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Topics - Lex

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The Newcomer's Forum / Kustom wanna-be-tube
« on: October 22, 2020, 02:00:32 PM »
Hello all you lovers of tube* amp's,

already been discussed about this little quirky amp
so not to go back to that topic what is too difficult (read: technical) for me to apply all-or-some of mod's,
I went for the very first and easiest mod: replaced ax7 with au7 lamp.

Now is Gain more controllable and that typical rattling is gone.
It sounds really good. Removed the head and running it with Roland's external cab.
Happy days ..

Schematic was a problem as I can read it so I found one. 

I would like to apply Gain to the clean channel so if someone know-to ..  my eyes  are wide open.

tube* - well it's a hybrid.


The Newcomer's Forum / FX loop noise
« on: August 06, 2020, 05:41:48 AM »

Hi, I upgraded my gear with Roland 405.
When I connect Zoom G1on at fx loop I get at some presets terrible noise.
I never experienced (as inexperienced novice) that,
but on my Hotone Nano head Zoom trough Fx loop works perfectly.

Anyone an idea about what's going on here..?

Could it be that Zoom is not so much compatible with older Fx loop designs?



The Newcomer's Forum / TDA2030A based amp
« on: April 12, 2020, 08:15:54 AM »
While Squier ( ) is lend, got me a non working TDA2030A based amp. So I have sth to practice with/on..
It's fixed now and it works.
It's a non labeled kind of  Vox Pathfinder 10 / JT Classic 10 amp. Looking here ( ) I see a lot similarities even same transistors as JT.
Same cab too.

One difference is that there is no distortion switch but it kicks in with the Gain pot. 
It does sound reasonable on a big speaker, no humm / hismm / zoommm .. sounds.
Distortion does not sound very pleasant so I will probably make a multi-switch with cascading diodes.

One thing what I would like to do is to get rid of the trans and make it battery powered.
Im aware that TDA2030A suck maybe to much of the current for a reasonable sized lithium rechargeable battery (or batteries, salvaged from a laptop).

Would it be possible to change this TDA to other 5-legged amp with a lower power and to keep the rest on the board like it is ..?
If not, then in stead of original trans – a suitable laptop adaptor.
I suppose in this case would be just adding female jack and removing the trans.

Im also open to suggestions.
Everything what will teach me to understand / improve / change / tweak / upgrade .. existing and future amp(s). 



The Newcomer's Forum / DC output tweak
« on: April 10, 2020, 05:00:51 AM »

I have to test a device but Im without the right adaptor.
Have many adaptors from previous devices so I want to use one.

So I have one idea:
- I have to lower DC output from an adaptor that is 19V 2.5A to 18V 1.5A.

I suppose that I could do it adding one (or more) diode/resistors and placing it on the cable. I have to cut the cable and turn the polarity anyway.

Since I need to drop (only) 1V, I suppose i could use something  like a 5A diode and simply place it in series?
But now Im not sure about dropping current from 2.5A to 1.5A

I'm thinking in the right direction and this is possible to do,
or im just dreaming?



The Newcomer's Forum / Some wisdom regarding speakers
« on: February 16, 2020, 09:09:41 AM »

 Any worth of getting used 10 inch speakers from old Peavey Backstage (late '70, CST), so called 'squareback' for an external cab?
 I mean, Im 'educating' my self and trying many things just to understand what Im hearing (and why of course).
 It brings (un)necessary costs with it.

 So, would I be just better to go for a new modern speaker(s) or take a risk and spend less money (about 1/3 of the price of the new one) for my 'tests'?

 Im I reasonable ..?


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!


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