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Messages - polo16mi

#31
Bulb limiter is useful saving components. An alternative is dont use it, but.... everytime that something goes wrong, and some component die, you´ll pay the cost ($$$)

I recomend use it. Is no big deal. Just carefully mount it. No need to touch anything with tension.
#33
Maybe Mr. JM thinking about brown color over the main transformer? (overloaded, so blew?).

I wondering what happens if Mr. ipoo2 measure voltages between each screw of that six over the main pcb, and the chassis of amp. A pair of wire (plus GND), comes from the little pcb around the big transformer, with +VCC and -VCC. If reasonable values founded, then think next step is measuring the  state of the big transistors (2n3773 and his neighbors)

#34
First: i suggest you to do and USE this thing LImiter bulb light

Can you check if you have some DC tension reading between the two wires at the speaker output jack?
#35
Quote from: ipoo2 on April 03, 2012, 05:23:29 AM
Although slapping the pickup does produce a noise.

No sound variation at all or i made a wrong traslation?

In other hand, assuming that this thing didn´t work, cause he says that purchased it as spare parts....sounds to my posible that somebody sells something that work fine, thinking that didnt work, but no very probable.
#36
In advance, if you could post several pictures of it here, some guys here can help. No easy to tell anything if we can´t see inside and you have no knowledge about electronic stuff.



#37
Hi there:

I made an amp using a sansamp clone http://www.pisotones.com/GT2/GT2.htm as preamp, and LM3886 Chipamp as amp. It is wired straight the output of sansamp to LM3886 input.


I wondering how can i add an CD/MP3 input as, say, MG15CD, so i can jam a backing track.

My first idea, is wire a jack in parallel with sansamp output, directly to poweramp input, join Left and Right channels to + signal input, and gnd-gnd. Not sure if any trouble in that way.  :-\


I see MG15CDR squematics, and it use a 10uf cap in series with a 10K resistor from preamp output, and a 3.3K from cd input. Joins resistors terminals and go to the power amp input.

Why they use that resistors? Not sure if it is for protection purpose or impedance dealing.

Can any help?
#38
This is what you want:

Go straight forward for a LM3886 chipamp power stage. Simple, easy, reliable, and mounted hundred of times with success. Kind of cheap too.

http://www.generalguitargadgets.com/projects/13-amps/58-lm3886-amp

In the same page you can browse several preamps.

Hope help.
#39
Hi there:

I´m not really know how to help you fix your amp, but at first step, im pretty sure that you´ll find usefull this Light Bulb Limiter, to save several component$$$.

http://www.ssguitar.com/index.php?topic=2093.msg17092#msg17092

I sure too, that you wait for a while here, and you get some more usefull help.


#40
HI there:

Sounds to me, that the pins of the input jack breakup of the board (pcb). With some luck, you wont be broken the pcb, so, is matter to buy same type of input jack and change it (asuming that you have a solder, and some soldering skill, no big deal).

Maybe help open it, look inside, take some pictures of suspicious part, then upload here.

#41
Hi there:

Has been long time since last post:

Here some pict for my last proyect.

I had inspired in a JCM900 1x12, and make my self version.

It has a 50W chipamp, and kind of GT2 clone as a preamp.  Its sound good enough to my, and already tested in a coupled of jam sessions last night.

I need some suggestion about how to record some samples to load here....


#42
Amplifier Discussion / Re: Light Bulb Limiter
February 15, 2012, 09:58:47 PM
Hi JM

You are a guru of amp repair!.

i had mounted it as you suggested time ago, and it save me several fuses, and now i happy, running  my LM3886-SansAmps Clone pre. (comming soon pictures and samples).

It is a "to do" homework for any that want throubbleshooting amp help.

Regards.
#43
Preamps and Effects / Re: Perfboard question
December 09, 2011, 08:38:45 PM
Quote from: J M Fahey on December 09, 2011, 05:11:00 PM
CADSOFT(EAGLE) says:
QuoteFreeware
The EAGLE Light Edition can be used for free!
How do I get it?
Follow these steps to install the free EAGLE Light Edition on your system:
    * Go to the Download area and get the file that contains the EAGLE program installation data for your operating system (Linux, Windows or Mac).
    * Install the file you have downloaded onto your system.
    * When you first start EAGLE, you will be asked whether you have a personalized license disk, or whether you want to run EAGLE as Freeware. To use the Freeware license select the "Run as freeware" button.
Limitations
The following limitations apply to the EAGLE Light Edition in general:
    * The useable board area is limited to 100 x 80 mm (4 x 3.2 inches).
    * Only two signal layers can be used (Top and Bottom).
    * The schematic editor can only create one sheet.
So you either paid U$1500 to get the Commercial version or .... better don´t ask  ;)
To check "official" pricing:
http://www.cadsoftusa.com/shop/pricing/?language=en

Ejem..... of course.... a friend of mine let my use its pay version on your computer..... i know what it cost.  :cheesy:

I just installed the trial version, and it has like you say, that limitation.
#44
Preamps and Effects / Re: Perfboard question
December 09, 2011, 03:32:22 PM
Quote from: J M Fahey on December 08, 2011, 10:17:25 AM
Eagle is good, but the size limits kill me.

Im using Eagle v5.6.0 and dont see any restriction about board size.  ???

Here you have a sample of file with 7 pot and inputs at front.

#45
Preamps and Effects / Re: Perfboard question
December 07, 2011, 09:35:44 PM
Maybe sounds to you crazy, but using eagle for design component position and track route. I dont like how (or i dont know how) eagle use size for each tracks, therefore as soon as i get a design good enough to me, i copy it in Autocad, and draw the tracks at sizes and shape that i like it. I have already created blocks for resistors, caps, and others components, so i copy and paste in needed position and draw the tracks. I use cad for my job, but its realy easy to measure a component and draw it just one time for library it.

Plus, plot design at laser printer directly. 

Besides, if you wanna do a perfboard design, i dont know if exist a specific software for it, but im sure that the use of Autocad is very properly and easy for it.

I sorry for my english, but i am kind of missing link between spanish and english