Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Amplifier Discussion => Topic started by: trialabc on July 23, 2010, 02:07:51 AM

Title: Amp using TDA2030
Post by: trialabc on July 23, 2010, 02:07:51 AM
Dear all,

   I was planning to use TDA2030 to build an amp which have separate frequency band amplification. In this way, I can get higher power output without using ICs like LM3886 together with large heat sink. I plan to use TD2040's datasheet's suggested circuit to give two output : one to woofer and one to tweeter. Or maybe I can cascade several TDA2040 to give higher power output.
   The problem is that this IC is for Hi-fi, and the suggested frequency band of interest is not suitable for a guitar amp. I would like to know what frequency band are of interest to guitar so that I can keep using that circuit.

Thanks in advance!

Title: Re: Amp using TDA2030
Post by: J M Fahey on July 23, 2010, 07:24:46 AM
Hi trialabc.
Don't worry too much about that, the frequency shaping and sound characteristics will come from the preamp.
The power amp will faithfully reproduce what you feed it.
As of the heatsinks, you will still need them, even if they end up being a flat sheet of aluminum (even the chassis itself )
No matter what the chip, it will dissipate around 40% of its rated power output as heat, which must go somewhere.
A tda2030 will dissipate less heat (and require a smaller/simpler heat sink) than a 3886, only because it provides 15W compared to 60.
Any special reason for biamping?
Good luck.
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 23, 2010, 09:09:39 AM
Also, keep in mind that a proper guitar speaker will cut the higher frequencies appropriately. LM3886's are also Hi-Fi chips, but work great as guitar power amplification.
Title: Re: Amp using TDA2030
Post by: trialabc on July 23, 2010, 12:51:38 PM
I choose to use TDA2030 simply because I can easily find it in stores.

I have used TDA2030 before and I know that it still require a heat sink, otherwise it will still burnt out even if I am just using two 9v batteries!!

I wanna bi-amping is because I still wanna try make a battery-powered amp which can sustain outdoor for at least 3~4 hours. Using this scheme, I hope the overall power could be large enough for outdoor activity. LM3886 seems so large that I am afraid that a lot of heat would be produced. It would be better if there is a way to cascade small power amp to produce large power output.
Well, to me, the heat produced by SS components is hardly bearable and I have not tried tube amp which one could fry eggs on them.

I thought I just need a power amp. Is a preamp necessary?

Thanks in advance!
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 23, 2010, 02:23:47 PM
Don't misunderstand my point about the lm3886. I was just saying that lm3886 designs prove that using a hi-fi chip for a power amp is no problem. Of course, there are several tda2040 guitar amp designs that prove the same thing, so maybe mentioning the lm3886 was unnecessary all together. A tda2030 or tda2040 is fine.

You might run into a problem with running the amp from two 9v batteries. I could be wrong, but I bet that a 9V battery will not supply the current you need. If you want a battery-based +- 9V supply, consider using a couple of 12V motorcycle batteries (or any lead-acid batteries with a weight you consider acceptable). That will give you more than +-9V and will supply all the current you need.

And yes, you do need a preamp. There are many suitable preamp designs on this sight and elsewhere on the net. Also, if you get a decent guitar speaker, you do not need to worry about a woofer and a tweeter. If budget is an issue, I suggest one of the Jensen Mod speakers. While using HiFi power amp chips is plenty ok, using Hi Fi speakers for a guitar amp isn't a great idea (Except, I guess, for accoustic guitar amps).
Title: Re: Amp using TDA2030
Post by: bry melvin on July 23, 2010, 07:00:30 PM
There is at the moment another source of good budget guitar speakers.

Carvinguitars.com is currently selling their "british" speaker, which was their speaker for the SS SX series fro a long time for $29

Carivn on EBAY is selling the vintage 12 for about the same price. This is the belair (vintage tube) speaker

Both speakers have identical electrical specs. Not sure if there is any difference at all other than label.

They are rates at 70 watts
Title: Re: Amp using TDA2030
Post by: trialabc on July 26, 2010, 03:03:22 AM
Speaker is not my main concern at the moment. For preamp, I don't really know what it is.... So I don't know how to kick start.

