Vox styled build: Thrills 'n Chills!

*Obnoxious long 1st post*

Hey gang! I'm back for my second build.
1st build: http://www.tdpri.com/forum/shock-brothers-diy-amps/312008-my-tweed-champ-kit.html
I'm posting a tad prematurely while waiting for parts, but I intend to do a thorough build share and have lots of info to start.
Background: After dropping several hints about doing a Dave Hunter Two Stroke and getting as far as procuring transformers, I have switched to an AC15 styled amp build!! I used to not like the Vox because I was in a band as the lead guitarist using a Deluxe Reverb, while the singer played rhythm through an AC15. He always cut through the mix live and on recordings, while I constantly needed to turn up to be heard, which prompted the keyboard player to turn up, which made our stage volume too loud! However, now that i'm in a 3 piece rock band, I'm craving that chimey crunch that the original Voxs are famous for.
Thanks: Tdpri for hosting such a fun forum, Steve Hunter for tolerating me as a part time assistant tech and inspiring and guiding the build, Vox! for obvious reasons, and all who "chime" in with insights etc.
To be continued for future skipping of this post...

The Amp: A Vox AC15 hybrid in a combo amp. AC15 normal channel (12ax7, not ef86 at the recommendation of my friend who likes the ef86 in a head, but thought for a combo amp it would be/ become microphonic) and the Top boost channel from an AC30.
Layout: Normal channel: Volume, Tone. Top Boost channel: Volume, Treble, Bass, Presence. Of course I love reverb and trem, but already have a Peavey valverb and fender reverb unit, and this is only my second build for goodness sake!!!! Steve did throw out a wild card option for a tremolo circuit from an ampeg design. Tubes: 3 x 12ax7, 2 x el84, 1 x 6ca4 rectifier.
Look: Subject to change, but I ordered an oversized 5e3 bare cabinet (more info in parts list) I plan to tolex with my bunch of left over daphne blue and silver grill cloth. I'm so obsessed with slant front designs, I can't do the box.
Parts:
-Turret board and multicolored chicken head knobs (treb= yellow, bass= blue, presence which will go in place of mid on 18watt marshall chassis= green) dim: 300mm x 60 mm (may be too long not sure yet) from AES.
-Eminence Red Coat Red Fang from friend used.
-Chassis for combo from GDS amps. It's their 18 watt marshall chassis which should translate very well with the exception of me adding a choke and relabeling the faceplate mid as presence.
-Transformers from GDS amps. Their vintage inspired 18 watt Marshall design looks to be a great match for my build.
-Choke from my friend, Mercury Mags Tone Clone.
-Oversized 5e3 unfinished cab with 1 12". Dimensions are 20" wide x 17 1/2" tall x 11" deep at bottom slanted to 10" deep at top. Custom chassis cutout of 16 3/8" x 2 1/2" from TRM guitar cabs (wolfgang2204 on ebay so nice to do a custom cutout) This was my one cost cutting measure, as i'll be spending lots less over buying a vox repro or 18 watt Marshall combo. Adventures in tolexing to ensue!!!!!!
-Guts etc. from my friend. I'll update a complete parts list as I find out!!! This build is being governed by my friend Steve Hunter.

I estimate a total cost of around $700, you may do better or worse if you're playing along at home, you can do the math and see i'm getting some good deals along the way. Considering the end result will very much rival the utmost boutique amps costing $2000+, i'd say we're doing ok :)

So homework for the lurkers and newbs (me included).
I'm spending the weekend collecting schematics and will draw my own layout. taking notes on pinouts for the tubes.

Finally a pic!
The awesome Red Fang (A key part to this amp being awesome and boutique)
nobs and turret board and some great reading for fun!

Just a question/suggestion. Why have a separate tone on the normal channel and a presence on the top boost? Typically they have a shared cut knob. The cut knob is THE big factor in an AC15/AC30. IMHO it would make it a little easier for you as well.

http://i37.tinypic.com/2d1u7hk.jpg
http://www.jedistar.com/images/amp2/valvetech_hayseed.jpg

That so very well may be!! I'll update if the layout changes. I'm still shy of many details and am operating on a blind faith :)
Thanks!

No problem!

