How else is one to obtain a specification when no other information is available? 😕 (confused face)
So using this diagram, what resisters be changed to what value to reduce down to 300VDC so we can use the graphs?
Another advantage for a PP: "BTW, going DC for power tubes heaters in a PP amp is useless: the two legs are out of phase and any common mode induced hum will cancel thru the PT."
If understand correctly, the 115VAC transformer when 125VAC applied in worse case scenario, is an eight percent increase, so within the 10 percent tolerance of the heaters. 9VAC to 6,3VAC is a required drop of 2,7 volt drop. Using Ohm's Law, we therefore have 2,7VAC/2,38A giving a resistor value of 1,13Ω. This does not seem a common size, though gives a drop of 2,6 volts which if the primary is at 125VAC give 8VAC at the heaters, over the 7VAC maximum. Hmmm, that is interesting. Running 2,25Ω parallel achieves 1,125Ω. In short, a 9VAC secondary in parallel provides for both mono blocks satisfactorily. 2,78A by the way.
All this calculating for the tube input transformer now seems silly when find a transformer providing the required voltage has 0,513A, seems more than plenty. Correct?
Approximate total cost of input transformers is about $120, not terrible.
Why on one schematic specifics 8kΩ to 10kΩ OPT and the other 8kΩ OPT?
Looks to be either a Hammond 1608 or 1609.
An idea crossed my mind of adding a variable resister to adjust plate voltage, especially as the IPT is 4 volts over. Thought(s)?
Got a full day tomorrow, including a memorial service for my friend's mother (partly going as think help him having a dog around, he loves my Service Dog).
All this calculating for the tube input transformer now seems silly when find a transformer providing the required voltage has 0,513A, seems more than plenty. Correct?
Approximate total cost of input transformers is about $120, not terrible.
Why on one schematic specifics 8kΩ to 10kΩ OPT and the other 8kΩ OPT?
Looks to be either a Hammond 1608 or 1609.
An idea crossed my mind of adding a variable resister to adjust plate voltage, especially as the IPT is 4 volts over. Thought(s)?
Got a full day tomorrow, including a memorial service for my friend's mother (partly going as think help him having a dog around, he loves my Service Dog).
I really reccommend that you build a circuit exactly as designed. It takes a lot of exoperience to be able to make adaptions and deal with all the consequences. A tube amplifier is like an old fashioned car engine with gaps in spark plugs, timing, metering of fuel, idling rpm, etc. The schematic has the optimum values for the engine to tick over without polluting the neighbourhood, and beat the next guy from the green light without backfiring.
The Tubelab SPP board here on DiyAudio has masses of support, and you can then start to ask specific questions about a particular build. At the end of that build you will have all the reference points you need to answer your own questions from above.
The Tubelab SPP board here on DiyAudio has masses of support, and you can then start to ask specific questions about a particular build. At the end of that build you will have all the reference points you need to answer your own questions from above.
Adriel,
Not all push pull amplifiers have low hum out if they have AC filaments.
DHT effects sometimes are the cause.
One amplifier with 2A3 push pull had very low ripple B+.
But the various effects of 2A3 with AC filaments, did cause hum at the output.
There are other threads in Tubes / Valves that discuss the causes.
Generalizations are Generally true, but not always.
Not all push pull amplifiers have low hum out if they have AC filaments.
DHT effects sometimes are the cause.
One amplifier with 2A3 push pull had very low ripple B+.
But the various effects of 2A3 with AC filaments, did cause hum at the output.
There are other threads in Tubes / Valves that discuss the causes.
Generalizations are Generally true, but not always.
As I said before and will keep saying, I agree.
Say it again, I don't want to change the plans.
That is why I spent two days finding transformers. Where did anyone say what the specification was?
Or was I somehow not clear?
I do have trouble communicating, sometimes gets so frustrating I wish didn't have dogs, take a handful of sleeping pills and be done with it. But, it is just temporary frustration that is just a brief cold shower passing through, need to remember the sun is always shining even if it can't be seen on those moonless nights.
Where did I say I want to change the valves? I am confused. 😕
In fact, it is the opposite, I rather have a design built for a specific tube than many tubes (I am all ears to hearing I am incorrect about TubeLab's designs). Again, seems an example of my mental retardation hindering communication.
I know this, though are any of them willing to help to the end? Based on my experience with the speakers and the Audio Lab clone build (granted, less folks have built them), I get started and then abandoned. Folks don't seem able to be able to handle a mentally retarded person (another temporary frustration and why prefer staying home than going out, too painful). So I go spend $2.000USD in parts and then can't get it finished, there went more than two months of income down the drain. Please understand voicing a concern so I can be corrected. 🙂
If the cost of building mono blocks is to build stereo first, can the finished kit be sold near the same cost?
I have way too much stuff in my life and thus my hang up on building several systems to teach myself how to build an amplifier. Probably cost less in the end, too (figuring on $2.000USD each build). 🤔
I have a recollection the mono blocks were a recommendation. Additionally, my thinking is can build one channel and learn for the next channel, plus simpler. Is it better to build stereo first?
