Tubes and there sweet spots.
If you where to triamp what tubes would you use for high, mid and bass? ~15wpc hf, ~30wpc mid, ~50wpc bass. Triode or tetrode, pushpull or ultralinear? I was thinking 6v6 high. 6l6 mid, 807 bass. I don't mind buying expensive tubes as long as they are not 300b expensive.
thanks
If you where to triamp what tubes would you use for high, mid and bass? ~15wpc hf, ~30wpc mid, ~50wpc bass. Triode or tetrode, pushpull or ultralinear? I was thinking 6v6 high. 6l6 mid, 807 bass. I don't mind buying expensive tubes as long as they are not 300b expensive.
thanks
Hi,
Not if each are driven correctly and depending on crossover and speaker efficiency. If you have a SPL balanced 3-way, you're unlikely to notice. Actually, with the tweeter being SE, there's less chance of hard clipping and better chance saving a precious ribbon during overload
(power based on a rule of thumb for 100W bass, 10W midrange and 1W tweeter for average listening)
ak_47_boy said:
Not if each are driven correctly and depending on crossover and speaker efficiency. If you have a SPL balanced 3-way, you're unlikely to notice. Actually, with the tweeter being SE, there's less chance of hard clipping and better chance saving a precious ribbon during overload
(power based on a rule of thumb for 100W bass, 10W midrange and 1W tweeter for average listening)
I've looked at scope traces of filtered audio signals from various CD's.
Based on that if I were to make a triamped system this is probably how I would do it .
Bass 100 watt ( continuous rated )
Mid 50 watt ( continuous rated )
Tweeter 50 watt ( max rated - means smaller heat sink !)
Some transients are very large , you don't want them clipped.
However the average tweeter power level is very low and while the amp should have enough transient capability it can get away with a small heat sink because of the average low power .
If mids start from say 100 Hz upwards the heatsinking must be adequate . If mids start from say 500Hz then you can again get away with a smaller heat sink than one required for continuous power dissipation.
If you play electronically generated music or possibly "metal" then you may need larger sinks because of the much higher HF content in them .
Basically you choose power based on transient requirement in that band and the average power levels.
Even a 100 watt bass / 25 watt mid / 25 watt tweeter will sound great. Active systems always tend to sound louder ( and cleaner ) than their equivalent passive version .
Cheers.
Based on that if I were to make a triamped system this is probably how I would do it .
Bass 100 watt ( continuous rated )
Mid 50 watt ( continuous rated )
Tweeter 50 watt ( max rated - means smaller heat sink !)
Some transients are very large , you don't want them clipped.
However the average tweeter power level is very low and while the amp should have enough transient capability it can get away with a small heat sink because of the average low power .
If mids start from say 100 Hz upwards the heatsinking must be adequate . If mids start from say 500Hz then you can again get away with a smaller heat sink than one required for continuous power dissipation.
If you play electronically generated music or possibly "metal" then you may need larger sinks because of the much higher HF content in them .
Basically you choose power based on transient requirement in that band and the average power levels.
Even a 100 watt bass / 25 watt mid / 25 watt tweeter will sound great. Active systems always tend to sound louder ( and cleaner ) than their equivalent passive version .
Cheers.
Why deafening levels at the tweeter ? Want to blow your ears ?
They are priceless !
There is a catch in all this. One has to take into consideration the sensitivity level of the drivers. So if the tweeter is very sensitive , like say 100db/ watt/meter , then you can get away probably with a 5 watt tweeter amp ! You get the drift ........
In any case 100 +25 +25 watts will NOT get you into the deafening range . Is that what you are looking for ?
Cheers.
They are priceless !
There is a catch in all this. One has to take into consideration the sensitivity level of the drivers. So if the tweeter is very sensitive , like say 100db/ watt/meter , then you can get away probably with a 5 watt tweeter amp ! You get the drift ........
In any case 100 +25 +25 watts will NOT get you into the deafening range . Is that what you are looking for ?
Cheers.
It's in my intention to build an hybrid system with a tubes amplifier for high-mid and a mosfet (or hexfet) for bass.
What can I do with preamplifier?
I have 12au7 and 12at7wa tubes.
My idea is to build a preamp with 12au7 (that I can change later with an ECC82) but i don't know what to do to have 2 different output lines.
Any idea to control it and to have the same volume levels between the different final amplifier?
Thank you
What can I do with preamplifier?
I have 12au7 and 12at7wa tubes.
My idea is to build a preamp with 12au7 (that I can change later with an ECC82) but i don't know what to do to have 2 different output lines.
Any idea to control it and to have the same volume levels between the different final amplifier?
Thank you
leimaster said:
Well, I believe that the usual way to do bi or tri-amping is to feed a normal preamp (single output) into an active crossover that splits the signal into the different frequency bands and sends them to the power amps. The crossover and/or amplifier inputs handle equalizing volume level across the amps.
Given this, all you need to do is build a standard preamp, and make sure it can drive your crossover, which shouldn't be a problem.
Hope this helps.
ak_47_boy said:
Yes, but actually no.
I think ashok's point is that a musical signal of one watt average level can have transients, momentary power levels, many many times greater. And I agree.
But shouldn't any well designed one watt amplifier be able to handle that?
That's not a rhetorical question.
Using an active crossover you are putting something between tubes sound. In my opinion is better if I try to arrange something that can be used by the bi or triamp connections of the loudspeakers.
Isn't it?
Can be an idea to put trimmers in the "in" connections of the amplifiers to control gain?
Isn't it?
Can be an idea to put trimmers in the "in" connections of the amplifiers to control gain?
DrDeville said:
No. If you have a typical transistor amp, the maximum output voltage is the rail voltage (less a little, depending on the design). That determines peak ouput, no matter how short the transient. It may be different if you add transformers into the mix. It might be that inductive effects could allow output voltages to swing higher than steady state voltages with some topologies. But I'll let the experts tell us how much practical benefit, if any, can be gained that way.
Tube amps do clip much more gradually than most SS amps, so that even though a transient peak is clipped, you get the benefit of the area under the peak (volume), without the nasties of hard clipping. But it seems a reasonable assumption that a rounded peak will make sound a little less dynamic than if it were not clipped. And increased dynamic impact is what people who use high powered amps report.
Sheldon
leimaster said:
If you connect a pre-amp to multiple amps, you have to calculate the input impedance of all the power amps in parallel and make sure you can drive the total with your pre-amp. If you add voltage dividers or trimmers between the pre and amps, you will also have to parallel the impedance of each of those in your calculations, and add that to the load your preamp will see.
Sheldon
leimaster said:
You'd need one of those for each channel. If you are going to go that far, why not just go active with tubes. For the same number of tubes plus some resistors and caps, you can include all your crossover filters and level adjusters. This inexpensive program will calculate it all for you: http://glass-ware.stores.yahoo.net/tcjfildes.html
Sheldon
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