I did something like that back in 1995. It was a hybrid; 12ax7 preamp, a single-channel AC30 TB but with only 2 EL84s. I skipped the cut knob because I couldn't figure when I would ever want to cut something. Mine was built with found parts (based on a Traynor chassis and transformers). I built a closed-back box (also from found materials) w/ a 15" JBL. That amp sounded great. I used it for 5 years (rehearsal every week, 2-4 shows per month) and never had a failure... in fact I never even changed any tubes. Total cost to build the amp and cab was about $20; the speaker was $50.

I still have the amp in the cellar, but it got flooded and is waiting for some attention.
http://www.tdpri.com/telephoto/data/500/rusty_amp.jpg

Wow! Awesome!!
That sucks that it got flooded.
Re: cut/presence. Having played my friends, I thought it contributed a lot to the tone shaping.

Yeah, the cut knob can factor in pretty heavily to the overall sound/feel. I've believe people have stated here that Vox took the idea of the cut control from Gibson. Just remember that it works in reverse, so the further you turn it up the more muffled it sounds, unlike a standard presence control.

when I look at the circuit it looks like it just cancels out high frequencies. Where do you usually set that thing? I have never played a real Vox so I don't know how it works.

Well I'd say it depends on the player, guitar, pedals, speakers, etc. Also, my main amp is a Valvetech Hayseed 30, which is a 60's Vox clone, w/Celestion Blues. For me, usually somewhere around 9 o'clock to 12, but keep in mind, like I said, the knob works in reverse from a presence control. There's more highs all the way down/off and less as you increase it. It took me a while to understand it, but I used to have two Marshalls with a contour control which is essentially the same thing but for mids. Once I understood it, it's really helpful and I think that the simple controls are part of what makes those amps sound so pure. It's like a 5E3 deluxe, the less knobs the better. I used to like amps with tons of control, but it adds extra filtering of your sound. I've been on bills with that amp with other guys playing Mesa Boogies that have more knobs on the back than mine does in the front.
Dr. Z has also incorporated the cut knob on many of his original amps.

*notes* money money money money MUH-NAY *notes*

Now I just need my cabinet, and the ensuing misery of tolexing...oh yeah and to understand what I'm making!!!! :)

Looks like fun. You have inspired me to join the bandwagon. I will order some 18 watt style chassis and boards tomorrow. What are the differences between the VOX and the Marshall?

I know the standard Marshall uses the EF86 preamp tubes. There is a modded layout found on the intertubes that uses 12AX7's.

I am eager to see your schematic and layout for the VOX in the Marshall 18 watt Chassis.

Looks like fun. You have inspired me to join the bandwagon. I will order some 18 watt style chassis and boards tomorrow. What are the differences between the VOX and the Marshall?

I know the standard Marshall uses the EF86 preamp tubes. There is a modded layout found on the intertubes that uses 12AX7's.

I am eager to see your schematic and layout for the VOX in the Marshall 18 watt Chassis.

Yes!!
I made a little progress on my layout. I don't have the schematics for the Marshalls, though I believe a layout is up @ ceriatone. I got to look at the guts of a pretty faithful ac30 head build today (North Coast Music cab, whacky 90 degree double chassis etc), to help with my layout. And I was soo impressed with the ef86 sound, it's so rich and gainy, hard to describe.
I'm hoping by the weekend to have a little better understanding of how to wire this! I'm still super weak re: schematics...

@JulianP - thanks for the description of the Cut knob. You also mentioned a Contour control on some Marshalls. I'd be interested to see that circuit. Do you know what model # amp schematic would show that ?

No problem! The Marshall Valvestate 8100 series had the Contour control. The legendary Shredmaster pedal has it as well.

Deviations from the GDS Amps chassis:
Drilled holes for OT. Will run choke through predrilled holes. Drilled hole for speaker jack (widened the small hole between the pre and PI tube sockets).
I wrote Graydon from GDS to inquire about the 110v lug on the PT. he says it will be ok. I really don't want to use a variac for every show! I guess the voltage readings later will reveal. As an aside GDS Amps has been awesome w/ communication and shipping time.

aren't you supposed to turn one of those 90 degrees?

