Ah, see now back to confusion-town.
I see a lot of specs for that amp listed as 4ohm, so where did the "30 W @ 10% THD into 8 ohms" numbers come from? If I use 2x the Ohm, I get 1/2 the Watts? Because I know some of the speakers I've looked at had a 4/8/16ohm option... including that Reaper.... though the store I was looking to buy from only carries the 8/16ohm. May be able to make a special request.
Ideally, if I got a 50w speaker, I'd like to be able to get 40w of clean sound. That's why I was looking at that 60w amp, because listed it as being 50w @ 1% THD. So should put out 40w no problem.
Just, hate the idea of buying a 50w speaker, and knowing it's only good for 15-20w.
EDIT - Ha, I could go back to my 2x75w original idea, updated with Bluetooth for music!
150W + 75W*2 TAS5613 2.1 Bluetooth Power Amplifier Class D AMP | eBay
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If the 60w amp is only good for 15-20w on that 8ohm 50w speaker.... Would something like this be more appropriate? 100w amp, mono... maybe this and that PSU I linked to earlier? eBay
Actually found a decent little calculator.
Speaker Impedance Changes Amplifier Power - Geoff the Grey Geek
Using that calculator... I would want a 200w2ohm amp on a 50w8ohm speaker to get 50w... power supply being powerful enough of course.
That sound right?
Actually found a decent little calculator.
Speaker Impedance Changes Amplifier Power - Geoff the Grey Geek
Using that calculator... I would want a 200w2ohm amp on a 50w8ohm speaker to get 50w... power supply being powerful enough of course.
That sound right?
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Exactly. Look back at the formula I gave you in post #12 - see step 4? You divide by the speaker impedance to calculate the power output. If you divide by 8 (instead of dividing by 4), you get half the output watts.
For simplicity, I put together a little spreadsheet showing power output over a range of supply voltages for both 4 and 8 ohm speakers (attached). Hopefully this will help you make an informed decision.
Even a 1000W amp of this type (BTL or bridged transformerless) will only put out about 30 watts into an 8 ohm speaker if you run it from 24 volts...
The 1000W tells you the maximum power the amp can put out without burning out or going into shutdown. But the actual power delivered to the speaker is decided by the power supply voltage, and the speaker impedance. Nothing more.
I understand that, it feels like a shame to pay for something you can't use, especially when it's an expensive item like a guitar speaker.Just, hate the idea of buying a 50w speaker, and knowing it's only good for 15-20w.
My suggestion: can you temporarily get access to a guitar speaker, maybe a friends, maybe one that's already in a guitar amp you own? That will let you get an idea how many watts you can actually use at home. You might very well find that 5 watts is more than the neighbours will tolerate without calling the cops, in which case, you might decide to re-think the whole "50 W speaker" thing.
-Gnobuddy
Attachments
No - you only need a 50W amp...but it must be able to run on a 32V DC power supply, and you must find such a power supply.
Doesn't matter if the amp is rated 50W or 5000W....with an 8 ohm speaker, you will get a little over 50W if you use a 32V DC power supply capable of good voltage regulation, and at least 2 amps continuous current.
What you mustn't do is (a) Try to use a 20 watt amp (or anything rated for less than 50 W), or (b) use any amp not specified for a 32V DC (or more) power supply voltage.
Those power ratings you find on Ebay and Amazon are pretty much total fiction - go by the specified power supply voltage, or if you want to dig a bit deeper, find out what chip is used, and Google for that chip's datasheet to find out the real skinny.
My "100W + 100W" class D board actually has 32-volt rated electrolytic capacitors on the board. It uses a TDA7498 chip. The chip manufacturer (ST Electronics) says it can handle a maximum power supply voltage of 45 volts DC. But because the manufacturer of this particular circuit board chose to cheap out with 32V filter caps, I can't apply more than maybe 28 volts to it - and the nearest power supply voltage that's readily available is only 24V.
So my mighty "100 W + 100 W" TDA7498 class-D amp turns into a pipsqueak "30 W + 30 W" amp if I use 8 ohm speakers and a 24V power supply.
(Actually 30 W is only about 5 dB less power than 100 W. And if 30 W is already too loud, who the heck cares?)
