Dumbleator Questions

[surfsup]

I'm looking to put this together soon. Just found a couple schemos for it, so...

How critical is the value for the two 10M resistors? I want to order everything from AES to save on shipping and they don't have any 10M resistors and I don't have any in the stash. So I was thinking getting the 1/2W 8.2M carbon comps instead which would total 16.5M total. Geez I'd hate to hit Mouser for a couple Rs...

Anyone use the P-TF47609 PT at AES? My ceriatone C-Lator chassis is sitting in the baby room right now, so as a bonus if anyone knows if the 2.3" width of that PT fits the chassis that would be great, too. I don't want to wake her up tonight going in there clanking around metal stuff 'cuz my dumbass forgot to take the chassis out before bedtime.

The 56k 3W supplying the first stage CF, I have a 56k 2W. I figure about 3mA max through that resistor for 0.5W rating, does anyone know for sure if the 3W is total overkill?

[ToneMerc]

16.5M can be used and that PT is too tall(2.03") for a 1RU chassis if that is what you're asking.

TM

[surfsup]

Is there a PT that works for this to fit inside the 2" C-lator chassis (I am assuming it is 2" tall). In the picture it looks like the one Ceriatone shows is perfect (below). I did find Hammond PTs that might work. I figure a 250VAC CT PT would get me about 345-350 at the first supply node.

261E6 might be perfect and the dimension is 1.85", but it seems pricey at Mouser $40 and non-stocked...sigh:

261E6 29 250V C.T. @ 91ma 6.3V @ 1A 1 3.69 1.85 2.31 3.13 0.187 1.7
http://www.hammondmfg.com/pdf/5c0030.pdf

Here's the ceriatone shot:

[img:120:90]http://www.ceriatone.com/images/complet ... ck_p2B.jpg[/img]

[surfsup]

This looks like it will work with a FWB and AES has it for $40 where Mouser it is unstocked:

http://www.tubesandmore.com/scripts/fox ... m=P-T261C6

250VAC CT, 50mA, 1A 6.3VAC

Yes?

[martin manning]

I don't think so. I guess you don't have the chassis in hand, but if it's a 1u rack box it's 1.75" high (outside dimension). Allen-Heyboer TP-2X will likely fit inside, use a FWB rectifier, then just cover the hole in the back. Looks like the Ceriatone PT is a knock-off of the out-of-production unit that HAD used. Revised schematic is here: https://tubeamparchive.com/viewtopic.ph ... highlight=

[ToneMerc]

Surf, if you haven't made the power boards the Allen PT and fwb works. However, if you are already setup as a doubler supply I had Heyboer make me a few small vertical PT's that fit inside most 1RU enclosures. I don't have any spares on hand and hadn't planned on ordering more but that could change.

TM

[surfsup]

Martin, thanks again. I'll look into the Allen PT.

ToneMerc. I am in no rush, and there were a couple boards already made. I'll take a look at them tonight and figure out what the layout is doing. I'll get back to you guys later thanks so much, glad I asked a few Qs.

[rogb]

I can measure my Ctone PT if it will help.
I got mine in anticipation of the Dlator build when I ordered stuff from Nik.

[surfsup]

THat would be helpful thanks.

[ToneMerc]

Here's the case specs of the Triad R-2C HAD used.
H= 1-3/4 , W= 1-7/8, D= 1-9/16.

TM

[ecisthebest]

This looks like it will work with a FWB and AES has it for $40 where Mouser it is unstocked:

http://www.tubesandmore.com/scripts/fox ... m=P-T261C6

250VAC CT, 50mA, 1A 6.3VAC

Yes?

i have this one, and although it measures 1.5" wide at the narrowest part, the output is 250vAC ct, which is 125-0-125. on my dumbleator the HT is only at 200vDC with just a full wave rectifier, you might want to use a voltage doubler, or 1.5x because 200vDC is imo a bit low. i didn't have enough room in mine. :p:

dimensions are 1.5"W x 3.25"L x 2"H. length including the wings to mount the screw.

[IMG:596:799]http://i78.photobucket.com/albums/j106/ ... 0a1632.jpg[/img]

[surfsup]

martin, yes the chassis is 1.75". Thanks for pointing that out.

tonemerc that Triad is perfect, but I don't want to ebay and pay shipping on 10 different shipments but I'll keep it in mind. can't find one googling ebay or craigslist right now anyway.

ericisthebest, since it seems I may have to go with the hammond due to availability, could you clarify? You are using a full wave, the rectifier at bottom left of the pdf, not a full wave bridge, right? I'm not sure what you're referring to when you use the term 'voltage doubler'

http://www.hammondmfg.com/pdf/5c007.pdf

I was planning to use the FWB and tape off the centertap so I should see 250*1.4 = ~350V at B+. So I thought the Hammonds would work fine with 250VAC, but your post concerns me.

I'll have to see if Allen can supply me the PT, the choke and a bunch of other stuff before I order. I want to minimize shipping.

[ToneMerc]

Yeah that Triad unit has been out of production for over 20 years. However, NOS(Onlinecomponents.com) pieces are out there if one is willing to pay crazy prices for the exact thing. Nik's is just a clone of the Triad piece. I faintly thought about cloning the Triad, but why worry with cutting a hole in the back of a rack chassis, as cutting an IEC hole is PITA enough.

TM

[surfsup]

If I use a FWB and tape off the CT on the hammond that will work right? I just need to be sure. If anything I can get that from AES or mouser and just use a 1k resistor instead of the 1k choke for the B1.

[LeftyStrat]

Not sure this would work, but you may want to also look at the toroidal transformer that Doug Hoffman carries on his site. It uses the back-to-back transformer trick to provide 240 B+.

The wall wart is an AC 12 adapter with 1 amp capability. Plenty for the heater current.

The toroidal is less than an inch in height and maybe 1.5 in width and length.

Of course that totals $37 plus shipping, but it is another option.