Hmm. He doesn't stipulate 220va for mono or stereo. I always "assumed" he wanted it on the high end and "guessed" he meant 220va per channel.
I used a single 400va in my original TP stereo set.
I am using Steve Dunlaps' 160va in each mono amp now.
Again I "personally" would not use less than ~160va for a full range or main system channel.
I would happily use as low as 100va per channel for a high-passed or low volume (Adult bedroom) system.
I used a single 400va in my original TP stereo set.
I am using Steve Dunlaps' 160va in each mono amp now.
Again I "personally" would not use less than ~160va for a full range or main system channel.
I would happily use as low as 100va per channel for a high-passed or low volume (Adult bedroom) system.
To those struggling to successfully complete building their amps, let me offer this encouragement: keep at it and you will be rewarded. I don't mean to brag here, but mine went together easily and worked very well right from the start. I have not put them in enclosures yet; they're just mounted on pieces of wood with junk power cords (I mean junk!) and everything exposed and loose inputs and outputs hanging off the boards. Not very sturdy or safe, but totally silent.
To those who have completed them or are close to doing so, let me offer this advice: the input coupling cap, C13, is a critical element in how your amp will sound. I strongly recommend substituting a better cap than the one supplied with the kit. Spending a few extra dollars on this single component will do more to improve the sound than any other single element.
I admire Dario's approach to directly couple the input with use of a jumper over that position, then tune the amplifier properly with that variable eliminated. For those not interested in altering other components, concentrate on using the highest quality C13 you can afford, and it will raise the performance of this already excellent design.
So far, I have tried four different caps there, and the best by far is now playing. The stock cap is okay, but gives a somewhat hi-fi sound, with somewhat tizzy highs and decent bass. I replaced it with a Vishay stacked film and foil MKP, and that wasn't much of an improvement over the stock part. I had some 1.5uF Bennic metalized poly caps laying around and tried those. Big step backward: the sound became very hazy and bright on top, with bloated bass. Now I am using a 1.0uF AudioCap Theta poly and tin foil cap, and this is making beautiful music. The cap is not expensive by boutique standards, but it pays huge dividends in quality of sound. Without any break-in period, I already hear very clear, smooth, extended highs, a sweet, layered, buttery midrange, and very solid bass. The cap is available from Parts Express. It doesn't fit on the board, but I placed mine directly next to the board and ran one cap lead right to the board and connected the input directly to the other lead. I put a short length of teflon tube insulation over the exposed cap leads. There is no added noise or hum in this configuration.
I would say that, with the substitution of this cap, the amps have moved up from the equivalent of $600 per monoblock to $1000 monoblocks. They sound very tubelike. The midrange is very sweet and layered, and the highs are spacious, detailed yet smooth. As a reference, the amp I normally use is an ARC 100.2, a $3500 100 watt/channel balanced amp. This is the best solid state amp I've ever heard, and the little My Ref gives it a pretty good run. Not quite there yet, but I don't really expect it to ever achieve that level of performance.
I am sure there are better caps available, but I don't know if I can afford them or if they'll improve the sound that much more.
Experiment and let us know the results. That's what DIY is all about.
Peace,
Tom E
To those who have completed them or are close to doing so, let me offer this advice: the input coupling cap, C13, is a critical element in how your amp will sound. I strongly recommend substituting a better cap than the one supplied with the kit. Spending a few extra dollars on this single component will do more to improve the sound than any other single element.
I admire Dario's approach to directly couple the input with use of a jumper over that position, then tune the amplifier properly with that variable eliminated. For those not interested in altering other components, concentrate on using the highest quality C13 you can afford, and it will raise the performance of this already excellent design.
So far, I have tried four different caps there, and the best by far is now playing. The stock cap is okay, but gives a somewhat hi-fi sound, with somewhat tizzy highs and decent bass. I replaced it with a Vishay stacked film and foil MKP, and that wasn't much of an improvement over the stock part. I had some 1.5uF Bennic metalized poly caps laying around and tried those. Big step backward: the sound became very hazy and bright on top, with bloated bass. Now I am using a 1.0uF AudioCap Theta poly and tin foil cap, and this is making beautiful music. The cap is not expensive by boutique standards, but it pays huge dividends in quality of sound. Without any break-in period, I already hear very clear, smooth, extended highs, a sweet, layered, buttery midrange, and very solid bass. The cap is available from Parts Express. It doesn't fit on the board, but I placed mine directly next to the board and ran one cap lead right to the board and connected the input directly to the other lead. I put a short length of teflon tube insulation over the exposed cap leads. There is no added noise or hum in this configuration.