Perhaps a little help? I think equalizer is not a preamp but a effect within preamp?
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 26, 2010, 09:21:38 AM
The speaker might not be your main concern at the moment, but be sure not to dismiss speaker choice as being trivial. The main purpose of a preamp is to provide at least enough voltage gain for the signal to be useable by the power amp. And yes, preamps often incorporate eq's and other effects. Many preamps are made to be overdriven while others are made to be run clean. Many distortion pedals qualify as preamps. Amps with multiple channels basically have multiple preamps. With preamps, you're not to concerned with power gain. On the other hand, power amps provide significant current gain as well as a little voltage gain to produce power.

You should really read Teemuk's book to become familiar with different guitar amp concepts. His book really kicks lots of ass and it's free. Then, decide what kind of sound you want. Then choose a preamp design that will produce that sound. Letting us know what kind of sound you're looking for will help us recommend a preamp design.
Title: Re: Amp using TDA2030
Post by: trialabc on July 26, 2010, 01:53:48 PM
Thanks for the reply. Well, I just need to have clean sound. There is no need to have any effects.

Therefore, I thought I just need a power gain. As you have mentioned, preamp is used to tune the signal to the desired voltage signal level, I think for my case it is not really a big deal. Perhaps just use a CMOS N-channel will do. Hopefully I am not thinking too ideal.

Of course, I think having a equalizer in the preamp will be good. But for this experimental moment, I thought the most simplest preamp design will do.

I do think up of using a 12V lead acid battery. However, I will have to make up a charger before hand so that I can charge it up. Since power issue is not really quite a big deal and can be easily solved my money, it is not a critical concern for this moment.
Title: Re: Amp using TDA2030
Post by: J M Fahey on July 26, 2010, 06:13:49 PM
Please define what you want to do, as a 12V amp is very different from an AC powered one, unless 5 or 6 W are enough for you.
A TDA 2030 or better will give you even less than that, because they are optimized for higher voltages.
A TDA2003/LM383 will provide 5 or 6W into 4 ohms, 10W into 2 ohms.
To get 16/20W into 4 ohms you'll need a bridged TDA2005; for higher outputs you'll need a switching converter to rise those 12V up to what the circuit needs.
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 26, 2010, 06:23:13 PM
That's why I had suggested two lead acid batteries, though bridged tda2005's might be better (and much lighter with just one battery).
Title: Re: Amp using TDA2030
Post by: trialabc on July 26, 2010, 08:53:06 PM
I miss out the important part about the power output upon the voltage given. After reading through the specification of TDA2030, I think it is likely that I will try out using two lead acid batteries. +- 12V with bridge configuration should give me 16W for a 8ohm speaker. Hope that it would be enough.

Now I understand why so many of us like the chip LM3886. Hopefully in the future I should give it a try.

Thanks guys for the reminder about the power supply. I really miss its importance.
Title: Re: Amp using TDA2030
Post by: J M Fahey on July 27, 2010, 01:31:03 AM
Well, a single TDA2005 and a single 12V7A gel battery will give you 16 very clean watts into 4 ohms, and will be much lighter and portable.
I've sold *many* of them in different configurations.
Similar commercial amps are the Peavey Solo and the Fender AmpCan.
Search and study them, they'll give you many good ideas.
Both are relatively simple, tried and true designs, and very popular.
And believe me, the difference between one and two batteries, is abismal, much more than what you imagine.
Remember you'll also carry your guitar, maybe a microphone stand, some pedals, an MP3 player for backing tracks, maybe a folding stool ... weight always adds up, never substracts.
Good luck.
Title: Re: Amp using TDA2030
Post by: trialabc on July 27, 2010, 02:41:08 AM
Oh.... how about the preamp part? What do I need? Which design I can use as reference if I just wanna have clean sound?
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 27, 2010, 09:05:09 AM
I've got a jfet preamp design that works well for clean. But you may do just as well with a simple textbook op amp gain stage. You might check out this thread: http://www.ssguitar.com/index.php?topic=1426.0;wap2 (http://www.ssguitar.com/index.php?topic=1426.0;wap2).
Title: Re: Amp using TDA2030
Post by: J M Fahey on July 28, 2010, 08:29:38 PM
Download and read the AmpCan and Solo amplifier schematics; Nobel's Streetman if you find it.
I'm a firm believer in commercial amplifiers, even if simplified or stripped to the bare bones, rather than well-meaning but lacking in skills or experience amateur "designs" .
Not wanting to hurt anybody, far from that, but I'm sick of seeing the "Minibooster" or the "Electra distortion" or a poorly biased (that's an understatement) Fet with "magical/mojo" values copied verbatim from a famous "X" brand amp (absolutely ridiculous values) repeated over and over, ad-nauseam.
Learn about Op Amps, the general purpose building block, and the easiest to implement.
Besides, that's what 99.9% of commercial products use.
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 28, 2010, 10:38:17 PM
He probably should follow your advice and check out the AmpCan and Solo schematics, or even the  Rod Elliott project 27 schematic you recommended in the http://www.ssguitar.com/index.php?topic=1426.0;wap2 thread. However, don't be too quick to crap all over jfet designs.

