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Topics - saturated

Tubes and Hybrids / Tube Amp Trouble
March 18, 2024, 06:20:21 PM
Newly acquired Savage Rohr 15

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When I got it it seemed to work ok both channels four inputs...

I thought it didn't seem to have much gain but figured it was what it was.

I guess it had/has a problem because later it seemed to get quieter and quieter and finally one channel appearing inop and the other both volume knobs can be max and strumming a guitar 🎸 can be heard at low volume.

I worked up enough courage to take a look and perhaps see something.

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I looked at the chassis but did not touch or 🥢 chopstick anything.

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Also I reconnected the speaker before powering on.

Btw here is the tubes

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When I powered it on I noticed one 12ax7 was not glowing as well as the uncovered tube on the end which I presume to be a 12at7 (?)

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I guess I made a big mistake by not swapping a preamp tube to see if it was the tube or the chassis.

I carefully put everything back together and not too eager to further investigate until I can watch hours of reruns on YouTube about at least some basics of working on and around these units.

I also have read a bunch of the threads in this section so I'm expecting to be told check voltage ⚡ on pins xx on vx.


But alas I think this is gonna be on the back burner for a while.  I just don't yet have the stomach for poking around this amp.



Amplifier Discussion / Savage Amplifier
March 08, 2024, 04:15:12 PM
Saw this today...never heard of them.  Not much info out there.

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 :-[  :P

Looks pretty nice..kinda like a red 5150 combo

Amplifier Discussion / NAD (its orange)
January 20, 2024, 08:41:12 PM
I saw this today and tried to leave it alone
went home and watched football
about 1630 called the shop to see if the owner was still there
he was  :P
so I went and offered $40 for it
i own it now  :P

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I just finished making a bunch of noise with it.  Im pleased.

I was surprised how loud it can get I had to keep it low.

also maybe its brand new idk but the pots are squeaky clean usually when i drag an old amp home its static city and rice crispies for a while.  all good elsewhere no hiss squeals or hum.

I admit I only bought it because its orange.

figured i was starting too many threads and it would be better to keep it all in one place

gonna be posting some stuff that is painfully obvious to the more skilled members here yet is an epiphany for me  ::)

btw everybody here has been super cool and helpful

so here we go

I decided to try and figure out what this TO-3 was....and if it was good

so a probing I went

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and here is the device under test  :P

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I kinda want to look it up and see if i am right....

but i will wait


so I am previewing this looking back at my data thinking maybe those reverse bias? readings look kinda low.....oh well too late to chicken out now

i say
-its a PNP and its good (no shorts)

 :P  ::)
The Newcomer's Forum / transformer test 5 Sept 2023
September 05, 2023, 01:30:30 PM
fortunately this didnt have more than three wires on the secondary side

green to green

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then each green to yellow/green

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 that last pic looks a little too close for comfort

I presume that yellow/green is the center tap.... :P

time to read about center tap(s)

the two green went to a bridge rectifier

the yellow green went to an 8 pin chip...and back to the primary fuse holder.... :o

hope you had a nice labor day weekend

wanted to input signal to BB and check it out

seems SG needs to be added in series

so here we go....
randomly chose 1k resistor then connected SG as PS

didnt want to kill my "new" scope so checked with multimeter first

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being cautious was tough to get any kind of output...I started on the low output and cranked it some mv reading finally

connected my scope and couldnt get a triggered signal worth crap

repeated the above on high output

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was still surprised to see small output....idk

but finally got signal on my scope and tried to adjust pp

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then I remembered what G1 said about dc offset so i checked it and it works like he said but wierd if i went to far it got cut off...clipping?

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so that was a lot of fun  gonna put this stuff up and contemplate todays events

like why i get the same reading when scope is set to ac or dc...

but i was happy to see the amplitude change when volts per div was changed

as usual thanks for listening
The Newcomer's Forum / a start to a raggedy work space
September 01, 2023, 03:56:09 PM
mocked it up with my jams

still need a set of shelves on the bottom

them wood blocks got to go

in the middle where those speakers are will be scope, ps, sg etc

all 100% roadside acquisition...obviously  ::)

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maybe it will evolve from here
finally unpacked some of this stuff

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dc offset moves but doesnt hold

anyhow feelin pretty good even though i feel like i parachuted into another planet

have no idea whatsoever about these controls or adjustments

should be fun

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cant believe that hickock works...awesome the dc offset moves the trace but falls back

I wanted to fix my heathkit scope and i (we) will in time but i ordered another one so i could get on with my journey here which is happening at a snails pace

gonna have to do a lot of reading and watching videos

Im happy to report that i took a major step in my learning journey.  Having finally procured a few items to start using breadboards and actually DOING AND SEEING THINGS rather than reading about them and trying to visualise mentally. 

here is the first ever experiment directions

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and here is my assembled circuit

measuring voltage drop across the resistor

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and voltage drop across the diode

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in the grand scheme of things i have a long way to go ha ha

but every journey begins with a single step

thanks for being a part of it

(because i hope you can be part of it when i start hooking up transistors and capacitors and signals and scopes.....and start crying out for help   :)  :'(  8)
im gonna see if the small shop will take it back (let me donate it, not sell it back)
if not I will try to get a lowball offer from GC

it is like new, bought it in 2020....nice amp i enjoyed it but I have too much stuff and it has been on CL for a while at ridiculously low price...with not one inquiry.

its easy to have scorn for this new stuff but i did play the heck out of it

I know one thing though some people are really good at dialing i  different presets...and some arent....(raises hand)

nevertheless...i had some cool presets with corny names...

