Here are my component values, any comments?

[Tdale]

Here are the values I plan to use for my Hybrid-a project. Do they seem right?

Clean1:
Plate - 220K
Cathode - 3.3K
Cathode bypass - 4.7 uF
Grid resistor - 22K


Clean2:
Plate - 150K
Cathode - 2.2K
Cathode bypass - 1 uF
Coupler - 0.047 uF
Grid resistor - 220K
Grid resistor bypass - 500 pF

Tone:
Two 500 pF in paralell, one switchable


OD1:
Plate - 180K
Cathode - 2.7K
Cathode bypass - 4.7 uF
Coupler - 0.01 uF
OD entrance: 180K into 100K trim into 68K grid resistor
After coupler: 100K into Drive pot


OD2:
Plate - 150K
Cathode - 2.2K
Cthode bypass - 4.7 uF
Coupler - 0.0047 uF
Grid resistor - 180K
After coupler - 150K into level pot


PI:
Pin 2 cap - 0.02 uF
Pin 7 cap - 0.1 uF

Grid resistors for 6L6 - 3.3 K

Does these look right?

[Bob-I]

Pretty close. A few things I'd change and a few values missing that I'd like to see.

1) Change CL2 bypass to 10uF
2) Change OD2 bypass to 5 (4.7)uF
3) Not as critical Change OD2 coupler to .005uF or .0056uF (PS series orange drops make these values)

What are your values in the tone stack?
What are the pot values and taper?
What's your screen resistors?
What's the rest of the values, plate resistors, tail resistor, presence control etc, on the PI?

BTW, I used 1.5K on the 6L6 grids. I don't know what the difference will be with 3.3K but I've seen schems with as high as 5.1K.

[Tdale]

Pretty close. A few things I'd change and a few values missing that I'd like to see.

1) Change CL2 bypass to 10uF
2) Change OD2 bypass to 5 (4.7)uF

I have the OD2 bypass at 4.7...did you mean CL2?

The rest of the PI is:

1M - 1M - 820 - 24K

Precense is 4.7K
Precense control is 1uF and 390R I'm having trouble getting a 2K pot, so I might go for a 5K and wire it to be 2K..

I'm going for a 250K mid pot, since I was adviced that.

Tone is 150K - 0.1 for bass and 0.047 for mid.

Screen 1K

The rest of the pots are standard hybrid-a values, not sure about log or lin at this moment..

By the way: CL1 is the first stage, CL2 is the second stage in my list, just to avoid any misunderstandings, you recommend:

CL1: 4.7 uF?
CL2: 10 uF?

Tommy

[Tdale]

or did I misunderstand..did you mean change from 4.7 to 5.0 ?

Tommy

[Bob-I]

Pretty close. A few things I'd change and a few values missing that I'd like to see.

1) Change CL2 bypass to 10uF
2) Change OD2 bypass to 5 (4.7)uF

I have the OD2 bypass at 4.7...did you mean CL2?

Sorry, you're correct then. I must be having reading problems

The rest of the PI is:

1M - 1M - 820 - 24K

Precense is 4.7K
Precense control is 1uF and 390R I'm having trouble getting a 2K pot, so I might go for a 5K and wire it to be 2K..

I actually didn't have much success with that. If you can't find a 2K pot PM me, I should have an extra I can send you. If I don't I'll order one the next time I place an order. They're about $2.

I'm going for a 250K mid pot, since I was adviced that.

Tone is 150K - 0.1 for bass and 0.047 for mid.

Screen 1K

The rest of the pots are standard hybrid-a values, not sure about log or lin at this moment..

By the way: CL1 is the first stage, CL2 is the second stage in my list, just to avoid any misunderstandings, you recommend:

CL1: 4.7 uF?
CL2: 10 uF?

Tommy[/quote]

Yep, that's what I ended up with on my amp, sounds GREAT.

The coupling caps to the PI are critical too. YOu've got .02uF for the input, make sure you have .1uF for plate 2.

I 'm a little torn on the 250k mid pot. I think it may lower the effectivness of the treble, but adds to the effectivness of the mids. You might want ot experiment yourself on that one.

[Bob-I]

or did I misunderstand..did you mean change from 4.7 to 5.0 ?

Tommy

The only reason I pt the 5uF is that dogears feels that even a small change in these caps has an effect. I ordered a bunch of 5uF caps to see if I can hear it too.

[Tdale]

In the PI, I use 0.1 for both plates, right?

Tommy

[Tdale]

I'm ordering some parts from mouser, and they have a 2K alpha pot, so I'm getting that.

Tommy

[dogears]

Actually Bob, I feel it is more important on the V1 tube. The V2 tube should be fine with 4.7uf. The issue on V1 is more of tolerence. Electrolytics have huge ranges! Sometimes 20% or worse!

I like the caps on the high side tolerence on V1 tube....

I'd also suggest trying the .01uf midcap when the amp is done. See which one you like more.

or did I misunderstand..did you mean change from 4.7 to 5.0 ?

Tommy

The only reason I pt the 5uF is that dogears feels that even a small change in these caps has an effect. I ordered a bunch of 5uF caps to see if I can hear it too.

[Bob-I]

Actually Bob, I feel it is more important on the V1 tube. The V2 tube should be fine with 4.7uf. The issue on V1 is more of tolerence. Electrolytics have huge ranges! Sometimes 20% or worse!

Which is why I order 10 when I need 2.

I like the caps on the high side tolerence on V1 tube....

I'll remember that. I need a cap meter now, mine's apparently hit the skids.

[Tdale]

To be sure:

Cathode bypass caps:

CL1 - 5
CL2 - 10

OD1 - 4.7
OD2 - 4.7

Is this a good start?

Tommy