Millett "Starving Student" hybrid amp - Page 125

Would high-quality resistors have any real world effect at the inputs? If not I'll just pick up whatever radio shack has instead of paying $5 shipping and waiting for a mouser order.

Another question, this was suggested awhile back:
I have the 2 extra film caps sitting around, what would adding these do and do you just solder them to the junction before and after the output electrolytic caps?

My point was just that metal-film 1% resistors are commonly available at my local electronics shop (Al Lasher's -- hardly a high-end boutique but rather the kind of place one's grateful still exists) and worth it to me to match channels. But I have not compared with RS standard issue so I can't claim to hear any difference.

You wire the film caps in parallel with the electrolytics. In other words, the films attach to the same points as the 'lytics.

thanks that makes sense, but how would the film caps effect the sound?

Caps act as a sort of reservoir of power. So, for example, when a big bass note hits, there is a larger momentary demand for power. The capacitor is what supplies this. A good analogy is a sink of water. The faucet can only supply a steady amount of water, but what if the size of the drain varied? The sink would be able to buffer the needed water. Does that makes sense?

OK, now if you understand what the caps are doing, then you can understand what the extra caps do in this circuit. Electrolytics are slow (relatively speaking) to respond to those changes in demand, but they hold a lot of power in them. Film caps respond very quickly, but are very small reservoirs of power. When you put the two in parallel, you have the big capacity of the electrolytic combined with the fast response of the film.

I'm sure this is an over simplification, but it's the way I think of it. Someone can correct me if I'm wrong

Thanks for the simple explanation. I know how capacitors work so I got the power reserve part. But I did not get how the tiny film cap would make a difference. Nice to know electrolytics are slow and films fast, makes sense now.

I've put a few hours of listening on this and it sounds good, but not amazing. I was expecting to be able to hear a considerable difference between the SS and the built in amp in my emu0404, yet I can hardly tell the difference between them. Although I am impressed with there being no noticeable hiss or hum, after building it I was half expecting some noise from a poor joint or something.

I am having a hard time locating two sets of tubes. Any suggestions?

Try Orlando Vacuum Tubes

They are very reliable and quick.

If you could, try and find some top square getter tubes as I have found them to be the best sounding of any of the tube types with the much more common side D getter style comming in second. The top square getter also have a bit more treble than the other tube types so keep that in mind.

Well I checked with Orlando Tubes and they are out. He said that he ordered about a thousand a while back and they went quick. He is expecting some in about a week or two.

Here is the frustration. I was going to give a SS away at the local meet this weekend and I am not going to have them. If someone can give up 2 pairs I would appreciate it.

I guess when they some in I will need to order many pairs.

Someone pointed out to me that my description was accurate for a power coupling cap, but the ones your asking about are DC decoupling caps. I liked the analogy he shared with me, so I'm gonna steal it and take all the credit

(just kidding, ruZZ.il deserves the credit for pointing out my error)

Let's build on the water/sink analogy. We will call the water flow DC current. The AC (the music signal) is represented by changes in the flow or pressure. Now lets put a rubber membrane into the pipe to block the water. So now it won't let the water flow (DC) but the changes in vibration will make the membrane vibrate, so those are transferred down the pipe (ie the AC signal or music). Again, the difference between the caps is a speed issue. Films respond faster, but to smaller vibrations. 'Lytics respond to the larger changes at lower frequencies. It makes sense to me, but I'm not sure I'm explaining it well.

Thanks for the PM ruZZ.il
I'm learning a lot about electronics still, so every little bit helps

^I think you explained it very well.
Cap size(capacitance) would equate to the membrane size and flexibility, or with your film/lytic it is the ability of the membrane to "snap back" or "recover" to it's original position, as the AC signal(music) goes back and forth.

'mazing - all those tubes are gone already...i have a hunch the SS will become an expensive and sought after piece of collectible in the future...i think the design should be modded to accept other tubes to keep it going...pete - how bout the rolling tube SS mod?
k

no prob. I'm learning a lot too =)

I just nabbed 2 pair myself. Now to grab the backordered caps, and the sockets for the tubes, then a building I shall go.