Author Topic: 1482Esq (Read 32460 times)

shooter · « **Reply #50 on:** October 13, 2019, 04:57:39 pm »

I new better but...
2 broke bits n some ugly later

it'll get some cleanup n a paint job later, no one will know

time to hunt up the web for slider pots n switches, that'll be fun cutting in

shooter · « **Reply #51 on:** October 25, 2019, 06:28:06 pm »

Tube sorting n winter packing
1 6V6

Lots of 6K6 (I think, it�s a lower watt 6V6-like)
Lots of 6BQ6

Found this thread � GREAT analysis!
http://el34world.com/Forum/index.php?topic=11766.msg109161#msg109161

what I�ve gleaned I want ~120vdc @ ~ 50mA for 2 tubes?
Is it possible to get close with a 1:1 isolation transformer for wall power?
I know, go fish
also unburied a 5K : 8 (still SE 40%ul @25W, still edcor:)

Thanks
dave

shooter · « **Reply #52 on:** February 16, 2020, 11:50:40 am »

Back to the mini-ice-age so back to this build

Using 6K6 tubes for prototyping since I have 10 n 0 6V6s.
(I will probably buy a "proper" PP OT, but stil gotta get to 12k making sense)

Getting hung on plate to plate effective load, data sheet shows 12K
When I take 285vdc / 60mA it suggests 4750 Ω
So I�m missing something I forgot !

The other hang-up is the graph. My OT is way off (SE UL, discussed previously) but with speaker impedance manipulation, I can get to 7k Ω, or 14k Ω
Plotting a line on the graph at 7k looks to be a good option, better than 4750 (math) and 12k data-sheet

Thanks

dave

DummyLoad · « **Reply #53 on:** February 16, 2020, 05:33:17 pm »

sorry - what i had posted was not relevant to the Q. not relevant to your question.

PRR gave us a lecture on+ P-P in class A1 some years back - basically SE calculation x 2.

salt & pepper to taste. around these parts we like chili's and jalapenos.

--pete
EDIT: content.

shooter · « **Reply #54 on:** February 16, 2020, 06:44:17 pm »

ok, so translating So. Texas to farm Michigan, the OT impedance is arbitrary within reason?

all my builds so far are based on data sheet n ballparking based on plate volts n current which are close-ish. The data sheet n math are pretty far apart here

thanks

PRR · « **Reply #55 on:** February 16, 2020, 08:14:42 pm »

> plate to plate effective load, data sheet shows 12K
When I take 285vdc / 60mA it suggests 4750 Ω

Looks like SE math on a P-P amplifier.

shooter · « **Reply #56 on:** February 17, 2020, 07:09:06 am »

I'm Myopic that way

so I'd double that math in PP? or find something new

still kinda hung on the graph, I added green lines, the left vertical ~ matches the math, the 12k appears to show power out n distortion ~ the same

kagliostro · « **Reply #57 on:** February 17, 2020, 07:39:53 am »

http://www.valvewizard.co.uk/pp.html

http://www.valvewizard.co.uk/se.html

Franco

shooter · « **Reply #58 on:** February 17, 2020, 10:06:38 am »

Thanks K, was heading there next, you just pushed me

did steal this math for cheating;
P = 2 * (HT-50)^2 / Rload. just got to get Rload on the other side of ='s

one thing, the data sheet above is for PP class A1 (unless that's a typo), I was assuming it would operation closer to 2SE than AB1. Now I gotta go refresh my brain on amp class operation

PRR · « **Reply #59 on:** February 17, 2020, 01:06:57 pm »

> still kinda hung on the graph

That is for Single Ended.