-Gnobuddy
Ah I was about to ask that... seems that the power to the speaker seems less about the amp being a 50w amp or 100w amp, and more about using a power supply big enough to power it.
Cap wise... I guess always the option to swap those out? Like I was doing on my original amp. I watched a guy with the same amp doing a demo and halfway through the demo the cap blew. Used a 19v PSU from a laptop which I had as well, amp was rated up to 24v... but the caps were all like 20v. Guy swapped them and that's when realized they were fakes, stuck in name brands with a 50v max and worked great. For the arcade cabinet, the 19v PSU from a laptop was fine because I didn't need 100 watts of speaker power 24 inches from my head playing the Mario Bros. theme.
Upside is I have every size of cap imaginable, bought a whole bunch for a few projects and upgrades, repaired a pair of 4:3 ratio Samsung monitors with blown caps as well. So if I get a no-name board off eBay China, if the caps are rated less than 32v, I can upgrade them all to 50v+ in a jiffy.
So... in short
Find an amp 50w+ mono and do not exceed the recommended PSU voltage. To get 50w, I need 32V, maybe 30v to keep it a bit under the speaker's max.
Man... lot more involved than I expected. I would have just gone online, picked out a 50w speaker, an amp off ebay that said 50w, and matched the PSU to whatever the ebay listing for the amp said.
I'll poke about tonight online, see what I can find and maybe post the components tomorrow... see if what I pick will work well.
The pre-amp mentioned way back... still a good option? It's range is 12-34v so I guess safe for a 32v PSU
12-35V NE5532 Preamplifier Preamp Board DC Single Power Supply NEW | eBay
Cap wise... I guess always the option to swap those out? Like I was doing on my original amp. I watched a guy with the same amp doing a demo and halfway through the demo the cap blew. Used a 19v PSU from a laptop which I had as well, amp was rated up to 24v... but the caps were all like 20v. Guy swapped them and that's when realized they were fakes, stuck in name brands with a 50v max and worked great. For the arcade cabinet, the 19v PSU from a laptop was fine because I didn't need 100 watts of speaker power 24 inches from my head playing the Mario Bros. theme.
Upside is I have every size of cap imaginable, bought a whole bunch for a few projects and upgrades, repaired a pair of 4:3 ratio Samsung monitors with blown caps as well. So if I get a no-name board off eBay China, if the caps are rated less than 32v, I can upgrade them all to 50v+ in a jiffy.
So... in short
Find an amp 50w+ mono and do not exceed the recommended PSU voltage. To get 50w, I need 32V, maybe 30v to keep it a bit under the speaker's max.
Man... lot more involved than I expected.
I would have just gone online, picked out a 50w speaker, an amp off ebay that said 50w, and matched the PSU to whatever the ebay listing for the amp said.I'll poke about tonight online, see what I can find and maybe post the components tomorrow... see if what I pick will work well.
The pre-amp mentioned way back... still a good option? It's range is 12-34v so I guess safe for a 32v PSU
12-35V NE5532 Preamplifier Preamp Board DC Single Power Supply NEW | eBay
Question about the amp... From what im reading, class A would be a better amp... How about something like
Assembled UPC1298V mono amplifier board class A power AMP 80W | eBay
32v psu seems uncommon vs 24v and 36v... But is the voltage only an issue if i crank up the volume? Or would the 36v kill a 50w speaker?
Assembled UPC1298V mono amplifier board class A power AMP 80W | eBay
32v psu seems uncommon vs 24v and 36v... But is the voltage only an issue if i crank up the volume? Or would the 36v kill a 50w speaker?
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Explain. (Think first.)
That board you linked to might just-maybe be possible to bias into class A, but it would have to start with a HUGE power supply and a HUGER heat sink. (I suspect the ad listing is mostly wish-fulfillment, not technical truth.)
You got to love the Chinese. Or it might just be Google Translate that needs some work.
That aside, BTL, 30W@24V. 1PCS DC 12V-24V TPA3118 BTL 60W Mono Digital Audio Power Amplifier Board Module | eBay
I thought it would have been obvious in my post but I guess not.
