Guys, I would like to build a tube amp and have being looking at the circuit for the Kit 1 300B by Audio Note, I have also seen that this amps PCB is available from ebay. All other info regarding parts and construction is readily available from AN. Looks to be well reviewed but I know nothing of Valve amps. I have a really small budget and will need to gradually build this and it will prob take me a year.
I am modifying a Yaquin Ms23b to the Lesbox soon and that will be my very first experience with Valve amplification. I have very little knowledge of electronics, only a basic understanding and need pictures and set instruction to be successful, but I have been playing with basic electronics since I was a kid.
There is one thing I cannot grasp.
How is it possible to have such massive transformers on an amp, have it weigh 15 kg and still only put out 8 watts, I just don't get it. How is it possible to get the basic 80-100 watt floor speaker even to drive at 8 watts, my ghettoblaster in the 80's was 15 watts. What am I missing, how can you spend 2500$ on a Kit that only drives 8 watt per channel. Can someone please explain in basic terms and principle?
I am modifying a Yaquin Ms23b to the Lesbox soon and that will be my very first experience with Valve amplification. I have very little knowledge of electronics, only a basic understanding and need pictures and set instruction to be successful, but I have been playing with basic electronics since I was a kid.
There is one thing I cannot grasp.
How is it possible to have such massive transformers on an amp, have it weigh 15 kg and still only put out 8 watts, I just don't get it. How is it possible to get the basic 80-100 watt floor speaker even to drive at 8 watts, my ghettoblaster in the 80's was 15 watts. What am I missing, how can you spend 2500$ on a Kit that only drives 8 watt per channel. Can someone please explain in basic terms and principle?
I build 0.1W to 2W amps and have 86dB/W sensitivity speakers, and quite a bit of hearing loss from my band days.
I can't sit 1 meter away from my speakers if I play them full volume, it's too loud. Neighbours will complain if I keep it up more than a brief test.
You have some serious misconceptions about power, I'm assuming.
SS amps need a massive power reserve, because they completely trip on their feet and have to spend some time getting up if they clip.
Normal loud listening level is mostly something like 0.1W or so, with 10W transients, occasionally more.
Tube amps CAN be designed to have practically instant transient clipping recovery. While most are not that way, at least they clip much more gracefully than SS amps.
My response would be: you can, but you shouldn't.
I can't sit 1 meter away from my speakers if I play them full volume, it's too loud. Neighbours will complain if I keep it up more than a brief test.
You have some serious misconceptions about power, I'm assuming.
SS amps need a massive power reserve, because they completely trip on their feet and have to spend some time getting up if they clip.
Normal loud listening level is mostly something like 0.1W or so, with 10W transients, occasionally more.
Tube amps CAN be designed to have practically instant transient clipping recovery. While most are not that way, at least they clip much more gracefully than SS amps.
My response would be: you can, but you shouldn't.
I think tubes have got mixed up with some crazy fashion, perhaps they are now made by Peruvian virgins, they have always been oxygen free!! I used to design and build tube PA's a long time ago, I can assure you they can push the power alright, for example a quad 807 output on 800V gets you nearly 400Wrms and quad EL34's on about 550V gets about 200Wrms. 15Kgs sounds a bit far fetched for 8W, are you sure your scales are not crazy ? A modern 1500W trafo weighs about 10Kgs!!
OK maybe I do have serious misconceptions regarding power output. My current amp is Pioneer ax4asi tranny and I think is rated to 120Watt, my speakers are rated to 110watt at 96db, maybe I listen to music very loud then, a good volume for me is 50% on my amp and I can feel the woofer drivers starting to kick and the sub giving some decent rumble down the low end. I like to feel my music but with clarity, yet still have all the air in the world and location with every slide od a finger and pluck of a string on a mandolin definitively present, for this sort of listening I am down to 40% volume acoustic music oriented, my rock I like to feel the kick though, will an 8 watt amp do this for me?
Kit I 300B specs for weight and such are here, and yep its not pounds.