A simple translation to push-pull would Double the impedance.

shooter · « **Reply #60 on:** February 17, 2020, 01:57:48 pm »

Quote

That is for Single Ended

thank you !!
shoulda seen that with the left side reading 3.5W

now I can sleep well!!

one more annoying question,
the green lines do "appear" to yield the same results at ~ 5k and 12K.
my guess the tube works less hard for the same output (power) because the impedance is closer to ideal at 12k

appreciate the time, thanks

dave

shooter · « **Reply #61 on:** February 17, 2020, 04:05:02 pm »

When n bit the 30-30 and ordered this OT

XPP15-10K, good price, shipping was NOT

figure 10k is close enough to 12k n I get the UL taps I want. The dimensions look like it might fit below decks so the wires will be out of the way to unsuspecting fingers

shooter · « **Reply #62 on:** February 19, 2020, 05:02:54 pm »

I'm pretty confident in my ability NOT to do a flaw free 'old style P2P build so I basturdized one of Sluckeys master pieces

still an in-progress paint edit

DummyLoad · « **Reply #63 on:** February 19, 2020, 08:26:35 pm »

10k gonna work fine. it's not Hi-fi.

or is it?

--pete

shooter · « **Reply #64 on:** February 20, 2020, 08:57:12 am »

Quote

it's not Hi-fi. or is it?

the amp, no. the OT

. It is UL, over rated for the build n Edcor made so it could swing either way shy of cork-sniffer Hi-Fi. Plan on mating it with my Altec VoT 15"

In my cobwebs I "hear" clean chimey til ~ 6. from there to 10 progressively crankier

shooter · « **Reply #65 on:** February 22, 2020, 07:33:53 pm »

decided to move to crayons

sluckey · « **Reply #66 on:** February 22, 2020, 08:10:41 pm »

When you gonna come over to the dark side and quit painting on those purty Visio drawings? Visio will unleash a whole new artist in you. Easy peasy for you.

DummyLoad · « **Reply #67 on:** February 23, 2020, 12:57:18 am »

Quote from: shooter on February 22, 2020, 07:33:53 pm

decided to move to crayons

https://www.libreoffice.org/discover/draw/

dude! it's free!

--pete

shooter · « **Reply #68 on:** February 23, 2020, 08:25:09 am »

I have a fully loaded Correl draw on a Win '95, but it ain't been booted in 12yrs

I can even do a pretty good layout with .sch(.pcb) but there is something therapeutic about putting DOWN the mouse and picking up drafting templates n pencils

thanks for trying though

DummyLoad · « **Reply #69 on:** February 23, 2020, 09:06:32 am »

i use CAD to design stuff i'll probably never build. just the opposite, but that's my therapy.

the PCB is for a AB763 preamp minus the tremelo + plexi preamp: switching and LTPI are on another PCB and board uses eyelets for external connections.

--pete

shooter · « **Reply #70 on:** February 23, 2020, 10:29:36 am »

Quote

just the opposite

I did a complete set of drawings for my house, 11 pages, with Correl draw. when I submitted them for my building permits the guy ask what Architect firm I used

At heart though, I will always be Analog by default

I'm working with the township to help draft an Ordinance to restrict BIG energy from putting 300' towers with propellers in our back yards. I asked where they had the research data, the reply FB, I laughed since FB won't let me look because I won't join their gang

shooter · « **Reply #71 on:** February 24, 2020, 04:13:32 pm »

Quote

PRR gave us a lecture on+ P-P in class A1 some years back - basically SE calculation x 2.

sorry missed THAT reply!

I'm finalizing the BOM, the datasheet says 400ohms Rk. I have 2, but I've seen enough original schematics that typically use 1 Rk.

Can I assume the datasheet means 2 400's

DummyLoad · « **Reply #72 on:** February 24, 2020, 11:16:12 pm »

Quote from: shooter on February 24, 2020, 04:13:32 pm

Quote
PRR gave us a lecture on+ P-P in class A1 some years back - basically SE calculation x 2.

sorry missed THAT reply!

I'm finalizing the BOM, the datasheet says 400ohms Rk. I have 2, but I've seen enough original schematics that typically use 1 Rk.