Sure, with op-amps, you don't have the biasing concerns that you have with jfets. But there are some nice sounding jfet designs out there. I think the Dr. Boogey circuit absolutely kicks ass. And while I haven't built any of the ROG circuits (well, other than a few ruby amps), they seem pretty good to go. I think I might try building a BSIAB II one of these days. Most of us aren't going to be mass producing amplifiers, and some of us do not mind spending a little time biasing a FET stage or two every now and then (or maybe we're just gluttons for punishment).  No one should be discouraged from trying their own designs either, whether based on op-amps, jfets, tubes, or whatever. One can learn only so much by copying other designs.
Title: Re: Amp using TDA2030
Post by: J M Fahey on July 29, 2010, 11:30:48 AM
Hi Rowdy, fully agree with you. :tu:
In fact, I do use Fets a lot, and have for years.
But I spend all of 30 seconds extra and bias them.
My heart hurts when I see somebody "copies" some classic tube design (hey, the idea is excellent, by itself) but places a 1k5 resistor source to ground "because Fender did that" or a 2k7 "because Marshall did that" or even worse, 820 ohms, which is poor biasing (too hot) even on a tube amp.
That's just magic thinking.
Then everybody lies to himself thinking that they have a 100K "plate" resistor, "just as the original did".
Fact is, that is a 100K trimmer, and the actual resistance value they set to "bias" (really they do not set bias but load) is way below that.
I encourage you to build any of those stages, and post the actual "plate" resistor value set. You'll see it's nothing like 100K.
Fender , in fact, did get those biasing values from 12AX7 datasheets, which precisely state, for around 250V supplies, 1k5 cathode and 100K anode resistors.
You change +B, you change those values, there's nothing magic or immutable about that.
You change tube type, they also change (just read the datasheets).
Imagine what happens when you do not even use tubes but Fets, which to boot vary a lot from unit to unit, and to change things even further, use 9V !!!
Then those 820, 1K5 or 2K7 resistors lose all meaning.
Of course, the allmighty 100K trimmer comes to your rescue !!! ... sort of.
I fully agree with "spending a little time biasing a FET stage or two ", precisely that's my point !!
I think that the right place for those trimmers is source to ground, because there they become real "bias" trimmers; of course I suggest using 10K trimmers.
Another way to do that (which I use) is buying a few extra Fets and Protoboard a simple test jig and get the actual bias voltage needed , then label them, and later use the right source resistor to get that voltage.
It takes 30 seconds per Fet.
As you see, I encourage actual testing, not superstition or Mojo .
There's even a simple sound test I suggest:
build a 12AX7 stage, with 1K5 resistor on its cathode (bypassed by 10uF), 100K on its plate, +250V (the real Mc Coy); and a 9V powered Fet stage, with the same value resistors (well, using a 100K trimpot) , with grid and gate connected to the same 1M resistor to ground and an input jack, outputs taken from identical .047uF x400V Polyester caps , DC discharged to ground through 1M resistors to avoid popping; then hook your guitar, play a chord and switch back and forth between both outputs. An MP3 or even a You Tube video would be very useful.
Good luck. :tu:
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 29, 2010, 12:00:36 PM
Ok, gotcha. :tu:

I've wondered myself why use a pot for the drain resistor rather than the source. I also prefer using a test rig and using the proper value resistors rather than use a trimpot. It makes building a circuit a bit cheaper too when you can get resistors for a couple cents a piece verses more than a $1.00 (U.S) per trimmer. I've noticed that with a fixed Rd, if Rd is too high, you can't midpoint bias the stage without setting Rs so high that you have less than unity gain, which, of course, proves your point that one really needs to choose resistor values for each individual jfet. When I built my first headphone amp way back when (with mpf102's), I wondered why adding jfet stages made it quieter  :lmao:. I suppose since Rd has an effect on output impedance, it makes a bit of difference tone wise. If someone wants a Rd close to a specific value for a good reason (not just because some plate resistor in a tube amp design used that value), then he or she should probably hand pick a jfet that fits that Rd value.
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 29, 2010, 12:07:31 PM
Quote
I suppose since Rd has an effect on output impedance, it makes a bit of difference tone wise. If someone wants a Rd close to a specific value for a....