Specifications:
Power: 8 Watts Class A
Output Tubes: 2 x 300B
1st Stage Gain: 6SN7
Rectifier Tube: 5U4GB
Front Insert Plate:: Solid Copper
Inputs: 1 (option of 3)
Option of Elma 3 input selector at $75
Outputs: 1 x Stereo Pair 4, 8, 16 ohms
Recommended Speakers: min 88dB
Width: 53 cm
Height: 20 cm
Depth: 45 cm
Weight: 18 Kilos
Chassis: 3mm Aluminum with Black Powder Coat
Specifications:
Power: 8 Watts Class A
Output Tubes: 2 x 300B
1st Stage Gain: 6SN7
Rectifier Tube: 5U4GB
Front Insert Plate:: Solid Copper
Inputs: 1 (option of 3)
Option of Elma 3 input selector at $75
Outputs: 1 x Stereo Pair 4, 8, 16 ohms
Recommended Speakers: min 88dB
Width: 53 cm
Height: 20 cm
Depth: 45 cm
Weight: 18 Kilos
Chassis: 3mm Aluminum with Black Powder Coat
Tubes and output transformers are very expensive. Tubes also cost more then most high power output transistors. Single ended tube amps need a very clean power supply. That means there are chokes and capacitors in them. That weight can add up quick.
But MrCurwen is right, most people has misconception about what power is needed per given volume. If you want to fill a stadium with 90 db Of sound you'll need many kilowatts. But to do the same in a average room through 90 db per watt meter speakers would probably take a watt or maybe a little less.
I've gone the crazy power route. I ran my 100 db per watt meter bass horns with a 1000 watt amplifier. I was just goofing around. It was insane. I was producing SPL of 120 db 3 meters away from the speakers. And the amp wasn't even clipping.
I'm very happy running the same bass horns with a triode wired push pull el34 amp.
So 9 times out of 10 most people with reasonably efficient speakers would be happy with around 20 watts. That gives you a bit of head room to crank it up when you've had a few beers too
Nick
But MrCurwen is right, most people has misconception about what power is needed per given volume. If you want to fill a stadium with 90 db Of sound you'll need many kilowatts. But to do the same in a average room through 90 db per watt meter speakers would probably take a watt or maybe a little less.
I've gone the crazy power route. I ran my 100 db per watt meter bass horns with a 1000 watt amplifier. I was just goofing around. It was insane. I was producing SPL of 120 db 3 meters away from the speakers. And the amp wasn't even clipping.
I'm very happy running the same bass horns with a triode wired push pull el34 amp.
So 9 times out of 10 most people with reasonably efficient speakers would be happy with around 20 watts. That gives you a bit of head room to crank it up when you've had a few beers too
Nick
That kind of design was the peak of Hi Fi and Audio Technology ... in the 30's , some 80 years ago.
You can't, modern speakers are usually in the 85 something dB efficiency.
Those old amps NEEDED a very high efficiency speaker like the Klipschorn, some 105 dB/W efficiency, 100 times more, so 8W into them is like 800W into a modern one
... no kidding :
An externally hosted image should be here but it was not working when we last tested it.
to boot, they used the room corners as part of the horns (by design) so you were actually sitting *inside* the speaker cabinet . Gut wrenching.
Remember those guys listened to Symphonic Music, which has huge dynamic range and can achieve very high SPL peaks.
Low efficiency bookshelf speakers (Acoustic Research) appeared when power became cheap and plentiful.
Well, there's people who drives a 30's Rolls Royce which any cheap Toyota or Honda can beat with both hands tied to their backs
Amish still ride their horse powered buggies
A 1W amp will do that for you, provided it has first class transient capability.
The kick is not about power, it is about transient capability. Increasing output power is the brute force way of getting that; it's not the only way.
Based just on the specs of the kit, you will not get what you want from it. The kit is for a traditional sounding amp, 1930's sound. It will have nice qualities, but 'speed', 'kick' and dynamic range will definitely not be among those.
While designing amps and testing them, for me the mark of a good design is when you feel that "high power kick" when playing music at a very low volume (even if the amp can do bigger volume).
Hi,
If you want a 8W per channel SE amplifier take a look at :
Easy-to-build SE amplifier ⋆ Lundahl Transformers
rgds, sreten.
