Where are all the new build threads?

Teleguy61 · Post by **Teleguy61** » Fri May 18, 2012 6:07 pm

Ok. Here it is so far.
This started life as a Weber kit, a Natalie, a 4X 6V6 output with a Marshall-stlye 45 watt OPT, and a plexi-style preamp, and some PI and FB variations. An interesting idea that didn't quite work out. I wound up using it with 6L6s most of the time, and I have plenty of 6L6 amps, so.........
With the incredible information on this site, and the layouts, schematics and comments from Normster, mdroberts, Tom, Mark, and many others (Thank you all gentlemen. Your generosity is an inspiration) I stripped it out, kept the tag board and PT and went at it.
Pretty close to a 1.5 Rev version. You can see some of the tweak parts still in it. Mid cap .01. post V1 coupling cap .02, LNFB , GNFB 6.2K.
Added a 270K bridged with 140pf (at this point) before the 220K OD entrance, not a final decision yet there.
.0015 into 270pf treble cap, PAB and Mid Boost switched together. That rocks!
You can see I have one empty octal hole (the Nat had a tube rec) which I plan to use for a tube for a loop, when parts come in and I figure out where to put it. Real estate is at a premium as it's the same size chassis as a 5F6A or JTM45.
Also have a half power switch.
The goal is a grab and go, switchable 15/30 watt, in a combo, with a pedal for reverb/delay. Sounds great with a EVM12L from Tony, OPT is a New Sensor Bassman copy made by Mag Comp from swiv. Sounds good also with D120 and K120. Will also try a couple of Weber Neomags I have, for the weight advantage.
Heading out to start cutting boards for the cab.
You've all heard it a hundred times, but this is a great, great site.
Thank you Allen, thank you Omar, thank you.

67plexi · Post by **67plexi** » Sat May 19, 2012 2:13 pm

I just received the chassis yesterday. Low plate classic tone stack. This should give me a better understanding Of the SSS tone stack. Black face fender Iron. OPT 4 & 8 ohm taps.
Need to order a few parts.

Steve.

trane34 · Post by **trane34** » Mon May 21, 2012 7:12 am

Steve have you used old iron before in a build? I haven't but I bet it would sound killer. I had a blue face Twin Reverb for a while that was far and away better than any twin variation I have built with new iron. There were two K120s in it and I sold it after I threw out my back. That was the one that got away from me that I'd like to have back. I would have just put it in a head cabinet and called it done.

67plexi · Post by **67plexi** » Mon May 21, 2012 3:53 pm

I only have 4 each D-style builds so far, all but one has vintage Iron.
#60 non reverb has Haybour new manufacture transformers and it is my favorite amp so far.
It may be the clean and overdrive ratio pots and not the transformers.

Steve.

Luthierwnc · Post by **Luthierwnc** » Fri May 25, 2012 6:36 pm

Just back from the laser shop. As usual, I put some holes in the wrong places. On this one I programmed a new way of notching the corners without reducing the dimensions so it ended up too big for the cab I'd built. I also forgot to tell the shop to make the welds on the inside making it even wider. Both my fault. Still, they do really nice work and do one-offs with a smile.

Skip

PS If anyone is interested in the cab, PM me after you look at this pic:

https://tubeamparchive.com/viewtopic.ph ... rry#199927

ID: 19.375" wide, 9.5" back to front panel -- 10.25" OAL, 8.6875" high. Gap in front 2.5" tall. Pic makes it look yellow but it is normal color. Watco finish. Back panel is solid cherry too except for a Marshall-style screen vent. Tubes up design. I can take more pictures if you want. $100 shipped. Thanks, sh

Luthierwnc · Post by **Luthierwnc** » Tue May 29, 2012 5:38 am

Got busy over the weekend. Still need to clean up some lead dress under the relay board and install the footswitch jack. Waiting on some glass too. I figure another hour and a half until I'm ready to spark-test. That and I have to haul the Thieles downstairs. sh

trane34 · Post by **trane34** » Thu May 31, 2012 9:21 pm

Luthierwnc I like the boards. You make them yourself? What's the layout on the front?

Luthierwnc · Post by **Luthierwnc** » Sat Jun 02, 2012 2:41 am

I just use a drill press for the holes and a sharpened bolt to splay the lugs. The preamp board is 1/8" garo with no backing. The power board is 1/16" garo with a bottom backer. I used hex spacers on the power transformer bolts with machine screws through the top to anchor it since the loop takes up some extra length on the pre board. The relay board I etched using a Paint program, printed on a magazine page with a laser printer and ironed on to 1/16" copper clad. Sometimes a Sharpie helps.

