That looks pretty cool, but its still running as a common drain amplifier, right? My tube preamp doesn't have enough gain to drive a MoFo to anything past about 1.5w
. That's why I'm kinda trying to make a common source MoFo that has at least some voltage gain (and no feedback I suppose in this case).Also, are you using microwave oven transformers for the chokes? How much inductance do they have?
You need a high swinging preamp capable of 40Vpp with low distortion. Look no further than Aksa Lender or Yarra/Melbourne.
AKSA's Lender Preamp with 40Vpp Ouput GB
The YARRA Preamplifier/HPA for Melbourne DB Group Buy
And Btw, the amp sounds fantastic with the 10F/RS225 FAST speakers (which I think you know how they sound).
But then why don't you just make the ABBB - a 52w SE Class A amp with hybrid Aleph active CCS? The ABBB is a complete package with state of the art PSU with active bridge/CRC/Cap Mx and SSR DC protection all built in. Just connect a 400w 32v trafo per channel and speakers.
The Alpha Big Boy with Buttah (ABBB) 52w Class A Amp GB
AKSA's Lender Preamp with 40Vpp Ouput GB
The YARRA Preamplifier/HPA for Melbourne DB Group Buy
And Btw, the amp sounds fantastic with the 10F/RS225 FAST speakers (which I think you know how they sound).
But then why don't you just make the ABBB - a 52w SE Class A amp with hybrid Aleph active CCS? The ABBB is a complete package with state of the art PSU with active bridge/CRC/Cap Mx and SSR DC protection all built in. Just connect a 400w 32v trafo per channel and speakers.
The Alpha Big Boy with Buttah (ABBB) 52w Class A Amp GB
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I'm Back!
Ok, I finally got around to making a proper schematic of what I want to build. It's really just a combination of the De-Luxe De-Lite circuit with the L'Amp 193V power supply.
I remember reading that inductor loaded amps are trickier to bias than those with an active or resistor load. Can anyone shed some light on this? Would it require a scope to measure the output and its distortion?
Might be a neat thing to build, make a couple monoblocks on some nice pieces of wood. I just want to make sure that the circuit isn't so bad that I can't fix it if it doesn't work. I do want to try something riskier than my ACA though
Ok, I finally got around to making a proper schematic of what I want to build. It's really just a combination of the De-Luxe De-Lite circuit with the L'Amp 193V power supply.
I remember reading that inductor loaded amps are trickier to bias than those with an active or resistor load. Can anyone shed some light on this? Would it require a scope to measure the output and its distortion?
Might be a neat thing to build, make a couple monoblocks on some nice pieces of wood. I just want to make sure that the circuit isn't so bad that I can't fix it if it doesn't work. I do want to try something riskier than my ACA though
Hi reviving this, seems to be very interesting. I want to build a pure class A, single ended. Here are the requirements:
1. Drive my Magnepans 3.6 or 1.6. I have changed crossovers on both with Mondurf gold caps and seem a little more "sensitive".
2. I can suffer heat from FETs at about 300W, I will use liquid cooling.
3. Preamp will be Symphonic Line RG3+
4. I will use best capacitors in the market, so the less capacitors the better, so I am thinking last implementation from firstwatt. In general, I want to follow a very minimal approach, with excellent quality parts.
So questions,
1.how the schematic should be? Is it feasible?
2. Could this implementation compete/beat my Symphonic Line RG7 monoblocks? Or should I look some other implementation and maybe not Class A?
1. Drive my Magnepans 3.6 or 1.6. I have changed crossovers on both with Mondurf gold caps and seem a little more "sensitive".
2. I can suffer heat from FETs at about 300W, I will use liquid cooling.
3. Preamp will be Symphonic Line RG3+
4. I will use best capacitors in the market, so the less capacitors the better, so I am thinking last implementation from firstwatt. In general, I want to follow a very minimal approach, with excellent quality parts.
So questions,
1.how the schematic should be? Is it feasible?
2. Could this implementation compete/beat my Symphonic Line RG7 monoblocks? Or should I look some other implementation and maybe not Class A?