Well, read a few A vs D articles, and a YouTube vid that seemed to imply that sound wise A is better than D, A/B is about as good as A but more power efficient... I guess signal or no signal the A amp is either running full power to the speaker or it's converting to heat.
Consensus seems to say that A is more natural sounding, which is a plus for a modelling amp... but D is much more efficient.
Just seems to be fewer of them on eBay (A class) as a board with any decent data listed. Most of the D class seem to have a chart included of specs at least.
PSU won't be an issue I don't think, see a lot of 46v PSU's available, if that's enough. Heat sinks, I have coming out the wazoo. I work at an appliance shop and we get a lot of control boards in to scrap and some of the higher end ones have massive heat sinks. sorta why I wanted to start learning about DIY electronics... lots of parts to salvage.
Few tube amps caught my eye but a bit harder to figure out, I think the tube stuff is mostly pre-amps? which I need anyways... though all seem to be stereo, though can probably wire up a split going to a mono 1/4" and a stereo 3.5mm since I may use for my MP3 player when working on the car and such.
6J1 AC12V Amplifier Valve Pre-amp Tube Board Fidelity X10-D Circuit+Acryliv Case | eBay
Consensus seems to say that A is more natural sounding, which is a plus for a modelling amp... but D is much more efficient.
Just seems to be fewer of them on eBay (A class) as a board with any decent data listed. Most of the D class seem to have a chart included of specs at least.
PSU won't be an issue I don't think, see a lot of 46v PSU's available, if that's enough. Heat sinks, I have coming out the wazoo. I work at an appliance shop and we get a lot of control boards in to scrap and some of the higher end ones have massive heat sinks. sorta why I wanted to start learning about DIY electronics... lots of parts to salvage.
Few tube amps caught my eye but a bit harder to figure out, I think the tube stuff is mostly pre-amps? which I need anyways... though all seem to be stereo, though can probably wire up a split going to a mono 1/4" and a stereo 3.5mm since I may use for my MP3 player when working on the car and such.
6J1 AC12V Amplifier Valve Pre-amp Tube Board Fidelity X10-D Circuit+Acryliv Case | eBay
Nope.
What part of it is Google Translate mistakery? and why?
Sorta what I was saying in my last post (think we posted same time) the Class A ones seems to have 0 data. I tried looking up the chip online for specs, but always seems to default to a similar but stereo chip with different specs.
Weird, link now shows a different board, I guess they updated the photo.
I'd look at 100w into 8ohm (28v RMS swing, 40v rails) and get a half-decent 12" coaxial, or maybe something like the Eminence Beta-12 LTA or Fane triple cone.
When it comes to modelling an amplifier, all you want to do is take the signal from the modeller, and make it louder. All of the amp crunch, cone distortion, etc is all done in the modeller, so you want something clean and linear.
Class A amplifiers require a lot of headsink, and a power supply to match. You don't want that in a portable guitar rig - it's heavy to carry around, and you'll start tripping breakers. Class D is smaller, cheaper, lighter, more efficient, and sounds identical after the drummer starts up.
Chris
When it comes to modelling an amplifier, all you want to do is take the signal from the modeller, and make it louder. All of the amp crunch, cone distortion, etc is all done in the modeller, so you want something clean and linear.
Class A amplifiers require a lot of headsink, and a power supply to match. You don't want that in a portable guitar rig - it's heavy to carry around, and you'll start tripping breakers. Class D is smaller, cheaper, lighter, more efficient, and sounds identical after the drummer starts up.
Chris
So far.... my build list is the below...
Amp, still a bit iffy... seems to match the specs, except noticed that it's 3ohm not 2ohm like everything else I looked at. So at 200w3ohm would be more for a 75w8ohm speaker... PSU aside... I could get the 16ohm speaker and get 34w out of the 50w speaker. Then I would only need a 24v PSU?
... my math make any sense?
Also looks like it takes a laptop power supply which I can change by de-soldering the jack probably and wiring direct.
So... (if math makes sense)... 200w 3ohm amp with max 36v, 50w 16ohm speaker (no idea what the max/rms values are, not seeing it on their site, but assuming 50w max and probably around 35w RMS, 24v3a53w power supply (should make about 34w) and a pre-amp that seems to fall within the right specs.
