Hotone Nano Legacy Amps - Heart Attack  [traced]

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phatt
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Post by phatt »

I'm not sure what "ITE use only" means (in fine print) but a fair bet it's not for Audio use so likely it will be noise prone.
Sadly there won't be many around that will be dead quite. :(
My advice is go find your local Salvation Army shops or charity op shops and like places as they often have a box full of old computer supplies and like electronics junk, you can pick them up for $2 ~$5 in my part of the world.
Phil.

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Post by Ice-9 »

Just looking at the psu enclosure from Thomman I would say it is a switched mode psu, You pay your money and take your chances, or build a linear psu yourself and the cost will likely be cheaper to make your own. The other alternative is to buy a decent power brick with an 18v DC output.

To test your circuit for other noise you could use 2x9v batteries in series to get your 18v DC and that will give you clean power to the circuit for testing.

Off topic and not aimed at the poster here but It always amazes me that some people will spend large amounts of money on the newest/best pedals but are not willing to spend more than £2 on a psu then complain that the pedals are noisy. The first thing in any audio system is the power supply and if this is injecting noise into your audio then no matter what you do to the pedals or circuits that will always be there.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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Post by Ichabod_Crane »

You right, man.
For my pedals I have a old version of Boss PSU 9v 200mA. And that is really ok.
For this amp I really didn't think about the noise when I bought the PSU. I tried a 12v of my external hard drive, and that works fine.

I'm wondering if I can buy a laptop psu, and to use (in case) a little DIY filter to put into the amp box. But just something simple. A kind of filter that the good psu should have.

Something like this:
Image
http://www.instructables.com/id/Noise-f ... ts-pedals/
Maybe modded for my case, eventually.

Or this:
Image
http://ka7oei.blogspot.com.au/2014/08/c ... power.html

Thanks, phatt!

Just caps, resistors and few else.

Thanks for helping!

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Post by phatt »

Well yes but with only a filter on the output you may still have issues. You need one on the mains input as well,,They come with built in RFI filter.
just Google "mains filter iec socket" You can get them for nothing out of old electrical junk. That will save you having to build it.
Some even come with a built in fuse holder,, very safe as you can't remove the fuse while power is on. A Clever design. :thumbsup :thumbsup :thumbsup

Here are some pics of my pedal board which has an IEC mains filter, a 9VDC supply for pedals and a 18VDC supply for the Phatt Box which is just Mictesters Comp, a simple OD and Cab sim designed by me. (the ugly DIY black box)
The 18VDC supply is a laptop supply which to my surprise has no noise while the 9VDC supply clearly states is for Audio and Video yet had a fair bit of RFI hash,, :evil: Hence the output filter hanging from the end. So it's a gamble when buying a Smode supply. :hmmm:
Note the mains plug is buried in the corner, the IEC connector with the filter built in.
So the only thing I have not done is the metal casing but noise is only evident if you wind everything to max you can start to hear a little bit of whine hash,, but at that level the gig is so loud you would never notice. :mrgreen:

If you are only building a preamp with EQ and OD/dist and a couple of other chips then you would only need maybe 200mA at 18VDC but if you want a power stage to drive a speaker then yes you would need more current capacity. Those little Boss Smode supplies are rated at 1Amp,, I have one and it's noise free.

Both the supplies I've pictured were purchased for a couple of dollars from the local opshop. The IEC main Con was from an old TV set. So I have a Pedal board on a budget. At my age, pretty does not impress,, as long as it delivers. 8)

I Agree with *Ice9* make sure your circuit is noise free before you blame the PSU. If there are noise issues on battery power then time to rethink the circuit. :blackeye
Phil.
Attachments
18VDC Detail
18VDC Detail
18VDC Smode at back
18VDC Smode at back
9VDC Detail
9VDC Detail
9VDC Smode + filter +IEC con
9VDC Smode + filter +IEC con

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Post by Ichabod_Crane »

Sorry, maybe I forgot to tell, with an externl hard drive's psu 12v 1.5A the TDA2003 is noise free.
I forgot even the filter before the psu.
Unfortunately is a bit hard for me find some old electrical junk in my place.

I found on Amazon that 19v laptop psu, Targus APA03EU... 117 € :D
Elsewhere, about 35 €.
Those are kit multi plug.
In case...

Keep looking for.