Opps, I forgot that you were discussing magic Rs values. Still, 100k may be to much to get unity gain for many fets, especially ones with relatively high Idss.
Title: Re: Amp using TDA2030
Post by: trialabc on July 29, 2010, 12:14:50 PM
Guys, thanks for all your suggestions. I have scanned through the schematics of Solo and AmpCan.

Sorry that I am not that keen on circuit design for the moment. Although I would like to learn the behind working principal of the JFET stages, I could hardly understand what you are talking about...

By the way, when I study the schematic of AmpCan, I find diode D1 and D2 are in opposite directions and connecting in parallel. 0.0  Can't understand how it works.... Mind a little more help?

For this moment, I think Op amp will do. Don't wanna mess up the biasing problem.... Seems so difficult....
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 29, 2010, 12:21:05 PM
When the voltage across those diode is high enough for the diodes to start conducting, they increase the feedback current dynamically reducing the gain. The result is soft clipping. Read up on the theory behind the Tube Screamer for a better description. Here's a pretty good description: http://www.bteaudio.com/articles/TSS/TSS.html (http://www.bteaudio.com/articles/TSS/TSS.html).
Title: Re: Amp using TDA2030
Post by: trialabc on July 29, 2010, 09:54:12 PM
Thanks a lot rowdy_riemer !!

Now I really learn something instead of just copying the circuit.....

Hopefully I should have time to start building the amp by this weekend. See if I can finish it, try it and post a picture here. Oh... how to post a photo or schematic?
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 29, 2010, 10:27:35 PM
Quote
Thanks a lot rowdy_riemer !!

I'm glad to help. To upload an image, click the arrow next to Additional Options and you'll get the UI for attaching a file. Also, you can put a link to a url to a file using the "insert image" toolbutton above.

BTW, my 7 year old daughter is right next to me bugging me about letting her put a smiley face on this reply, so here it is.  :tu:
Title: Re: Amp using TDA2030
Post by: J M Fahey on July 30, 2010, 01:43:05 AM
An "off the shelf" Fet gain block that *works* is the Stratoblaster.(Google it)
It uses 9V, 12K source, 22K drain, and doubtlessly (at least on the original ones) a "good" Fet, that's to say one with low Vp (cutoff) and high channel resistance.
I know this is counterintuitive, or "against logic" but it's so.
Unfortunately most cheap and widely available Fets today have the opposite parameters, which makes them good for switching and poor for audio.
Tomorrow I'l Proto one and post what I measure, but from what I remember, gain was not much more than 5x or thereabouts.
With a properly bised Fet and +20 to +30V supply I was able to get 20x gain with available (poor) Fets.
A side note to  Rowdy about his Daughter: "start getting used to it, it's just the beginning".
 Mine is 16 and it has been impossible to say her "no" for about, should we say, ¿15 years? :o  ;D
Title: Re: Amp using TDA2030
Post by: rowdy_riemer on July 30, 2010, 09:53:17 AM
Quote
An "off the shelf" Fet gain block that *works* is the Stratoblaster.(Google it)

It's funny but the schematic for it on General Guitar Gadgets says to use either a "j201, 2n5457, or other FET". Wow, FET variation is bad enough using the same type from the same manufacturer.  :duh. But GGG's bad recommendation aside, the circuit looks good to go. If I built one, though, I'd still pick the Rs that most closely suits whatever fet I chose. Then again, being a first gain stage in the chain, one's probably not going to overdrive this, and with the way their doing their gain control I guess a predictable Rd to Rs ratio might be a little more important than a approximate midpoint bias. It looks like they want a minimum of unity gain (I think I got this right), and I guess that might not be so simple with varying Rd to Rs ratios.