I'm currently building water cooling choke loaded 50W+ SE amp. On test bench, it works flawlessly. You have to get Sony SIT, or use something else there. Tokin is still available.
https://www.diyaudio.com/forums/pass-labs/357180-sit-50w-single-amp-beta-4.html#post6296943
https://www.diyaudio.com/forums/pass-labs/357180-sit-50w-single-amp-beta-4.html#post6296943
I read some part of the threads, they are huge in content....
I decided to go really pure, at least for start and see where I will go.
This is what I will do.
I ordered the FET from Germany.
For prototype I have all the rest except the transformer. i am going for 50V 800VA, I am ordering any time soon.
I will use Coolermaster liquid cooling.
I am excited. my first audiophile creation.
I am electrical engineer but my job has nothing to do with electronics, so it is what I remember from Polytechnical school (almost nothing), at least I understand what I read here but for sure I am far from creating stuff my own.
I won't do it fast, because I am really busy and I have to finish two other projects.
I am creating a home UPS, 1KW, 1 KWh, (expandable upto 85A48V) with 18650 batteries and true sine wave output. Maybe I use this to feed the amplifier.
I decided to go really pure, at least for start and see where I will go.
This is what I will do.
I ordered the FET from Germany.
For prototype I have all the rest except the transformer. i am going for 50V 800VA, I am ordering any time soon.
I will use Coolermaster liquid cooling.
I am excited
. my first audiophile creation. I am electrical engineer but my job has nothing to do with electronics, so it is what I remember from Polytechnical school (almost nothing), at least I understand what I read here but for sure I am far from creating stuff my own.
I won't do it fast, because I am really busy and I have to finish two other projects.
I am creating a home UPS, 1KW, 1 KWh, (expandable upto 85A48V) with 18650 batteries and true sine wave output. Maybe I use this to feed the amplifier.
Attachments
i believe about 300W. I also changed from coolermaster to corsair 360. Reading reviews seems more reliable.Reading reviews of overclocking the i7s i9s, they seem to produce more than 300W in 5 GHz+ range. Coolers manage to keep CPUs upto 75 degC which seems good for mosfets.
Now I am thinking power supply. It should be able to produce upto 100V but I should have it variable, so I I can experiment. I 've seen schematics but upto 50V. I ll search for something better.
One question. I have seen that audio PSUs are not stabilized. It should not be, or it doesn't matter?
Now I am thinking power supply. It should be able to produce upto 100V but I should have it variable, so I I can experiment. I 've seen schematics but upto 50V. I ll search for something better.
One question. I have seen that audio PSUs are not stabilized. It should not be, or it doesn't matter?
Yeah, I also have read several CPU cooler reviews, but I was not sure if those numbers are based on continuous or peak 300W dissipation... Well, please let us know your result.
I guess regulated PSUs are just too inefficient for class-A power amps. You can also consider stacked 48V SMPS, but check withstand voltage. SMPS is considered to be good for class-A amp because it has constant current draw. I have briefly compared SMPS with unregulated PSU in one of those simple class-A amps, and I find no difference in sound, while SMPS is measured quieter. PSU placement would be more important than PSU itself, especially SMPS. I put PSU in separate chassis these days.
I guess regulated PSUs are just too inefficient for class-A power amps. You can also consider stacked 48V SMPS, but check withstand voltage. SMPS is considered to be good for class-A amp because it has constant current draw. I have briefly compared SMPS with unregulated PSU in one of those simple class-A amps, and I find no difference in sound, while SMPS is measured quieter. PSU placement would be more important than PSU itself, especially SMPS. I put PSU in separate chassis these days.
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I have some of these available....
20200911_111106.jpg - Google Drive
These are 12V 300VA. I want to use them before the main parts arrive from China, so I can experiment
Questions:
1. can I use two of them in parallel to produce 24V?
2. How many uFs for capacitors in PS in CRC topology?
3. I understand that my road is to get one Hammond 193V. Till this arrives, could I use one of these toroidals? On the low voltage side?
4. I guess I need 14Ohm for R2. Is this resistance or impedance?
5. C3 what capacitance for 4ohm speaker load? And what type?
20200911_111106.jpg - Google Drive
These are 12V 300VA. I want to use them before the main parts arrive from China, so I can experiment
Questions:
1. can I use two of them in parallel to produce 24V?