Can I assume the datasheet means 2 400's

respectfully, but query is ambiguous - a specific datasheet/case would be helpful. 400Ω for one tube or two? is datasheet SE class A or P-P class A

--pete

shooter · « **Reply #73 on:** February 25, 2020, 08:51:32 am »

sorry, the one I posted earlier above.

it's PP A1
I looked at a couple datasheets then amps with 1Rk, making a crayon note to self datasheets are 1Rk per tube, which is logical.

DummyLoad · « **Reply #74 on:** February 25, 2020, 01:58:07 pm »

if it states "values for two tubes" then the cathode resistor value given is for both tubes. if you want to split cathode resistor, one for each 6k6, then you'd need 800ohm for each 6k6.

--pete

shooter · « **Reply #75 on:** February 25, 2020, 03:02:33 pm »

Quote

"values for two tubes"

Yup verbatim! and that's why I posed the ?
but then I re-read data sheet n since plate vdc is 285, I was pretty sure that didn't mean 570 each.
62years and I still struggle with my native language

thanks Pete. I'll make sure I have some double values on hand

shooter · « **Reply #76 on:** March 06, 2020, 04:49:49 pm »

got the rubber meeting the road

and my 1st

up

the last drop R should be 10K, now 2.2k, gonna leave for now til I load it up n see where plate volts land.
can't cut up chassis, missing my OT, and it TOO cold to play with contact cement

shooter · « **Reply #77 on:** March 08, 2020, 05:09:12 pm »

spent the day wandering the inland sea, watching the well-to-do watch their homes move closer to the edge

the boards wired 80% (not shown:), drillin wire holes tonight
dug up an old head box I built for my revibe spaghetti mess, to cold to paint though

shooter · « **Reply #78 on:** March 08, 2020, 06:50:47 pm »

I re-did the red dots to remove PA cathode parts
missed a couple

I didn't want to do over so...It fits

should be 2 weeks then Edocr will wind n ship my coil in about an hour... and 6 weeks

it's warming up so I can wait outside

shooter · « **Reply #79 on:** March 11, 2020, 05:04:33 pm »

My friends in New Mexico got bored, OT in the mail!

Me of low knob count has used more than my last 3 builds

the layout I have for the 1471 has kitty-wampiss knobs, so i'll bite

(random parts are stand ins :)

shooter · « **Reply #80 on:** March 12, 2020, 02:42:01 pm »

the Gov'mnt worker brought my OT!
it's even 48 degrees without SUN!

since I left 3 miles of un-needed board, jugglin pieces is interesting

gonna watch this layout for now, maybe when the crayons come out it'll change

shooter · « **Reply #81 on:** March 13, 2020, 06:59:42 pm »

busy with life, took time to throw chips, and tweak to artistic

shooter · « **Reply #82 on:** March 14, 2020, 04:48:43 pm »

carbonized 30 cubic FT of shipping boxes eating at my floor!
that opened up enough to find tools, which lead to fitting the big n heavy parts

assembles real easy, dis-assembly requires either LOTS of Sailor speak or Zen patience

hunting for the dremel next to cut the board since it cannot be removed without removing the OT

Neither can be removed once I wiggle the bridge in

I berated mechanical engineers my whole professional life, this is karma coming around

still not 100% committed to tube position, but real close

shooter · « **Reply #83 on:** March 16, 2020, 04:50:51 pm »

real life ate up most of the day
managed to get the square holes made n fitted, Lowes was a ghost store

the EIA came too close to the OT so I have a couple spare holes

not worth a pic

[/EDITi]:
kinds hung, I missed the pot, now I gotta clean up. designed a dpdt, ordered a spst

here's my cheat, never build NFB so any electronic "issues", even blaring design faults
was gonna play with hard-wiring the cap during tweaking phase

Platefire · « **Reply #84 on:** March 16, 2020, 08:12:14 pm »

Just discovered this! Glad I'm not the only one the projects span a two years

Well I'm looking forward to see what you get.

The reason for my center-0ff switches was allow myself to switch back to original no-NFB. Same reason with cathode bypass caps on the instrument channel.

