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cGil

Baby Will project

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Okay, here's the porn of the Baby Will I just finished up.

 

Notice this thing has a Valve Standard PT for the maximum 18 watts of output power that may not be available with the VJr PT. It's also built into a v1 VJr chassis, which meant I had to squeeze the turretboards.com Heyboer OT slightly off the back side to get it away from that noisy VStd PT and give the tubes clearance they needed for heat dissipation. It was the only way to make the OT totally quiet and stop picking up hum from the PT. The addition of the 100R Fender hum balance pot and 100R/1w metal oxide resistor eliminated all heater hum. This 18watt lite Baby Will is punchy and loud and about as good as it gets for 18watt Marshall tone.

 

Gil...

 

http://i166.photobucket.com/albums/u103/cgil155/BabyWill-1.jpg

http://i166.photobucket.com/albums/u103/cgil155/BabyWill-2.jpg

http://i166.photobucket.com/albums/u103/cgil155/BabyWill-3.jpg

http://i166.photobucket.com/albums/u103/cgil155/BabyWill-4.jpg

http://i166.photobucket.com/albums/u103/cgil155/BabyWill-5.jpg

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Gil, thanks for posting these- this has really made up my mind on whether or not I was gonna do one. (I've already

downloaded the manual and put it into a ring binder) Your tip on finding a cheap Ver1. on Ebay was good advice as well that's already got me on the hunt for one. Couple, (of many to come I'm sure), questions... what is the pot on top of the chassis without a knob? How do you get two 8 ohm taps and a 16 instead of the usual 4,8, 16? Are you using the regular gold mod values or have you tweaked a few and if so to what end? What are you currently running for tubes and is it now imperative that they be matched pairs? Finally, (at least for now), what are your plans for speakers cabs to maintain the 18watt Marshall vibe? The porn looks great, I got a stiffy from it.....

 

Wedgie

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Well, my take on it at this point is that the whole build would be a little easier if I had started with a v2 or v3 chassis. Not much, but a little for the sake of transfomer location. Either way, there's still a whole lot of drilling going on, just to get the board mounted.

 

The pot on top without a knob is the 100r/2w linear Fender hum balance pot. It's the one you'll see inside the chassis by the power cord jack. I already had this pot, so I used it. The small, 10-turn 200r, pcb-mounted trimpot that's recommended in the Mouser parts list would probably be the better option.

 

The OT is a Heyboer from Turretboards.com. That OT only has the 8 and 16 ohm taps, so, I rigged up parallel 8 ohm jacks in case there was a need of hooking up two 16 ohm cabs (8 ohm load).

 

The amp is pretty much built according to the schematic with a few minor tweaks. I added 0.68uF poly caps in parallel to the regular electrolytic cathode bypass caps cuz I like the smoother sparkle and chime they help get passed through the amp to the speakers. And I used a 47uF in the first filter cap to kill a squeal, and for the rest I used old 22uF filter caps I had pulled from old VJr's. Since I used a VStd PT, I used a 300r sag resistor to drop a few of the extra volts on the rail.

 

I used the original 18watt trem channels input jacks, the high gain channels parallel input stage, and the trem channels standard tweed tone pot. I also added a Loop-D-Jr, right before the volume pot, of course!

 

The amp isn't mine, and the tubes in it aren't matched. Just gives less headroom and earlier crunch. And maybe you have to tweak the hum balance pot a little farther one way or another. No sweat.

 

Subjectively speaking, I think it sounds best through my Heritage G12M 20w Greenback. Perfect bottom end, mids that'll cut through anything, and sparkle and chime to die for. Kinda risky, though if I run it full blast all the time for hours on end with this amp. Someday I'd like to get a matching 1x12 extension cab with a Heritage G12H 55Hz 30w, to help spread the juice, add more beef, and raise the combo cab up closer to ear level. Some folks prefer the 55Hz G12H to the 75Hz G12M Greenback for the extra definition down low, and for the extra power handling when there is only a single speaker involved.

 

These 18watt amps also sound really good through a Jensen P10r, but it's not as efficient of a speaker, so it's just not quite as loud as the Greenback. With my Celestion Alnico Blue it sounds like it's got a blanket over it. With my Vintage 30's I just want to yawn and nod off. With my EV12L's it's too screechy and I wanna run and hide. :-k

 

Get your bibs on. Here's what Baby Will would look like if it could. The chassis, face plate, iron, and board came from Graydon at GDS Amps. The equally impeccable quality cab came from Anthony at Reason Amps.

http://i166.photobucket.com/albums/u103/cgil155/18watt01.jpg

http://i166.photobucket.com/albums/u103/cgil155/18watt01-4.jpg

 

Gil...

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Purdy! Nice looking amps!

 

I personally don't think that teeny tiny, flimsy little 10 turn trimmer should be on an amp at all. I had no hum whasoever simply using 2 x 100r fixed resistors. Of course, matched tube pairs then becomes a must, but that's a no-brainer.

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Yes, the VVR will work on just about any amp, as far as I know, although the bigger they are, the more heatsinking is required. For this one, simply getting a super-clean, super-flat place on the chassis to mount to, and using a good insulator along with heatsink compound will suffice.

 

I've got a complete board from Dana that I'm not using. Email me if you're interested.