Update!
Per the good people @ Heyboer the PT is indeed 120v. The label says 110 which must be for a vintage look :). So jazzed!

aren't you supposed to turn one of those 90 degrees?

yep, it's best practice.

Interesting. So OT and choke @ 90 degrees. Is that for hum reduction? I can do that, thanks!
Made some serious headway on the layout!
Ran out of space and will need to make a new one. My turret board has two rows of 30 lugs. I may need to run the 68ks off the input jacks, though everything in a line looks so cool!

Yes hum reduction. Are you making your own turret board? What are the choke specs?

I've got a few 18W TMB Head Style Chassis on the way.

Looks like fun. You have inspired me to join the bandwagon. I will order some 18 watt style chassis and boards tomorrow. What are the differences between the VOX and the Marshall?

I know the standard Marshall uses the EF86 preamp tubes. There is a modded layout found on the intertubes that uses 12AX7's.

I am eager to see your schematic and layout for the VOX in the Marshall 18 watt Chassis.

The 18 Watt uses ECC83 or 12AX7 preamp tubes, same as the later AC15's.
The early Vox's used a EF86. I built an 18 Watt but dropped the tremolo channel and added the AC15 circuit with a EF86 and it's a beast.

Yes hum reduction. Are you making your own turret board? What are the choke specs?

I've got a few 18W TMB Head Style Chassis on the way.

10 Henrys. no I bought a 30x30 lug board from aes.
Awesome re: your order!
Just to clarify, I'll ask my friend too. So from reading do I turn just my choke 90 degrees? Cause it looks like the OT and PT already are at 90 from each other.
Thanks!

The 18 Watt uses ECC83 or 12AX7 preamp tubes, same as the later AC15's.
The early Vox's used a EF86. I built an 18 Watt but dropped the tremolo channel and added the AC15 circuit with a EF86 and it's a beast.

Is it a head or combo? I want an ef86 channel so bad!

2X10 Combo. with cut and a 6 way rotary tone control like a DC30.

http://img444.imageshack.us/img444/6231/dsc01133ny.jpg (http://imageshack.us/photo/my-images/444/dsc01133ny.jpg/)

Looks nice, Shep. What are your three preamp tubes from right to left? I see the cap can. Is that 32uF plus 32uF?

What transformers are you using?

2X10 Combo. with cut and a 6 way rotary tone control like a DC30.



Man, so awesome! Thank you for posting that. If i may ask, what is that little world of caps and resistors on the board near the first input? It looks like a really great layout!!
Must be one kick a$$ amp :)

I wouldn't sweat the orientation of the choke just yet. If hum presents a problem you can always re-orient it later.

Id be more concerned if it was an SE amp.

Cool, that's the plan since I already drilled the holes. Thanks!

Looks nice, Shep. What are your three preamp tubes from right to left? I see the cap can. Is that 32uF plus 32uF?

What transformers are you using?

EF86,12AX7,12AX7 and you are right about the cap can.

Man, so awesome! Thank you for posting that. If i may ask, what is that little world of caps and resistors on the board near the first input? It looks like a really great layout!!
Must be one kick a$$ amp :)

Those are the caps for the 6 position contour switch. Most people just mount them on the switch but it gets too crowded so I put them on the board. I've also added VVR on the far side.

Just too messy with all the caps and resistors on the switch.
117743

Cool, thanks!

OMG it begins!!
Today's my birthday. @ The Electric Church (where I'm apprenticing) we're all caught up and my friend helped me finish my layout. Also, we did a slight grounding change to my '71 Princeton reverb and got rid of all hum! So far one of the best birthdays in recent memory :)
I'm going to populate the board on Sun cause I'm playing a show tomorrow.
I bought about 95% of the parts @ work, but need to place a small order to mouser for the few missing pieces.

To any techs on here who have ever accepted an apprentice, you are amazing and I salute you.

Major realization.
The gds amps chassis dimensions are 20 x 6 x 2.5". The faceplate is 18 x 2.5 x 1/8ths" thick (not listed on the site currently). I thought the chassis was 18" dunno why. I'll have to do a couple shenanigans to stuff it in the 5e3 cab I bought (20x17.5x11->10). Still waiting for cab so we'll see what else needs doing (mounting?).
Definitely going to wait to screw any parts to chassis, but will be cutting an inch off each side to fit the cab. Oh yeah and the pot holes aren't 3/8" all the pots I'm using are too big! *cue drill again*

*my boards looking very Halloween-y!!*

Would you either PM me a shot of your completed layout or post it here?