... am I on the right track?
Sure Electronics' webstore 1 x 200 Watt Class D Audio Amplifier Board - T-AMP
LRS-50-24 Mean Well USA Inc. | Power Supplies - External/Internal (Off-Board) | DigiKey
12-35V NE5532 Preamplifier Preamp Board DC Single Power Supply NEW | eBay
WGS 12" Reaper HP - 50W 16ohm - Canada
Amp, still a bit iffy... seems to match the specs, except noticed that it's 3ohm not 2ohm like everything else I looked at. So at 200w3ohm would be more for a 75w8ohm speaker... PSU aside... I could get the 16ohm speaker and get 34w out of the 50w speaker. Then I would only need a 24v PSU?
... my math make any sense?
Also looks like it takes a laptop power supply which I can change by de-soldering the jack probably and wiring direct.
So... (if math makes sense)... 200w 3ohm amp with max 36v, 50w 16ohm speaker (no idea what the max/rms values are, not seeing it on their site, but assuming 50w max and probably around 35w RMS, 24v3a53w power supply (should make about 34w) and a pre-amp that seems to fall within the right specs.
... am I on the right track?
Sure Electronics' webstore 1 x 200 Watt Class D Audio Amplifier Board - T-AMP
LRS-50-24 Mean Well USA Inc. | Power Supplies - External/Internal (Off-Board) | DigiKey
12-35V NE5532 Preamplifier Preamp Board DC Single Power Supply NEW | eBay
WGS 12" Reaper HP - 50W 16ohm - Canada
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Translating from Chinese a Class D amp into a Class A amp in English.Nope.
What part of it is Google Translate mistakery? and why?
Why would you go 16 ohm and make your life harder? With 8 ohm you need a lower PS voltage and a few chip options.
@Chris661 - Those Beta 12's, around 125w aren't they? Might be a bit much... though guess because 12w doesn't mean I have to run at 125w.
$40 cheaper than the Warehouse as well.
Was really hoping to stay around $100CAD for a speaker so, that may be a better option.
Still not sure which specs I'm looking at to know if a 'flat' speaker. For the Warehouse I just contacted the manufacturer and asked them if they can recommend one. I have no idea how the Warehouse compares to the Eminence.
$40 cheaper than the Warehouse as well.
Was really hoping to stay around $100CAD for a speaker so, that may be a better option.
Still not sure which specs I'm looking at to know if a 'flat' speaker. For the Warehouse I just contacted the manufacturer and asked them if they can recommend one. I have no idea how the Warehouse compares to the Eminence.
Oh so that's not even a Class A amp listed then? Ya, that's a bit deceptive.
16ohm vs 8ohm... I used an online calculator based on the amp specs.
Amp = 200w 3 ohm
With a 2 ohm speaker, maximum power = 300 watts
With a 4 ohm speaker, maximum power = 150 watts
With a 6 ohm speaker, maximum power = 100 watts
With a 8 ohm speaker, maximum power = 75 watts
With a 16 ohm speaker, maximum power = 38 watts
Then using another calculator to get voltage needed
Put in 50w 16ohm, says would need 28.28v and 1.76A. If I put in 24v 16ohm, says 36w, which is probably closer to the RMS of a 50w speaker if anything like car audio specs seem to be.
16ohm was because the amp listed was showing 200w3ohm not 200w2ohm. From what the online calculator says it would output max power more than the speaker is. Switching to 16ohm seemed to bring it below max.
225w IIRC. That number tells you how many watts you have to put in before it'll slowly melt. More watts will melt it quicker, and 225w or less is how many watts the speaker can deal with for a timescale of hours.
The one they've recommended is still a guitar speaker, and will sound like one.
Chris
Ya I guess that's true... even a flat guitar speaker will affect the modelling with some... not sure the term, colour? flavour? because of what it is.
Shame... those warehouse ones look really nice. Yup... I know in a box so who cares... they still look nice.
Eminence I can get easily enough... FANE in Canada, haven't seen any stores online that sell it here yet. UK I can find easily, but after exchange, duty, shipping... forget it.
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