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Messages - Lex

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The Newcomer's Forum / Re: Kustom wanna-be-tube
« on: November 15, 2020, 02:12:31 PM »

With pot at minimum resistance the distortion will be at maximum but the signal level will start to suffer.

yes got it ! this is the right information that explains to me the roll of this resistor.

Hi Phil thanx again for your writing.

I have some Sim already installed on my comp. But im still far away from 'simulating' amp circuit.
I hope that graduately I will understand and learn more and more.
A breadboard will come for some simple stuff as I find it interesting and there is a lot on-line to look-at-and-copy.

After thoroughly examining this circuit I realised that  the reading is from left to right, and then I also realised that 'i knew that' but I was never aware of it. Somehow it was logical to me so I have never paid any attention to it.
However, motorbike and car elec circuits (that I know and understand) are also from left to right .. also never thought about that.

Ok ill report when I find the time to tweak this resistor with a pot,



The Newcomer's Forum / Re: Kustom wanna-be-tube
« on: November 08, 2020, 07:12:17 AM »
Im aware about my question(s) and 101.
However I reed somewhere on this forum: there are no stupid questions ... so Im taking my chance.

Found The Valve Wizard site, thanx. Havent see it before and I did an extensive research.
Found also a pdf, downloaded .. but the more I read (learn) - the more questions I have.
It could be a typical syndrome when you know some stuff but not having a proper foundation. Could be like learning to write with the opposite hand, or learning to play guitar with the opposite hand.

Thanx for the circuit explanation Phil !

I'll give a pot a place instead of R14.
And a question about 10K vs 100K vs ***K;
 -  pot's are going from 0 to their max value. So if I take 250K (for an example) and I turn it only till 10k or 100K, its still OK?
Or im missing here (again) some basic electro knowledge ?



The Newcomer's Forum / Re: Kustom wanna-be-tube
« on: October 28, 2020, 08:51:26 AM »
ok Phil, learned something again, 

That something is actually - im getting more confused what is a clear sign of my elec knowledge around amp circuits.

Does it work like this;
- SW1A (Gain) is ON > so it gives the power trough 2 > then trough the tube V1A > and then sends it to 1 > and further to the tone stack?
- signal goes back to the tube > V2A > amp > speaker ?
- if this is correct, I cant see from the circuit how OD works only when Gain is on

about the pot - well sins I started being interested how an amp works, been thinking of: "why is there only off-on switch for OD instead of a pot.."
So you gave me a good idea that I should try to implement.

Thanx for the time and willing to explain stuff,


The Newcomer's Forum / Re: Kustom wanna-be-tube
« on: October 24, 2020, 07:16:42 AM »
Hi Phil, thanx,

Im getting what you wrote, this about single / double circuit is logical to me.

I was thinking that the easy solution would be to make a switch to clipping diodes.
However, from the factory those 4 diodes are covered in some white plastic/hard glue.
Like they want to prevent people modifying it.
I suppose it would be possible to melt that stuff with soldering iron.

But also, just to try OD channel without clipping diodes Im thinking to 'jump' them instead of removing them from the circuit (much less work).
Is this something as DO it or NO No nooo ...  cant imagine that I could burn something as is the same thing as removing diodes all together and placing a jumper.

OD channel with gain on 0 behaves as the clean channel.

Im keeping everything on 'the budget' side while learning. Im not expecting huge changes, but even little ones will boost my enthusiasm.

Of course pedals are the way to go, thats clear to me.


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 / Re: FX loop noise
« on: October 22, 2020, 01:33:05 PM »
Thanx Phil for reply.

Have to try suggested, amp was cleaned away from the room during the late summer, now im making a new setup.

Getting rid of Fender / Squier and going further with Roland, Hotone and Kustom Tube*.

Im aware of your taste for Zoom stuff.
Well me as a 'beginner' I have to say it does do everything I need and is a great learning tool.
But I see now that Im outgrowing it.


The Newcomer's Forum / Re: FX loop noise
« on: August 07, 2020, 05:43:42 AM »

> Try the guitar into the Zoom & then go into the FX Return jack.

This is something new to me, Ill try it, thanx!

I have put Zoom infront of the amp Guitar > zoom > amp - and is normal, how is should be.

Later I have connected Zoom back to Fx loop, selected noisy presets (now with the headphones on) and went into the setup menu of each added effect / amp.
With muting an effect the noise was gone.
So I suppose that what you say -the gain could be the problem, maybe with the heavy distortion, flanger  ..
But I didnt have too much time now to go deeper in setup, so thats Todo


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?



I have the same Zoom and I play it through several amps without a problem.
The thing is to find within Zoom deep menu the right setting that works for you.
This is imo the only 'less' thing about this wonderful device ... going deep in the menu.
However, "ToneLib Zoom" editor gives you an opportunity to connect Zoom to an external device (with a bigger screen) for easy access to the menu.

The Newcomer's Forum / Re: TDA2030A based amp
« on: April 22, 2020, 04:45:41 AM »

You could make it lighter with a pair of 5,000mah 11.1v Li-ion batteries tied in series.

ok, i have an idea where it is going ..  Thanx !


Amplifier Discussion / Re: Customized Kustom 12 Gauge
« on: April 22, 2020, 04:42:32 AM »

I have a question: is this model the same as 'Tube 12A" but with 12" speaker ?


The Newcomer's Forum / Re: TDA2030A based amp
« on: April 16, 2020, 03:36:53 AM »

If you are good with about 10w output on a 4ohm speaker, you could use two 12v SLA batteries tied in series.  You should get about an hour of run time for every 1AH of battery pairs you put in.  IE: two 12v 1AH SLAs would give you one hour of play time.  Or two 12v 5AH batteries together would give you 5 hours play time.  This is what I would suggest though I'd have to see the exact schematic to tell you if it would work 100% or not.  Worth a try, it certainly won't break anything by trying it.

Hi, all I could do is to make a pictures of the board and post it here.
I doubt that there is a schematics for this particular amp.
But someone will probably recognise this nock-off ..

Well thanx for your wisdom about the battery.
I'll post pics.
Hearing now about 12v /5ah battery i start to wonder - does is have any sense with such adding so much space and wight.
However as a practise project could be interesting.


The Newcomer's Forum / Re: DC output tweak
« on: April 16, 2020, 03:31:06 AM »

This is a ferrite bead also known as a ferrite choke.  It removes high frequency noise from the power supply before it hits the amp.

Thanx for reply, learned sth again !

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). 



As I newbie may join this conversation;
  • 5W USB powered with rechargeable internal battery,
  • Full controls;  gain, mid, bass, volume, treble,
  • output 4 to 16 Ohm
  • easy accessible 'effects' board to exchange/combine diodes for the personal taste of sounds with kind of rotary or multi-switch

I base my idea on what I have: small 3W Donner amp for carry on or while sitting on the couch  practicing
For what it is (and the cost of it) it's a very handy piece of hardware. Of course it has limitations but the concept is great and it does sounds 'good' for such a small amp.
When I need 'more' from this amp I connect Zoom G1on/xon ..
An idea to have the best of both worlds in a small package would be great.
+ the process of learning amp / electronic things for ppl like me ..



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