I would say that, with the substitution of this cap, the amps have moved up from the equivalent of $600 per monoblock to $1000 monoblocks. They sound very tubelike. The midrange is very sweet and layered, and the highs are spacious, detailed yet smooth. As a reference, the amp I normally use is an ARC 100.2, a $3500 100 watt/channel balanced amp. This is the best solid state amp I've ever heard, and the little My Ref gives it a pretty good run. Not quite there yet, but I don't really expect it to ever achieve that level of performance.
I am sure there are better caps available, but I don't know if I can afford them or if they'll improve the sound that much more.
Experiment and let us know the results. That's what DIY is all about.
Peace,
Tom E
C13 and sound
To be honest, after a few days’ listening I started to have second thoughts about the MyRef. It was much more detailed but not musical, not easy to listen to. Sure, I could hear each and every instrument. The cymbals sounded like cymbals etc. – but!!!
Note that my CD player is a Sony DVP NS900V which is known to be on the tight side already. The speakers are 10inch Audio Super Nirvana 96Db+ full range
I had to admit that my modified Sonic T-Amp gave easier listening.
The main mod to the T-Amp had been to change the input filter caps. I chose the 2.2uF Obbilgato which was a real tight fit in the original box. This morning I took the Obbilgatos out of the T-Amp and replaced them with 2.7uF Audyn caps with hardly any noticeable change to the T-Amp.
I then put the Obbilgatos in the MyRef (offboard like Tom). The result was a much more musical sound; easier to listen to. Glen Gould got back his Steinway Grand - before he had been playing on my wife’s upright. The cost was a loss of detail – it was overall marginally better that T-Amp.
I believe that one should be able to obtain more detail without loss of musicality so that listening pleasure, be it subjective, is increased and not decreased. I will follow with interest the discussions on cap choice, but in the meantime all suggestions are welcome.
I also have another small hum problem but will come back to that another day.
To be honest, after a few days’ listening I started to have second thoughts about the MyRef. It was much more detailed but not musical, not easy to listen to. Sure, I could hear each and every instrument. The cymbals sounded like cymbals etc. – but!!!
Note that my CD player is a Sony DVP NS900V which is known to be on the tight side already. The speakers are 10inch Audio Super Nirvana 96Db+ full range
I had to admit that my modified Sonic T-Amp gave easier listening.
The main mod to the T-Amp had been to change the input filter caps. I chose the 2.2uF Obbilgato which was a real tight fit in the original box. This morning I took the Obbilgatos out of the T-Amp and replaced them with 2.7uF Audyn caps with hardly any noticeable change to the T-Amp.
I then put the Obbilgatos in the MyRef (offboard like Tom). The result was a much more musical sound; easier to listen to. Glen Gould got back his Steinway Grand - before he had been playing on my wife’s upright. The cost was a loss of detail – it was overall marginally better that T-Amp.
I believe that one should be able to obtain more detail without loss of musicality so that listening pleasure, be it subjective, is increased and not decreased. I will follow with interest the discussions on cap choice, but in the meantime all suggestions are welcome.
I also have another small hum problem but will come back to that another day.
Attachments
AndrewT said:
Thanks for clarity that, will try to purchase some good cap to replace the one that come with the Kit.
Thanks for clarify me that
what sound diference will get using same cap brand/model and diferent values? for example 0.10uF, 1uf, 8uf, 10uf, 100uf..... ?
i want to know because i never do an mod like that in any amp, so i want to know wich value purchase to test!
The smaller value cap you use, the more it will affect bass response. The minimum recommended value is 0.47uF, which will reduce the very low bass below about 30Hz. If your speakers don't go that low, then 0.47uF is all you need. I tried a 0.22uF, and it did reduce bass output. The cap I have in there now is 1.0uF, and that seems to have no affect at all on the bass. This amp does not produce really solid low bass anyway, so you don't want to compromise what is there. I would suggest no smaller value than 0.47uf, preferably something between that and 1.0uF. A larger value will cost a lot more with not much better results, plus it will be a bigger cap and might be harder to fit into an enclosure.