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Hi M.. I have the Dana VVR boards in my VJ's but if you read the thread on SEwatt there was an initial problem with the VVR in the Baby Will.

 

I think someone has "fixed" this issue on 18watt.com

I seem to remember they had a really cool VVR pot with a switch on it for a/c.

So instead of a big red button and a dial for the VVR the pot/switch acted as one unit. switch on and then power scale what you wanted.

I'll head back to 18watt to see if I can track down where they got that pot/switch.

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there was an initial problem with the VVR in the Baby Will.

It's only an issue when you reduce the volume significantly (well below half power on the VVR). I don't believe it's got anything specifically to do with this particular amp, however. It seems that it's something that would/could be a potential issue anytime the VVR is installed and is used to create significant power reduction.

 

As I recall, the "fix" is to install a PPIMV, if you must use the amp at low enough volumes that the VVR voltage leak issue becomes problematic, so that you can keep the VVR higher and maintain lower volumes. My "fix" was to deal with the very minor volume pot scratch issue until I decided that I really didn't need the VVR after all.

 

Btw, and fwiw, scope readings indicate that the VVR barely touches output tube bias, until you get down to about 1/4 throttle and below (which, of course, is also the point at which it's creating pot scratch, when it does).

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Howdy folks,

 

Well I took Gils advice after my last post several months back to do a Baby Will. I kinda ordered a bit at a time and have all the parts together to start except for a few 2 month back orderded parts from mouser I'm really impatient to get and am looking for tips on where I can get these 1 watt 100k metal film resistors and a few others. Which sort of leads me to wanting a deeper understanding of some of these parts - like for instance can I just use a Carbon Film or Metal Oxide of the same value and how much it might effect the tone. I know I certainly felt like I could hear that little bit of Mojo when I put the Carbon comp in my EVJr's and so I don't want to mess with the intended tone too much inadvertantly. Any insight or tips on further online reading would be appreciated.

 

Thanks!

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The current incarnation of the Baby Will pcb is much quieter than the original one I built up. I'm sure you'll love it.

 

For the preamp, 1/2 watt resistors are the bare minimum rating required for the job, so if you can find 1/2w metal film resistors, those will do. However, I generally use 1w carbon film resistors in the preamp and they're plenty quiet. I wouldn't recommend a 1/2w carbon composition resistor anywhere but the PI plate resistors. It's a signal to noise ratio thing; so those CC's will be pretty hissy if you use 'em on the input tube's plates. Use only Metal Oxide (flame resistant) or ceramic wirewound (cement block) power resistors in the power supply and power tube's bias resistor.

 

Gil...

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Really nice!! I will try to copy that as exactly as I can.

otherwise I may wind up with....

never mind!

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[thumbup] I just gotta bump this thread up having finished my Baby Will (after 3 EV Jr mods) and all I can say is do it now! If you've already done tweaks you love on 1 of them just be sure you got your safety thing together (google or talk to an amp tech until your clear on how to drain your filter caps and take readings safely) and then convert that EVJr into a Baby Will!! It is a really great sounding amp - lots of sparkle and plenty of girth - enough that my P-bass sounded good through it too!!!

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Very nice! Some "tube sniffers" would dis the PCB instead of PTP wiring' date=' but if it's done properly, I don't see a thing wrong with it...rock on! =d> [/quote']

 

Nuthin' wrong with using PCB..but.. PTP is "old school"..was good enough for Leo

(Fender) and it should be good enough for us.

 

As long as one can do it neatly and ensure the lead dress is done properly. :-({|=

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The board that I got for the Baby Will is really built like a tank - a fine piece of workmanship and design - basically idiot proof and that's part of what makes it a great first project graduating from the EVJr's - and it drops right into the EVJr chassis with just a few tweaks : )

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Nuthin' wrong with using PCB..but.. PTP is "old school"..was good enough for Leo

(Fender) and it should be good enough for us.

 

As long as one can do it neatly and ensure the lead dress is done properly. [confused]

 

Actually none of Leo's amps were true PTP.....they were eyelet board construction for the record. True PTP has no turret,eyelet or tag boards at all.

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He was just thinking about the way I do it.. *L*

 

I got another noisy one today.

Hoping it's the star ground up front being too close under the board to R5.

 

salimw.jpg

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Someday soon Twang - I think I've got maybe one more paint by number build and a bit more reading to do before I take the leap into PTP... not that it's killing any of the joy I felt when I heard Baby Will for the first time - gotta get this thing out and about but the old F-30 might be up Craiglist soon as happy as I am with it so far : )

 

You know while I'm at it I'd really like to thank the bunch of you here again for the help on the several builds - I may not be posting often but I've gotten so much mileage out of the builds I've done and there's nothing quite like bringing your own build to a jam and blowing away your boutique amp buying buddies (not that I wouldn't if I could ; ) with something you've built yourself!

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I need to make my boards about half an inch longer on the preamp side..and maybe as much toward the rear panel as well.

but I had this stuff already cut.

 

I want to find the black stuff that's not so fiberglassy toxic.. mcmaster carr, I think.. but I don't know the part no.

It would certainly make building the boards up a lot less icky. I hate that huge mask.

 

I really dig playing my vj for people that drop by. It's pretty neat to hear someone say their mesa boogy, or other.. sounds just like that!

 

TWANG

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