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Post by Ichabod_Crane »

J0K3RX wrote: The power supply is an 18v DC / 1.5A. [...]
inside the pedal the 18v power from the power supply goes directly to the TDA2003 power amp and also splits off to a 78L09 voltage regulator going to the preamp.
[...]
I was wondering, a technical question. Does the 7809 support max 1A? I need to use with my amp (still projecting) 2-3A or more psu. :hmmm:

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Post by J0K3RX »

Can't really say without a schematic of whatever it is you're building...7809 max output current is 100mA. Use a LM317

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Post by Ichabod_Crane »

I just found something about it.
phatt wrote:I'm not sure what "ITE use only" means (in fine print) but a fair bet it's not for Audio use so likely it will be noise prone.
Sadly there won't be many around that will be dead quite. :(
My advice is go find your local Salvation Army shops or charity op shops and like places as they often have a box full of old computer supplies and like electronics junk, you can pick them up for $2 ~$5 in my part of the world.
Phil.
«I.T.E. stands for Information Technology Equipment. There are certain standards, such as in the EU, specifically for ITE that dictate tolerances for electromagnetic radiation etc.»

Rock Power psu are sold by Musikding, Thomann, and other music shop, even on amazon or ebay. Some models include daisy chain like those for our pedals. In the reviews I can see someone used it to power up some pedals, in an another description says it is compatible with the multiFX of some brand. A guy used it to power a giradischi, an old style record player for vinyl disc.
I think there's no doubt it is for pedal or similar stuff.

About the 7809, maybe I misunderstood something. I'll try to explain better than possible with my english.
I meant, I need a 18v psu and at least 2000mA to power the whole amp, TDA2003 and the other circuits. So the other circuits want just 9v, I can use a regulator. I thought that the 7809 can't receive the 2000mA coming from the 18v psu.
Probably I was wrong.
If now I get, instead it can receive the 2000mA, because it doesn't care about it, and from the 7809 can go out just its max output current, and it should be 1000mA. Is it right? 1000mA not 100mA.
I found the LM317, too. Could be nice, I guess a trimmer can "feed" to the other circuits of the amp how much volts I want in a certain range I set up. 9-15v, for example. But this an advanced step.

Sorry, I guess I am off topic.

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Post by J0K3RX »

lm7809 - output current up to 1A / 78L09 - output current up to 0.1A or 100mA

if you have 18V 2000mA on the V-in it will just use the current that it needs from the 2000mA.

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Post by phatt »

Arrh I think I see the problem. :hmmm:
To elaborate on Jokrx's comment, it may help if you think of it like so; "Current is Drawn not Pushed".
Even if you connect your preamp to a 12 volt car battery (some can deliver over 100Amps) your preamp will still Draw the same Current.
HTH, Phil.

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Post by Ichabod_Crane »

None push I thought. At the beginning I probably confused the current can go IN the regulator with that can go OUT from it. The LM7809 can use the 2000mA, or even more, but I can use after it the max output current 1000mA.
For two preamps, booster and buffer (all pedal's circuit) 1000mA are enough.

Sorry for my misunderstanding.

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Post by phatt »

Ichabod_Crane wrote:None push I thought. At the beginning I probably confused the current can go IN the regulator with that can go OUT from it. The LM7809 can use the 2000mA, or even more, but I can use after it the max output current 1000mA.
For two preamps, booster and buffer (all pedal's circuit) 1000mA are enough.

Sorry for my misunderstanding.
No worries :thumbsup

If it helps,,,Max Current draw for a TL072 is ~ 5mA (2.5mA per amp) so if you had 3 x TL074 opamps in the preamp then max current draw is only 30mA so current is a non issue. Other commonly used chips would have similar specs. :thumbsup

BTW,,Thanks for the explanation of ITE :thumbsup
Magnetic interference is easy as it's covered by design as there are no iron transformers in a Smode supply so EMI (Electromagnetic Magnetic Interference) is close to nil.
But there seems to be little info or understanding about RFI issues with Smode power. :scratch:
Phil.

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Post by Ichabod_Crane »

phatt wrote: If it helps,,,Max Current draw for a TL072 is ~ 5mA (2.5mA per amp) so if you had 3 x TL074 opamps in the preamp then max current draw is only 30mA so current is a non issue. Other commonly used chips would have similar specs. :thumbsup
Thanks for the info. Anyway, I'll measure all the circuit singularly. Then there are the leds, and I'm planning to insert a switching relais sistem. :twisted:
phatt wrote: BTW,,Thanks for the explanation of ITE :thumbsup
Magnetic interference is easy as it's covered by design as there are no iron transformers in a Smode supply so EMI (Electromagnetic Magnetic Interference) is close to nil.
Glad to be useful when I can. :wink:
phatt wrote: But there seems to be little info or understanding about RFI issues with Smode power. :scratch:
Phil.
Do you mean generally?