Blizzard Lead

Faces Losing You


Enthralled  (named for Pat Thrall)

and some others i cant recall atm

it had a nice built in tuner though

I just started another book and it is really good but they immediately had me doing Thevenin and Norton exercises.

I was like "oh no not again plugging and chugging exercises.."

but I guess i will work through it and get to the good stuff...lots of circuits...yeah  :)

I reckon knowing it will help me somehow down the line

The Newcomer's Forum / SSGUITAR success storie(s)
May 03, 2023, 02:45:31 PM
the guys at SSGuitar fixed my Peavey amp.  I bought it from a place where it had been collecting dust for probably decades.  I brought it home and it worked good but would cut out (go silent) sometimes coming back on and sometimes not.  I figured it was a sketchy input jack or some crusty old connection having problems.
It was frustrating but the sound was so killer \m/ i loved using it and putting up with it.
eventually it went silent and remained silent.  I read and watched lots of stuff about the effects loop and headphone jack etc to no avail.
I joined this place and the guys jumped right in to help.  they asked me different questions and asked me to check different things.
eventually they focused on a voltage measurement that didnt make sense and upon their recommendation I ordered the inexpensive component and replaced it.
and the amp now works...and sounds awesome.
no high tech tools were used.  just a multimeter, soldering iron, solder, desoldering wick and some hand tools.
it was kinda tricky getting the board out and inverted to work on it...and honestly when I soldered the new part in I was more nervous than someone doing brain surgery.
but it was a success and I want to shout out to the members here thanks for all of your help.

The Newcomer's Forum / Peavey speaker polarity
May 02, 2023, 10:55:03 AM
I have read that yellow and red are pos
and blue and black are neg...
but i can not find any markings on the speakers or terminal

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meanwhile I will keep sounds good to me as is idk

THANKS AGAIN FOR FIXING MY AMP!!!!!!!!!!!!!!!!!!!!!!!!!!!

picked this stuff up today...a decade resistance box, box of nos components, and a plastic tool box for $30
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this def needs some cleaning and a binding post...I wonder how accurate it will be
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lots of ic? and sockets
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I hope these 4040BE are useful...whatever they are

and the rest of the lot
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time to figure out if any of this is useful

The Newcomer's Forum / noob trying to solder
April 21, 2023, 11:30:49 AM
I have some older solder (among various types and ages)

seems like it would be awesome due to the diameter

but maybe it is so old the rosin stuff inside has degraded?

the reason I ask is everytime I try to use it I get awful crumbly crap. it will every so often behave and melt nicely but then mess up again.

I thought maybe it was just the end of it exposed to air amd moisture maybe it would get better but it hasnt.

hate to toss it but I cant get it to work.  I have other stuff that works good.

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thanks for your help
The Newcomer's Forum / my oscilloscope
April 15, 2023, 12:41:15 PM
did not power on
found an open fuse
replaced fuse
put on dbt looked good
powered on but has no trace

crt is glowing a little but not much

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the slide switches are extremely stubborn

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you practically need a hammer and chisel to move them


I am aware there are crazy high voltages in these things so I havent fooled with it  :) 
hello ssguitar enthusiasts

I am ordering some components as listed in an old lab book for experiments.
Listed are transistors, scr, diodes, resistors and capacitors

I am familiar with electrolytic capacitors as most are polar and marked as such..seems like for a breadboard I would want capacitors that can be installed either way?
maybe film or ceramic?  maybe price will be a consideration idk

I am assuming the diodes and resistors will not need to be anything special or unusual.

thanks for your help I have some Jameco breadboards.

hello all
I have a realistic power supply 13.8v 3A
I want to hook up and test an old 7808CT removed from my amp.  I dont know much but I am thinking 3 amps is gonna blow this thing up or melt it....
(I dont want to reuse it this is just me trying to learn some stuff...)
I also have a topwon 6303A that I havent unpacked yet maybe I can dial current down..
also I read the data sheet on some of the semiconductors...about a I could find was the output current.
I did some preliminary diode type tests per seems to be good idk....if its good its good I will replace it regardless that dag blasted glue had to come off anyway.  Anyhow mucho beer and pizza to all I really appreciate it all the help I have gotten here.
I have an amp (Peavey Audition Chorus) that used to play and intermittently cut out (silence) and a while back it cut out for good.

I was thinking about checking continuity on each volume, tone etc pot