Welcome, Guest. Please login or register.

April 05, 2020, 12:21:30 AM

Login with username, password and session length

Recent Posts

Author Topic: Introduction, a question and a hope for some insight / help  (Read 1103 times)

Lex

  • Regular
  • **
  • Posts: 19
  • Chip Points: 2
    • View Profile
Introduction, a question and a hope for some insight / help
« on: February 04, 2020, 06:38:40 AM »
Hello good people from SSGuitar forum.

It's nice to see enthusiasts and professionals who are still in love with old stuff.
I've been reading for a few days several treads and now decided to post mine.
But first about my skills;
- Im a mechanic by default,
- I have some experience with electronics. I can repair electronic stuff, solder, exchange components and such.
But I dont know why certain resistor or diode or capacitor is placed somewhere and what that particular part is doing there.

I have one Fender Frontman / Bullet 15W Reverb Pr-241.
It's doing good, exept this well known BUZZZ ..
Found out that I need a really good grounding and I took a wire from the radiator and connected to the chassis.
Buzz gone.
Then I removed the wires from the speaker, removed (external) ground wire and connected to 12" Celestion. No Buzz and very good sound.
Well done Fender, this amp sounds good.

Now I have the second small SS amp, a Squire Champ 15GR Pr-CPR1.
Overall is working good, however it does not sound good as it's brother- the Frontman. A difference in sound as night and day.
This model has 2 GAIN pot's and no distortion switch and no AUX input.
Also Im not sure about the schematics, If I found on-line a good one as non of them are with 2 GAIN's.

Now what I would like to change or improve on this Champ amp:
 1. First and most important:
 - there is a 'light' distortion sound all the time, with or without Reverb, I can hear it all the time so also on the clean channel (the matter of a setup of 2 GAIN pots),
 2. the overall sound is kind of 'shallow' .. 'flat'.., I miss the richness of the Frontman. Tried it also on 12" Celestion.
  - so a bit nicer, fuller, richer sound would be appreciated.

Both amps will be NOT PLAYED on stock speakers but on a external cab.
 
I found on this forum some good stuff about diferent kind of diodes and swapping them, however I could not spot the right part on my board to compare it.

So my humble question would be:
 - if someone could 'guide' me to the right place on the board for exchanging diodes / resistors ... like I found in other treads regarded to Squier 15w.
 
I hope I was clear with my explanation (and my English).
If there are some other / more questions Im more than ready to answer them - only way to lean new things!

Greetings
« Last Edit: February 04, 2020, 11:05:43 AM by Lex »

joecool85

  • SSGuitar Admin
  • Legendary
  • ******
  • Posts: 3230
  • Chip Points: 988
  • SSG Creator
    • View Profile
    • thatraymond.com
Re: Introduction, a question and a hope for some insight / help
« Reply #1 on: February 04, 2020, 10:32:15 AM »
Hello good people from SSGuitar forum.

It's nice to see enthusiasts and professionals who are still in love with old stuff.
I've been reading for a few days several treads and now decided to post mine.
But first about my skills;
- Im a mechanic by default,
- I have some experience with electronics. I can repair electronic stuff, solder, exchange components and such.
But I dont know why certain resistor or diode or capacitor is placed somewhere and what that particular part is doing there.

I have one Fender Frontman / Bullet 15W Reverb Pr-241.
It's doing good, exept this well known BUZZZ ..
Found out that I need a really good grounding and I took a wire from the radiator and connected to the chassis.
Buzz gone.
Then I removed the wires from the speaker, removed (external) ground wire and connected to 12" Celestion. No Buzz and very good sound.
Well done Fender, this amp sounds good.

Now I have the second small SS amp, a Squire Champ 15GR Pr-CPR1.
Overall is working good, however it does not sound good as it's brother- the Frontman. A difference in sound as night and day.
This model has 2 GAIN pot's and no distortion switch and no AUX input.
Also Im sure about the schematics, If I found on-line a good one as non of them are with 2 GAIN's.

Now what I would like to change or improve on this Champ amp:
 1. First and most important:
 - there is a 'light' distortion sound all the time, with or without Reverb, I can hear it all the time so also on the clean channel (the matter of a setup of 2 GAIN pots),
 2. the overall sound is kind of 'shallow' .. 'flat'.., I miss the richness of the Frontman. Tried it also on 12" Celestion.
  - so a bit nicer, fuller, richer sound would be appreciated.

