Coming soon: Rocket!

[keithrick]

Hi everyone,

It seems like John is going to get the best of both worlds!!

Paul, Nice comparison of the different values, the switch sounds like a great idea.

I do not want to derail the thread because I believe everyone is learning from this discussion but I had a question about the best way to impliment the switch.

What is the best way to impliment the switch? In series using a DPTP switch?

For example: Have your values on the board, 300pf treble cap and 1000pf coupling cap. Then switching in (series wiring on each side of switch) a 55pf treble cap and another 1000pf treble cap mounted on the switch. Effectively giving you a 47 pf treble cap and 500pf with the switch engaged?

Can anyone describe the sonic differences between switching series or in parallel? Is there a preferred way? WWKD? (What would Ken do)

[tubedogsmith]

Paul, what are you using for an OT. I'm using a 4k, 50 watt, HiFi design, no farty stuff at all. Did you try .047 in the PI. That may work better with your trannie.

[johnspeck]

Time to add a swtich. John! need to decide if that switch goes on top of the chassis, hidden away or if you want it right on the front face.

- Paul

Where do you think it would best be located? I don't mind it on the top of the chassis, accessable from the back.

[Mark]

Dear Tubedog Smith

I have a couple of questions. Why did you decide to use a ceramic cap for the 50pF treble cap?

How come you ditched the bright cap across the volume control?
I love what that does to a Strat.

Last question audio from both parties?

I will have to get my prototype in one piece and record it, just for comparsion sake.

[paulruby]

Time to add a swtich. John! need to decide if that switch goes on top of the chassis, hidden away or if you want it right on the front face.

- Paul

Where do you think it would best be located? I don't mind it on the top of the chassis, accessable from the back.

Hi John,

There is an obvious spot for it on the front face, right where the express bright switch is. BUT, since we didn't paln for it, there is no lettering for a switch. It would be a "mystery" switch. If it were me, I would put in on the front anyway. But, it's your amp and I cn just as easily put in on the top of the chassis to keep it hidden. Your choice! But, I do think the amp should have a switch for this.

[paulruby]

What is the best way to impliment the switch? In series using a DPTP switch?

Parallel caps of the same type will sound identical to a single cap. So, I will implement using the smaller values hardwired on the board and thw switch will be a DPST to add the larger values in parallel.

The board will have 470pf coupling cap and 47pf treble cap. The switch will add 470pf to the coupling cap and 220pf to the treble cap.

[paulruby]

Paul, what are you using for an OT. I'm using a 4k, 50 watt, HiFi design, no farty stuff at all. Did you try .047 in the PI. That may work better with your trannie.

I'm already only using 22nf PI coupling caps. The iron is from Moose (standard wreck iron). Running 360V B+.

The bass content is perfect for the neck pickup playing clean very nice lush tone. Early breakup is FAT and bluesy (Fendery). Heavy break up is a little farty, but not nearly as farty as a Fender would be. Seems to need a touch of NFB or a bit more bass roll-off up in the preamp to really paly it hard.

I think I'll try reducing the coupling cap value a bit more tonight...

[paulruby]

Last question audio from both parties?

I suck at making audio clips. They NEVER capture what I'm really hearing and don't give me the same gut response. So... I avoid trying to make them...

But, I have a freakin' studio and pro recording gear... So... Maybe I should stop being a weenie and just do it.

[paulruby]

What is the best way to impliment the switch? In series using a DPTP switch?

Parallel caps of the same type will sound identical to a single cap. So, I will implement using the smaller values hardwired on the board and thw switch will be a DPST to add the larger values in parallel.

The board will have 470pf coupling cap and 47pf treble cap. The switch will add 470pf to the coupling cap and 220pf to the treble cap.

Oh yeah... And 2.2M resistors across the switch to avoid a POP when switching.

[johnspeck]

FWIW, I run top boost AC30's as follows, so you can try this and see if it farts:

volume full
bass and treb at "0", cut completely clockwise (which is no cut, IIRC)

Then I add a small amount of bass, usually no more than 9 on the clock, and maybe a teeny bit of treble if I'm using humbuckers.

Running into an open-back cab with two 16 ohm Weber 30-watt alnico Blue Dogs @ 8 ohms total.

That's where I'll probably start tweaking.

[johnspeck]

Paul, I don't mind the switch up front where the bright would be on an Express. I prefer a spartan layout, so I'm all for no labeling.

Thanks for all the cool work! It's very much appreciated.

[paulruby]

FWIW, I run top boost AC30's as follows, so you can try this and see if it farts:

volume full
bass and treb at "0", cut completely clockwise (which is no cut, IIRC)

Then I add a small amount of bass, usually no more than 9 on the clock, and maybe a teeny bit of treble if I'm using humbuckers.

Running into an open-back cab with two 16 ohm Weber 30-watt alnico Blue Dogs @ 8 ohms total.

That's where I'll probably start tweaking.

Will do! And the switch will go up front.

[tubedogsmith]

Paul, what are you using for an OT. I'm using a 4k, 50 watt, HiFi design, no farty stuff at all. Did you try .047 in the PI. That may work better with your trannie.

I'm already only using 22nf PI coupling caps. The iron is from Moose (standard wreck iron). Running 360V B+.

The bass content is perfect for the neck pickup playing clean very nice lush tone. Early breakup is FAT and bluesy (Fendery). Heavy break up is a little farty, but not nearly as farty as a Fender would be. Seems to need a touch of NFB or a bit more bass roll-off up in the preamp to really paly it hard.

I think I'll try reducing the coupling cap value a bit more tonight...

You're using one of the 5.2k/6.6k OT's?

[paulruby]

Yes. 5.2k.

[tubedogsmith]

We're talking apples and oranges. My amp runs 300v b+ on the output tubes. I'm using a 220k plate resistor on the first stage too so the voltage is pretty low all the way through. Even with the lower voltages I'll get a bit more headroom and a smoother tone with less hair on it with the 4k trannie. I just went and looked at the stuff in the files section and the schem posted there looks like the one Two Rock used on some of their Wreck clone amps. The .001 mid cap and 500pf treble cap is a pretty smooth sound with tons of midrange. They use the 500pf input cap too.