gain for directly driving the 2a3. It would have enough grid current - IIRC 2a3 is about 3-4 uA. However as said the 2a3 needs a far larger voltage swing on the grid vs my amp is low gain class A push pull.
The ecc99 and 12bh7A can drive the 2a3. The 12BH7A could at a push possibly drive it from the cascode or use the driver stage with modification. However not directly from the current headphone jack without modifications.
So TL;DR is we don't know enough about the power amp stage and how it's connected. There may be a driver stage sat before the 2a3 or there may not. That would be the next point to clarify - understand output required for the power amp.
I hope that clarifies my comment.
Thanks for your elaborate answer but I do not want to be a "constant pain in the %^@%" but that abbreviation:
oomph. What is it?
oomph. What is it?
Oomph is an:
In this case, associated to the sound made by somebody lifting a large weight and similar actions and releasing some breath, so indirectly meaning "strength, power, physical force", etc.
A little over the top applied to a preamp (would fit perfectly in a POWER amp) but hey, we are using colloquial English. so ..... fine with me.
When you lift a heavy weight, you say 'Oomph', and your Diaphragm tightens.
Much of the lifting power is in the diaphragm.
If the diaphragm is weak, you may be going to the chiropractor to get your back fixed.
Much of the lifting power is in the diaphragm.
If the diaphragm is weak, you may be going to the chiropractor to get your back fixed.
Diaphragm is not involved in weight lifting beyond making the lungs work. Skeletal muscles do the lifting. Diaphragm may well tighten during a lift, but it does not add mechanical advantage, since it's not connected in any way to the skeletal levers (bones) supporting the lifted weight. As for the back, that depends on posture during lifting.
That "Oomph" means that it does not saturate when loaded on headphones. That means, loaded on 10-100k resistance of a power amp it would distort even much less. According to Ohm law the current is the output voltage divided by the load resistance, so "Oomph" would not "Oops", however if output capacitors are not leaky, and do not cause DC at output on a high impedance load. In my Preamp Plus I have relays that shunt outputs until tubes are hot and caps charged. You may add additional like 1 uF film caps with 100k resistors going to the ground, if yours does "Thump" when powered on/off.
Correct,
The diaphragm and stomach muscles are different.
Now, please do an Oomph really loud! Your stomach muscles will also tighten.
Or, try a good Achoo!
So often the two muscles work in tandem.
Many people can not properly operate their little finger and the next finger over 'independently'.
Just saying.
Some words are cultural, and thereby confusing.
So are TLAs (three letter acronyms).
FLA . . . Four letter acronyms, five letter acronyms, forty letter acronyms.
AMA . . . Is it American Medical Association, Or American Management Association?
In electronics, there are lots of acronyms. Write it out to reduce confusion.
The diaphragm and stomach muscles are different.
Now, please do an Oomph really loud! Your stomach muscles will also tighten.
Or, try a good Achoo!
So often the two muscles work in tandem.
Many people can not properly operate their little finger and the next finger over 'independently'.
Just saying.
Some words are cultural, and thereby confusing.
So are TLAs (three letter acronyms).
FLA . . . Four letter acronyms, five letter acronyms, forty letter acronyms.
AMA . . . Is it American Medical Association, Or American Management Association?
In electronics, there are lots of acronyms. Write it out to reduce confusion.
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A relay that connects a parallel shunt on the preamp output during mute, and the cap is a bypass to allow the shunt of the AC signal to ground?
The answer is no, there is no reason it would not work as a preamp. There are reasons why you should not choose to. Everything matters in design. You need to make concessions in a OTL headphone amp (or just a general power amp) that are somewhat non-issues because of the higher signal voltages. You don't have to do that in a real preamp. FWIW, if you look at Audio Research tube pres, some of the highest rated in the world, they literally say can output 20-40V, which could easily kill some solid state stuff. So don't turn it up and unless your OTL is spectacular, expect less than what you could get from a dedicated preamp.