If you want a 8W per channel SE amplifier take a look at :
Easy-to-build SE amplifier ⋆ Lundahl Transformers
rgds, sreten.
It might make do as an integrated, just give it a volume pot and an input selector before the input tube. For some low output devices such as phones and computer sound card outputs it might not have enough gain. One of my sound cards provides something like 400mVpp full scale output, and that's not nearly enough, since the thing has an input sensitivity of 2V (not specified if Vpp or Vrms, though).
One thing about it though... That Byrith paper is well worth a read and a really good example of documenting ones ideas (how's and why's) for a design. I'd really have to stretch to come up with something as thorough.
Ok, it's just been my exp wit tranny amps that basically the more power you have available the better the ability to drive your speakers without overworking your amp and running out of headroom, this has also resulted in the kick I was speaking of. The audio note was only of interest as the pcb is available separately and component makeup is decided by the individual if you go that path. If anyone has any suggestions where I can find a suitable amp in stereo format not in mono blocks and if 40 to 60 watts will be more than sufficient for my needs, I can't afford a kit so o need a more modern performer for my needs. I am not inclined to go eBay although there's plenty of Yaqin on there that will fit my budget but the mods might overcapitalise the build and component replacement may also not warrant purchase. Is there a good resource for amp builds? For us diy ers obviously this site but I am talking step by step for a novice, I don't mind if transformers or valves or caps etc are expensive as it is a progression project but I don't want to spend the time building for a year at some cost and not be happy with the end result.
If your music doesn't sound distorted, you are certainly not using more than a small fraction of the amp power on average,
especially on acoustic music. Of course, you need more than that to handle the peaks without clipping.
The last amp that I built was a 6v6pp with the output tubes in triode mode. I can get about 7 watts max power out of it into a pair of B&W dm330i speakers, which are 90db spl, I decided to really test this out after my wife left the house to run errands.
I put on a pair of ear muff type hearing protectors and started turning the volume up. I couldn't get to full volume without the noise level becoming very uncomfortable. I might have been able to go to 100 percent had I also used foam ear plugs along with the muffs, but as it was I just turned it back down and called it a day.
You will be surprised at just how little power you actually need if you have a fairly decent pair of speakers. Like I said, mine are only rated at 90db spl, not even close to what the old horn speakers would be rated at but I have absolutely no issue with volume level. My musical choices range from classic jazz to pink floyd, so yeah I do get into music that would be listened to at higher volume levels. I've never had a problem with this amp.
If you do decide to build a tube amp you won't be disappointed. One thing that you will discover is that you can alter the sound of your amp by changing the manufacturer of the output tubes or the driver tubes. You can alter the sound by the types of caps that you use for coupling the driver to the output stage. It's a tweakers dream. You can't exactly do that with a solid state amp.
Just something to think about.......
I put on a pair of ear muff type hearing protectors and started turning the volume up. I couldn't get to full volume without the noise level becoming very uncomfortable. I might have been able to go to 100 percent had I also used foam ear plugs along with the muffs, but as it was I just turned it back down and called it a day.
You will be surprised at just how little power you actually need if you have a fairly decent pair of speakers. Like I said, mine are only rated at 90db spl, not even close to what the old horn speakers would be rated at but I have absolutely no issue with volume level. My musical choices range from classic jazz to pink floyd, so yeah I do get into music that would be listened to at higher volume levels. I've never had a problem with this amp.
If you do decide to build a tube amp you won't be disappointed. One thing that you will discover is that you can alter the sound of your amp by changing the manufacturer of the output tubes or the driver tubes. You can alter the sound by the types of caps that you use for coupling the driver to the output stage. It's a tweakers dream. You can't exactly do that with a solid state amp.
Just something to think about.......
If you can deal with their 4-5 week delivery schedule.
Edcor Transformers (made in Carlsbad, NM) are pretty good bang-for-your-buck!
Using less popular (and much less expensive) NOS tubes, can save you significant $$$$!
A 6AV6 tube is HALF of a 12AX7, but will cost peanuts compared to a NOS 12AX7 tube.
A 5V6GT tube is identical to a 6V6GT tube.....except.....for it's 5V filament requirement, which can be dealt with with either a dropping resistor or dropping diodes.
