Tube vs Solid State?

[skeptic]

I have always felt current is more important than wattage.

Ahem, ahem, pardon me but....Current IS wattage. Power =current squared times R where R is the resistance of the load.

[300A]

Ahem, ahem, pardon me but....Current IS wattage. Power =current squared times R where R is the resistance of the load.

I know what you meant Skeptic, but for the newbys, it is current times voltage (assuming no phase shifts) that is wattage.

One of the derivations of that formula is, as you mentioned, current squared times resistance. For those who are learning, that formula "breaks" down to current times resistance equals the voltage and then times the current again gives the wattage.

The current in the formula is RMS current, not peak or peak to peak current, for RMS wattage.

Just a technical correction.

[Geoffcin]

Ahem, ahem, pardon me but....Current IS wattage. Power =current squared times R where R is the resistance of the load.

Exactly, but I think what he means is an amplifier capable of delivering current into a low resistance load. As you know more than most people here, speaker resistance is not uniform. Some speakers dip as low as 2 or 3 ohms. If you hook one of these up to some poor designed amp, then ask it to deliver decent current, they get all flustered, and often just shut down.

A true sign of a "high current" amp is one that doubles wattage as the resistance lowers - i.e. 200 wpc into 8 ohms, 400 into 4 ohms, 800 in two ohms, ect.

[bturk667]

Ahem, ahem, pardon me but....Current IS wattage. Power =current squared times R where R is the resistance of the load.

Not all amps of similar wattage put out the same current. My 100 wpc amp put out more current than a 200 wpc amp that I was looking at. That's one of the reasons I chose my amp!

[300A]

Exactly, but I think what he means is an amplifier capable of delivering current into a low resistance load. As you know more than most people here, speaker resistance is not uniform. Some speakers dip as low as 2 or 3 ohms. If you hook one of these up to some poor designed amp, then ask it to deliver decent current, they get all flustered, and often just shut down.

A true sign of a "high current" amp is one that doubles wattage as the resistance lowers - i.e. 200 wpc into 8 ohms, 400 into 4 ohms, 800 in two ohms, ect.

True, it is another form of distortion if the current "can't" flow as it should when lower resistance loads are encountered. The current should increase, as the load is decreased, in a linear manner until clipping. Hopefully, the clipping will be soft in manner.

[topspeed]

Nothing like a good blood feud to warm up the new forum. How 'bout we debate Ford vs. Chevy now?

[FLZapped]

http://www.capacitors.com/picking_ca...rs/pickcap.htm

Picking Capacitors by Walter Jung and Dr. Richard Marsh from MIT.

Read the actual measurements for DA of electrolytic capacitors, the capacitance change vs temp, frequency etc.

DA factors of several percent for electrolytics, not what you seem to mislead below:

At what impedance? Did you miss the statement by the author that indicated the effect was swamped out as the circuit impedance went down? He actually mentions it twice. Now what was the circuit impedance we're talking about again? The output of an SS amp you say? Fraction of an ohm for the source and 8 ohms for the load. Hmmmm......

While this was in part a good article, it didn't shed any new light for those who were already experienced with all these things he mentioned in it.

-Bruce

[FLZapped]

Some people just refuse to learn. No SS amps use capacitor outputs, and if they did, they sure would NOT use electrolytics.

You forgot class A power amps:

http://sound.westhost.com/project36.htm

Looks like an output coupling cap to me. (Figure 1.)
Oh and don't forget the amp design in Figure 4.

And remember Dynaco?

http://home.insightbb.com/~dunn.greg/ST120/schem2.jpg

Can ya read japanese?

http://www.intio.or.jp/jf10zl/EF.htm

Can't resist, one more:

http://www.tcaas.btinternet.co.uk/jlh1996.pdf

See page 6.

And SS doesn't need output transformers. Your making no sense.

Gee, someone should tell McIntosh.

Get a grip on yourself Skeptic and at least try to learn. Ignorance is not to be celebrated.

Ahhhh, ad hominem attacks. You're beginning to sound like Jon Risch.

-Bruce

[FLZapped]

You have got to be kidding. Name some brands that use caps on the output. I want to read those high quality brands.

Now you're squirming....you made no mention of brand in your original assertion.

