TOS build

[punkykatt]

Finally getting around to putting this amp together. Im using iron from a mid 60`s Hammond organ(PT) and a Stromburg Carlson mid 60`s stereo(OPT).  I decided to use the VVR  because it worked out well in another build. I fired it up and the 220k 3w bleeder resister smoked on the first filter cap off the rectifyer. Using my continuity test light and also my ohm meter, I can not find any short with the VVR circuit or the power rail. All the 1N4007`s are installed correct and test good, all filter caps have correct polarity.  I have to be missing something?  My brain is tired, any help is much appreciated.  Thanks
Punky

[PRR]

The only way that bleeder can smoke is if you have connected for over 900V DC.

Did you use a FWB on a 2-diode PT?

Did that Hammond have a BIG choke?

[Tiny_Daddy]

"All the 1N4007's"? Bridge rectifier?

[punkykatt]

No choke on the original Hammond schematic the PT came from. On the  Hammond schematic the 5AR4 rectifyer shows 450vdc off pin 8 to supply rail. (real life) unloaded I measure 365vac to ground on pins  4 and 6. Im using  a 5AR4. The 1N4007`s are in the VVR circuit.

[tubenit]

unloaded I measure 365vac to ground on pins  4 and 6

Don't go by the Hammond schematic voltage.

What voltage do you have on pins 2 & 8 withOUT the VVR hooked up?  And then with the VVR hooked up at each node?

Any chance (if you used Dana Hall's VVR) that you have the "in" & "out" wires hooked up incorrectly?

With respect, Tubenit

[punkykatt]

Thanks Tubenit.  Yes, i have the VVR wired just as the schematic above, and checked it countless times. I disconnected that burnt 220k bleeder R and fired it up. At the out put of the VVR, turning the pot, the voltage ranges from 40vdc to 450vdc.  At the input of the VVR , the voltage ranges from 465vdc (VVR pot at max) to 495vdc (VVR pot at min)(My 1st filter cap is rated 500v, kinda close?). Before I fired it up this time I added a second insulator heatsink pad underneath the mosfet. Do these voltages look normal? Do you think adding that second insulating pad may have helped?
Thanks  Punky

[tubenit]

I think the voltages look reasonable from what I can tell by your description. That is sort of the thing I see with the 4 VVR installations I've done.

I would probably consider using two filter caps in series for a higher voltage rating at that first filter cap prior to splitting off the VVR and preamp. After doing that, I'd probably wire up another 220k/3w bleeding resistor and see what happens?

With respect, Tubenit

[Geezer]

the 220k 3w bleeder resister smoked

Are you sure that was 220K, & not 220R? 

[punkykatt]

Its a strong possibilty it may have been a 22k. I usually test them as a strick rule before installing. Sometimes if Im a bit tired my eyes look but don`t see and read the meter wrong.  I didnt have any 220R`s in the box I was pulling the resisters out of.

I removed the 1st filter cap and burnt bleeder R and took tubenits advise and installed 2 47uf/350v caps in series for 23.5uf/700v with 220k(for sure this time) balance resisters. The amp seems to be working fine so far. GREAT TONE!!!!  Im using a small chassis 17" x 8" x 3" so layout for me was very critical for hum/noise /osclation.  I ended up taking out the Fatness control and wiring it direct at the sockets, and move the Clean Master next to the Clean Tone control. I used sheilded cable on all pot runs to the board, input jack, switching relay and efx loop.  Termination(grounding)  of shielding was critical, moving an inch or so on the 14awg copper buss ground wire above the pots made a huge difference. One of the shields from a wire on the switching board, I had to add about 10" of wire, bend and twist to get rid of hum. At first I tried a short a wire as possible thinking thats best. Hum was worst. Go figuire? That trick of using those aligator clip jumper wires to find the quietest ground really saved my butt with this one.  I will do some more voltage checks tomorrow and see if I can get some pics of the guts and cabinet I have built for this.  Im going to have to make up a new face plate.

Thanks Tubenit and Geezer for sharing your fine creation with us.
Punky

[punkykatt]

I let the amp warm up for a while and took voltage readings. All voltages are within reason, nothing getting overly hot. VVR seems to be working properly, Bias is good. The amp sounds great.  I took some pics, hope they come out ok. I may have to do several posts.  Thanks everyone for your input. Much appreciated. Punky

[punkykatt]

Another gut shot

[punkykatt]

Chassis top

[punkykatt]

Cabinet

[punkykatt]

cabinet

[tubenit]

Very very impressive!!   I like it alot.  Very cool looking amp. You did a nice job with the chassis and layout and wiring.

I am curious, how did you get the color on the wood? Stain or analine dye?

With respect, Tubenit

[punkykatt]

Thanks Tubinet, that means a lot coming from you.  Dont slap me when I tell you this, but its  Minwax Cherry Blossom clear tint water base wood stain. Two coats. First coat came out pink with orange knots ( I was about to puke) I was pleased with the result of the second coat and applied three coats of water base poly. Not as easy to apply as oils. The plus side is they can mix a wide variety of unique colors.  The Cabinet is made with an $8 piece of 2nd grade pine from Lowes. Speaker baffle is 1/2" birch ply.  Punky

[simonallaway]

Cool looking cabinet! I know you're pleased with the tone, but do you have any recordings?

