Hi everyone... I'm just a newbie that has a bass amplifier but wants more power to drive bigger speakers.
Currently I own and old Peavey Mark IV 400BH bass amplifier that was built in the earlies 80's, this amp works well but has a little problem for me... It lacks power to drive bigger speaker cabinets and it gets too hot when driven hard so i was thinking in a way to replace the 400BH power amplifier of this baby and put a D class amp board and integrate all in the bass head chassis. (Sounds like crazy) This amp can give a total of 300 watts at 2 ohms but I need it to handle 600 watts rms at 8 ohms. Sorry for my english, this is not my native language, but I try
. My knowledge in electronics are low medium but i am going to use a friend's help that is a technician. I Will attach the original schematic:
Currently I own and old Peavey Mark IV 400BH bass amplifier that was built in the earlies 80's, this amp works well but has a little problem for me... It lacks power to drive bigger speaker cabinets and it gets too hot when driven hard so i was thinking in a way to replace the 400BH power amplifier of this baby and put a D class amp board and integrate all in the bass head chassis. (Sounds like crazy) This amp can give a total of 300 watts at 2 ohms but I need it to handle 600 watts rms at 8 ohms. Sorry for my english, this is not my native language, but I try
. My knowledge in electronics are low medium but i am going to use a friend's help that is a technician. I Will attach the original schematic:Attachments
Short answer:
1) leave amplifier as is.
use it as a preamp only, don´t touch the power supply and power amp; IF someday you need a mid sized head, use it as original.
If you do not connect speakers to it, power amp will stay cold.
2) get a cheap but powerful Rack type power amp.
If necessary, you can use both channels bridged to get high power into 8 ohms.
You stack: speaker, rack amp, and your Peavey on top.
3) just curious, what "8 ohm 600W" Bass speaker will you use?
Unless it{s a *beast* you´ll destroy it (unless it´s actually a 4 x 10" Bass cabinet or similar).
1) leave amplifier as is.
use it as a preamp only, don´t touch the power supply and power amp; IF someday you need a mid sized head, use it as original.
If you do not connect speakers to it, power amp will stay cold.
2) get a cheap but powerful Rack type power amp.
If necessary, you can use both channels bridged to get high power into 8 ohms.
You stack: speaker, rack amp, and your Peavey on top.
3) just curious, what "8 ohm 600W" Bass speaker will you use?
Unless it{s a *beast* you´ll destroy it (unless it´s actually a 4 x 10" Bass cabinet or similar).
Thanks for replying...
Well I rig that bass head everywhere I go and currently to drive most 8x10" bass cabinets like Hartke HyDrive 810 / Ampeg SVT 810 (similar 8x10" cabinets you need from 800 watts to more than 1200 at 4 ohms) or using a single 4x10" ampeg at 8 ohms that needs 500 watts rms, or a 1x15" + 4x10" in parallel.
I haved used that configuration of using the head as a preamp and run a rack power amp but it's bulky and heavy, I would love to integrate all in the head... What I understand about this particular head is that is built in modules, one module for preamplification (front) a power current module (transformer and rectifier) and the power amp board. (I think that in the schematic is all that specified, there is a cable that transmit the signal from the preamp to the amp and that's it) integrating a class d amplifier board with it's power supply is way smaller than the actual amplification stage that this head has.
Well I rig that bass head everywhere I go and currently to drive most 8x10" bass cabinets like Hartke HyDrive 810 / Ampeg SVT 810 (similar 8x10" cabinets you need from 800 watts to more than 1200 at 4 ohms) or using a single 4x10" ampeg at 8 ohms that needs 500 watts rms, or a 1x15" + 4x10" in parallel.
I haved used that configuration of using the head as a preamp and run a rack power amp but it's bulky and heavy, I would love to integrate all in the head... What I understand about this particular head is that is built in modules, one module for preamplification (front) a power current module (transformer and rectifier) and the power amp board. (I think that in the schematic is all that specified, there is a cable that transmit the signal from the preamp to the amp and that's it) integrating a class d amplifier board with it's power supply is way smaller than the actual amplification stage that this head has.
On this picture it is listed 800W max power from mains: https://www.talkbass.com/attachments/fullsizerender-4-jpg.937116/
Is the transformer inside 800W?
The supply voltage is +/-52 on the schematics, so you'll need two class D modules, which to work in bridge mode and will have about 400-450W at 8 ohm speaker. With 4 ohm speaker configuration you will blow the power transformer at full power and continuous usage.
Is the transformer inside 800W?
The supply voltage is +/-52 on the schematics, so you'll need two class D modules, which to work in bridge mode and will have about 400-450W at 8 ohm speaker. With 4 ohm speaker configuration you will blow the power transformer at full power and continuous usage.
That's what i figured too
That being said, turning up to a gig with a humongous bass rig AND running it full-blast is a sure way to 1) pi*s off the sound-guy, 2) potentially pi*s off your bandmates, and 3) making your whole band sound like a*s...
Sounds silly perhaps, but i'd rather invest in some in-ear monitoring. Less "stage bleed" (bass guitar bleeding into all the other mics), and you (would) get to save your hearing too
That being said, turning up to a gig with a humongous bass rig AND running it full-blast is a sure way to 1) pi*s off the sound-guy, 2) potentially pi*s off your bandmates, and 3) making your whole band sound like a*s...
Sounds silly perhaps, but i'd rather invest in some in-ear monitoring. Less "stage bleed" (bass guitar bleeding into all the other mics), and you (would) get to save your hearing too
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On top of all the other discouragement in this thread, even if you were to change the power stage to class D, you'll still be lugging around the old line transformer and rectifier supply, which means your marginally more powerful cool running amplifier will be just as heavy.
If this head bothers you, sell it and buy a switcher/ class D amp.
Of course you can do anything else for the raw educational benefit..
If this head bothers you, sell it and buy a switcher/ class D amp.
Of course you can do anything else for the raw educational benefit..
I will not sell this head because:
- It has two independent channels with sends and returns jacks for effects each one, each channel has it's own equalizer, pre and post, send to master eq and bright switch.
- A Crossover that is variable so I can run a Biamp configuration.
- Main graphic Equalizer.
- Clean Preamp.
- Footswitch to change channels or mix both.
Currently I don't know any actual bass head that has all of this features and is reliable enough to go anywhere I go without any problem, and If and actual head could had all of these, would cost a LOOOOT.
What's the purpose of having more power for me? It's called "Headroom" Indeed if I could modify this head, the only original part would be the preamplification stage.
- It has two independent channels with sends and returns jacks for effects each one, each channel has it's own equalizer, pre and post, send to master eq and bright switch.
- A Crossover that is variable so I can run a Biamp configuration.
- Main graphic Equalizer.
- Clean Preamp.
- Footswitch to change channels or mix both.
Currently I don't know any actual bass head that has all of this features and is reliable enough to go anywhere I go without any problem, and If and actual head could had all of these, would cost a LOOOOT.
What's the purpose of having more power for me? It's called "Headroom"
Indeed if I could modify this head, the only original part would be the preamplification stage.Well carrying this head is like carrying my sign. It's like 20 kilograms I think so but I don't care to transport it anywhere I go. I guess that having from 500 to 600 watts at 8 ohm would be just perfect. Most new cabinets has this rating. And changing the 1/4 speaker jacks into some Speakon running in parallel.
Thanks for all your replies.
Thanks for all your replies.
"Headroom" for what, exactly? So you don't risk the amp clipping?
At that level, you can be sure the speakers will be distorting more than a bit And anyway, what sort of SPL's do you need / want, really?
But since pretty much all you really need is everything-else-but-the-power-amp, what you could do would be to remove the big fat power transformer and the heatsinks (since those will be the main contributor to the weight), maybe sell those off to recoup some cash, install a smaller transformer just to power the preamp section (opamps etc), and get some class-D power amp, and you should be set.
Best of both worlds
At that level, you can be sure the speakers will be distorting more than a bit
And anyway, what sort of SPL's do you need / want, really?But since pretty much all you really need is everything-else-but-the-power-amp, what you could do would be to remove the big fat power transformer and the heatsinks (since those will be the main contributor to the weight), maybe sell those off to recoup some cash, install a smaller transformer just to power the preamp section (opamps etc), and get some class-D power amp, and you should be set.
Best of both worlds
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Was chiming in to sat about the same:
1) the way that particular head is built, you have 2 fully separate modules, not only electrically but mechanically, which is quite uncommon.
2) you can keep cabinet and front panel/preamp, momentarily discard power transformer and back power amp and power supply.
3) you will need to build a small and light +/-15V supply for the preamp.
4) you have now a large alnmost empty cabinet head
5) you will need to fabricate a new C shaped back panel out of 1.5mm (minimum) to 2mm aluminum to mount the Class D power amp and supply, speakon out, power cable and switch, etc.
A problem for most DIY hobbyists is not the *electronic* area, but the *mechanical* one: can you cut/bend/punch/drill aluminum sheet?
Plus not *indispensable* but "nice to have" finishing (painting/sandblasting/brushing/etc.)
6) you can buy an ICE Power module, which is very compact (and relatively "cold" , hence the "Ice" name he he) which includes an SMPS power supply, a big power amp and can supply some raw +/-25V to power "something else", you can easily regulate that down to +/-15V or whatever´s needed for the preamp.