Quote
It uses 9V, 12K source, 22K drain, and doubtlessly (at least on the original ones) a "good" Fet, that's to say one with low Vp (cutoff) and high channel resistance.
I know this is counterintuitive, or "against logic" but it's so.
Unfortunately most cheap and widely available Fets today have the opposite parameters, which makes them good for switching and poor for audio.

I know it's harder to get much gain out of  a FET like a 2n5457 (relatively high Idss, relatively high Vp), but aren't they less noisey? It seems like when playing around with a super simple booster design of mine, 2n5457's were less noisey than j201's. But then again, I really didn't give them the comparison they deserve, so I'm not that sure. I know the first version I built has one j201 and is certainly more noisey than my two stage 2n5457 version. With the first version, I used a couple of mpf102's simply because my 2n5457's had not arrived yet. Of course, even with an 18V supply, one doesn't get much gain from a mpf102, so I added a j201 stage. Of course the noise I'm hearing might not be the j201's fault. Maybe it's the mpf102's causing the problem. Or maybe something else entirely. Since this was just something I wanted to work on while waiting for my 2n5457's to come in, I really didn't investigate. Maybe my impression that low Idss FETs are noisier (noisiness inversely perportional to Idss) is totally bogus? What does your experience with FETs tell you?

Quote
A side note to  Rowdy about his Daughter: "start getting used to it, it's just the beginning".
 Mine is 16 and it has been impossible to say her "no" for about, should we say, ¿15 years?

 :lmao: Yeah, she started getting her way (well alot of the time) when she was about 1, so I've had 6 years to try to get used to it. She's got a very good "puppydog face" she uses against me if I try to tell her no.
Title: Re: Amp using TDA2030
Post by: J M Fahey on July 30, 2010, 12:21:05 PM
Hi Rowdy.
Those Fets are "reccommended by GGG" which is only a suggestion of available Fets.
I'm sure the original ones "unspecified in the schematic" were specially selected ones.
I use a lot of Fets, but usually as switchers or limiters/compressors, so for me , finding 10 "excellent" ones and another 15 "good" ones in a bag of 100 is fine.
Maybe that becomes a little steep for an average experimenter who only needs 2 or 3 of them.
My usual crop (out of 100) and only measuring  Vp is: around 10 with Vp close to 1.5V (excellent, good to copy Tube stages, they can be biased with the "magic 1k5") they can provide gain up to 20x; around 15 with Vp close to 2.5V which *do* have some gain, say 6x or 7x; 10 real bad with Vp around 4V , useful only as switchers, and all others, Vp 3.5V, usable as compressors or switchers.
Yes, they have that much variation !!!!
That apparently high  12K Source resistor used by Alembic/Stratoblaster sort of "irons out" differences.
Besides, their intention was not making a metal monster, but boosting a relatively weak classic Strat from the early 70's.
There, 3x gain is enough to put it on the same level of a hot Les Paul or SG, its main contenders way back then, and keeping Fender twang to boot.
On this weekend I'll Proto some Fet stages and post results.
No, no simulation for me.
In Music Electronics Forum somebody dialed the datasheet specified transconductance for a high voltage Fet and a 100K load resistor, and came out with an 80dB gain.
Fact is, that transconductance is specified at , say, 500mA, but that load resistor dictates less than 1 mA. Absolutely different.
Title: Re: Amp using TDA2030
Post by: JayFett on July 30, 2010, 05:29:17 PM
The Vox Pathfinder 15 and 15R use the TDA2030 chip, and the amp always gets mentioned as one of the favorite good-sounding solid state guitar amplifiers on various forums. Here is a link to a schematic of the non-reverb '15' version...

http://www.diyaudio.com/forums/attachments/musical-instruments/153152d1262970400-vox-pathfinder-15-r-schematics-wanted-vox-pathfinder-15.pdf (http://www.diyaudio.com/forums/attachments/musical-instruments/153152d1262970400-vox-pathfinder-15-r-schematics-wanted-vox-pathfinder-15.pdf)

