(http://www.pbase.com/image/78204921.jpg)
(http://www.pbase.com/image/78205197.jpg)
(http://www.pbase.com/image/78204946.jpg)
(http://www.pbase.com/image/78205167.jpg)
http://aronnelson.com/gallery/albums/Martys-layouts-and-photos/tda_demo.mp3
sound file recorded with a mic - rough but sounds pretty cool !!
No enclosure yet - need to think of something "funky" for it.
Really sounds amazing - not valve but a damm fine SS attempt !!
Well worth picking up a TDA2050 for one of these, it'll take just an hour or two
get a BIG heatsink for it though !!!
The colours just keep me "safe" at the wire up point !! :icon_redface:
enjoy, MM
interesting. did you use one of the appnote schems??
Looks cool, what are you powering it with?
Quote from: slacker on May 04, 2007, 12:18:35 PM
Looks cool, what are you powering it with?
A psu from an old answering machine !
It's 18v DC 300ma - regulated, seems quite hum free !
MM
Marty, are you using some limiting output device on the amp? Like a resistor after vol. pot.........
TDA2050 can suck a lot current, I burned a 2040 a year ago using a 15V@500mA ps ..... :-\
I`d increase the heatsink, on the long run... :icon_wink:
Quote from: Victor on May 04, 2007, 01:05:02 PM
Marty, are you using some limiting output device on the amp? Like a resistor after vol. pot.........
TDA2050 can suck a lot current, I burned a 2040 a year ago using a 15V@500mA ps ..... :-\
No, all I've done is add a volume pot, strapped across pins 2 & 4.
I used a "lower limit" 390ohm so, as my vol pot is reversed :icon_redface: it means that once
the amp is at a low bedroom level, it does'nt turn totally off.
I'll fix that, but the chip has that huge heatsink - which is keeping it so it's "just" warm and the
PSU hardly got warm after 1 hr.
It gets LOUD but doesn't seem like 30 watts to me .... more like 10/15 watts .. but I'm much
more used to valve amps !!
From my schem that I found, output from pin 4 had a 2.2ohm with a 680n cap to ground, then
1000uf cap and out to speaker, I got close by using 3 x 10ohm paralleled resistors here.
Speaker is 8 ohm, perhaps this is helping ? I'm not SO sure with amp/spkr impedances !
Bias to pin 1 (+ input) is 22k from V+ with 22k to a 100uf/22k node to ground, I replaced a further 22k
which DID go between 2&4 with a 22k pot for volume control.
MM
Quote from: MartyMart on May 04, 2007, 01:23:05 PM
It gets LOUD but doesn't seem like 30 watts to me .... more like 10/15 watts .. but I'm much
more used to valve amps !!
according to the datasheet to get 30 watts you need to run it at 36volts at least and that's with a 4ohm speaker. Running it off 18volts gets about 10 watts, so your ears are spot on :)
That sound pretty darn good Marty! Is that straight into the power amp no pre amp?
Well that gives me hope! Got a couple of ampless, speaker-loaded practice-amp cabs sitting around and some TDA2030s, LM1875s and a TDA2050 or two. I would have though that a 500ma supply would be on the weak side, but clearly I can still get some oomph from them, and obviously more from a 12VAC/1A supply, especially if double-ended.
Thanks for that morale booster!
Quote from: RLBJR65 on May 04, 2007, 02:08:41 PM
That sound pretty darn good Marty! Is that straight into the power amp no pre amp?
I wondered about that too.. It sounds impossible :icon_eek:
I'm guessing that's the Thor.
I would imagine this is marty's mosfet/mu thingy no?
Sound nice marty!
Gotta love the simplicity with that amp!
John
Quote from: Steben on May 04, 2007, 02:54:43 PM
Quote from: RLBJR65 on May 04, 2007, 02:08:41 PM
That sound pretty darn good Marty! Is that straight into the power amp no pre amp?
I wondered about that too.. It sounds impossible :icon_eek:
Quote from: sfx1999 on May 04, 2007, 03:28:23 PM
I'm guessing that's the Thor.
It has my new little "Mos-Mu" circuit up front on that sample :D
I've also tried it with :
Thor
English Channel
Bassman '59
Dr Boogie .... and they all sound FABULOUS !!! :icon_mrgreen:
I wanted to put a preamp on the board but can't decide which !!
I hope my little 18v PSU holds up, if not i do have a large 24v DC 10 amp "Brick" that weighs about 4 kilos !!