See, me sharing my understanding is not to ever argue, to instead find out where the misunderstanding is, correct it, and learn how to better. 🙂
Again, thank you for the help and advice, certainly appreciated! 😀
I appreciate letting me know, thank you! 😀
Again, I have said before, I will build it "stock" and if desire to make a change, I can do that after have it working. This is why I have been seemingly difficult, rather not get the itch to change even before it is built. 😉
As for the specific design, I am planning to use perf board rather an a chassis. If I want to get fancy, can rebate (or is rabbit?) a wood frame for it to sit into. This not only I find appealing visually (partly the athletics and expressing the design especially lack of any SS), also appealing changes can be made easier.
Looking for the meaning of "ECA" find this: https://worldradiohistory.com/BOOKS...fier-Circuits-Pettit-McWhorter-1961-Adobe.pdf.
Mind informing me of which chapters are pertinent?
Thanks in advance! 🙂
Mind informing me of which chapters are pertinent?
Thanks in advance! 🙂
Hi Adriel, do you still have these parts?
I missed the requirement that you have to build monoblocks. I checked the start of the thread and it was not clear in the first few posts. You mention selling? Is the goal to try and build a kit and sell it, making a few bucks along the way?
What is your goal just in simple terms? No mention of tubes or amplifier types.
Cheers, Richard
Hey Richard (or is it Rickard?), I appreciate cheering me (maybe even both meanings of the word) and the help, thank you! 😀
As I start to recover, realize what a mess I am. For example, missing the bottom most circuit is for the tube heaters. Duh. 🙄 Speaking of which, even virtually building, via creating a BOM, I am learning (ex. the two diodes (D5 and 6) are converting AC to DC heaters).
Sorry the future tense was not clear. Still working on the BOM.
Not a requirement, a preference unless my aforementioned understandings are false.
Because as I been generously given information and advice, my plan has changed. Some point, I have to stop and settle on a design, kind of feeling near that point?
I asked because don't want stuff here I am not using. If build the monoblocks instead, then it is moot, as the final design.
The whole system? Over all, a system that is fairly accurate and somewhat neutral sound, rather than overly warm and especially overly bright.
In regards to components:
A phono pre for moving coil cartridge (already have for a MM).
A pre amp that has additional inputs, be nice if can use my existing system's components, of really high quality and love the sound and ability. Not sure if even need a pre amp. With this requirement not expecting a simple design.
An amp of simple design that will be of at least medium quality so not itching right away to go mucking with it (in other words, comparable or better than the SU-Z600 integrated).
Active crossovers.
Preference be bi-amping, with SS for the woofer and tube for the upper and high ranges.
BIB speaker cabinets with mid grade speakers.
As I start to recover, realize what a mess I am. For example, missing the bottom most circuit is for the tube heaters. Duh. 🙄 Speaking of which, even virtually building, via creating a BOM, I am learning (ex. the two diodes (D5 and 6) are converting AC to DC heaters).
Sorry the future tense was not clear. Still working on the BOM.
Not a requirement, a preference unless my aforementioned understandings are false.
Because as I been generously given information and advice, my plan has changed. Some point, I have to stop and settle on a design, kind of feeling near that point?
I asked because don't want stuff here I am not using. If build the monoblocks instead, then it is moot, as the final design.
The whole system? Over all, a system that is fairly accurate and somewhat neutral sound, rather than overly warm and especially overly bright.
In regards to components:
A phono pre for moving coil cartridge (already have for a MM).
A pre amp that has additional inputs, be nice if can use my existing system's components, of really high quality and love the sound and ability. Not sure if even need a pre amp. With this requirement not expecting a simple design.
An amp of simple design that will be of at least medium quality so not itching right away to go mucking with it (in other words, comparable or better than the SU-Z600 integrated).
Active crossovers.
Preference be bi-amping, with SS for the woofer and tube for the upper and high ranges.
BIB speaker cabinets with mid grade speakers.
Not sure where you get the end of the Modulus-86 from. The only challenge with the Modulus-86 is the availability of the LM3886. I have some and I have 1 kU on order. That's how I'm able to deliver Modulus-86 kits. I have every intention of keeping the Modulus-86 going. The Modulus-286 and Modulus-686 will keep going as well.
The assembly cost of the Modulus-686 went up 40+ % since the last batch. I am assuming this means the assembly cost of the Modulus-186 and Modulus-286 will increase as well. The Modulus-186 was marginally sustainable anyway, so any increase would push it over the edge. That's why the Modulus-186 is on the chopping block.
Yep.
Tom
Thank you for the correction and information. The difference between the 86 and 186 is the former is only available in stereo, correct?
I currently have the Modulus-86 available as a bare board (you buy the parts separately) here: https://neurochrome.com/products/modulus-86
You can buy one if all you need is a single, lonely, mono channel.