Peace,
Tom E
Peace,
Tom E
the DC blocking cap acts as the high pass input filter.
It should NOT be considered alone when selecting a range of appropriate values.
This input filter MUST prevent extreme LF signals getting into the amplifier and causing various parts of the circuit to misbehave.
I do not know enough about the feedback of this composite amplifier and cannot offer advice on limiting values for the DC blocking capacitor.
However, the frequency of the PSU must be at least one octave below the frequency of the input filter. That sets the first limit on the DC blocking cap value.
The frequencies you want out of the amplifier eg. 20Hz, sets a second limit for this input cap.
It should NOT be considered alone when selecting a range of appropriate values.
This input filter MUST prevent extreme LF signals getting into the amplifier and causing various parts of the circuit to misbehave.
I do not know enough about the feedback of this composite amplifier and cannot offer advice on limiting values for the DC blocking capacitor.
However, the frequency of the PSU must be at least one octave below the frequency of the input filter. That sets the first limit on the DC blocking cap value.
The frequencies you want out of the amplifier eg. 20Hz, sets a second limit for this input cap.
samsagaz said:
Lets remember that this is NOT an LM3886 amp. Its a LM318 amp for all intents and purposes. The LM3886 is just there to allow more current through.
I had lack of bass but then my speakers are full range so I wondered if it was speakers/amp/what? I didnt know.
I bought a ADC soundshaper for $5 on ebay and reconditioned it. Its an equalizer. I turned up the bass and found that my speakers can handle outputting more bass so I came to the conclusion that the amp has less bass output than my ears want. Equalizer fixed it. The amp is really just reproducing whats on the CD so I kind of shy away from saying that an amp "HAS" or doesnt "HAVE" bass. The speakers and room have a lot to do with it. My right speaker is in a corner. It "HAS" way more bass than the left. Equalizer helps this to.
WHen I was in high school a buddy had a truck with huge speakers. Hard to breath when they hit hard. Thats extreme but I missed the feel of the bass and so I enhanced it with the equalizer. I dont think the amp really adds or subtracts bass as long as the input cap and output cap are allowing the frequency to pass through and it seems that the bass that really thumps will pass through. That 30Hz bass isnt the stuff that hits you in the chest. So, the caps on the board are allowing all the necessary frequencies through.
Just my opinion. But strong enough that I bought a DEQ2946 after my ADC soundshaper experience. Cant wait to get home and try it out.
Ri
If anyone has the gear it would be very easy to measure the response of the amp and "see" if it is flat +/- x or if it has a "curve".
My bet from hearing my 2 pairs is that it is pretty flat and the bass sounds thinner than we are used to hearing because it is more defined.
The last commercial amp I owned was the JRDG Model 2. Great amp and I missed it until I built my first Rev_C. THAT is when I realized it is possible to build something VERY close (not equal to) to that commercial unit myself.
My bet from hearing my 2 pairs is that it is pretty flat and the bass sounds thinner than we are used to hearing because it is more defined.
The last commercial amp I owned was the JRDG Model 2. Great amp and I missed it until I built my first Rev_C. THAT is when I realized it is possible to build something VERY close (not equal to) to that commercial unit myself.
udailey said:
Surely the (ideal) amp by itself doesn't adds or subtracts bass as long as the input cap and output cap are allowing the frequency to pass through but every component has its frequency response and sonic signature.
When you change a capacitor (e.g. C9) with another with same value in the signal path (but also on PS...
) it adds it's character to the circuit.If you change the Panny FM with a Elna Silmic (both burned-in) the effect is clearly audible: less harshness, thicker and firmer bass, more soundstage and you loose the excess of highs.
I know you don't like Silmics
I've compared them with FMs because the different signature is SO evident.Also if you change C21 from AVX BQ (which sounds nicer than what seemed from my previous post about caps) to Wima MKS2 you gain more soundstage and a bit thicker bass.
troystg said:
I agree, bass is more defined but in my case (both from Marantz power section and from my Gainclone) I've also gained in bass quantity.
But my 10000uF are different from the ones in kits and this could give different results.