Hi Guy's I am an ex electronics tech and have not been doing that for 30 years but decided after having my plinius SA250 die (having it repaired) ....it was time to look at DIY again.
I like Class A and the simplicity of the circuits etc. The big question is what amp is the best to build. I have martin logan SL3's not an easy load but i don't play them super loud and prefer sound stage and presence over volume.
So given I use to build and design instruments in a science lab I know I can build anything no issue there just wanting advice and opinions on which amp of all these options will provide the best sound? I need Balanced input too as I run a balanced Theta Casablanca Preamp.
Thanks in Advance.
Rick
I like Class A and the simplicity of the circuits etc. The big question is what amp is the best to build. I have martin logan SL3's not an easy load but i don't play them super loud and prefer sound stage and presence over volume.
So given I use to build and design instruments in a science lab I know I can build anything no issue there just wanting advice and opinions on which amp of all these options will provide the best sound? I need Balanced input too as I run a balanced Theta Casablanca Preamp.
Thanks in Advance.
Rick
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Just finished building the Aleph J and I love it with my horns but into 4 ohms it will not put out a lot of power. From the spec's it only has 13 watts at 4 ohms and those speakers will require more than that if you want more than casual listening. Electrostatics as a rule need power to wake up.
Do you have any other suggestions i assume a F5Turbo might fit but it looks like it is singled ended not sure if it can be bridged and or run balanced?
Thanks Rick
A class A diy to drive those speakers is a tall order to fill. I am in the process right now building the Honey Badger. Single ended but it has the same type LTP front end so building it to be balanced should not be too hard. A/B amps run in class A to a certain point depending on bias. Many have biased the HB up to run in Class A longer so I would take a look there. Present the question on the HB build thread about how to run balanced. I am just not sure a Firstwatt clone is going to fill your bill being that most are 25 watts max.
rickdry, I would suggest to measure how many watts you will ever need at first. Wattage is very important when to choose Class A amp.
1. Playback music at your loudest volume you'll ever listen to music.
2. Play -12dB 1K sine wave (or something like that), and measure the voltage @ between amp and speaker.
3. You can predict how many watts you'll ever need. (if it's 2.5V RMS at -12dB, the answer should be 25 watt@4ohm).
dB dBu dBFS dBV to volts audio conversion digital - calculator volt to dBu and dBV dB mW SPL dB decibels 0 dBFS - convert dB volt normal decibels relatioship relation explanation analog audio absolute level true rms convertor converter decibel to dbf
1. Playback music at your loudest volume you'll ever listen to music.
2. Play -12dB 1K sine wave (or something like that), and measure the voltage @ between amp and speaker.
3. You can predict how many watts you'll ever need. (if it's 2.5V RMS at -12dB, the answer should be 25 watt@4ohm).
dB dBu dBFS dBV to volts audio conversion digital - calculator volt to dBu and dBV dB mW SPL dB decibels 0 dBFS - convert dB volt normal decibels relatioship relation explanation analog audio absolute level true rms convertor converter decibel to dbf
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The BA3 seems to not be a balanced schematic like BA1/2 is their a BBA3 Balanced schematic somewhere? This Burning amp looks more appropriate to me at least. I also have a 50 watt class a plinius and will see how that drives my sl3's as a simple first step. If that is satisfactory i will know 50 watts should be enough.
Thanks
Thanks
Thanks good info I am correct in assuming this sets up a mono block with - and + output to each driver channel? So for that arrangement one of these boards is needed and for stereo I would need two ... would not be fully balanced to speakers but would give two channels in single chassis. Assuming I am correct what do we do with negative signal left over from bba3?
Yes
Yes. You'll need two front end boards and at least 4 output stage boards for a set of balanced monoblocks.
No. It will be fully balanced. Each half of a single board for each phase. Very tiny change to the schematic to "tie R5" to go from a stereo board to a balanced single channel. Some people have come up with really neat switching mechanisms (from DIPs to toggles etc) allowing switching between stereo and balanced mono.
If you go the route of the BA-3, I don't think you'll be disappointed. The only downside is that there are sooooooo many options and possible configurations to play with... which is also the upside. OK, and essentially doubling the build cost
Have fun!
Clarification
Thanks for the help.
I think i would like to start out with a balanced stereo. So use two balanced BBA3 to drive each side in a stereo setup in a single chassis. Set it up for mono block switching as you suggested so i can add another unit later if i feel the need. When its monoblock one of the BBA3 boards would be idol i assume, however in stereo they operate one per channel and out -ve and -ve out to output driver boards.
So total of two BA3 and a 2 output driver boards one for each per channel for stereo setup.
One question is the -ve and +ve outup of the bba3 180 degrees out of phase going to the driver board as you would expect for balanced differential circuits?
thanks
Thanks for the help.
I think i would like to start out with a balanced stereo. So use two balanced BBA3 to drive each side in a stereo setup in a single chassis. Set it up for mono block switching as you suggested so i can add another unit later if i feel the need. When its monoblock one of the BBA3 boards would be idol i assume, however in stereo they operate one per channel and out -ve and -ve out to output driver boards.
So total of two BA3 and a 2 output driver boards one for each per channel for stereo setup.
One question is the -ve and +ve outup of the bba3 180 degrees out of phase going to the driver board as you would expect for balanced differential circuits?
thanks
Any time. I would never say never, but that would be a big chassis with some big heatsinks. I'm not experienced enough to discourage that path, but my early math showed that I couldn't fully get what I wanted even out of balanced monoblocks using 5U 400 heatsinks. Did you really mean balanced stereo in one chassis?
Wait... I'm confused now. Someone may need to chime in. If you build a balanced stereo set up in one chassis... you would not add another. If you build a SE stereo version, you can then easily (relatively) change it over to balanced monoblock and add another. If that's what you mean... cool. No part of the single board would be idle. If you're describing something different, someone else will most likely have to chime in.
If you're talking about balanced, add two more output / bias boards. You may be able to do it with only 2, but I would not know how.
I think what you may be describing, but I don't want to put words into your mouth is starting off with a non-balanced stereo amp, then (using switching or) converting that amp to a balanced monoblock; and then adding another monoblock. If so, that's the path I've chosen.
Not sure what you're asking, sorry. That may be a bit over my head. For balanced, one output board is for "positive", and the other is for the "negative" or inverted signal, I believe. Someone will surely chime in.
There is probably something i am missing here, if i want to go balanced then you need two output boards? One taking -ve other taking positive.
If i go single ended then i can run one output board per channel. But that means RCA in.
Id there a Balanced input option for stereo pair in the same case.
Is it possible to run the output boards direct from the preamp ?
If i go single ended then i can run one output board per channel. But that means RCA in.
Id there a Balanced input option for stereo pair in the same case.
Is it possible to run the output boards direct from the preamp ?
I'm pretty sure that 50W is more than sufficient for you. FirstAmp rating is accurate, and someone says 50W here, it's really 50W.
Is the burining amp the only 50Watt option?
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