Steve
Edcor Transformers (made in Carlsbad, NM) are pretty good bang-for-your-buck!
Using less popular (and much less expensive) NOS tubes, can save you significant $$$$!
A 6AV6 tube is HALF of a 12AX7, but will cost peanuts compared to a NOS 12AX7 tube.
A 5V6GT tube is identical to a 6V6GT tube.....except.....for it's 5V filament requirement, which can be dealt with with either a dropping resistor or dropping diodes.
Steve
The explanation is really quite simple. This is a single ended design. Therefore, it must operate in Class A, as that's the only way to reproduce the entire audio cycles. Given that it's SE, all the bias current flows through the primary of the OPT, and that causes quite a bit of DC magnetization, which requires a greater core X-section to avoid core saturation. Therefore, a larger, heavier OPT.
Pure audiophoolery, that's how. These commercial designs are rated in Whats, nor Watts. Each manufacturer has some very strange "ratings" that inflate the power rating over and above the only criterion that makes sense: average power:
P= VI
Where voltage and current are RMS values. Just because the manufacturer says it's a "100W" amp, doesn't mean that it'll ever come close to pumping 100W into an 8R test resistor. It won't get there before severe clipping, and/or something poofs if you try it.
"What am I missing, how can you spend 2500$ on a Kit that only drives 8 watt per channel"
It's a SE design, and that means highly inefficient, and low power. Class A, SE has a nominal efficiency of 25%. $2500 on a PP design will get you the bigwatts. PP OPTs don't have that DC-mag problem, and are smaller, cheaper, and easier to design. Get away from the usual audiophool expensive power finals, and you can get that cost way down. There are just esssss-loads of RF finals and TV horizontal and vertical deflection power finals that aren't expensive, and can really put out some bigwatts, certainly well within the neighborhood of 80 -- 100W. One of the nicest things about these TV tubes is that a lot of them come with odd heater voltages, as they were originally designed for series string operation direct from the AC mains. Even if your 6.3V versions are uber pricey, you can often find some odd voltage versions that are still commonly available, and for not too much.
its been a good informative thread for me and a big thanks to you all for speaking in blunt non tech terms that I can relate to. I have been looking at sub$1000 AUD kits at the moment and have found two, although one is not a kit both are similar in design being PP. And I will forewarn you all yes I have had to look to the land of the orient namely China for these, I unfortunately have not been able to find schematic diagrams of circuitry for either sorry. Both of these I am hoping will be able to be up specd in components and am hoping you guys can give me a nod on one of them.
Fist up: And Yes its Yaqin MC5881A linear push-pull circuit Integrated, I have one available here in Australia this one will set me back around 800$ AUD.
Type :Headphone Integrated Amplifier
Input Power :110V-240V AVAILABLEOutput Power :46W (4 ohm-8 ohm)Valve / Tubes :6L6GC x 4 / 12AX7 / 12AU7 / 6N6Lose true degree :<5%Frequency :6Hz-70KHz(-2 dB)
Signal/Noise Ratio :78dB (A weight)
Load impedance :8ohm or 4ohmInputs impedance :>20K ohmAudio Input :4 groupsAudio Output :2 groups
Weight :18kg
There seems to be a few more valves than is quoted in the product pic though.
Second is a Kit and again its a noodler by Raphaelite DPK6L 6L6 Push-pull, it is a kit though but at a higher cost in the $1000 Aud range
Article: DPK6L 6L6 Push-pull DIY KIT
Model: DPK6L Tubes: 5Z3P/5AR4/5U4G×1 6N3/5670×1 6N1/ECC85×2 6P3P/6L6×4 Input Sensitivity: 210mV Power
Output: 2×18W (RMS THD<10% ,1KHz)
S / N Ratio: 85dB
Input Impedance: 100KΩ Output Impedance: 4Ω, 8Ω (optional)
AC Input: 100V-240V/50-60Hz
Power Consumption 140w
Frequency Response: 12Hz – 45KHz -1dB 8Hz – 80KHz -3dB
Dimension: 340×230×190(W-D-H)
Net Weight: 15KG
Is this closer to what I should be looking for by avoiding the 70's tone and a more modern push pull designs for my music tastes?
