One ON/OFF that triggers all the other equipment boxes is a lot handier than what I have.
It's a plan for some time in the future and I will base what I do on the ideas in ESP.
Two close coupled woofers each powered from their own amplifier will automatically give the listener an extra 3dB throughout the woofers passband. In addition where the close coupling allows there is upto 3dB available as extra SPL especially at the lowest frequencies. That gives the woofer volume an extra 6dB compared to the other drivers.
This is equivalent to using a woofer with a 400W amplifier at the lower frequencies. And you still power those woofer amplifiers from the same PSU as the Mid and Treble amplifiers.
If this potential SPL frightens you, then build the system with 70W, or even 50W amplifiers. Now you're into National chipamp territory with dual 25Vac transformers.
It's a plan for some time in the future and I will base what I do on the ideas in ESP.
Two close coupled woofers each powered from their own amplifier will automatically give the listener an extra 3dB throughout the woofers passband. In addition where the close coupling allows there is upto 3dB available as extra SPL especially at the lowest frequencies. That gives the woofer volume an extra 6dB compared to the other drivers.
This is equivalent to using a woofer with a 400W amplifier at the lower frequencies. And you still power those woofer amplifiers from the same PSU as the Mid and Treble amplifiers.
If this potential SPL frightens you, then build the system with 70W, or even 50W amplifiers. Now you're into National chipamp territory with dual 25Vac transformers.
Last edited:
My DIY speakers, as described in my signature, have an enclosure in the bottom, separate to the speaker box itself, which houses all four amps, crossover, PSU, and speaker protectors. I run a balanced line through a wall socket and each speaker is fed from their corresponding outlet (I don't have non-traffic areas either side).
Last edited:
But teeters and mids need only around half or three quarter of the power of the woofer. (this is my perception, I am not a big audio guru!) Then it will be a better idea to power the mid and tweeter using LM3886s and the woofer with P3A. Rod's P3A is a great sounding amp, have enough punch for a woofer.
Tweeters only need a couple of watts, but mids actually take some power, too. I might cross this mid as low as 200 Hz.
For the most part, I feel like the simplicity of one amp for all channels, one power supply, etc., is worth the power overkill.
After reading on here about the P3A, it seems a lot of people are "meh" about it and say it has brittle highs, etc. Contrast this with all the love for the P101 MOSFET amp... Don't think I've read a single negative opinion about it.
The "low power" version outputs 140w at 4 ohms, and requires similar heat sinks per channel as P3A. I might go that route instead, now.
Any thoughts on P101 all around for a three-way?
The "low power" version outputs 140w at 4 ohms, and requires similar heat sinks per channel as P3A. I might go that route instead, now.
Any thoughts on P101 all around for a three-way?
P101 is a really good amp. I have one in dual mono configuration.
P3A is also very good. however, P101 is a more robust due to the use of lateral MOSFETs.
I'm not too concerned about robustness; since the amp and speakers are being built as a bespoke set, I'm going to use Neutrik Speakon connectors to make them more easily plug-and-play, and to help protect tweeters from being hooked up to bass. Bonus of the Speakons is they can't be shorted.
Since you've used both amps, between P3A, and P101, which would you pick for this project? The main attraction to me for P3A is simplicity of construction, since two channels are on one board, which simplifies heatsink requirements a little. On the other hand, I suppose there's no reason I couldn't put two P101s on one heatsink, assuming the heatsink is sufficient for the combined thermal output of both boards, and it's dimensionally large enough.
I'm not too concerned about robustness; since the amp and speakers are being built as a bespoke set, I'm going to use Neutrik Speakon connectors to make them more easily plug-and-play, and to help protect tweeters from being hooked up to bass. Bonus of the Speakons is they can't be shorted.
Great, however depending on your experience building audio amplifiers sometimes mistakes could lead to the destruction of it. P101 is much more robust is this context compared to P3A.
I see! Yeah, I built some mic preamp kits years ago... My first board fried a resistor at power-up because I'd put a polarized capacitor in backward. Another board fried a resistor because NPN and PNP transistors were swapped (friend of mine did that, and in her defense, the markings were extremely smudgy and hard to read).
Point taken.
OK, so new plan. 8x P101, low-power version. Woofer amps will have four transistors each, but still be driven off the 42v PSU (for better thermals, better peak power, etc., as described by Rod). Per the ESP page, the heat sink should be "no smaller than 1C/W". So, what do you guys think about two boards on one 0.4C/W heatsink? Gives wiggle room, but is that enough wiggle room?
This was a very useful forum, although it’s been a year since anyone posted...
Soundman1402 did you build the amps?
I’ve been debating on building the P3A; it’s an interesting circuit and the all of the components are easily sourced. I’d consider building the P101 but I am having some trouble finding lateral MOSFETs. Does anyone know of any that are still in production?
Soundman1402 did you build the amps?
I’ve been debating on building the P3A; it’s an interesting circuit and the all of the components are easily sourced. I’d consider building the P101 but I am having some trouble finding lateral MOSFETs. Does anyone know of any that are still in production?
I bought the boards and parts for P101 but haven't started yet; life interfered. Haha!
Get your lateral MOSFETs here:
Lateral MOSFETs | Profusion
Get your lateral MOSFETs here:
Lateral MOSFETs | Profusion
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.