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Hoffman Amps Forum image Author Topic: Sans Tubes  (Read 7866 times)

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Offline shooter

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Sans Tubes
« on: May 17, 2019, 08:12:02 pm »
Tube version here;
http://el34world.com/Forum/index.php?topic=24536.0

stripped down tube section, made a "hole plate", then I realized, home alone, sooo I moved the amp back to the turntable n speakers.  Started with Charlie Pride singin a whole album of Hank Sr., ended with Uneasy Rider  :icon_biggrin:
Went Class C for efficiency

Offline shooter

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Re: Sans Tubes
« Reply #1 on: May 24, 2019, 01:46:02 pm »
Sun lasted 14hrs, back to the monsoons!
a little steam punk addon  :icon_biggrin:
gonna wait to wire the mains on the Center amp till I can drag the cab to the barn, did manage to sweep up and get chairs out  :icon_biggrin:

Went Class C for efficiency

Offline shooter

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Re: Sans Tubes
« Reply #2 on: May 25, 2019, 05:00:57 pm »
 :m17

Barn's officially open!!
center cannel wired, need to re-build the HF/LF pad it cuts 80% signal and don't care what freq  :think1:
straight to the speaker with a blankie out front and the bass hits great.  The Klipsh pick up from mid bass and just run!
Pedestals next for the L/R.  My old notebook has a soundcard glitch, makes a record skip sound about every 30 seconds  :cussing:
She's a true Hill-Jack setup, but i'll put it on a sidebyside with any $800 setup AND win  :icon_biggrin:

EDIT:
WOW, took the win7 asus with SSD, new media player, tweaked eq to a grin, She's now moved into the over $1k crowd! :icon_biggrin: and the barn just resonates, you can be 30' outside n still hear ALL the nuances
10W L/R 25W center  :icon_biggrin:
« Last Edit: May 25, 2019, 09:30:53 pm by shooter »
Went Class C for efficiency

Offline shooter

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Re: Sans Tubes
« Reply #3 on: June 16, 2019, 06:34:06 pm »
after a month of listening, moving speakers, chairs and.... :think1:

The amp doesn't have separate volume for Center Channel, it's overdriving the L/R's
so time to upgrade  :icon_biggrin:
besides a separate volume, I'm upping the L/R from 10Wea to ~ 25W

working on the PS, found an old boom-box with a +/-24v toroidal.  It had 2 TDA 7276 but one side was dead and the caps were sketchy, so save tranny, back to the heap for the rest.

so far got .042F worth of reformed caps, once charged they dropped (unloaded) 2.5vdc over a 3hr sample. good enough (probably order enough cap to get to ~ .1F)
probably get an order out for the 2 TDA7276 mono boards
 by the time I get it upgraded i'll have( :w2: ) the other speaker stand done!

EDIT: slid decimal where it belonged  :think1:  added PS schematic
« Last Edit: June 16, 2019, 08:40:16 pm by shooter »
Went Class C for efficiency

Offline shooter

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Re: Sans Tubes
« Reply #4 on: June 17, 2019, 07:26:06 pm »
watchin paint dry  :icon_biggrin:
still tweakin the PS as I read more, updated schematic
Went Class C for efficiency

Offline shooter

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Re: Sans Tubes
« Reply #5 on: June 19, 2019, 04:51:42 pm »
got the amp kits ordered, still studying PS design  :think1:

The piece of Apple isn't fixed, I need to figure out where the heat-sink will go.  So far scavenged pieces only;
the PS box is from a failed Philips voice/video to fiber MRI add-on.  The netgear box became obsolete when the T1 line went in.  The tranny "cover" is a pulley made from some phenolic funky stuff GE used to "scale" the optical encoder for table travel, what a Ruep contraption  :think1: The caps from old linear PS's and the tranny from a '90s boom-box  :icon_biggrin:
Went Class C for efficiency

Offline shooter

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Re: Sans Tubes
« Reply #6 on: June 21, 2019, 08:10:59 pm »
The underside  :think1:,  me n Mr. Dremel had it out, the holes lost  :cussing:
Doug should be back from the Post office on his Ebike so should be testing early week.  Amp kit should be soon.  I stole the right side of this PS TI suggested design, the left side might be an after-market addon, still head-scratchin
Went Class C for efficiency

Offline shooter

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Re: Sans Tubes
« Reply #7 on: June 26, 2019, 06:02:24 pm »
Doug Came through, warmed up the Weller, about all you get at the barn is warm  :think1:

quick test with 1k load checked ok.  when I get the porch finished i'll get some full load testing.
Got update on shipping for the amp the PS goes with; 5/5 - 5/22  :think1:
I can just see the encrypted txt; "hey, that next shipment of Fentanyl, smuggle in that 40W amp kit"  :icon_biggrin:
Went Class C for efficiency

Offline shooter

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Re: Sans Tubes
« Reply #8 on: July 03, 2019, 09:06:33 pm »
the slow boat finally showed up  :think1:
took about an hr a board at slow-poke speed  :icon_biggrin:
since it's the 4th tomorrow, good day for a smoke test n smoke n test n... :icon_biggrin:

UPDATE:
powered up, played well, 30min and the fins were to hot to touch, 30min after power-down they reached ambient.
Fidelity met expectations, audible loud was not quiet there, I think an 11 on vol would get where I expected but it's not a scope day
DC landed where I expected, ripple same, except @vol 10, then ripple trebled in amplitude
« Last Edit: July 04, 2019, 09:29:26 pm by shooter »
Went Class C for efficiency

Offline shooter

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Re: Sans Tubes
« Reply #9 on: July 26, 2019, 08:32:07 pm »
Made time, little progress  :laugh:
had a blown set of Jensen's, put in a pair of TangBang 3.5".  rear speakers!  The baffle plate was a pain to cut X2!
started wire-up of CH 4 & 5.  Rain for early next week, maybe  I can finish then, too nice til then  :icon_biggrin:
Went Class C for efficiency

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Re: Sans Tubes
« Reply #10 on: July 27, 2019, 06:18:43 pm »
Some ‘90s teens showed up, when they left I was limited to soldering  :icon_biggrin:
So, finished my official SolidState Class AB 5channel! The left amp takes care of center and rear L/R.  The left amp handles the front L/R

The monster PS stays real clean til ~ 80% max then she starts some spike-e action to ~~ .3vac.  The chips have a built in PS rejection of -56db so that helps
Very low slow sag, < 200mV from steady rail volts
C ch  ~ 25W audio
Front ~ 20W audio
Rear  ~ 10W audio

Cable‘ln  up as whole system and tweaking speakers next, finish out the night LOUD

UPDATE:
ok, I know where NOT to dial the pots n source so it's final til I get bored in Jan then i'll do scope work
The chip is rated 50W more like 15W
did meet, barely, my design expectation of ~20W clean.
I found speakers behind me annoying but moved forward fills in great!!
overall got me very close to very happy  :icon_biggrin:
 
« Last Edit: July 27, 2019, 08:41:26 pm by shooter »
Went Class C for efficiency

Offline Bantam

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Re: Sans Tubes
« Reply #11 on: September 16, 2019, 06:02:56 pm »
Great looking project, and that barn/space looks like a slice of heaven! maybe a little cooler?

Offline shooter

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Re: Sans Tubes
« Reply #12 on: September 17, 2019, 08:57:03 am »
 :laugh: thx, ya, with no AC in the house, the barn will typically be ~~10deg below ambient, plus with the N-S doors it typically has a small convection(?) breeze.
I bought the barn, they gave my Wife a house  :icon_biggrin:
Went Class C for efficiency

 


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