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January 20, 2021, 10:42:42 AM

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11
The Newcomer's Forum / Re: Soldering Iron Tips
« Last post by flester on January 19, 2021, 05:21:07 AM »
I really need to get a better iron/station. Any recommendations around €100/$120 or so?
The cheapo is useful but it seems shame to bin it after a day. You get what you pay for, right? I think I've found a source for suitable tips now but I'll also try the workarounds mentioned below.

Sent from my SM-G935F using Tapatalk

12
The Newcomer's Forum / Re: Soldering Iron Tips
« Last post by edvard on January 18, 2021, 08:36:10 PM »
If you know of someplace where you can find or buy an old-style float and arm style toilet valve, that arm is often copper or brass, and the diameter will fit in most soldering irons.  Cut off small sections and file one end into a tip. 

If you want REALLY budget tips, I have been known to buy a screwdriver or two from the local hardware store that sells cheap junk.  Found one with a shaft diameter that fit and cut it into sections with my Dremel.  No, it doesn't work as good as a proper tip, but it'll get you by while you save up for a nice tip.
13
Guitar News / Re: SSG-AMP-1 "Honey" - The new battery amp kit you need to have!
« Last post by joecool85 on January 18, 2021, 05:05:41 PM »
42% funded, we're on our way there!  :dbtu:
14
Amplifier Discussion / Re: Rocktron Rampage R80 - No Sound problem
« Last post by dmeek on January 18, 2021, 02:34:40 PM »
The wire from CN2 IN on the preamp board is the reverb send. It plugs into IN on the reverb unit. OUT goes to CN3
15
Amplifier Discussion / Re: Rocktron Rampage R80 - No Sound problem
« Last post by paolone on January 18, 2021, 01:05:32 PM »
Hy

Thanks to all of you.

@dmeek  I've just make a test with a cord between effect send-return, The sound is more noisily.

@Phatt  I have test the reverb box (Accutronics 1EB2C1A) with a multimeter:
IN = 57 ohm
OUT = 196 ohm
Reading the instruction in the pdf i think it's ok...

@dmeek  the cord that starts from the board pin "IN" goes to the reverb box pin "OUT" (cord colour: RED). Impedance misured from cord pin 100 ohm
the cord that starts from the board pin "OUT" goes to the reverb box pin "IN" (cord colour WHITE). Impedance misured from cord pin -LO-


I have cleaned the 2 boards and the terminals with the electronic components cleaning spry.
Do i have to use the sand paper?

Now that i have all the boards unmounted, do i have something other to do before to remount and test them? (check capacitors...)

Thanks
 
Paolo
16
Amplifier Discussion / Re: Power supply/ power amp question
« Last post by NPreston on January 18, 2021, 10:24:15 AM »
Hi..

Thanks for the replies.
I agree the voltages I have are nothing to take lightly.  Making a conscious effort to not touch anything with my left hand when working on this and ensuring caps are discharged enough before I go poking around.

when I ordered this transformer a couple years ago, I had expected to get a 36-0-36 supply, but I guess I missed the target on that one..

I've been reading and trying to understand how power amps/inside of opamps work and its starting to make sense..  I will definitely look into https://sound-au.com/projects-0.htm#mus for more understanding.

I've hacked together couple power amp circuits (albeit crude ones) at lower voltages with some success.. 
Trying to actually calculate things properly and really understand exactly what is happening where this time around.

Thanks

17
Amplifier Discussion / Re: Rocktron Rampage R80 - No Sound problem
« Last post by dmeek on January 17, 2021, 11:03:29 PM »
Here is a rough schematic of the preamp output. Another possibility for the reverb is the input and output jacks might be reversed.

18
Amplifier Discussion / Re: Power supply/ power amp question
« Last post by Enzo on January 17, 2021, 09:45:40 PM »
Transformers produce AC voltages, and those voltages are called RMS voltages.  SInce AC voltage changes all the time, we use an average.

36v AC, moves from zero up to a peak of About 51v, then back down through zero and out to -51v and back.   The average of that zero to 51v is 36v.  When you rectify and filter that, the caps charge up to the peak of 51vDC.   This is how it works.  You take the RMS AC voltage of the transformer, and multiply by 1.414 to get the peak voltage, which will be the rectified and filtered result.We might subtract a volt or two for losses in the rectifiers or some such, but that basic formula is close enough.
19
Amplifier Discussion / Re: Rocktron Rampage R80 - No Sound problem
« Last post by phatt on January 17, 2021, 09:27:07 PM »
Plug a cord from Effects Send to Effects Return and see if it works. It could be the Effects Return jack switch.
Dmeek beat me to it,, Yep FX loop is the most likely culprit. they are *Switching sockets* the switch terminals corrode and give the symptoms you are describing. 
Also looks like it may have a Preamp out and Poweramp input,, which is another fail point. link them as well.

As to reverb not working,,pull the RCA plugs and clean the pins.
Also flip the tank and use a DMM to check you have continuity of the little transducers,, there are 2 of them. if no reading look close for broken wires.

As for the big difference in Volume between clean and dirty,, well that is how most of them work,, Normal. ;)
Phil.
20
Amplifier Discussion / Re: Power supply/ power amp question
« Last post by phatt on January 17, 2021, 09:17:24 PM »
Welcome,,
 If this is your first project I would suggest you do some reading first.
The power supply voltage you have is likely too high for a novice.
with 50VDC rails it's possible to end up dead,, the you accidentally touch both rails then it's 100Volts across your heart.  xP

You need a supply of around 35-0-35VDC would be a lot safer and far less chance of blowing up your circuit and dying as well. 8|

Working with anything over about 80Volts is a potential death trap. ???

Go here and do a lot of reading; https://sound-au.com/projects-0.htm#mus

Look at Project27; It's a 100Watt guitar amp running from a
SAFE 35-0-35VDC. You can even purchase a PCB from Rod which will save you a lot of blood and sweat trying to make your own.

This is by far one of the best places for those wanting to DIY an amplifier,, tons of stuff and written for folks like you who do not have the skill to go it alone.
Cheers Phil.
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