Across the front are the:

Input,
Gain,
Bright: up for on, down for off and middle for on clean-only,
Raw: up for LNFB off, down for on and middle for off clean-only. The middle positions for the first two switches are controlled by a parallel 2nd OD relay,
Strat: up for 10uf bypass on V1a and .047 mid cap. Down for .68uf bypass cap and .015 mid cap value,
Starve: (wrong name but I like it) drops entrance capacitance to .015 from .05. Might bump it to .025,
Treble,
Middle,
Bass,
OD Drive (trimmer is on the back of the amp),
OD Level,
MV -- actually the Return control. The usual MV is a divider on the board since the loop is internal. Send control is on the back too,
Presence,
Standby and ON/OFF.

The bright and raw designs are in some of my previous posts if you are interested. It is ready to spark test once some tubes arrive.

Cheers, sh

Luthierwnc · Post by **Luthierwnc** » Sat Jun 02, 2012 1:15 pm

Got a couple PMs for the bright/raw design so here it is. The switches are ordinary SPDT on-off-on minis.

On the question about the etched relay board, I use a simple resistor at the bottom of the stack for the PAB. The #1 lug on the mid pot has a wiring going to the relay and a 180k resistor going to the buss bar. In the normally-closed position on the relay, that lug is grounded. In the normally-open position, the circuit is open so the stack has to go through the resistor. It only uses two of the six pins on the relay switch.

BTW, using the laser toner on cheap paper method really helps the dyslexic since you don't have to reverse the design. If you imagine the board from the top, right-side-up, the print is going to be iron-transferred to the bottom of the board the same way. FWIW, sh

dcribbs1412 · Post by **dcribbs1412** » Sat Jun 02, 2012 2:44 pm

Thanks Luthierwnc
congrats on a great looking build
relay board and raw/bright switching is ingenious
thanks for sharing...
What value caps you using for PS/loop...
Hard to tell from pic
hope spark test goes well.

Darin

Luthierwnc · Post by **Luthierwnc** » Sat Jun 02, 2012 5:26 pm

I screwed up on the description of the switches. On the Bright, up is on, middle is off and down is bright only when the OD isn't engaged. On the Raw switch, up disconnects the LNFB, middle engages it and in the down position it is only engaged in OD. You are looking at the back of the switches in the diagram so up on the face is down on the drawing.

Darin, I took a lead off the B+2, ran it through a 15k resistor, put a 22uf cap there and then to the plate resistors. I've done it with 32uf on each of the plates like the D-lator drawings but this seems to work fine since it is the third downstream node. I'll play with the plate resistor values to get them in the highish two-hundreds. sh

Luthierwnc · Post by **Luthierwnc** » Wed Jun 06, 2012 12:15 am

Knocked out the new cab over the weekend. I cut the tails on a router table and made a jig for matching pin cuts on the table saw. There is a little hand work to chop the pins back but the saw makes that much less tedious.

Red oak with a bookmatched walnut front. There is a handle on top but the side holes make it a lot easier to lift the thing above waist level. Adds some ventilation too.

Cheers, Skip

Guitarman18 · Post by **Guitarman18** » Sun Jun 10, 2012 9:40 pm

Luthierwnc wrote;

Strat: up for 10uf bypass on V1a and .047 mid cap. Down for .68uf bypass cap and .015 mid cap value

Skip,

I'd be interested in knowing how you went about implementing this switching arrangement. Do you get pops when you flip the switch? I fully understand if you feel uncomfortable sharing this info.

Head cab looks great BTW.

Cheers,

Paul.

10thTx · Post by **10thTx** » Mon Jun 11, 2012 1:39 am

Love the cab! Very nice job, Skip. And thanks for sharing information about your build. It is appreciated.

with respect, 10thtx

Luthierwnc · Post by **Luthierwnc** » Mon Jun 11, 2012 4:36 pm

Thanks guys,

Guitarman18, the idea that I have any secrets is quite flattering!

Attached is a drawing of the Strat switch. It is a DPDT on-on mini on the panel. In the normally closed position, the bypass cap is .68 and a resistor on the larger cap keeps it out of the circuit. You could season that to taste. On the other side of the switch, the .05 and .02 are in series which drops the capacitance down to about .015. There is a big leak resistor to keep it from popping. You could accomplish the same thing by putting a .01 and a .047 in parallel. The lower bypass and mid-cap values should serve buckers better.

In the normally open position, you put the 10uf cap in parallel with the .68 and you bypass the .02 mid cap putting the full .05 in play. This setting should favor single-coils a bit more.

Hope this makes sense, Skip

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