Info on my floor speakers, Atlanta APC 2000 Denmark, Sinus load:180w, Music load:250w, Frequency:22-20000hz, SPL 96db 1m:1,2w, Impedance:4-8 ohm
No info on the manufacturer, none on the www, cant give impedance curve so I am guessing 4-8 ohm is the best I can do as labelled. I have had these since new and are the first set I purchased in my teens early 90's, have been refoamed at the mids and fitted Mundorf Mcaps to xover and changed uf of caps to recommendations of a chap I met online from Denmark, I am quite happy with their performance.
I really appreciate what you guys are trying to do for me here, I am not ignorant nor dumb but am finding wrapping my head round this valve caper a sharp curve ball, Thankyou for your patience in advance, there is a similar thread active but I did not want to hijack this with my own interests, and instead of starting another thought it best to persist where I am with the info related to me in this one.
Fist up: And Yes its Yaqin MC5881A linear push-pull circuit Integrated, I have one available here in Australia this one will set me back around 800$ AUD.
Type :Headphone Integrated Amplifier
Input Power :110V-240V AVAILABLEOutput Power :46W (4 ohm-8 ohm)Valve / Tubes :6L6GC x 4 / 12AX7 / 12AU7 / 6N6Lose true degree :<5%Frequency :6Hz-70KHz(-2 dB)
Signal/Noise Ratio :78dB (A weight)
Load impedance :8ohm or 4ohmInputs impedance :>20K ohmAudio Input :4 groupsAudio Output :2 groups
Weight :18kg
There seems to be a few more valves than is quoted in the product pic though.
Second is a Kit and again its a noodler by Raphaelite DPK6L 6L6 Push-pull, it is a kit though but at a higher cost in the $1000 Aud range
Article: DPK6L 6L6 Push-pull DIY KIT
Model: DPK6L Tubes: 5Z3P/5AR4/5U4G×1 6N3/5670×1 6N1/ECC85×2 6P3P/6L6×4 Input Sensitivity: 210mV Power
Output: 2×18W (RMS THD<10% ,1KHz)
S / N Ratio: 85dB
Input Impedance: 100KΩ Output Impedance: 4Ω, 8Ω (optional)
AC Input: 100V-240V/50-60Hz
Power Consumption 140w
Frequency Response: 12Hz – 45KHz -1dB 8Hz – 80KHz -3dB
Dimension: 340×230×190(W-D-H)
Net Weight: 15KG
Is this closer to what I should be looking for by avoiding the 70's tone and a more modern push pull designs for my music tastes?
Info on my floor speakers, Atlanta APC 2000 Denmark, Sinus load:180w, Music load:250w, Frequency:22-20000hz, SPL 96db 1m:1,2w, Impedance:4-8 ohm
No info on the manufacturer, none on the www, cant give impedance curve so I am guessing 4-8 ohm is the best I can do as labelled. I have had these since new and are the first set I purchased in my teens early 90's, have been refoamed at the mids and fitted Mundorf Mcaps to xover and changed uf of caps to recommendations of a chap I met online from Denmark, I am quite happy with their performance.
I really appreciate what you guys are trying to do for me here, I am not ignorant nor dumb but am finding wrapping my head round this valve caper a sharp curve ball, Thankyou for your patience in advance, there is a similar thread active but I did not want to hijack this with my own interests, and instead of starting another thought it best to persist where I am with the info related to me in this one.
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You could get a kit and build it, then come back and ask for mods. Things like gyrator plate loads and CCS tails and more will make your amp more 'modern' and clearer. They can be added to most designs (at least most simple designs, which I assume a kit would have).
Or, you could save a lot of money and look up tutorials online. There are many projects that are very extensively documented and surely are approachable to beginners. Of course a commercial kit might have a finished chassis that maybe you can't do at home at the moment, but buying cheap tools you might still get ahead moneywise.
Or, you could save a lot of money and look up tutorials online. There are many projects that are very extensively documented and surely are approachable to beginners. Of course a commercial kit might have a finished chassis that maybe you can't do at home at the moment, but buying cheap tools you might still get ahead moneywise.
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