[DummyLoad]

nice! and very  :glasses9:

[tubenit]

Punky,

I don't know if you have recording equipment to do a sound bit but I'd sure love to hear clips if you can share some.

Here are some pretty good FREE backing tracks that one can use to play along with.

http://www.guitarbackingtrack.com/bands/B.htm

Also I would love to hear a description of the tone you're hearing?

With respect, Tubenit

[Willabe]

Punky,

         VERY NICE !     

Man you guys do some very nice work ! Looks great inside and out ! Im a carpenter and have done  -some- wood working, have also done a few builds, but they were pre-punched chassis/standard Fender clones. I did make a nice solid pine 4x10/head that I finger jointed with a Porter Cable jig, stained it with Watco danish oil (light walnut)and used Marshall caine speaker cloth (light tan color) turned out nice. But you guys, man, the whole 9 yards and then some!   

Ive been gathering parts for 6/7 years now, blank chassis, Greenlee punches, 7/8 different sizes (5/8" to 1 1/4"),PTs & OTs, passives, speakers, ref. books, ect. Figured the price was just going to go up so why not ? As long as I store them properly they should be OK. Also, I did finally build my self a (IMHO) very nice work bench, its 3'x8' and solid as a rock !

Anyway, havent really had the time or heart to build anything. My dad passed away 6/7 years ago, and I took in my brother to take care of him. He just passed away now on the 18 of Nov. here at home, Hospice was here and I cant say enough about them, they were great!  So Im thinking it might be good for me to start to build something, anything to take my mind off of his passing. He (Buff) had a number of health problems, he was blind since age 2 , 2 1/2 because of a brain tumor that chocked off his optic nerves.  Was operated on at that young age, the doctors said he'd never leave the hospital alive but he surprised us all and lived to be fifty! That operation caused him to have bad seizures later on in life and he was on a lot of meds for it.  He also had a hiatal hernia, scoliosis of the back--he used to be 5'10" and ended up 5'4" and the list goes on.   But he was my brother and I'm glad he stayed with me.  What ended up being his bedroom was originally going to be my workshop--it was an easy choice to make. Sorry for the ramble.

Punky, how did you make the face and back plate ? They look great !  Im always curious about how guys make there finish trim, more than one way to skin a cat.     
   

One more ?  Punky is that a 2 tone/color cab or is it just the pic/light, the wood face plate looks like more of a shade of brown than the cherry else where on the rest of the cab ?  maybe to match the grill cloth ?  Again great work !

         Thanks,        Brad     

[punkykatt]

Sorry, No,  I dont have recording equipment as of yet.  The band has a gig at the Moose Lodge tomorrow night ( laid back oldies show for the pre-babyboomers) We call our-selves "The Rockadile`s" for those kinda  shows and "Badd Ju-Ju" for the rock shows.  Probably wont be able to crank it up too much then but its a better test than playing in my 9`x 16` shop.  I will give a rundown Sat morning.

[punkykatt]

Willabe,  So sorry to hear about your brother. My condolences. Death of a family member is never easy.

Yes, the front wood panel is stained dark brown to contrast the Cherry and the grill cloth. That white spot on the left must be from the camera flash?

I made the face plates using Front Panel Designer (free down load). Print it out on high quality picture paper. I usually print on regular 11x14 paper first to sample, and use as a template to mark holes on the chassis. Then I use 1/16" plexiglass to cover the print out face plate.

Thank you all for the nice comments.    Punky

[punkykatt]

Last nights Moose Club gig. Had to stay on the quite side. Didnt get to use the OD channel much.  The clean channel tone on this amp to me so far is somewhat like the 5E3 circuit but with compression, In other words, if you pick the strings very lightly the volume was there more than you wanted, which is good and bad depending on the song and the feeling you want to present. If you pick real hard and turn the guitar volume up the amp dosent get that much louder and  biteier(is that a word?) compared a 5E3 or Princeton Reverb type amp. Would be nice if that can be switched in and out.  That is my feeling so far on the clean channel. I still need to experiment with the 12A_7`s in the preamp. Over all nice rich warm tone. FYI Im using 7591 power tubes and a Patriot Cannabis Rex speaker. At the monemt Im playing a Strat with Tex Mex pups.  Punky.

[tubenit]

You're saying that even with the VVR ........ the OD was too loud?

In other words, if you pick the strings very lightly the volume was there more than you wanted, which is good and bad depending on the song

 

If you pick real hard and turn the guitar volume up the amp dosent get that much louder and  biteier(is that a word?

I would say both my TOS amps are very touch sensitive & one way that comes up is that if you pick lightly the volume is lighter also. Pick harder and the tone has more oomph and overdrive to it.  Not sure if that is what you're describing or you're describing something different than that?

With respect, Tubenit

[punkykatt]

Tubenit, Im talking about the clean channel only.  VVR set 75%. It seemed to have compression on it as if I were using a MXR Dyna Comp? I didnt get to use the OD channel enough to get the flavor of that .

[Willabe]

Punkykatt,

Thanks for the kind words. He was my yonger (only) brother, have always felt the need to protect him, just couldnt fight/beat this #%$@&^  tumor thing anymore.

Back on subject, I thought that was/is a 2 tone cab. very nice!

Thanks for the info on face/back plates as well, again very nice!       

      Thanks,   Brad