Pm sent. I'm a teensy bit hesitant re: posting it to thread, may have a couple acknowledgement conditions, haven't decided. Largely because soo much credit is due to Steve H, and we've already done a couple deviations (ex Princeton-esque tone control off norm channel and wiring cut in reverse (more on this later)). But so far if there were a friends list on tdpri you'd be on it :). Also, the layout is subject to change once it's all up and running, some tweaks may be in order.
In other news, I bought a step bit today, love those little guys!

Thanks. Step Bits are the ticket for making small holes bigger cleanly and precisely.

Andy, nice layout drawing.

Andy, nice layout drawing.

Thank you! I did about 10% on my own (the obvious stuff) and the rest was shown to me as we read the schematics, it was my birthday present! It's crazy what can take a pro seconds to look at would have literally stopped me in my tracks.

Anal wiring. (wait that sounds gross...)
I'm only going to get these done, as the Mrs. and I are going on vacation. Mother-in-law is going to house sit Shorty :)

Only missing a 50/50 on the lugs w/ the 135ohm/10w, and the 1.5k w/ the 25/25 on the other end. I drilled the holes a little bigger for the stand offs in 3 places. Under the gargantuan 30/500 f & t hides another cathode to ground 1.5k & 25/25. Gonna wait to solder it, unless I get a wild hair up my butt when I should be packing!!
I found some flat head screws which should stay out of the way of the components. Plus some scavenged stand offs.

Pack your amp kit in your suitcase and take it with you. If you haven't got those 2 missing parts coming, I'll mail them to you. Let me know.

Lol! I know! No, they're only off the board until i screw it to the chassis, thank you though! We're going to LA to see some friends (plus I'm trying to talk my wife into moving there) all would be annoyed if I were holed up at the B&B soldering.
On the upside I think I'll be coming home to see my cabinet!!

http://img600.imageshack.us/img600/7838/cliffjacks001.jpg (http://imageshack.us/photo/my-images/600/cliffjacks001.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)
Here is an alternative method for these jacks.
http://img607.imageshack.us/img607/4176/cliffhilo2.gif (http://imageshack.us/photo/my-images/607/cliffhilo2.gif/)

The method I used is on the right. Basically, I folded the jacks onto themselves, which saves another step or two. Bend the input tab on the low jack (upper jack in photo) outward. Bend the opposing tab inward. Diagonal leg of the 1M resistor connects to that inward tab.

Uploaded with ImageShack.us (http://imageshack.us)

That's the way I wired my champ, I thought I'd try the other way to keep the Hi on top and to ground on the right. I do like the alternate method though.

Sposeda get my cabinet today!!
Finished my board (pic is in nearly finished state)
And the other pic is the cool way I was shown to wire jacks. It's a 70s champ that someone butchered all the caps and pots for some crazy reason

Got my cabinet!!! The eBay seller: wolfgang2204 did a hell of a job. Ordered Mar 1st received today. Very well crafted and surprisingly light! Packaged tight and professionally. Joints and edges skillfully done, sanded smoothly. $129 and $18 shipping; money so very well spent :)

A few pics! With PR for scale.
And a cry to help! I'm gonna tolex this thang myself......sigh..... I've got sonic/daphne blue and silver grill cloth.

Stunned the naysayers (my friend); carefully cut down the chassis with my dremel to fit the cab. Need to drill a new ac hole. Thankfully plenty of clearance on the tube side.
Cut down the cleats (?) so the chassis fits super snug and will slide right into place along additional support (in photo). Gonna reuse the chassis end as L bracket to underside of top of cab. S#its gonna be tight :).
Will need to make a new back panel long enough to guard the tubes some and reach the cleats.
Mock fitting with transforms and speaker was a success with plenty of room!!
I got lucky :)
I've gotta be in small company here : Vox circuit, Marshall chassis, Fender cab! It's like the history of rock and roll in one amp :)
Debut show mid Apr...

Sorted!