I guess the op-amp based preamp must work quite well for this amplifier to get as much respect as it does. Folks say the clean setting sounds very tube-like. Check out various reviews.
Title: Re: Amp using TDA2030
Post by: darwindeathcat on August 08, 2010, 06:34:48 PM
I just bought a used Jay Turser Classic 10 amp which uses the tda2030 as the power amp stage. (http://www.jayturser.com/classic-10.php (http://www.jayturser.com/classic-10.php)). It sounds REMARKABLY good for an amp that only costs ~$80 new, and which I bought used for only $35. I have not traced the circuit, but merely looked at the component side of the board (see gut shot below). Preamp stage is a single FET front end (J103) followed with a 4558P opamp. There seems to be two red LED's in this stage, most probably for clipping. The preamp stage has one gain control, and a "higain" switch. IMO, the higain switch is pretty useless, as it doesn't change the voice of the distortion, but rather just bumps the gain in the first stage. This means that it's the same tone, but just that you can use a smaller sweep of the gain pot before feedback. There is a no-name transistor (it's marked with a number, and then "Ge", so possibly a germanium?) after the opamp, probably used as a gain stage to follows the very effective but also very interactive triple band tone control section. After this, there is the master volume control that goes straight into TDA 2030 power amp stage. The amp uses a 6" 4ohm no-name speaker.

This amp is dual powered. Either straight in from AC (discreet diode full wave rectified single rail ps to +12v, with 2200uf cap to filter), or direct from onboard rechargeable 12v battery pack (probably NiCad, but maybe NiMh. I didn't open the battery pack to confirm). The battery charges when amp is plugged into AC.

Component quality is pretty good too. 1/8watt carbon film resistors in the signal chain, 10watt metal film ones in the PS. Mostly Poly film caps (the green ones) in the signal chain, but a few ceramic in low values (eg 0.001 uf and lower). Decent run-of-the-mill electrolytic can caps in the PS and elsewhere. Could have a little bit more filtering in the PS, but the amp is very low noise as it is, so I'm not too worried about that. A very low hum is only audible with the gain and volume cranked. Plastic jacks for input and headphone out, but that does not bother me as they are all mounted very securely. There's little worry of breaking them. Plenty of heatsink for the chip (a mediumish aluminum heatsink that is also thermally coupled to the larger steel chassis). The electronics are housed in a really nice steel chassis, so no worries over interference. The transformer could be bigger, and it is a standard iron lump (ie. not a toroidal), but seems to be quite adequate. I have no idea what the VA rating is, however. The cab is pretty well constructed, and is a combination of solid wood (for the front and internal supports) and particle board (sides and back). It's VERY cool looking, with the inlaid wood frontplate and the tweed covering on all other sides. Battery life seems good. I played it for a couple of hours on battery life, and it showed no signs of draining. Probably 3 hours will be the max bat life. One could potentially increase this by building a custom battery pack to increase the AmpHour rating. Probably have to stick to NiCad (or NiMh if it's that), and not lead acid, as the charging circuits are sure to be different.

This amp sounds VERY good. Plenty of tonal variety, good volume output for only 12v power (it claims 10w, but probably more like 6-7 as JMFahey says), and the no-name 6inch speaker sounds surprisingly good! It actually puts out respectable levels of bass! One could definitely fit in an 8"speaker in the space available, and that could potentially increase volume output and improve the tone a bit, but the stock speaker sounds pretty damn good! I bought it for busking, and I think it sounds WAY better than the Legendary Pignose I used to own, or the Roland Microcube I was also considering to buy. I'll be mainly playing harp through it, but it also sounded really good with my Cigar Box Guitar, which has a homemade single coil pickup in it. You can get quite clean (although only at a notably lower volume), and you can get ridiculously dirty (metalish). This amp is best at a nice overdrive tone (bluesy). At this setting, you can get deep and dark by cranking bass and dialing down the treble and mids, or you can get bright and cutting by dialing down the bass and uping the trebel and mids. Very different tones, but all at the same gain/volume level.

Overall, I think that if you are thinking of making an amp on the 2030, you'll be better off buying this amp and modifying it. The chassis alone is worth the money, plus you'll be getting the tranny, the power supply, the battery, the pots, the jacks, etc... Having built several chipamps completely from scratch now, I think that finding a good pre-fabbed amp, and modifying the circuit a bit (ie. changing or adding components to the preamp and tone control stages) is the best way to go.

 Possible mods are 1) upgrading the tranny. 2) upgrading battery pack 3) changing what the "higain" switch does 4)changing the voicing of the preamp section (need to trace the circuit first) 4) changing out the speaker 5)adding a speaker out jack to run  bigger cab. But the amp sounds quite good stock anyway, so even these things would be mostly just for "fun".


Here's a gut shot: