Just thought I would show my little trannies 
I have a pair and they are rated at 2x 38Vac, 2kw, UI-core...almost about the size of a shoebox
They were made fore a balanced 500-1000w classA, watercooling and computer controlled
Intended fore high quality studio/PA
I think they used 4 of those trafos
They are quite old by now, and I have also had them fore a while
I really dont need them now, but cant get myself to sell them either, I think I would miss them
Maybe I will build a couple of AB mono wooferamps I have my eye on Holton, but its a bit expencive
Would surely be easier with an SMPS, but not sure how reliable that is and it surely wont last forever, and I dont like the noice risk
I have a pair and they are rated at 2x 38Vac, 2kw, UI-core...almost about the size of a shoebox
They were made fore a balanced 500-1000w classA, watercooling and computer controlled
Intended fore high quality studio/PA
I think they used 4 of those trafos
They are quite old by now, and I have also had them fore a while
I really dont need them now, but cant get myself to sell them either, I think I would miss them
Maybe I will build a couple of AB mono wooferamps
I have my eye on Holton, but its a bit expenciveWould surely be easier with an SMPS, but not sure how reliable that is and it surely wont last forever, and I dont like the noice risk
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G.Kleinschmidt said:
Oh I get it now. this whole thread is supposed to be a joke.
You don't know where "the B went off too". I guess you've already forgotten the title you gave this thread: "Building a monster......Class A"
No joke here ..
I'm serious, but as a new member here seeing that there a lot of knowledgeable minds here!
I always believed in Over building things to have the extra grunt if EVER needed.... for example .. what whats the point of any of the big 3 to produce engines in excess of 250HP ??? its not like you can use it in the city when the speed limits are 50km/h !! anyways back on topic...
Besides having all these ideas flung around and making valid points will all really gonna go on paper and be revised for usability and practicality. The way i look at is is to have all the options depleted before the build, and having the actual input and the knowledge of some of the great minds here on DIYAudio is sometimes not even what a team of engineers can do because they are always in the search for more and more complicated ways of doing it.
I always said "give something simple to an engineer and see how it becomes a nightmare!"
Adrculda said:
That analogy isn't very good and a 6kVA transformer still doesn't make a lot of sense.
Besides that a 550W/8 ohm amplifier for PA is a relatively straightforward affair.
To keep it simple build a bridged amp with MJL21193/MJL21194. An off-the-self 1kVA toroid (with dual 45V secondary windings) for each channel would be ample.
Cheers,
Glen
Adrculda said:
Just use two 45-0-45's 1kVAs (in series or parallel) and you're good to go. You'll have the option for bridged mode, S-Leach, class G, or class H. And it will still be 40% more toroid than used in an RMX5050 and the same as a MA5000VZ.
Even at extremely high load, the DC won't get below the original AC RMS secondary voltage - assume you lose that factor of 1.4. That's how I figure output for back-of-the envelope calculations. At infinite load, where it acts like a choke input filter, the DC value will drop to 90% of the AC RMS secondary value. You usually do better than that even at 5x overload to the VA rating.
Adrculda said:
Yeah - they like to size the current limits on those SMPSs for the average draw for 1/8 power pink noise. Otherwise, you'd blow those little ETD cores and the IGBTs that drive them to kingdom come. And "full sized" ones would have impossible parasitics. Heavy iron can go ahead and put out more for a few minutes and not really notice as long as the average over say, a 15 minute period is within rating.
In any case, you must build an amplifier which has been tried in real life conditions, and not this ESP which you had selected in the beginning because this is a project (as noted by R.Eliot) only in the paper.
Here, there are many guys with a lot of skill building big power AB class amps which are tested in real life. Get a tried plan from these, proceed to build, and during you will have all the help that you will need for completing with success your amp.
From my view, all people here in your thread, are real "CATS" in such type works. Cat we call in Greece a man with big ability (like a cat of course). We say for a good craftsman: this guy is a big cat.
Regs
Fotios
Here, there are many guys with a lot of skill building big power AB class amps which are tested in real life. Get a tried plan from these, proceed to build, and during you will have all the help that you will need for completing with success your amp.
From my view, all people here in your thread, are real "CATS" in such type works. Cat we call in Greece a man with big ability (like a cat of course). We say for a good craftsman: this guy is a big cat.
Regs
Fotios
OK...
im going to deal with the power supply for now untill i figgure out whats going on.
SO....
I been trying to figure out to make a more suitable Soft Start circuit for all transformers 1KVA and larger to deal with the large inrush current based on a Current Transformer and a simple OP-amp circuit to switch the relay over to NORMAL when the start-up current has reached IDLE mode. This can be easily achieved by either by sensing voltage from the supply itself to keep in NORMAL once voltage above the set point, or with the
this would be a great feature for those with dual voltage primaries, allowing start up on the higher voltage primary cutting start up current significantly, once preset voltage has been achieved relay will switch over to the appropriate voltage.
This would eliminate the Need of large power switches as this would be done with a simple low amperage power switch and a Relay.
If desired we could even isolate the power supply completely with readily available 30A relays ( maybe only a hand full of individuals might be pulling more current than that )
Also ...
on a side note ...
What software are you guys using for your schematic and board layouts. I'm currently using ExpressPCB's Software and is quite limited
im going to deal with the power supply for now untill i figgure out whats going on.
SO....
I been trying to figure out to make a more suitable Soft Start circuit for all transformers 1KVA and larger to deal with the large inrush current based on a Current Transformer and a simple OP-amp circuit to switch the relay over to NORMAL when the start-up current has reached IDLE mode. This can be easily achieved by either by sensing voltage from the supply itself to keep in NORMAL once voltage above the set point, or with the
this would be a great feature for those with dual voltage primaries, allowing start up on the higher voltage primary cutting start up current significantly, once preset voltage has been achieved relay will switch over to the appropriate voltage.
This would eliminate the Need of large power switches as this would be done with a simple low amperage power switch and a Relay.
If desired we could even isolate the power supply completely with readily available 30A relays ( maybe only a hand full of individuals might be pulling more current than that )
Also ...
on a side note ...
What software are you guys using for your schematic and board layouts. I'm currently using ExpressPCB's Software and is quite limited
ok,
ur new, right?
...time to get off your post, your thread and spend the next 10-20 man-hours doing nothing but searching and reading in this Solid State section on topics that you need or want to know about...
You're going to need to know a whole lot more before you start to buy or gather up parts... forget about buying from Wakefield.
In practice you can "blow" any reasonable heatsink extrusion - IF you needed to. So you'd better figure out more about what you want to do, what you really want to build, and then do some paper to pencil to determine what you actually NEED.
You're thrashin' dude!
Let's recall that your originial post called for driving very low Z loads at some very high power levels - that's not merely a ~500w/8ohm amp. But if ur ok with AB, then the world is now opened up. (Putting a lot of OPTs on any given circuit isn't that much of a big deal.)
Anyhow, you need to read more here - some of what gets posted is like a graduate course in analog design, and some of it you can merely take in and just look at the resulting designs...
AGAIN, you are better off right now (other than bragging rights) buying some commercial amps for THIS application - even repairing some flammed out ones if you want a challenge - than building a brute of your own.
As I said before it is a better idea to put your time and money into building custom amps for the HIGH FREQUENCY part of your system - although it may not be as "sexy" in your mind - because that is what determines the sonic quality of what you and the audience hears more than anything else. The bass is easy, the highs are hard (usually literally).
Think more, read much more.
_-_-bear
PS. nothing wrong with building ur own amps - but it's a good idea to start with something that builds experience & knowledge first, and not spend a ton of $$ until ur sure it is worth spending... (unless ur blessed with "stupid money", in which case email me...)
ur new, right?
...time to get off your post, your thread and spend the next 10-20 man-hours doing nothing but searching and reading in this Solid State section on topics that you need or want to know about...
You're going to need to know a whole lot more before you start to buy or gather up parts... forget about buying from Wakefield.
In practice you can "blow" any reasonable heatsink extrusion - IF you needed to. So you'd better figure out more about what you want to do, what you really want to build, and then do some paper to pencil to determine what you actually NEED.
You're thrashin' dude!
Let's recall that your originial post called for driving very low Z loads at some very high power levels - that's not merely a ~500w/8ohm amp. But if ur ok with AB, then the world is now opened up. (Putting a lot of OPTs on any given circuit isn't that much of a big deal.)
Anyhow, you need to read more here - some of what gets posted is like a graduate course in analog design, and some of it you can merely take in and just look at the resulting designs...
AGAIN, you are better off right now (other than bragging rights) buying some commercial amps for THIS application - even repairing some flammed out ones if you want a challenge - than building a brute of your own.