Here are the scrap L brackets to secure the chassis.
Gonna make a trip to the hardware store for the back panel, then spray paint everything black before tolexing.
Is it wrong to be doing this on my 8 yr wedding anniversary? Yes, yes it is... (she's just surfing the web anyway :))

I just made a cradle similiar to this to mount mine. Alot easier to remove the chassis if it ever needs works.

http://silvatone.bravepages.com/18%20Watt%20Lite%20II/Graphics/Cab%20-%20Shelf%205.JPG

I just made a cradle similiar to this to mount mine. Alot easier to remove the chassis if it ever needs works.



I like it! I know, I'm starting to form a bias against companies with ridiculous to remove chassis.
(I'm looking @ you Fender...no not you Marshall, you're good :))

Calling it a day...
Knotted up the 4 and 16ohm OT leads and kept them outside the chassis.
Will hopefully finish all the wiring in the next couple of days. Waiting on the belton 9 pin tube sockets.
Added a fuse holder on the side.

Is that a custom faceplate? I was looking to get one made but it's expensive for a custom job and nobody does it locally. I ended up buying some acrylic from HD, printed out a decal then sprayed it gold. Not perfect but it turned out ok for $10 worth of material.

120891

Is that a custom faceplate? I was looking to get one made but it's expensive for a custom job and nobody does it locally. I ended up buying some acrylic from HD, printed out a decal then sprayed it gold. Not perfect but it turned out ok for $10 worth of material.



That looks perfect to me!
Mine was included with the 18watt Marshall chassis and transformers

Let the tolex games begin...

My wife's already putting her earplugs in; many a swear shall be heard, and I'll probably make up a couple new ones too!

What kind of glue you going with Andy? Be sure to always use sharp blades.

I bought the water based contact cement (I think!) from Lowes. It had a picture of a vinyl cover going on a wooden counter top so I was sold :)
I'm going to practice the rounded chassis cut out with duct tape so I don't eff it up.
This is my second tolexing and the first came out ok, but it didn't have complicated corners.

Metal corners are your friend :razz:
Here's a good tutorial http://silvatone.bravepages.com/18%20Watt%20Lite%20II/Build.htm

Great Tutorial, Shep.

Spent a couple hours soldering, procrastinating the tolex. Thanks Shepherd for the link!!!

What are the deets on that blue switch?

What are the deets on that blue switch?

It's a scavenged big honkin switch! Seems military grade or something.

Home stretch

Here goes nothing...
I stapled the bottom end to the cab beyond a point I'll cut off, and cut all the corners.
I do think metal corners will be in order.

You are a brave man, tackling the tolex! Best of luck.

Two sides and back panels done.
Here are some corner pics. The top and bottom pieces will overlap like on the tweed cabs and should clean it up a lot. Also, the metal corners will take it home (I don't know what that means...j/k). Out of 8 corners, I'd say 4 look super tight and perfect, the rest will deff. benefit from the overlap and metal corners
The chassis is 100% finished and Monday will be the test run with tubes and variac.

You are a brave man, tackling the tolex! Best of luck.

Lol! I'm not happy about it :). Especially since a quick eBay search for Bluesbreaker cabinet yields some cheap and nice looking results.
Hopefully, someone can learn from this and get it all right from the start. My reward is a smaller amp though, and I love big sounds from small amps :). As a rule though, cutting down the chassis to fit a smaller cab, is not something I ever want to repeat. Things could have gone bad...

Should have just stained it daphne blue, and let that gorgeous grain and workmanship shine through. If the tolex gets buggered up it might make sense to sand and stain.

*an awed hush fills the room...some sighs over a bloated build thread:)*

I finished my amp!! Worked first time and voltages were on the money.
Details recap:
Norm channel with brown face deluxe tone circuit. Top boost channel with treb bass. Presence control wired in reverse from vox cut so as you turn up it gets more present. 100pf bright cap like the old ac30.
At the risk of embarrassment here's a vid (with iPhone mic so not pro sound, but you'll get a good idea):
http://m.youtube.com/watch?v=vHEczAgEabI

Pic:

Nice work andyfromdenver! Sounds great too. Am I right to assume that the presence or cut knob is a variable resistor that allows you to adjust the amount of negative feedback? One day my 5F2A trannies will come in and I too can play with a little negative feedback mod. Thanks for sharing.

