I have been rereading the Burning Amp articles and came across this from Nelson in the BA-2 article,
"remember that Mosfets are better at higher current until they catch fire
and fulfill the promise of the amplifier's name"
Mine is now running at around 60C after a few hours. The mosfets are rated at 150C so I am not going to worry or install a fan. Even 65C does not scare me too much. It might shorten the life of the mosfets some but then at 67 years old one gets braver. I have read of brave diy'ers going up to 70C. The description of the sound by Nelson of both the BA-1 and BA-2 is very accurate to my ears. I own the F4 which is in effect close to the BA-2. The F4 appears to be somewhat better with bass but not by much. Probably influenced by the speakers I am using which do drop below 8 ohms in the bass region. Right now I have been using my LSK pre Nelson presented at the Burning Amp festival. I have a BA-3 pre also and I do have an extra BA-3 board I originally had intentions in installing inside this amplifier.
"remember that Mosfets are better at higher current until they catch fire
and fulfill the promise of the amplifier's name"
Mine is now running at around 60C after a few hours. The mosfets are rated at 150C so I am not going to worry or install a fan. Even 65C does not scare me too much. It might shorten the life of the mosfets some but then at 67 years old one gets braver. I have read of brave diy'ers going up to 70C. The description of the sound by Nelson of both the BA-1 and BA-2 is very accurate to my ears. I own the F4 which is in effect close to the BA-2. The F4 appears to be somewhat better with bass but not by much. Probably influenced by the speakers I am using which do drop below 8 ohms in the bass region. Right now I have been using my LSK pre Nelson presented at the Burning Amp festival. I have a BA-3 pre also and I do have an extra BA-3 board I originally had intentions in installing inside this amplifier.
Do you think you can hear any difference in the single ended BA-1 output stage and the F4 (push pull), that is down to this architecture and not due to differences in the number of output pairs or bias?
Seems like BA-1, if biased optimally and with the optimal number of pairs, might be preferred over the F4, assuming
a) one could buy the boards
b) one isn't too concerned about any difference in efficiency
cheers
Seems like BA-1, if biased optimally and with the optimal number of pairs, might be preferred over the F4, assuming
a) one could buy the boards
b) one isn't too concerned about any difference in efficiency
cheers
Nelson made this comment on the differences between the BA-1 and BA-2. The BA-2 using just one output board is considered close to a F4. This is from the BA-2 article
--------------------------------------------------------------------------------------.---
The Sound
The sonic signature of this sort of circuit is familiar to me after many years of playing with
variations on it. It's noted for a warm characteristic and a slightly soft top end. Both the BA-1
and BA-2 have a lineage that goes back to the A75 amplifier from 1992, and they sound a bit
like it.
The BA-1 is a little better sonically at low power levels, but is not as capable of being scaled
to higher power levels or driving low impedance loads. By contrast the BA-2 can be biased at
lower levels if necessary, and can drive low impedance loads without burping. The BA-2 is a
little bit softer at the top, and the BA-1 has a tad more detail at the top.
Both sound very good, and if you spend enough time with them, the warmth and soft top end
might tend to spoil you for other solid state pieces, so if you have a lot of money invested in
the L word, or the K word, or the H word, maybe it's best not to know
--------------------------------------------------------------------------------------.---
The Sound
The sonic signature of this sort of circuit is familiar to me after many years of playing with
variations on it. It's noted for a warm characteristic and a slightly soft top end. Both the BA-1
and BA-2 have a lineage that goes back to the A75 amplifier from 1992, and they sound a bit
like it.
The BA-1 is a little better sonically at low power levels, but is not as capable of being scaled
to higher power levels or driving low impedance loads. By contrast the BA-2 can be biased at
lower levels if necessary, and can drive low impedance loads without burping. The BA-2 is a
little bit softer at the top, and the BA-1 has a tad more detail at the top.
Both sound very good, and if you spend enough time with them, the warmth and soft top end
might tend to spoil you for other solid state pieces, so if you have a lot of money invested in
the L word, or the K word, or the H word, maybe it's best not to know
yeah, I've seen this. I wondered if one could hear it.
The F4 boards are available and its only worth chasing the BA1 SE architecture if you can note a difference.