As I said before it is a better idea to put your time and money into building custom amps for the HIGH FREQUENCY part of your system - although it may not be as "sexy" in your mind - because that is what determines the sonic quality of what you and the audience hears more than anything else. The bass is easy, the highs are hard (usually literally).
Think more, read much more.
_-_-bear
PS. nothing wrong with building ur own amps - but it's a good idea to start with something that builds experience & knowledge first, and not spend a ton of $$ until ur sure it is worth spending... (unless ur blessed with "stupid money", in which case email me...)
wg_ski said:
I'm still thinking about it, its not lost...
im just thinking about 2 things right now:
1. im the middle of changing some of my stuff since some of my equipment was way too larger for smaller gigs like house parties and such.
Long Story short the giy came and picked up my old equipment up and now im looking at new stuff a bit more "house" friendly rather than 2" Horns for HF, 4 12" horn loaded for Mids and 8 x 18's in folded horns for the low end !
As you can see that's not a neighbour friendly setup.
My new toys are 4 pairs of Cervin Vega CLS-215 that will be replacing my high and mids
The reason why im reconsidering is that id like to somehow sneak in a 4 Ch set up for bi-amping.
And that giant is still in my mind, but put in on hold.. for now
For a house party, a pair of 2x18 conventional reflex subs and either four small or two large tops is all that's required. A pair of PLX/RMX amps run 4 ohms per channel (no bridge) will do.
But that's no excuse to go and get rid of a big system capable of doing football fields or parking lots. When you need it, there's no substitute. Mine sits in the garage most of they year, only coming out to play a couple times a year. 8 labhorns, 8 12" folded midbass bins, and 6 2x8+2" horn loaded tops. The amps are slowly being upgraded a few at a time.
But that's no excuse to go and get rid of a big system capable of doing football fields or parking lots. When you need it, there's no substitute. Mine sits in the garage most of they year, only coming out to play a couple times a year. 8 labhorns, 8 12" folded midbass bins, and 6 2x8+2" horn loaded tops. The amps are slowly being upgraded
a few at a time.the reason why i sold them is i have 10x more small gigs than i had the big stuff to deal with.
and also i got a smoking offer for them so i took it and run
i heard the CLS215 and they are not to be underestimated
they might not be in the low end in large halls but when adding in the 18's thing will "bump"
Also my house "dragon" might be a little bit more please with the astetics compared to my bins, as she put it "looks like a bunch of wood chippers" in the living room.
Also my dog latelly mad a habit of hiding his toys in there and along with my daughter trying to crawl in.
and also i got a smoking offer for them so i took it and run
i heard the CLS215 and they are not to be underestimated
they might not be in the low end in large halls but when adding in the 18's thing will "bump"
Also my house "dragon" might be a little bit more please with the astetics compared to my bins, as she put it "looks like a bunch of wood chippers" in the living room.
Also my dog latelly mad a habit of hiding his toys in there and along with my daughter trying to crawl in.
Adrculda said:
These Cerwin-Vega speakers are very nice... I have sold 25 to 30 pairs (early models) equiped with 15" woofers in small clubs... this type loudspeakers belongs in a seperate category, the semi-proffesional because the suspension of woofers it is made from hard foam. Thus they can produce a most tight bass compared to other domestic speakers as well higher SPL.
I remember what said Cerwin-Vega for these loudspeakers:
"What a nice way to meet the neighbours!"
Fotios
fotios said:
These Cerwin-Vega speakers are very nice... I have sold 25 to 30 pairs (early models) equiped with 15" woofers in small clubs... this type loudspeakers belongs in a seperate category, the semi-proffesional because the suspension of woofers it is made from hard foam. Thus they can produce a most tight bass compared to other domestic speakers as well higher SPL.
I remember what said Cerwin-Vega for these loudspeakers:
"What a nice way to meet the neighbours!"
Fotios
sure is
Ohh well...
4 pairs in my living room will be fine by me...
Just need to work on this amp and see how it handles them.
If it give it thumbs up 3 more will be built, also have plenty of "control" equipment, including a nice crossover, A/D-D/A Converter, effects processor and a nice EQ ....
I picked all that up through a buddy of mine that knew this person that was "upgrading" his equipment so he wanted to get rid of it.
Works for me !!!
now i need to focus on those amps...
PS:I use the A/D-D/A Converter to input signal into the system without breaking the balanced loop i'm running
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