More wasted space

[jerluwoo]

Havnt had a connection for a bit so Im posting this up from a friends house. This is a very nice sounding little hybrid amp that i built recently. schematic is in 2 parts starting with the tube front end. I could tell you how i think this arraingement works but it would probly be false and misleading and im not in the habit of spreading propaganda. have fun and enjoy.

p.s. sorry for th e poor quality just did them up quick with paint.

 

[jerluwoo]

here is the transistor output section. the 20k pot sets offset and the 100 pot set bias current.

 

[SY]

Try cutting out the bypass cap across the LED. You might be pleasantly surprised.

 

[Sheldon]

Try cutting out the bypass cap across the LED. You might be pleasantly surprised.

I've wondered about this. In principle, the cap shouldn't have much work to do there, so shouldn't have a major effect. But of course, subtle cues are another matter. What kind of effects have you noticed?

Sheldon

 

[SY]

rdf did some work on this and found it to be a detriment. When you calculate how much capacitance you need to effectively bypass something with a 5 or 6 ohm impedance, you're talking about a pretty big cap, so the bypassing may be adding more than it's taking away.

 

[Sheldon]

rdf did some work on this and found it to be a detriment. When you calculate how much capacitance you need to effectively bypass something with a 5 or 6 ohm impedance, you're talking about a pretty big cap, so the bypassing may be adding more than it's taking away.

Hadn't thought of it that way. So it "suck it and see" as our friends from down unda might say.

Sheldon

 

[jerluwoo]

just a quick post of the power supplies i used.first the tube section.

 

[jerluwoo]

the ss section.

 

[jerluwoo]

Thanks for the tip SY will try removing the cap when I get home.

 

[jerluwoo]

Yes Sy eliminating the cap made a small but noticable difference. It seemed to make the amp sound "faster" most noticably in the midbass area. Made a couple of changes as well to schematic. I eliminated feedback alltogether and raised the 2.2k resistor in the tube section to 4.7k to raise the gain and eliminate the need for a preamp. It sounds much more open without the feedback and seems much easier for the source to drive it.