posted
Ok. In a lot of tube amplifiers, aren't transformers a very important part of the design? For impedance matching, etc etc..
Well, if most people like the sound of tube amplifiers, then the transformers cannot be affecting the sound *too* much.
With this in mind, because RCA signal is AC, why can't you use a transformer to up the voltage on a low voltage deck? Use a high quality transformer, and turn that old 2v deck into a new 8v deck?
This is an idea to get some discussion going in this channel, so lets work with it a little
ShadowStar
------------------
Computers are a lot like air conditioners.. Open Windows and they become useless..
The day Microsoft makes something that doesn't suck is the day they make vacuums.
Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
| IP: Logged |
posted
Hmm I beleive that would work. But Im no expert so what would a high quality transformer cost? Would the cost of a high quality transformer outweigh the few bucks you would save be not buying a line drive? Anyway good topic!
posted
Yes, you could use a transformer to up the voltage, but it would also lower the impedance seen by the head unit. I think if you matched everything up correctly it might work. The head unit might not be able to put anymore voltage than it is already putting out. I'm guessing here: Head units have a voltage rating, it seems to stay the same regaurdless what amp it is hooked up to, different amps have different input impedances and so the impedance seen by the head doesn't effect the voltage output. So when a transformer is used a higher voltage is not attained but a lower impedance is shown to the head. Can anyone verify this? Am I right?
Resistance affects current, because the voltage output of a head unit at a given volume is "??? Constantly relative to the level of the source signal (CD, Tape, Radio)???"
Therefore, the preamp simply produces a different level of current depending on the amplifier input impedance...
Can the voltage itself be jumped up with a good transformer?
ShadowStar
------------------
Computers are a lot like air conditioners.. Open Windows and they become useless..
The day Microsoft makes something that doesn't suck is the day they make vacuums.
Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
| IP: Logged |
posted
I would not use a transformer. Bad design. transformers have inductance, resistance and other losses. Inductance makes the electrons in the wire feel heavy to the head unit and amplifier. This equals muddy transients. only cheap stereos use transformers in there input and or output stages. I dont know much about tubes other than they use very high DC voltages which will require larger transforms. I also know that at very high power applications tubes must be used instead of transistors because transistors only get so big (physics). Tubes however get giant. Bigger than us I believe. If you want 8.5v from your 2.0v head unit try an amplifier. lets see, power = V^2/R so, 8.5^2 = 72.25 72.25/ 4ohms = 18 watts so a 20watt per ch amp will put out 8.5v but, your amps impedance is not 4ohms. so, use a high tolerance low inductance(not wire wound) resistor(20 watt!) in parrellel with your amp inputs. note: 4ohms // 40-50k ohms is still 4 ohms. where 40-50k ohms should be about your amp input impedance. You could use a 8ohm(10 watt). That will sound better. I would even try a 16ohm(5 watt). the less current you pull from that amp the better it will sound. Just make sure you adjust it so it doesnt put out to much voltage. And keep it close to your head unit! I dont know why people want such a high output voltage from there head units. all it will do is lower the s/n ratio between the head unit and amplifier assuming the amp sensitivity is adjusted low. what ever you feed to that amp from the head unit in terms of voltage is not added to the amps output. It is just sampled by a preamp. pobably an opamp.
------------------
Posts: 1247 | From: Fullerton. CA ,USA | Registered: Oct 1999
| IP: Logged |
Well, I wasn't trying for a free lunch (I have a 5v, 55ohm deck anyway ) But I was interested in the concept of doing it.. I mean, the manufacturers have to get voltage somehow, and some of them might actually do what I'm asking about.
ShadowStar
------------------
Computers are a lot like air conditioners.. Open Windows and they become useless..
The day Microsoft makes something that doesn't suck is the day they make vacuums.
Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
| IP: Logged |
Printer-friendly view of this topic