I have recently added a Modulus-86 Stereo Kit. As the name indicates it has two channels (stereo). You can find it here: https://neurochrome.com/products/modulus-86-stereo-kit
Each kit contains the circuit boards and the parts necessary to build a stereo amp, i.e., two boards + parts.
I've resisted kits for a long time. It's a lot of work putting them together. In fact a friend of mine and I just spent five hours putting together 26 kits. I hope the investment (both in terms of time and money) will be worthwhile. I chose to add the kit to deal with the supply chain issues. The LM3886 is hard to find these days, but I placed a few orders over a year ago that have started to show up, so I have a few on hand.
Tom
You can buy one if all you need is a single, lonely, mono channel.
I have recently added a Modulus-86 Stereo Kit. As the name indicates it has two channels (stereo). You can find it here: https://neurochrome.com/products/modulus-86-stereo-kit
Each kit contains the circuit boards and the parts necessary to build a stereo amp, i.e., two boards + parts.
I've resisted kits for a long time. It's a lot of work putting them together. In fact a friend of mine and I just spent five hours putting together 26 kits. I hope the investment (both in terms of time and money) will be worthwhile. I chose to add the kit to deal with the supply chain issues. The LM3886 is hard to find these days, but I placed a few orders over a year ago that have started to show up, so I have a few on hand.
Tom
Thank you for taking time to explain and provide links, it is appreciated. 😀
I see this possible miscommunication a learning opportunity. My understanding is monoblocks perform better, is this not the case with the 86? Or is the 86 a dual monoblock?
And as I am finding out, researching, sourcing, and creating a BOM, gives new appreciation to those who do it.
A whole year? 😳 Yikes. My guess be the Chinese government's response to COVID. Next 10 to 25 years is going to be interesting, including what is happening in Viet Nam.
I see this possible miscommunication a learning opportunity. My understanding is monoblocks perform better, is this not the case with the 86? Or is the 86 a dual monoblock?
And as I am finding out, researching, sourcing, and creating a BOM, gives new appreciation to those who do it.
A whole year? 😳 Yikes. My guess be the Chinese government's response to COVID. Next 10 to 25 years is going to be interesting, including what is happening in Viet Nam.
The advantage of a mono block is that there's as much separation between channels as you can get. The two channels within an amp can interact through direct coupling between the channels (one channel radiating/transmitting and the other receiving) and through the power supply. The direct coupling is not likely to be an issue in practice, but it could be in a poorly laid out amp. The supply coupling is likely the dominant coupling path. So having each channel have its own power supply, either in the form of a dual-mono build in one chassis or in the form of actual mono blocks, can be an advantage for some amps (specifically those with low PSRR).
Due to the error correction within the Modulus-86, the Modulus-86 is practically power supply agnostic. It has very high PSRR, so I would not expect it to show much - if any - benefit of mono builds.
That said, nothing stops you from buying a Modulus-86 Stereo Kit and building mono blocks with it. Just put each amp module into its own chassis, add a power supply, and <tada.wav> now you have a mono block.
Tom
Due to the error correction within the Modulus-86, the Modulus-86 is practically power supply agnostic. It has very high PSRR, so I would not expect it to show much - if any - benefit of mono builds.
That said, nothing stops you from buying a Modulus-86 Stereo Kit and building mono blocks with it. Just put each amp module into its own chassis, add a power supply, and <tada.wav> now you have a mono block.
Tom
I heard some of the Multi-chip Modulus-86 amplifiers in action at Burning Amp a couple years ago driving an LXmini setup. I am not exaggerating when I say that was the single best setup I have ever heard using solid state gear. I had brought along and donated a few genuine Ti LM3886 ICs to the raffle to go along with Tom's boards. Least I could do after bringing my hyper little toddler with me to the event 😆
Tom and @Lingwendil , sorry I forgot to respond. Thank you both your your responses, it is appreciated. 🙂
Tom, I asked the question because I can, and often, over think and/or get stuck on an idea or concept. You as the designer correcting the generalization and explaining the difference has changed my mind, no sense over complicating things. 😉
I remembered what questions need to ask you:
Does the 86 come with the slow start and the power supply or are these separate like the 186?
Does the 86 use the 2U chassis like the 186 or use the 1U?
By the way, a week or two ago watched all of the 186 build video thinking I might go that direction. Guess now should watch the 86 build.
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Oh really? The Pass Labs has a large following and surprises me something costing significantly less can surpass it. Anything stands out that makes it superior in your opinion?
Yep. That was a stack of three Modulus-686 in the Safe-n-Sane configuration.
The Modulus-86 is a different product than the Intelligent Soft Start. One does not come with the other. If you want both you have to buy both.
I suggest exploring my website a bit: www.neurochrome.com
The Modulus-86, Modulus-186, and Modulus-286 all use the same chassis: https://neurochrome.com/collections/connectors-parts/products/modulus-chassis
It's roughly 330x330 mm in footprint, 2U height.
Tom