Mark - Go for it , I'm SO impressed with this, I'll post the schem tomorrow, as it's a little different from the
standard app note :icon_wink:
MM.
Ah yes, you posted that in the other thread.
Maybe I will gut that old Peavey now and rebuild it! It's got a good transformer already. Rectified voltage is + / - 17 vdc according to the schematic.
Thanks Marty! Looking forward to seeing your schematic.
Cool! I built me a couple of this chip-based amps for a near-field monitoring on my hoome computer. The Pentawatt line is awesome!
Schematic - use a Jfet amp sim or similar up front .
(http://www.pbase.com/image/78436347/original.jpg)
I did a stereo version some weeks ago..it really sounds amazing as the cheap it is, and is so frickin´easy to do too!!
Anyway, youre not using the capabilities of the chip with such a small power source..
I use a 4 amp, 17vdc source simmetrical.. and man, i have to put something heavy over the speaker cabs cause they jump around playing loud with the tight strong bass response!
an with the dr boogie.. great combo!
Maybe I will gut that old Peavey now and rebuild it! It's got a good transformer already. Rectified voltage is + / - 17 vdc according to the schematic.
I would measure that with a DMM for goodness, then figure most of the hard stuff is already done [chassis, box, speaker mount, power supply]
I built a few LM3886TF [TF = insulated body], GGG amp projects using split ~17vdc supplies [IIRC they were seeing > +/- 18Vdc]. They work great, top bang for bukk with these little chip amps, especially when you have the PS iron already!
The only thing I may have overkilled on was running all separate ground wires back to the CT, I even ran the input jack and volume control separately, not sure if that's necessary.
I smoked a chip, then decided everafter to debug a few times before applying power.
Quote from: dschwartz on May 08, 2007, 10:43:47 AM
I did a stereo version some weeks ago..it really sounds amazing as the cheap it is, and is so frickin´easy to do too!!
Anyway, youre not using the capabilities of the chip with such a small power source..
I use a 4 amp, 17vdc source simmetrical.. and man, i have to put something heavy over the speaker cabs cause they jump around playing loud with the tight strong bass response!
an with the dr boogie.. great combo!
.... possibly, but it's still really "kickin" with that 18v single supply :D
I have a 3.2 amp traffo, with 230v primary and +/- 15v DC taps, so perhaps I'll try another that way and
see how THAT sounds ! :icon_wink:
Seems like a superb chip for a few bucks !
MM.
Thanks Pete, thats exactly what I was thinking :icon_wink: Got the iron, a 2040, decent speaker and a nice sturdy combo cab. If I knew it could sound that good I'd have taken it apart long ago. Now I need to look at the board to see if I can strip the stuff thats not needed and scab in a jfet pre amp w/ tone controlls so I can fill all the holes. Hmmm might be easier to make a new board.
Will the 20*0 pins fit in 5 holes straight in a row on perf / vero? I seem to recall they almost fit but not quite ???
Quote from: RLBJR65 on May 08, 2007, 06:21:01 PM
Will the 20*0 pins fit in 5 holes straight in a row on perf / vero? I seem to recall they almost fit but not quite ???
Not quite, I did get my 2050 pins in 5 adjacent vero holes, but had to do a little straightening of the pins.
I was playing it again today and have to say that I'm blown away, even on a single 18v supply !
Sounds FAB.
MM.
Thanks Marty, I'm going to try and work up a pcb layout tonight using DIY layout creator. I'll just make those pads a little over sized.
Thanks for the schematic too!
I was playing it again today and have to say that I'm blown away, even on a single 18v supply !
The amp that gets built is infinitely better than the one that doesn't.
how does it compare to the original park?
the park used a tda2030 too.
Quote from: scaesic on May 09, 2007, 03:11:44 AM
how does it compare to the original park?
the park used a tda2030 too.
IIRC.....
It seems to be louder and more "gutsy" than the original was, though it's been an empty shell
for quite a few months - intended for a small valve combo, using thw Park chassis.
With a decent preamp, such as an English channel etc - it 's in a different league from the original.
MM
iv been looking for something to replace my park with too.
i have the exact same amp, i plan on stripping it down to bare bones and using a mosfet boost as a pre into some sort of power amp. i may use the tda like you did.
do you reckon itd be easy enough to canabalise the power supply/heatsink from the original?
QuoteI have a 3.2 amp traffo, with 230v primary and +/- 15v DC taps, so perhaps I'll try another that way and
see how THAT sounds ! icon_wink
Marty, what Traffo is that exactly?
