Pictures of my finished Hybrid-A

[Tdale]

Here are som pictures of my (almost) finished Hybrid-A. I haven't connected the cathode resistors/bypass caps to ground yet, but that's about all I got left....and of course powering it up...

Some special features:

Two bias pots
10-turn pot for OD entrance, adjustable from underneath the chassis
10-turn pot for PI plates, adjustable from underneath the chassis
Switchable local negative feedback (two mini switches underneath)
Switchable effects loop / no effects loop, located underneath the chassis.

Grounding is the thing that always gives me trouble. Where should stuff be grounded..in what order, how many grounding points, bus or star ground. This is what I ended up with..and hopefully it'll work and be quiet!

If any of this turns out not to work, I'll just change it..it's as easy as that.

Now I need to make a cabinet..

[Tdale]

Here are a couple more

[Normster]

Get some tubes in that amp, Tommy! Time to crank it up!!!

[Tdale]

Tubes are on it's way.. I forgot about the 6L6's... never thought about that I don't have any until last thursday...so I ordered a matched pair of Electro Harmonix, and 3 EH 12AX7 too.. Not sure aobut them, but I'll try. I have some JJ preamp tubes on hand too, so I can try them aswell.

Just need to check the schematics again, and make sure every part is in place.

On the schematic, there is a 4.7M resistor to ground from the treble cap... is that necessery? I wired it a bit differently...I have the caps in paralell, and switches one in or out of the circuit, in stead of series, where one is bypassed.. should I use a resistor to ground there?

Tommy

[Normster]

Tubes are on it's way.. I forgot about the 6L6's... never thought about that I don't have any until last thursday...so I ordered a matched pair of Electro Harmonix, and 3 EH 12AX7 too.. Not sure aobut them, but I'll try. I have some JJ preamp tubes on hand too, so I can try them aswell.

Just need to check the schematics again, and make sure every part is in place.

On the schematic, there is a 4.7M resistor to ground from the treble cap... is that necessery? I wired it a bit differently...I have the caps in paralell, and switches one in or out of the circuit, in stead of series, where one is bypassed.. should I use a resistor to ground there?

Tommy

It's there to bleed the cap to ground so it doesn't pop when switching. No harm in leaving it off, and if you get popping while switching you know what to do about it.

[Tdale]

Since I have caps in paralell... do I put the resistor before or after them..? Before I'd guess....?

Tommy

[dogears]

Where are your snubbers on V2?? 270pf from 1 to 3 and 6 to 8

I'd also recommend cearmic instead of silver mica on the grid bypass of V1B.

[Icetech]

270pf?!?1 i have 390's in mine i think:( it never ends:)

[Tdale]

right! I forgot about them... thanks for reminding me. I'll cange the bypass too.

Tommy

[yeahyeah]

noob here, how/where do you guys get such nice looking chassis-es?

[Tdale]

I made mine of 3mm (1/8") aluminium. Went to a place where they make stuff of metal, and had them bend it and weld the sides, and then I drew the front and back, and sent it to a guy that makes stickers...

Tommy

[hipbluescat]

Hello

I am interested in the

10-turn pot for OD entrance, adjustable from underneath the chassis
10-turn pot for PI plates, adjustable from underneath the chassis
Switchable local negative feedback (two mini switches underneath)
Switchable effects loop / no effects loop, located underneath the chassis.

Is this the most practical way to have these pots located ?

Regards

[Tdale]

Here is an uptdate.

I removed the switch for the effect loop.

I only have one local negative feedback, but installed two switches if I ever need one. I'm having problem deciding if it sounds best with or withouth the LNF....

The two 10-turn pots are put where they are, in order to be as close to the circuit as possible. The pots aren't used very often, they are adjusted and stay in that position, still it's nice to be able to do adjustments without having to remove the chassis every time.

Have any of you had problems with the bis pots changing position if you play loud? Seems like the vibrations of the speakers could make the pots turn slightly.... I got different bias current readings than what I adjusted them to a couple of days ago. I taped them in place, just to be sure

Tommy

[RJ Guitars]

Dale,

Would you be willing to share your source for the front and rear panel stickers? I've got a design but no source to have them printed...

Thanks

rj

rjguitars at comcast dot net

[Tdale]

I used a friend who does that kind of work. But I'm located in Norway, so that might be a bit far.. There should be someone who does that kind of work in the us. Kinko has been mentioned. Maybe a google search would be helpful?

Tommy