Both amps will be NOT PLAYED on stock speakers but on a external cab.
 
I found on this forum some good stuff about diferent kind of diodes and swapping them, however I could not spot the right part on my board to compare it.

So my humble question would be:
 - if someone could 'guide' me to the right place on the board for exchanging diodes / resistors ... like I found in other treads regarded to Squier 15w.
 
I hope I was clear with my explanation (and my English).
If there are some other / more questions Im more than ready to answer them - only way to lean new things!

Greetings

You'll need the proper schematic.  According to Fender's list, you can get a PDF copy: https://support.fender.com/hc/en-us/articles/212774686-Fender-Guitar-and-Bass-Amplifier-Owner-s-Manuals-and-Schematics-Hard-Copy-Archives

There is an email address to write to linked at the top of that page.  Send them a message and they'll send you the PDF.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

Lex

  • Regular
  • **
  • Posts: 19
  • Chip Points: 2
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #2 on: February 04, 2020, 11:07:22 AM »

You'll need the proper schematic.  According to Fender's list, you can get a PDF copy: https://support.fender.com/hc/en-us/articles/212774686-Fender-Guitar-and-Bass-Amplifier-Owner-s-Manuals-and-Schematics-Hard-Copy-Archives

There is an email address to write to linked at the top of that page.  Send them a message and they'll send you the PDF.

Thanx , I'll check it there first

Greetings

Lex

  • Regular
  • **
  • Posts: 19
  • Chip Points: 2
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #3 on: February 10, 2020, 05:24:28 AM »
Hello,

got schematics from Fender, however its not really good read (for an amateur)  .. cant find those 2 GAIN pot's for the orientation ..

It's in the attachment so I hope some good ppl would understand it and being ready to advice,

Greetings

phatt

  • Legendary
  • ******
  • Posts: 2094
  • Chip Points: 251
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #4 on: February 10, 2020, 05:43:43 AM »
Just remove CR1 & CR2 for clean.
Or you could wire up a switch to switch those 2 diodes in or out of circuit for clean or dirt.
With diodes out of circuit you will find there will be a lot more clean but being a small amp it will still distort when volume is high.
Phil.

Lex

  • Regular
  • **
  • Posts: 19
  • Chip Points: 2
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #5 on: February 10, 2020, 03:05:31 PM »
Hello Phil,

thank you for the reaction.


Still a few questions;
   
Quote
Just remove CR1 & CR2 for clean.
   Or you could wire up a switch to switch those 2 diodes in or out of circuit for clean or dirt.

  •   this means for each diode 1 off/on switch?
     so when the switch is OFF, that means that same diode is disabled ?
  • for my purpose of learning: are those CR1 and CR2 a 'bad' diodes, are there a 'better' one for possible replacement - or it's just old school SS amp design?

edit: found an info at  http://www.tpub.com/neets/book7/27m.htm ,  is this diode mod about same/similar thing - "Rectifier action of CR1 and CR2. NEGATIVE / POSITIVE ALTERNATION ?
 
 
Quote
With diodes out of circuit you will find there will be a lot more clean but being a small amp it will still distort when volume is high.

  • being a small amp as 'small' aka SS 15w or small because of the speaker?
    I will use a single 12" or (2x) 10" - so to an external cab.

Greeting
« Last Edit: February 10, 2020, 03:18:35 PM by Lex »

joecool85

  • SSGuitar Admin
  • Legendary
  • ******
  • Posts: 3230
  • Chip Points: 988
  • SSG Creator
    • View Profile
    • thatraymond.com
Re: Introduction, a question and a hope for some insight / help
« Reply #6 on: February 10, 2020, 08:33:49 PM »
Hello Phil,

thank you for the reaction.


Still a few questions;
   
Quote
Just remove CR1 & CR2 for clean.
   Or you could wire up a switch to switch those 2 diodes in or out of circuit for clean or dirt.

  •   this means for each diode 1 off/on switch?
     so when the switch is OFF, that means that same diode is disabled ?
  • for my purpose of learning: are those CR1 and CR2 a 'bad' diodes, are there a 'better' one for possible replacement - or it's just old school SS amp design?

edit: found an info at  http://www.tpub.com/neets/book7/27m.htm ,  is this diode mod about same/similar thing - "Rectifier action of CR1 and CR2. NEGATIVE / POSITIVE ALTERNATION ?
 
 
Quote
With diodes out of circuit you will find there will be a lot more clean but being a small amp it will still distort when volume is high.