Thanks!
Re: cut. I don't think it's - feedback, but not sure. I sort of think it's just another eq in this circuit but off the PI as there's a .0047 cap to ground, but please don't quote me:). I'll ask my friend or I'm sure someone else here can say.

good work andy! have you posted a schematic for this beauty yet? I sure would like to see what you did.

I tried to watch your video but for some reason I can't get it to work...

Re: the layout please pm me. I'm keeping it offline @ present. :)

Watched your video...

I love the layout of controls - very versatile. I wouldn't be surprised if we start seeing an amp with this layout being produced.

The blue tolex looks great! Would love to see a video of this little baby recorded with a real mic.

Beautiful high quality build!!!!

Great work. Nice video too. Very impressive build.

Yay!!!
Thank you guys :)
If anyone is in Athens, GA this Friday I'll be debuting it with The Goons.
I've never had an amp that feeds back, I feel like a rock and roll empty place in my soul has been filled.
The GDS amps 18watt transformers are great btw. Voltages were good and the PT Having lugs instead of leads made for tidy wiring.
*courtesy pic of La Brea tar pits ;)

"every time I tried to leave my thread...they pulled me back in"
So I think I'm done tinkering with this bad boy.
Sounded great at the show. I ordered some fun colors of label tape so I could show the controls to my friends.

hey Andy - what kind of settings did you use at the show? I'm curious how that Cut/Presence control is working for you.

I'm liking it right in the middle. Too much and everything sounds a little "glassy(?)". You know what sound I mean? I don't think that's just the presence, just extreme settings. It's weird, I thought it would be louder than my Princeton Reverb, but I think they're about the same. I could neeever get my PR to feedback though.

God, I cut THE most embarrassing vent in the back panel. It was one of those late night beyond rash decisions. It looks like....a dildo :(
Gonna make a new one post haste.
*too embarrassing for a pic*

ha ha! come on Andy - now we have to see it!

God, I cut THE most embarrassing vent in the back panel. It was one of those late night beyond rash decisions. It looks like....a dildo :(
Gonna make a new one post haste.
*too embarrassing for a pic*

Maybe it was something that just crept out of the subconscious.

Omg. F it, I'm posting it, though the mods may move this to Celeste's ugly build thread (or possibly an entire new thread, "obscene builds...")

Before and after:

Omg. F it, I'm posting it, though the mods may move this to Celeste's ugly build thread (or possibly an entire new thread, "obscene builds...")

Before and after:

Defiantly subconscious.

Just trim the sides of the hole to give it a more pleasing shape.

Defiantly subconscious.

Just trim the sides of the hole to give it a more pleasing shape.

Lol!!! I'm booking a therapy session.
It was my wife who pointed it out, I swear! *now to go pump some iron and watch football*

With a table saw, cut the whole bottom portion off at the upper line of the phallic symbol.

With a table saw, cut the whole bottom portion off at the upper line of the phallic symbol.

Lolx1000.

In the process of making a new back panel I discovered one of my tubes is looking toasty!
Only one was affected seemingly. These are both brand new and the lettering should be nice and red (like the tube on the right). Going to do some in depth measuring tomorrow, hopefully it's just a poor ventilation issue! I've had the amp on maybe ten hours tops. Here's my new back panel. I'm tempted to do holes all the way across the bottom.

P.S. do you see a creepy horizontal alien face?

Ya I see a creepy alien face. He'll be the mojo living in your amp. Congrats on your new found talent boost!

Nice work andyfromdenver! Sounds great too. Am I right to assume that the presence or cut knob is a variable resistor that allows you to adjust the amount of negative feedback? One day my 5F2A trannies will come in and I too can play with a little negative feedback mod. Thanks for sharing.

I was wrong about the cut. It's not negative feedback related and there's no .0047 to ground. It works by phase canceling high frequencies in the PI (or something like that!!). Also i've learned that mine isn't really a presence control in the trad sense, just "cut" wired in reverse :) I don't understand it all, but bits and pieces are seeping into my brain!

Ya I see a creepy alien face. He'll be the mojo living in your amp. Congrats on your new found talent boost!

Lol!!!