Platefire

shooter · « **Reply #85 on:** March 17, 2020, 08:12:24 am »

I borrowed heavily from your version

and time in my new life is an abstract concept

I like having the center off, since I've never used NFB I can just leave it OFF if I don't like it, instead of unsoldering

Platefire · « **Reply #86 on:** March 17, 2020, 10:03:48 am »

I use my 1482 every week in Worship Services hooked in parallel to my DiY Champ. I am actually using NFB setting on it right now along with the channel with the Princeton(5F2) tone stack. For some reason I never like the effect of the different cathode bypass caps? seems like they add too much compression. I like compression but use a pedal, so I can adjust it.

LONG LIVE THE 1482 AND THE CONTINUED IMPROVEMENTS

shooter · « **Reply #87 on:** March 17, 2020, 04:32:34 pm »

couldn't get the leaves to carbonize so I bored the tube holes.
2 round n a rectangle hole left. Then it's be-burr, de-grease. Probably just have fun and try n channel some Jackson P. for the paint scheme

davidwpack · « **Reply #88 on:** March 17, 2020, 07:35:39 pm »

Nice! Just wondering: is your light in your switches clear? I bought a bunch of blue and green switches a while back thinking they'd illuminate blue or green. They put orange bulbs in them so they are orange when they illuminate. Anyways.... looking good!

sluckey · « **Reply #89 on:** March 17, 2020, 07:48:38 pm »

AFAIK, NE-2 only comes in orange.

davidwpack · « **Reply #90 on:** March 17, 2020, 08:16:51 pm »

Oh. I was just wondering. Kinda defeats the purpose of making them blue or green. They definitely don't look blue or green when they're on....at least the ones I have don't.

sluckey · « **Reply #91 on:** March 17, 2020, 08:41:43 pm »

All of my rocker switches are either red or orange. They keep true to color, but I'd expect blue and green to be off color a bit.

I have a green lamp on my Leslie footswitch. It uses that same orange NE-2 neon bulb. It looks green to me. It's shining in this pic...

davidwpack · « **Reply #92 on:** March 17, 2020, 08:55:07 pm »

Yeah that does keep it's color. I used a blue one for power and green for standby. They both look like identical orange switches when powered up. It's not a big issue for me but it would be cool if they looked blue and green when lit up.

shooter · « **Reply #93 on:** March 18, 2020, 08:34:06 am »

Quote

it would be cool if they looked blue

It looks as blue as Sluckey's looks green if that helps. I use 'em cause it's all in one.

the aesthetics is good, they came in all the colors you mentioned , amber, red, green, n blue.

think I settled on Pollocks, Black period, looking at the Dewalt, dark orange on black keeps humming in my head

PRR · « **Reply #94 on:** March 18, 2020, 12:57:56 pm »

Quote from: sluckey on March 17, 2020, 07:48:38 pm

AFAIK, NE-2 only comes in orange.

Yes; but there WERE some "NE-2**" variants. I had some with green phosphor (dunno what the gas color was). https://en.wikipedia.org/wiki/Neon_lamp#Color

If you must have non-orange, LEDs come in all colors, but need a very different power supply (not simply right across the line), and may be hard to retrofit in vintage switches (new switches can be had with LEDs).

shooter · « **Reply #95 on:** March 18, 2020, 03:42:20 pm »

crappy day out, so crayon time came early

working title "FluPoo"

2 weeks n it might be dry

davidwpack · « **Reply #96 on:** March 18, 2020, 04:00:57 pm »

Crazy! You gonna try to match some tolex to it?

shooter · « **Reply #97 on:** March 18, 2020, 04:57:20 pm »

I ONLY build chassis'
I do have a box (posted earlier), but it's rainy n cold so the barn is in isolation

davidwpack · « **Reply #98 on:** March 18, 2020, 06:39:04 pm »

Mind if I ask where you guys get your switches? Here's a couple on and off pictures.... neither blue nor green.

sluckey · « **Reply #99 on:** March 18, 2020, 08:18:50 pm »

That's crazy!

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Author Topic: 1482Esq (Read 32460 times)