  • being a small amp as 'small' aka SS 15w or small because of the speaker?
    I will use a single 12" or (2x) 10" - so to an external cab.

Greeting

CR1 and CR2 are 1n4148.  These are very similar to the old 1n914.  While there is nothing wrong with these diodes, I know from experience that they tend to have a more "fuzz" type of distortion.  If you would like more of an "overdrive" sound, try replacing those two diodes with red LEDs.  Make sure you have them with one facing one direction, and one the other (just like the original diodes).  An even better idea is to solder in two sockets and then you can swap diodes at will and see what sounds best.  Some circuits, like my own 5th Gear Overdrive, use two different diodes.  In my case, 1n914 and a red LED.

Here are some diodes that you could try: http://smallbear-electronics.mybigcommerce.com/silicon-signal-1/ and http://smallbear-electronics.mybigcommerce.com/led-t-1-3-4-5mm-diffused/

And the sockets: http://smallbear-electronics.mybigcommerce.com/single-in-line-mill-max/
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

Lex

  • Regular
  • **
  • Posts: 19
  • Chip Points: 2
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #7 on: February 12, 2020, 07:13:16 AM »
 Thanx, got it.

 This socket is a great thing, I was not aware of it.

 After your message I did my own research around this mod and I have learned that a lot of old SS amp's are based on the same principle.

 And I found out that there are mode diodes / combinations that could be used;
  • 1N4001 silicon
  • 1N34A germanium
  • 1N4148/1N34A
  • Red LED/1N34A 
  • Red LED
  • Yellow LED
  • Yellow LED/1N4148   
  • 1N4148/2x1N4001
....
 So if I understand it good, all this possibilities makes it kind of a pedal.
 Now I wonder (only if my understanding is right) if would be possible to make an extra circuit board, to put different diodes and combinations and to have switch(es) for selecting?
 Please, if this sound's silly .. it's only a thought of an amateur.
 
 Thanx again,
 
 Greetings

phatt

  • Legendary
  • ******
  • Posts: 2094
  • Chip Points: 251
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #8 on: February 12, 2020, 07:16:32 AM »
Hello Phil,

thank you for the reaction.


Still a few questions;
   
Quote
Just remove CR1 & CR2 for clean.
   Or you could wire up a switch to switch those 2 diodes in or out of circuit for clean or dirt.



  • being a small amp as 'small' aka SS 15w or small because of the speaker?
    I will use a single 12" or (2x) 10" - so to an external cab.

Greeting

Small Amp ; means small wattage and small speaker = not much clean headroom.
small chip amps distort very quickly once you try to get a large volume due to the simple fact that they run small transformers and low wattage chips.

Regards to how diodes work to create dist just study some of the OD dist pedal circuits.
The Back to back diodes has been around long before distortion pedals were invented.
basically they limit/clamp the signal swing to the voltage breakdown of whatever diode you use.
As Joe has already mentioned you can use Leds if you want as they have a higher breakdown voltage so distort later. the big gotcha with any diode dirt circuit is the dreaded fizz that often comes with the dirt and most of the low wattage bedroom amps don't bother to filter out the fizz and they often sound quite harsh.
Phil.

Lex

  • Regular
  • **
  • Posts: 19
  • Chip Points: 2
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #9 on: February 12, 2020, 07:38:35 AM »
Hi Phil,

thanx for your explanation.

I had to read it 3 x to really understand what you meant.
Im not that good within electro-language-slang.

But I got your message.

Quote
As Joe has already mentioned you can use Leds if you want as they have a higher breakdown voltage so distort later. the big gotcha with any diode dirt circuit is the dreaded fizz that often comes with the dirt and most of the low wattage bedroom amps don't bother to filter out the fizz and they often sound quite harsh.

Do you want to say just it's a too small / 'bad' amp for such experiment ?

Cheers

joecool85

  • SSGuitar Admin
  • Legendary
  • ******
  • Posts: 3230
  • Chip Points: 988
  • SSG Creator
    • View Profile
    • thatraymond.com
Re: Introduction, a question and a hope for some insight / help
« Reply #10 on: February 12, 2020, 08:51:24 AM »
Hi Phil,

thanx for your explanation.

I had to read it 3 x to really understand what you meant.
Im not that good within electro-language-slang.

But I got your message.

