Hi all, long time reader and I am considering my first amp build.
Here's my situation. I have an Adcom GFA-555 MKI that seems to be working great but it has never been modified, updated, or repaired. I use it exclusively for my two-channel listening; home theater being a separate system. Given that there is no speaker protection in this amp, I need to get it looked at or go a different direction.
I have been reading about Mr. Pass' Class A DIY amps and thought about building one if it would have enough juice to power my speakers.
Looking at all the options, the Amp Camp Amp seems really simple but I don't think it will work with my speakers, room, and listening habits. The F5 Turbo looks good power-wise but it seems to be a more complicated build. This brings me to the standard F5 at 25 watts.
My speakers are GoldenEar Triton Ones. Tower Speakers: Triton Towers Overview | GoldenEar Technology
They are 8-ohms with a sensitivity of 92db with a recommended power range of 20 - 650 watts. So, my main concern is wondering if 25 watts will be enough power. I do not listen at ear-splitting levels but like having plenty of power in reserve for peaks and good dynamic punch.
Given that the 25 watts will be going solely to the midrange and tweeter (it has a self-powered bass section) how will they do with an F5? I know that Sandy Gross from GoldenEar uses Pass Labs amps for demos but I bet they are much higher power versions. Does anyone have a similar setup? Thanks for your advice.
Here's my situation. I have an Adcom GFA-555 MKI that seems to be working great but it has never been modified, updated, or repaired. I use it exclusively for my two-channel listening; home theater being a separate system. Given that there is no speaker protection in this amp, I need to get it looked at or go a different direction.
I have been reading about Mr. Pass' Class A DIY amps and thought about building one if it would have enough juice to power my speakers.
Looking at all the options, the Amp Camp Amp seems really simple but I don't think it will work with my speakers, room, and listening habits. The F5 Turbo looks good power-wise but it seems to be a more complicated build. This brings me to the standard F5 at 25 watts.
My speakers are GoldenEar Triton Ones. Tower Speakers: Triton Towers Overview | GoldenEar Technology
They are 8-ohms with a sensitivity of 92db with a recommended power range of 20 - 650 watts. So, my main concern is wondering if 25 watts will be enough power. I do not listen at ear-splitting levels but like having plenty of power in reserve for peaks and good dynamic punch.
Given that the 25 watts will be going solely to the midrange and tweeter (it has a self-powered bass section) how will they do with an F5? I know that Sandy Gross from GoldenEar uses Pass Labs amps for demos but I bet they are much higher power versions. Does anyone have a similar setup? Thanks for your advice.
With 92 dB sensitivity for driving only the midrange and tweeters, you could even consider the mighty little ACA. It's very easy to build, very cost effective, and doesn't require exposing oneself to AC line voltages inside the chassis.
There are also a few of us who enjoy it so much that we've enhanced the simple design to put out just a little bit 'more'. It is the perfect gateway into diy Class A amplification.
There are also a few of us who enjoy it so much that we've enhanced the simple design to put out just a little bit 'more'. It is the perfect gateway into diy Class A amplification.
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The F6, M2, and F5 all have a listed rating of 25 watts into 8-ohms.
I'm sure the designs are different but I'm unsure of the real-world sonic or performance differences.
Here’s a great start to an answer Sound of various Pass amps
Check out the articles and manuals on FirstWatt.com
Also check out the articles on 6moons.com
Everyone plays music at different level, so I would recommend to measure the output voltage with current setup. This is what I do.
1. Playback pop music from a computer as loud as I want to.
2. Disconnect speakers and connect an appropriate resistor, then playback 0dB 100-1000Hz sine wave.
3. Measure output voltage of the amp.
5. Vrms*Speaker Impedance is the required max amplifier wattage.
If no computer, you can download 0dB test tone from internet, and burn CDR, or you can use your smartphone. I think you'll probably be surprised to find you only really need much lower wattage than what you are guessing.
1. Playback pop music from a computer as loud as I want to.
2. Disconnect speakers and connect an appropriate resistor, then playback 0dB 100-1000Hz sine wave.
3. Measure output voltage of the amp.
5. Vrms*Speaker Impedance is the required max amplifier wattage.
If no computer, you can download 0dB test tone from internet, and burn CDR, or you can use your smartphone. I think you'll probably be surprised to find you only really need much lower wattage than what you are guessing.
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F5 is very transparent, if your speaker tends towards the thin side, might not help as that will come straight through. I found F6 in same vein, really liked F5 better. I liked M2 better than both. Warm, organic with very nice imaging. Also consider Aleph J. In similar vein as M2, single ended, very nice.
For your high mid of 92 dB efficiency, consider Sissy Sit from Zenmod.
Russellc
For your high mid of 92 dB efficiency, consider Sissy Sit from Zenmod.
Russellc
Because your speakers have powered subwoofers, and the rest of them are quite efficient, there's really no wrong answer. You would be amazed with the little ACA, but a little bigger will get you into enough power to listen too loud when you want to turn it up.
25W of real Class-A is a fantastic and wonderful ear-opening experience, not just for the absolute superiority of the sonic qualities, but because Class-A watts absolutely feel 'bigger'. Dynamics, articulation, finesse, and overall musical qualities are all better in class-A. Aside from the inherent advantages of that much bias in the output devices, it has much to do with clipping behaviors and that the power supplies are insanely big compared to the power output.
Anyway, my standard list of amp suggestions, in order,
Aleph J, M2x, BA-3, F5
But more importantly, look around, and build the amp you find most interesting or intriguing first, since nobody builds just one....
25W of real Class-A is a fantastic and wonderful ear-opening experience, not just for the absolute superiority of the sonic qualities, but because Class-A watts absolutely feel 'bigger'. Dynamics, articulation, finesse, and overall musical qualities are all better in class-A. Aside from the inherent advantages of that much bias in the output devices, it has much to do with clipping behaviors and that the power supplies are insanely big compared to the power output.
Anyway, my standard list of amp suggestions, in order,
Aleph J, M2x, BA-3, F5
But more importantly, look around, and build the amp you find most interesting or intriguing first, since nobody builds just one....
6L6 and everyone, thank you for your responses. Looking at all the options can be a bit overwhelming when you cannot listen to any of the amp designs.
The Aleph J was the one, after the ACA, that caught my eye and will likely be the one to start but with there being so many amps with the same wattage specs, it's hard to know the differences and how they will sound.
Ideally, I am looking to buy a Pass Labs XA30.8 at some point. Will the Aleph J or another amp in the DIY store have a similar sound?
Also, the JFETS have been out of stock for quite some time. Where can I buy them? I keep reading about counterfeits and I have no way to tell which ones are legit. Thanks again.
The Aleph J was the one, after the ACA, that caught my eye and will likely be the one to start but with there being so many amps with the same wattage specs, it's hard to know the differences and how they will sound.
Ideally, I am looking to buy a Pass Labs XA30.8 at some point. Will the Aleph J or another amp in the DIY store have a similar sound?
Also, the JFETS have been out of stock for quite some time. Where can I buy them? I keep reading about counterfeits and I have no way to tell which ones are legit. Thanks again.
Maybe in some ways, but it is a different beast altogether. Here is a 6moons review that compared XA30.8 to F6 and One of the SIT amps, maybe it will answer a few questions.
6moons audioreviews: Pass Labs XA30.8
That said, you will enjoy Aleph J regardless.....
Russellc
6moons audioreviews: Pass Labs XA30.8
That said, you will enjoy Aleph J regardless.....
Russellc
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