To some extent I think my ears are not good enough /not educated enough, and certainly there is a lot of extravagant prose bandied around for different architectures, to which I don't necessarily subscribe just because I am cynical and until I have heard etc...
but you have both F4 and BA1 side by side so I figured you were in a better position than most to comment..
cheers
The F4 boards are available and its only worth chasing the BA1 SE architecture if you can note a difference.
To some extent I think my ears are not good enough /not educated enough, and certainly there is a lot of extravagant prose bandied around for different architectures, to which I don't necessarily subscribe just because I am cynical and until I have heard etc...
but you have both F4 and BA1 side by side so I figured you were in a better position than most to comment..
cheers
My first impression when first hearing the BA-1 was the F4 and it are very similar. Smooth, balanced very large sound stage. After some more hours I fell like the F4 bass is somewhat better but the BA-1 certainly has plenty of good solid bass. I have yet to do a direct A/B comparison though. I have been too busy enjoying my new build. The differences between the two amplifiers with my speakers is subtle.
Thanks RussellC - if you find any BA1 bards in your stash that would be a find.
I'm not in a hurry as I have to finish a PoddWatt and building some speakers so this is homework. F4 is probably the right direction for me, but I don't think I need a lot of power so the BA1 hold some curiosity...
cheers
I'm not in a hurry as I have to finish a PoddWatt and building some speakers so this is homework. F4 is probably the right direction for me, but I don't think I need a lot of power so the BA1 hold some curiosity...
cheers
I never got any BA1 boards, I was busy building F5 amps, which I have a number of different board versions of. I had plans for all sorts of F5 amps, turbo, (sold all those parts) non turbo, couple different store versions, some for muliple output pairs, cvillers, Peter Daniels, etc. Lost F5 interest when BA3 completed and sold a lot of boards and F5 stuff.
Russellc
I changed my mind and installed the BA-3 board inside this amplifier. Last night I used one of my LSK preamplifiers and to me it was more dynamic. I honestly like the sound better with all my FW clones with a preamplifier rather than a buffer. Probably just in my head. With a 1V computer output a preamplifier is not needed with my speakers. A buffer would be more than adequate. I believe I have improved the sound adding the BA-3 board.
I am totally surprised there is not more interest in members building this amplifier. I compared mine to one of my SE KT-88 amplifiers and even cold it was vastly better sounding with a better soundstage. Right now I have 7 complete up and running FW clones and this one ranks up in the top 2 or 3. #1 for a SE class A SS amplifier. I think it can only be beat with the SIT-1 or SIT-2 when it comes to single ended tube like sound. I can enjoy a SS PP amplifier, I consider the V-fet as the best one I own, but I still have a preference for the single end sound. My build is just one power board per channel where the complete BA-1 build requires a 2nd output diyaudio board. I can only imagine how much better it could sound. Maybe NP (I cannot call him Papa being the same age) can answer the question on what advantage a 2nd output board for each channel would add. I know the damping factor would be better but not sure if the difference would be audible.
I feel the same way about my BA3 complementary output amp. One of my favorites, and one of 6L6's as well.
Seems like there was more interest in the BA3 as a preamp. Quite a bit for the BBA3 as well, I have a box of boards, J fets and so forth if I decide to do a pair of BBA3 monoblocks. Lots of "project boxes" like that.....mostly finished Shunty Pumpkin, J2, F7, Vfet, soon to start M 25 Bablefish, BA2, as well as a couple more assembled M2 board sets....Oh, and since I decommissioned the F6 to build AlephJ, there is a F6 box to! never enough time.
Russellc
So as was suggested, and I have sentimental attachment to Burning Amp Stuff, I’m thinking of making the BA-1 since I already have various complementary F4 type amps. I have about 50 IRF 250’s andwhile I always misquote Nelson, I believe he said they are basically just a case with 2 IRF 240’s inside. Those huge heatsinks I have, have room for 16 TO-3’s per side. So that would be equivalent to 32 IRF240 MOSFETs per channel which seems excessive somehow.
Now if I skip every other mounting point that would be equal to 16 240’s per channel which seems about right! But what are the advantages of this many output devices? I would think I could bump up the PSU spec to 28volts for a bit more power, and maybe it would handle lower impedance speakers better, but what other advantages does so many have? And disadvantages? Did I once hear about gate capacitance or some such being a downside? All those classic Pass Labs amps are chock full of MOSFETS so......why?