Quote
As Joe has already mentioned you can use Leds if you want as they have a higher breakdown voltage so distort later. the big gotcha with any diode dirt circuit is the dreaded fizz that often comes with the dirt and most of the low wattage bedroom amps don't bother to filter out the fizz and they often sound quite harsh.

Do you want to say just it's a too small / 'bad' amp for such experiment ?

Cheers

That experiment would work, but I think what Phil means is that it may not sound great with anything due to the way the rest of the circuit is built.  I still suggest the sockets.  Then you can swap as much as you'd like.  If you find that you like more than one combination, you could build a little daughter board with switching to swap between the combinations as you talked about.  My guess though is that you will find one combo that works best and you'll stick with that.  Most circuits end up with a kind of "sweet spot" where things just fall in place.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

Lex

  • Regular
  • **
  • Posts: 19
  • Chip Points: 2
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #11 on: February 12, 2020, 09:21:00 AM »
Quote
That experiment would work, but I think what Phil means is that it may not sound great with anything due to the way the rest of the circuit is built.  I still suggest the sockets.  Then you can swap as much as you'd like.  If you find that you like more than one combination, you could build a little daughter board with switching to swap between the combinations as you talked about.  My guess though is that you will find one combo that works best and you'll stick with that.  Most circuits end up with a kind of "sweet spot" where things just fall in place.

Ok thanx, Im getting it.

I think most of my assumptions were correct.

So what I think that I need is 8 sockets, 2 switches, wire's, and few diodes, exchange them in the search for that 'sweet spot' (lucky me, I have just around the corner a shop with a lot of old school electric components) - the socket/diode Mod.

At the end, I still have a Zoom FX thing for all kind of sounds however I appreciate old school analogue handling and control.

Thanx all again, I got the answers.
I'll come back with the report over my achievement.

Please do not hesitate if you have other idea's about this small amp and possible mod's.

Greetings

Lex

  • Regular
  • **
  • Posts: 19
  • Chip Points: 2
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #12 on: February 15, 2020, 11:11:44 AM »
Hi all,

got carried away with this thought about multiple diodes and after some brainstorming I made a simple schematic (according to my knowledge based on auto-moto electronics) .. with some on-line schematics tool.

I would like to hear if my thinking is logical or not.

CR 1 & 2 are removed, there comes a socket (J1 & 2),
2 x switches (S1 & 2),
repeating diodes D1 - D10

Greetings



joecool85

  • SSGuitar Admin
  • Legendary
  • ******
  • Posts: 3230
  • Chip Points: 988
  • SSG Creator
    • View Profile
    • thatraymond.com
Re: Introduction, a question and a hope for some insight / help
« Reply #13 on: February 15, 2020, 06:54:54 PM »
Hi all,

got carried away with this thought about multiple diodes and after some brainstorming I made a simple schematic (according to my knowledge based on auto-moto electronics) .. with some on-line schematics tool.

I would like to hear if my thinking is logical or not.

CR 1 & 2 are removed, there comes a socket (J1 & 2),
2 x switches (S1 & 2),
repeating diodes D1 - D10

Greetings

This should work with the exception that it looks like all diodes are facing the same way.  The diodes in the "S1" section should face the opposite direction as the ones in the "S2" section.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

phatt

  • Legendary
  • ******
  • Posts: 2094
  • Chip Points: 251
    • View Profile
Re: Introduction, a question and a hope for some insight / help
« Reply #14 on: February 16, 2020, 02:03:24 AM »
Yes,, what Joe said.  You wire them back to back in that loop.
lay them side by side and they should look like this;
  + -
<     >
  - +
Just be aware that there is no magic diode involved here it's the combination of distortion (Dirt) or whatever diodes you use. The secret to great OD/Distortion/Fuzz is in the tone shaping of the circuits NOT so much the diode type.

So Leds might work for one circuit but sound crap in another amp circuit.
There are just so many combinations of how to do these tricks and then add to that; Each player might want something quite different.
Hence you see Utube clips where someone raves about how good the latest Dirt pedal sounds but you get it home and it sounds nothing like what you heard.
Because your guitar-Amp- speaker- style of music you play- talent level-blah blah.

As mentioned before, a lot of small bedroom amp designs are off the shelf circuits and they don't tend to put much effort into tone shaping to suit the speakers used.

I'm not trying to put you off ,, by all means experiment as that will slowly teach you how to interpret sound/tone.
I've been experimenting for years and it takes a while to find what works and what is a waste of time.
Phil.