-Bruce

[RGA]

Now you're squirming....you made no mention of brand in your original assertion.

-Bruce

I'm not a techie by any means. But My Sugden A48b according to the review is completely DC coupled and has no capacitors of any kind in the signal path.

"One feature of the A48B is its plug-in, d.c. coupled moving-coil/moving magnet phono board.../...[s]ince i have mentioned d.c. coupled--there is not a single capacitor--of any value or description -- anywhere in the signal path." (Australian Hi-Fi).

Whatever this gobbledygook actually means it sounds good and I won't have to replace the capacitors.

[FLZapped]

Not all amps of similar wattage put out the same current. My 100 wpc amp put out more current than a 200 wpc amp that I was looking at. That's one of the reasons I chose my amp!

Huh? This makes no sense, both amps into the same load and same power output will have exactly the same current output.

Care to rephrase that?

-Bruce

[mtrycraft]

Not all amps of similar wattage put out the same current. My 100 wpc amp put out more current than a 200 wpc amp that I was looking at. That's one of the reasons I chose my amp!

Well, first of all, 100 watts and 200 watts are not similar amps. One puts out 2X power, so it has to put out more current into the same load, no?
100watts into 8 ohms = 3.53A
200watts into 8 ohms= 5A

Please explain what you really mean.

[300A]

You forgot class A power amps:

http://sound.westhost.com/project36.htm

Looks like an output coupling cap to me. (Figure 1.)
Oh and don't forget the amp design in Figure 4.

And remember Dynaco?

http://home.insightbb.com/~dunn.greg/ST120/schem2.jpg

Can ya read japanese?

http://www.intio.or.jp/jf10zl/EF.htm

Can't resist, one more:

http://www.tcaas.btinternet.co.uk/jlh1996.pdf

See page 6.

considered to be the best in the world.


Gee, someone should tell McIntosh.




Ahhhh, ad hominem attacks. You're beginning to sound like Jon Risch.

-Bruce

In my opinion, the Dynaco and new Zen, are a long way from being the best sounding in the world. Didn't even look at the third. And only three listed? How many hundreds of better sounding brands don't use output caps.

[300A]

At what impedance? Did you miss the statement by the author that indicated the effect was swamped out as the circuit impedance went down? He actually mentions it twice. Now what was the circuit impedance we're talking about again? The output of an SS amp you say? Fraction of an ohm for the source and 8 ohms for the load. Hmmmm......

While this was in part a good article, it didn't shed any new light for those who were already experienced with all these things he mentioned in it.

-Bruce

Lower resistances only lower, to minimize the effect. However, the cap still has these effects. Simple experiment. Simply take a large bipolar and connect it in series with a DC couple amp. Now we are working with 8 or 4 ohms, so very low impedance circuit. But the sound changes substantially. Point made.

As a coupling capacitor is "swamped", the low frequency response also raises, so another problem. So we must now increase the capacitor size, adding more problems with DF or ESR.

Still not an ideal situation, to be sure.

[300A]

Huh? This makes no sense, both amps into the same load and same power output will have exactly the same current output.

Care to rephrase that?

-Bruce

Depends on the collector voltage, or Vcc. If Brand A has much higher Vcc voltage, but limited current rating, then it is designed for higher impedance loads.
The output devices may not be capable of sustained high currents like brand B.

Brand B may may have lower Vcc voltages, but is designed for lower impedance loads by using higher current output devices, or more of them.

[300A]

Well, first of all, 100 watts and 200 watts are not similar amps. One puts out 2X power, so it has to put out more current into the same load, no?
100watts into 8 ohms = 3.53A
200watts into 8 ohms= 5A

Please explain what you really mean.

Only partially true. The output devices will only put out the same current until the output devices of amp A reach their limit, either current capability of the device or collector dissapation, so is limited in the low impedance that can be applied without destroying the devices. Amp B probably has higher current devices and/or higher collector dissapation ratings.

[300A]

Now you're squirming....you made no mention of brand in your original assertion.

-Bruce

Ah, but I did mention PA and school systems didn't I. Nothing of high sonic quality, to be sure. Capacitors, in cheap systems, are used to keep DC off the 70.7 volt trannies, so they won't blow if an output transistor does blow. Reliability over sonics in these situations.