I suggest one of these:
from: ICEpower – Class D OEM audio amplifiers – Consumer & Professional Audio
7) you said
8) I said
9) your current +/-52V supply amplifier is only 200W into 4 ohm, some 300 into 2 ohm (not too practical today) and only 140/150W into 8 ohms, that´s why you find it lacking when driving a single 8 ohm cabinet
10) so in a nutshell: your project is doable, but requires access to a metal working shop (or paying somebody to do it) and don´t forget you will spend some money.
Go straight to the ICE modules, which are used by Fender, G&K, Aguilar and most other "pro" brands, do not WASTE time with "EBay" Class D modules, you will waste time and money.
11) Plan B if you carry your cabinets with you, rewire one 8 ohm 4 x 10" cabinet (which has 4 x 8 ohm speakers inside, *any* brand and model except the Ampeg one which has 4 x Eminence BP102 **32 ohm** speakers in parallel) into 2 ohms, all 8 ohm speakers in parallel, and dedicate it only for the Peavey head.
You will get the full 300W RMS (which you never had so far) and be surprised, it will be LOUD.
Just try it tomorrow before anything else, you can be testing in 30 minutes.
Post results
1) the way that particular head is built, you have 2 fully separate modules, not only electrically but mechanically, which is quite uncommon.
2) you can keep cabinet and front panel/preamp, momentarily discard power transformer and back power amp and power supply.
3) you will need to build a small and light +/-15V supply for the preamp.
4) you have now a large alnmost empty cabinet head
5) you will need to fabricate a new C shaped back panel out of 1.5mm (minimum) to 2mm aluminum to mount the Class D power amp and supply, speakon out, power cable and switch, etc.
A problem for most DIY hobbyists is not the *electronic* area, but the *mechanical* one: can you cut/bend/punch/drill aluminum sheet?
Plus not *indispensable* but "nice to have" finishing (painting/sandblasting/brushing/etc.)
6) you can buy an ICE Power module, which is very compact (and relatively "cold" , hence the "Ice" name he he) which includes an SMPS power supply, a big power amp and can supply some raw +/-25V to power "something else", you can easily regulate that down to +/-15V or whatever´s needed for the preamp.
I suggest one of these:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
from: ICEpower – Class D OEM audio amplifiers – Consumer & Professional Audio
7) you said
but you NEED to be able to drive 4 ohms effortlessly since all 8x10" "fridges" are 4 ohms, except the kinky 115+410 one made for SVT400T which is 2 x 4 ohms (split) or 1 x 8 8hms (full).
8) I said
because I suggest you build a compact 2 x 10" cabinet and mount them on the back, and keep it for backup, send some Bass to the drummer, or even play at small gigs driving it from a "Bass Preamp in a Pedal" or similar.
9) your current +/-52V supply amplifier is only 200W into 4 ohm, some 300 into 2 ohm (not too practical today) and only 140/150W into 8 ohms, that´s why you find it lacking when driving a single 8 ohm cabinet
10) so in a nutshell: your project is doable, but requires access to a metal working shop (or paying somebody to do it) and don´t forget you will spend some money.
Go straight to the ICE modules, which are used by Fender, G&K, Aguilar and most other "pro" brands, do not WASTE time with "EBay" Class D modules, you will waste time and money.
11) Plan B if you carry your cabinets with you, rewire one 8 ohm 4 x 10" cabinet (which has 4 x 8 ohm speakers inside, *any* brand and model except the Ampeg one which has 4 x Eminence BP102 **32 ohm** speakers in parallel) into 2 ohms, all 8 ohm speakers in parallel, and dedicate it only for the Peavey head.
You will get the full 300W RMS (which you never had so far) and be surprised, it will be LOUD.
Just try it tomorrow before anything else, you can be testing in 30 minutes.
Post results
THAT'S RIGHT WHAT I'M THINKING ABOUT!!! If I modify it, I'll have to change all the back of the amp and actually inside of it is plenty of room for the Class d power amp, it's power supply and the second smaller transformer for the preamp."Headroom" for what, exactly? So you don't risk the amp clipping?
At that level, you can be sure the speakers will be distorting more than a bit
But since pretty much all you really need is everything-else-but-the-power-amp, what you could do would be to remove the big fat power transformer and the heatsinks (since those will be the main contributor to the weight), maybe sell those off to recoup some cash, install a smaller transformer just to power the preamp section (opamps etc), and get some class-D power amp, and you should be set.
Best of both worlds
Thanks for your reply, I have access to mostly all, but some parts I have to import them, but that's not a real problem at all, with time and patience I can achieve to modify it. "Doable" was the word that I wanted to read. To most gigs I just carry the head, at home I have a 2X15 peavey cabinet and I do not carry with me, that cabinet weighs a lot and is just used mainly for practice at home. Most of the backlines here provide the cabinets so I just put my head straight. Thanks I will have in mind your advice and I will research about that ICE modules, they look amazing.Was chiming in to sat about the same:
1) the way that particular head is built, you have 2 fully separate modules, not only electrically but mechanically, which is quite uncommon.