I was thinking about the schematic of the 7809 in the Heart Attack, to come back on topic. I'm sorry to bring up always our friend J0K3RX. :lol: The only one who can help us in this.
Datasheet: http://tronixstuff.com/wp-content/uploa ... m7805c.pdf
and basic schematic:
Image

I don't need now, but maybe a section at the time we can reveal the whole schematic of the Heart Attack.

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Post by J0K3RX »

For starters, the regulator in the Heart Attack is a 78L09. :wink:

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Post by Ichabod_Crane »

My bad. I didn't remember nor I saw again the pics you linked. :roll:
I can't use that part of the schematic with my project, but never mind. We can't wait, aniway. :mrgreen:

Let us to know if or when you can take another look the the circuit.

Thank you.

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Post by Ichabod_Crane »

Finally, I tried the replace R2.
I used a 15v PSU, I still didn't tried a 18v.

The original value is 2.2R, and I tried not the 12R (like the Heart Attack) because I had none, but a 10R. It works about the distortion, indeed my Stratocaster MIM sounds cleaner though not the cleanest ever, but unfortunately I lost volume.
I tried a 4.7R, it sound slightly dirt and recover a bit of volume.
With a cleanear sound I notice a bit fo less treble. Perhaps I should considering Rx, from the datasheet: «Larger than recommended value -> Poor high frequency attenuation».

Of course I'm looking for a 18v PSU, this will help me to raise up the volume, but is there some alternative way to push the volume without get distortion?

J0K3RX didn't drawn it, but is there the Volume pot in the TDA2003 part of the Heart Attack? Maybe is the Volume pot a preamp control?

Thanks!

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Post by J0K3RX »

When I was tracing the power amp section I stopped at the fx-loop. Not sure where exactly in the preamp circuit the volume pot is but most likely the last thing before the power amp but there may be a buffer after that, not sure.. I may try to trace the entire preamp if I get some time and I will just leave the cap values with ?? because I don't want to remove them to get a value. I am comfortable with SMT but these are super small and won't take much to make a mess of things... I thought about strategically cutting traces to isolate the caps and then just repair the trace afterwards but, I am not gonna do that until after I trace the entire preamp.

I have used just the power amp via the fx-return with other preamps that I have built and it sounded damn good as I recall. I haven't tried any clean preamps though so maybe there is some distortion there that I am not hearing with high gain..

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Post by Ichabod_Crane »

Ok, thanks.
I heard in the video the Fenderish version, it can sound very clean.
Of course we can't know if the power amp is the same for all these version, nor if them are the same volume.
(My clean preamp version I'm going to use with the TDA2003 is a Tonemender.)

Anyway, with the 12R (and a 18v PSU) I surely can get a cleanest sound, but encreasing R2 the problem is the volume loss. The volume is one of the most important thing for me, I really wouldn't like have an ultra-elaborated amp like the one I'm projecting that is no much louder then an LM386. :shock:

Then the volume could be the last stage of the preamp, or sort of. Who knows, a simply output pot.

Well, some of us (especially me :thumbsup) can't wait to get the enitre amp schematic. Of course is not urgent, you know, I'm project a similar amp, the most important thing for could be the power amp, and now we get it.
Ok for the ?? cap, meanwhile we could image its value.

Can your preamps push the volume of the Heart Attack more then the on-board preamp?

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Post by FiveseveN »

Ichabod_Crane wrote:is there some alternative way to push the volume without get distortion?
Do you know what clipping is?!
The only way to get more power out is to have more headroom available, i.e. use that god damn 18 V supply. Look at figure 3 of the datasheet: 4 W output @ 12 V and 9 W @ 18 V.
Ignorance more frequently begets confidence than does knowledge. (Charles Darwin)

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Post by Ichabod_Crane »

Yes, that 18v PSU. I wish! :D

I have to use an 8 Ohm speaker cab, I have just it. I can't reach 9w, just 5w at max, at 18v. Is the Hotone configuration.
I still have "to try" the 18v netbook's PSU, I hope it's silent.

But the truth is I have to find for the final project a silent 18v with at least 2A, and hoping that is enough. My amp has the TDA2003 power amp, with two preamps, a boost, a buffer (probably), and some relais for footswitch control.
If this is not enough, I don't know where I can find it.

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