2. How many uFs for capacitors in PS in CRC topology?
3. I understand that my road is to get one Hammond 193V. Till this arrives, could I use one of these toroidals? On the low voltage side?
4. I guess I need 14Ohm for R2. Is this resistance or impedance?
5. C3 what capacitance for 4ohm speaker load? And what type?
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1. can I use two of them in parallel to produce 24V?
Yes.
2. How many uFs for capacitors in PS in CRC topology?
I would recommend to see ripple performance with PSUD or LTSpice.
3. I understand that my road is to get one Hammond 193V. Till this arrives, could I use one of these toroidals? On the low voltage side?
Most probably not enough for flat 20Hz. You can certainly check 1K signal with them.
4. I guess I need 14Ohm for R2. Is this resistance or impedance?
14 ohm is resistance. Are you going to use choke or resistor?
5. C3 what capacitance for 4ohm speaker load? And what type?
I would recommend to check low frequency response with LTSpice.
Yes.
2. How many uFs for capacitors in PS in CRC topology?
I would recommend to see ripple performance with PSUD or LTSpice.
3. I understand that my road is to get one Hammond 193V. Till this arrives, could I use one of these toroidals? On the low voltage side?
Most probably not enough for flat 20Hz. You can certainly check 1K signal with them.
4. I guess I need 14Ohm for R2. Is this resistance or impedance?
14 ohm is resistance. Are you going to use choke or resistor?
5. C3 what capacitance for 4ohm speaker load? And what type?
I would recommend to check low frequency response with LTSpice.
in series!
(primaries in parallel, but secondaries in series; take care of secondaries phasing - wrong way is no AC, proper way is 24Vac)
@ZenMod, ok I have seen a schema of 2 transformers in parallel to double voltage, I wanted your valuable opinion . So I ll go for it.
@plasnu I have just installed LTSpice for the first time in my life. I worked a couple of hours, i need many hours to understand how it works. I know I have to do my homework guys, haven't work with electronic circuits from university. I have a lot of work in front of me but I would like to learn, kids have grown up now and I need to have back my music...
I have read the other threads and I understood that 193V is the best solution, although lamps are fun. So I believe i will go with 193V, unless this is damaging my purist sound concept. Note I have chosen the schematic without the input capacitor, i want to have the simplest path for my sound signal travel.
Of course this will be the 1st approach, we will see what happens and if we need to go two stage (if this design has no success).
Again for (5), what type of capacitor? It seems electrolytic but I guess I don't want an electrolytic there
. So I ll go for it. @plasnu I have just installed LTSpice for the first time in my life. I worked a couple of hours, i need many hours to understand how it works. I know I have to do my homework guys, haven't work with electronic circuits from university. I have a lot of work in front of me but I would like to learn, kids have grown up now and I need to have back my music...
I have read the other threads and I understood that 193V is the best solution, although lamps are fun. So I believe i will go with 193V, unless this is damaging my purist sound concept. Note I have chosen the schematic without the input capacitor, i want to have the simplest path for my sound signal travel.
Of course this will be the 1st approach, we will see what happens and if we need to go two stage (if this design has no success).
Again for (5), what type of capacitor? It seems electrolytic but I guess I don't want an electrolytic there
I started leaning LTSpice with Michael Rothacher's Youtube video. Also, his blog has concise articles to understand the concept of zen style amp. Both highly recommended.
If you planning to pursue choke loaded amp in the future, get as large as possible choke. Better low frequency response, and I'm not really sure if you can get enough power with 3A limit of 193V.
Nelson Pass uses electrolytic + small bypass film for SIT-1 amp and F8(?), and the most of the other people do the same. I understand you do not want to see electrolytic there, but there is no other practical choice, I suppose.
If you planning to pursue choke loaded amp in the future, get as large as possible choke. Better low frequency response, and I'm not really sure if you can get enough power with 3A limit of 193V.
Nelson Pass uses electrolytic + small bypass film for SIT-1 amp and F8(?), and the most of the other people do the same. I understand you do not want to see electrolytic there, but there is no other practical choice, I suppose.
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