If you think dynaco SS amps are great sounding amps, LOL.

[bturk667]

Huh? This makes no sense, both amps into the same load and same power output will have exactly the same current output.

Care to rephrase that?

-Bruce

I don't think they will when it comes to peak output.

[maxg]

Tubes are expensive - Tee Hee
Tubes are low power - Tee Hee
Tubes dont do bass - Tee Hee

For what it is worth I bought a tube amp from a local manufacturer here in Greece (www.tsakiridis-devices.com) that is a 70 wpc amp (with EL34's - or 100 wpc with KT88's/6550's) - The powerhouse.

The price for that unit, brand new, and including the 8 EL34's (Harmonix), VAT, packaging and everything else except cabling was a princely 1,070 Euros (about $1200).

In other words about the same price as a reasonable SS 2 channel receiver (not a top of the range one).

This unit is a dual mono design with a single, separate power supply (1 KVA) and weighs in at a tidy 25 Kg for the unit itself (around 55 lbs) with another 14 Kg for the power supply.

How does it sound - well these things are in the eye of the beholder (or is that ear?) but suffice to say I have owned supposedly very good SS amps (Accuphase) and I prefer this (despite its being half the price of the cheapest Accuphase over here).

Of course if 70-100 wpc is not enough for you there are always the big brothers of mine to consider (the Electras) with 150 wpc using EL34's or 200 WPC using KT88s/6550s. (1750 euros or 2350 euros).

Of course they do the SET thing too. 300B amps with a mighty 8 wpc - but it just didnt drive my speakers so it wasnt for me.

[FLZapped]

Well, first of all, 100 watts and 200 watts are not similar amps. One puts out 2X power, so it has to put out more current into the same load, no?
100watts into 8 ohms = 3.53A
200watts into 8 ohms= 5A

Please explain what you really mean.

He was saying his 100 watt amp put out more current than his 200 watt amp originally, so I was trying to get a clarification......besides he fact that each running at the same power output would produce the same current flow into the same load impedance.

-Bruce

[FLZapped]

I don't think they will when it comes to peak output.

Okay, but then I also think if you go look at the specs and compare the two, you'll probably finds the 200 watt amp isn't rated for the same load range as the 100 watt amp, correct?

-Bruce

[FLZapped]

In my opinion, the Dynaco and new Zen, are a long way from being the best sounding in the world. Didn't even look at the third. And only three listed? How many hundreds of better sounding brands don't use output caps.

Hey, you made the blanket statement that SS amps do not use output coupling caps, nothing about brands, quality, yad, yada, yada.....

Well, you were obviously wrong, now are you just going to admit it, or continue to try and squirm out of the fact you made a blanket statement?

-Bruce

[FLZapped]

Lower resistances only lower, to minimize the effect. However, the cap still has these effects. Simple experiment. Simply take a large bipolar and connect it in series with a DC couple amp. Now we are working with 8 or 4 ohms, so very low impedance circuit. But the sound changes substantially. Point made.

PLease show any data that support the idea that the sound changes substantially in this configuration.

So we must now increase the capacitor size, adding more problems with DF or ESR.

Still not an ideal situation, to be sure.

Really, I guess you also missed that paralleling capacitors will help mitigate the effect, no? Granted it may not be ideal, but it isn't disasterous, either.

-Bruce

[FLZapped]

If you think dynaco SS amps are great sounding amps, LOL.

Oh wow, now you're a mind reader as well......

-Bruce

[FLZapped]

Ah, but I did mention PA and school systems didn't I. Nothing of high sonic quality, to be sure. Capacitors, in cheap systems, are used to keep DC off the 70.7 volt trannies, so they won't blow if an output transistor does blow. Reliability over sonics in these situations.

If you think dynaco SS amps are great sounding amps, LOL.

Really.......

Some people just refuse to learn. No SS amps use capacitor outputs, and if they did, they sure would NOT use electrolytics.
And SS doesn't need output transformers. Your making no sense.

Tubes can't use capacitor outputs unless in an OTL or Cyclotron designs. The current capabilities are too low and the output Z is too high. And if one uses a cap on the output of an OTL, it is for disaster protection, not because of the sonics. And even then Polys would be the choice, not electrolytics.



I don't see any such mention.

-Bruce