And then there’s Nelson’s comments as posted earlier in the thread:
“The BA-1 is a little better sonically at low power levels, but is not as capable of being scaled
to higher power levels or driving low impedance loads”
So would more devices help scaling to greater power and more difficult loads?
Now if I skip every other mounting point that would be equal to 16 240’s per channel which seems about right! But what are the advantages of this many output devices? I would think I could bump up the PSU spec to 28volts for a bit more power, and maybe it would handle lower impedance speakers better, but what other advantages does so many have? And disadvantages? Did I once hear about gate capacitance or some such being a downside? All those classic Pass Labs amps are chock full of MOSFETS so......why?
And then there’s Nelson’s comments as posted earlier in the thread:
“The BA-1 is a little better sonically at low power levels, but is not as capable of being scaled
to higher power levels or driving low impedance loads”
So would more devices help scaling to greater power and more difficult loads?
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broad subject
speaking of BA amps, there is simple fact - complementary follower OS are more scalable, simply because you can bias them high as you can ( think heat) and increase rails ( again think heat) and they're still able to make KlunK! going high on power, if and when needed....... while BA style no-complementary OS is practically having half of stage working while other one being CCS load ........ so unable to make KlunK!, thus your output power being current-limited .......... not voltage limited as with complementary
think of difference between later X amps and Aleph X amps - same story
so - you're having Plethora of TO3 cans, most likely snatched from Singing Bush;
- you can make only non- complementary OS
-you need to use L or T bracket
for me some mechanical work is not big deal - getting L or T bracket is matter of few emails and maybe some pro-facture paper; marking positions and making holes/drills/taps is nothing else than nice Zen practice, allowing me to get lost in pleasure, instead of thinking of all things I must do , promised to do, and ppl expecting me to do
so , no biggie
if you're same irresponsible as I am, liking to do some tapping as I do, go for it
if not - just buy few stripes of complementary mosfets and you're shorter for L/T brackets, less drilling/less than half tapping, and World is your Oyster - embracing some KlunK!
speaking of BA amps, there is simple fact - complementary follower OS are more scalable, simply because you can bias them high as you can ( think heat) and increase rails ( again think heat) and they're still able to make KlunK! going high on power, if and when needed....... while BA style no-complementary OS is practically having half of stage working while other one being CCS load ........ so unable to make KlunK!, thus your output power being current-limited .......... not voltage limited as with complementary
think of difference between later X amps and Aleph X amps - same story
so - you're having Plethora of TO3 cans, most likely snatched from Singing Bush;
- you can make only non- complementary OS
-you need to use L or T bracket
for me some mechanical work is not big deal - getting L or T bracket is matter of few emails and maybe some pro-facture paper; marking positions and making holes/drills/taps is nothing else than nice Zen practice, allowing me to get lost in pleasure, instead of thinking of all things I must do , promised to do, and ppl expecting me to do
so , no biggie
if you're same irresponsible as I am, liking to do some tapping as I do, go for it
if not - just buy few stripes of complementary mosfets and you're shorter for L/T brackets, less drilling/less than half tapping, and World is your Oyster - embracing some KlunK!
Ah, so soon ZM forgets! Those huge black heatsinks I have are already drilled for metal cans!
And did I mention huge? So, more devices are less current limited? Any other advantages?
I already have various large chassis’ with complementary banks of transistors, so I thought a single ended approach might be a nice change.
And did I mention huge? So, more devices are less current limited? Any other advantages?
I already have various large chassis’ with complementary banks of transistors, so I thought a single ended approach might be a nice change.
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The ones in this link!
Welcome Secrets of Home Theater and High Fidelity
I have explained how I got the sinks at the first BAF, but the 250’s were similar. A big tray of them still sitting there after the show, when the trays of 240’s were long gone. I asked Nelson about the 250’s since I didn’t know what they were,and he laughed.”people didn’t know that they are just 2 240’s. So they didn’t take them!” Pays to ask!
Welcome Secrets of Home Theater and High Fidelity
I have explained how I got the sinks at the first BAF, but the 250’s were similar. A big tray of them still sitting there after the show, when the trays of 240’s were long gone. I asked Nelson about the 250’s since I didn’t know what they were,and he laughed.”people didn’t know that they are just 2 240’s. So they didn’t take them!” Pays to ask!
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