P.S - why build an SS amp when you can pretty easily build a cool 5 watter all tube? (not to insult or anything, I'm just interested on why not go for valves...)
Thanks :)
Quote from: Phorhas on May 09, 2007, 07:18:52 AM
Marty, what Traffo is that exactly?
It's a chunky PCB mountable traffo from RS ( UK RS not radio shack !! )
P.S - why build an SS amp when you can pretty easily build a cool 5 watter all tube? (not to insult or anything, I'm just interested on why not go for valves...)
Been there already : http://www.pbase.com/martymart/se5a_build
My Park shell will house a "Heavy watter" 1.8 watt valve amp when it's done !
For now, the TDA is quite a good sounding unit - perhaps it will stay in there !!!
Quote from: scaesic on May 09, 2007, 07:04:05 AM
iv been looking for something to replace my park with too.
i have the exact same amp, i plan on stripping it down to bare bones and using a mosfet boost as a pre into some sort of power amp. i may use the tda like you did.
do you reckon itd be easy enough to canabalise the power supply/heatsink from the original?
The TDA2050 is more powerful and so will get hotter, while the power section may be fine, you'll need a heatsink at least
twice the size !!
I would also choose a nice pre-amp rather than just a boost, perhaps a Dr Boogey or English Channel would use up the
Parks "knob space" quite nicely :D
MM.
Gottcha :)
What about that Traffo Xforme r?
Quote from: Phorhas on May 09, 2007, 08:48:06 AM
Gottcha :)
What about that Traffo Xforme r?
see inside above post ! :icon_wink:
I think MM is using a WW, single ended supply...look for a WW with 18v and the biggest current rating or...
See GEO, Power supplies for effects, and build one with plenty of current and a split supply
Quote from: MartyMart on May 09, 2007, 08:04:56 AM
Quote from: Phorhas on May 09, 2007, 07:18:52 AM
Marty, what Traffo is that exactly?
It's a chunky PCB mountable traffo from RS ( UK RS not radio shack !! )
P.S - why build an SS amp when you can pretty easily build a cool 5 watter all tube? (not to insult or anything, I'm just interested on why not go for valves...)
Been there already : http://www.pbase.com/martymart/se5a_build
My Park shell will house a "Heavy watter" 1.8 watt valve amp when it's done !
For now, the TDA is quite a good sounding unit - perhaps it will stay in there !!!
Quote from: scaesic on May 09, 2007, 07:04:05 AM
iv been looking for something to replace my park with too.
i have the exact same amp, i plan on stripping it down to bare bones and using a mosfet boost as a pre into some sort of power amp. i may use the tda like you did.
do you reckon itd be easy enough to canabalise the power supply/heatsink from the original?
The TDA2050 is more powerful and so will get hotter, while the power section may be fine, you'll need a heatsink at least
twice the size !!
I would also choose a nice pre-amp rather than just a boost, perhaps a Dr Boogey or English Channel would use up the
Parks "knob space" quite nicely :D
MM.
the reason i was thiking about the mosfet boost was i want it for clean jazz tones, i had a look at the polytone schems, reckon i could pinch the tonestack just after the pre and stick it after a mosfet boost instead? i was thinking about sticking in two graphic eq's pre and post.
http://www.murchmusic.com/Polytone%20Info/Schem1.JPG
OT, ;) I had the same Park amp... actually I still have the cabinet&speaker somewhere in my garage... When I saw your picture I had some kind of dejà vù ...
oppinions?
(http://img337.imageshack.us/img337/6338/parkmodie5.jpg)
Just in case people forget, there is the generic TDA20x0 board project over at GGG: http://www.generalguitargadgets.com/pdf/ggg_20x0_amp.pdf
The pinouts for the 2030, 2040, and 2050 are identical. You can make yourself a couple of boards, stuff 'em with your choice of chip and power 'em with your choice of PSU.
Given how cheap and compact these amps are, let me once more put in a plug for the idea of a compact bi-amped combo amp. These days you can score all manner of subwoofers dirt cheap. Stick a 4" or 6" subwoofer facing downward or sideways in a combo cab, in tandem with an 8", powered separately, and you may be able to achieve the sort of big sound (albeit at more modest volumes) you'd get with a 12", or 15" speaker in a bigger cab. Since you're not trying to achieve flat frequency response, you can simply split your preamp output and feed the full signal to the power driving the 8" full range, and run the other output to a simple lowpass filter and into a separate power amp module driving the subwoofer. Heck, those of you guys dickering with 5W single-ended tube amps might also consider feeding the preamp output to a SS power amp and subwoofer in the same way. There may be plenty of reasons to want to use tubes for most of the frequency spectrum, but my guess is that in the world of distorted guitars, you probably would not notice the difference between tube-amplified and solid-state amplified content under 200hz.