2) you can keep cabinet and front panel/preamp, momentarily discard power transformer and back power amp and power supply.
3) you will need to build a small and light +/-15V supply for the preamp.
4) you have now a large alnmost empty cabinet head
5) you will need to fabricate a new C shaped back panel out of 1.5mm (minimum) to 2mm aluminum to mount the Class D power amp and supply, speakon out, power cable and switch, etc.
A problem for most DIY hobbyists is not the *electronic* area, but the *mechanical* one: can you cut/bend/punch/drill aluminum sheet?
Plus not *indispensable* but "nice to have" finishing (painting/sandblasting/brushing/etc.)
6) you can buy an ICE Power module, which is very compact (and relatively "cold" , hence the "Ice" name he he) which includes an SMPS power supply, a big power amp and can supply some raw +/-25V to power "something else", you can easily regulate that down to +/-15V or whatever´s needed for the preamp.
I suggest one of these:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
from: ICEpower – Class D OEM audio amplifiers – Consumer & Professional Audio
7) you said but you NEED to be able to drive 4 ohms effortlessly since all 8x10" "fridges" are 4 ohms, except the kinky 115+410 one made for SVT400T which is 2 x 4 ohms (split) or 1 x 8 8hms (full).
8) I said because I suggest you build a compact 2 x 10" cabinet and mount them on the back, and keep it for backup, send some Bass to the drummer, or even play at small gigs driving it from a "Bass Preamp in a Pedal" or similar.
9) your current +/-52V supply amplifier is only 200W into 4 ohm, some 300 into 2 ohm (not too practical today) and only 140/150W into 8 ohms, that´s why you find it lacking when driving a single 8 ohm cabinet
10) so in a nutshell: your project is doable, but requires access to a metal working shop (or paying somebody to do it) and don´t forget you will spend some money.
Go straight to the ICE modules, which are used by Fender, G&K, Aguilar and most other "pro" brands, do not WASTE time with "EBay" Class D modules, you will waste time and money.
11) Plan B if you carry your cabinets with you, rewire one 8 ohm 4 x 10" cabinet (which has 4 x 8 ohm speakers inside, *any* brand and model except the Ampeg one which has 4 x Eminence BP102 **32 ohm** speakers in parallel) into 2 ohms, all 8 ohm speakers in parallel, and dedicate it only for the Peavey head.
You will get the full 300W RMS (which you never had so far) and be surprised, it will be LOUD.
Just try it tomorrow before anything else, you can be testing in 30 minutes.
Post results
Cool
As reference, here´s your exact same idea, but made, not by a DIYer but by ... Fender!!!!
This is the Fender Rumble 350.
Notice it is "a Fender preamp and cabinet, housing a Class D power amp and SMPS supply".
Fender can not even give you the amplifier or supply schematic !!!!!
They show it as a "black box" , just assigned it a Fender Part Number, so if it fails within the warranty time, they give you another for free; if outside, they sell you a replacement and 3 or 6 years later, you are on your own.
Notice connecting the ICE module is simplicity itself: 220/240V mains in, you select voltage with a jumper (exactly like in PC supplies) , Audio In, Speaker Out (in this case it is bridged), enable Mute (I´d just leave amp ON always) and it offers +/-24V supplies for preamps or whatever.
You can do exactly the same with your amplifier.
In theory ICE modules are OEM (for manufacturers only) but all the time there is people who buys, say, 10 or 20 (maybe that´s the minimum order the Factory will accept) and sell excess at EBay and similar places.
Parts Express who are speaker stuff suppliers was offering a couple ICE "backplates" , those you mount on a cutout at the back of speaker cabinets to make them active.
As reference, here´s your exact same idea, but made, not by a DIYer but by ... Fender!!!!
This is the Fender Rumble 350.
Notice it is "a Fender preamp and cabinet, housing a Class D power amp and SMPS supply".
Fender can not even give you the amplifier or supply schematic !!!!!
They show it as a "black box" , just assigned it a Fender Part Number, so if it fails within the warranty time, they give you another for free; if outside, they sell you a replacement and 3 or 6 years later, you are on your own.
Notice connecting the ICE module is simplicity itself: 220/240V mains in, you select voltage with a jumper (exactly like in PC supplies) , Audio In, Speaker Out (in this case it is bridged), enable Mute (I´d just leave amp ON always) and it offers +/-24V supplies for preamps or whatever.
You can do exactly the same with your amplifier.
In theory ICE modules are OEM (for manufacturers only) but all the time there is people who buys, say, 10 or 20 (maybe that´s the minimum order the Factory will accept) and sell excess at EBay and similar places.
Parts Express who are speaker stuff suppliers was offering a couple ICE "backplates" , those you mount on a cutout at the back of speaker cabinets to make them active.
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