Incidentally, no reason why it HAS to be in the same cab. Rivera has their line of Los Lobottom powered subwoofer cabs to augment the main amp. T'would be an easy affair to have a small sealed subwoofer cab with a 4, 6, or 8" in it, fitting the footprint dimensions of the small combo amp. Pack a PSU, 30W of extra bass power, a 2-4-pole lowpass filter, a line input and volume control, and all you need is a line/preamp out from any amp to add a little more chest-shaking oomph to your tone.
SCAESIC,
You probably need a little more gain in the front end, unless you planned on running the proposed amp from line-level signals.
Quote from: Mark Hammer on May 09, 2007, 11:38:42 AM
SCAESIC,
You probably need a little more gain in the front end, unless you planned on running the proposed amp from line-level signals.
i was planning on using the amz mosfet boost. good/bad? im not sure if the mosfetboost is the best thing to use for jazz tones. also, im not sure whether to have the mosfet boost before or after the tonestack. i quite like the idea of having toneshaping pre and post though.
I'm looking at it purely from the standpoint of how much gain is applied, and distributed across the signal path, in the typical amplifier that sticks a power-amp chip at the end of it. The intent is not to achieve any sort of particular tone, but rather to simply assure that the signal applied to the input of the power amp stage is of sufficient amplitude to achieve the best S/N ratio and maximum clean output possible.
Power amp chips will want a line-level signal. After all the assorted tone shaping has been applied to the guitar signal in the suggested circit you posted (and there is nearly always passive loss from that), will there still be enough guitar signal left to do that? Maybe, maybe not. Of course, from the amp's point of view, it doesn't particularly care if that level-shifting of the signal happens after the input jack or before it, just as long as it happens somewhere. Given that gain is multiplicative, if you have a gain of x3 here and there in the amp chassis, and stick a gain of x10 and x3 here and there ahead of the amp, you may well end up meeting those specs. I'm just encouraging you to keep the entire signal path and gain structure in mind so that you can get the amp to do what you want it to do.
Bucks, Marty?? Don't you mean, oh, I don't know, quid, or something? :icon_biggrin:
Nice job on the amp, and thanks as always for sharing.
Ben
mark: i´he build it with the GGG layout...with the TDA2050 it exploded!!!
tda2050 its not mentioned for that layout, so i recommend making the datasheet circuit...
Quote from: Victor on May 04, 2007, 01:05:02 PM
TDA2050 can suck a lot current, I burned a 2040 a year ago using a 15V@500mA ps ..... :-\
what?why is that? ???
Hello,
I'm going to build this power-amp and I have a question:
Is this schematic from page 1 ok or should I change something?
http://www.pbase.com/image/78436347/original.jpg
And the ground: Does the (pedal) preamp-ground have to be connected to the poweramp-ground?
Greetings
Magnus
Quote from: Magnus on February 28, 2017, 03:47:20 PM
Hello,
I'm going to build this power-amp and I have a question:
Is this schematic from page 1 ok or should I change something?
http://www.pbase.com/image/78436347/original.jpg
And the ground: Does the (pedal) preamp-ground have to be connected to the poweramp-ground?
Greetings
Magnus
As for the ground question.. Yes, the cable you use to connect them together.. > preamp output to power amp input > That should do it. :icon_wink:
If you're gonna put both the preamp and the power amp in the same box then yeah, connect the grounds..
The schematic from the first page should be fine. It's the single supply configuration taken directly from the data sheet with a couple mods as he notes at the bottom of the pic.
Look at the data sheet and go to pages 6 and 7. Page 7 should help you if you need or want to make any changes... There is a board layout on page 6 also but, you may want to modify it or make your own unless you have some big 1000u electrolytic axials you need to find a home for..
http://www.edutek.ltd.uk/Binaries/Datasheets/Linear/TDA2050.pdf
I have built a couple of poweramps from that schematic without any problems (even copying Marty's vero layout from the photos).
Works perfectly and sounds great.
Remember a heatsink on TDA2050. It gets hot!