Well, I have read tens of articles on the net about the Gainclone. Some suggest mods, class A mod and so on.. I even have built one (non inverting) have read Thorsten's snipits on different sites and have salivated (no kidding ;-) ) at Peter Daniel's realisations and yes, I want to build "one" Gainclone, not a dozen, one that would sum up the major improvements found on this forum... What would you suggest as the definitive schematic?? coupling input cap or not? and so on..
Well, Peter Daniel, I make a prayer! please please pretty please??
😉
Well, Peter Daniel, I make a prayer! please please pretty please??
😉
Well, finally I can feel like Herb Reichert describing his 300B amp.😉
So, those are the components and if built this way, it sounds pretty good. If you build it any other way, it will be your amp, not mine.😉
The PS consists of four 12 V/7.2 Ah Panasonic batteries and there are 1000u/50 BG N caps on ea. channel's rail. If you decide not to use batteries, use at least 400VA/22V AC toroid and double MUR860 bridges. The umbilical cord consists of 8 Cardas hook up wires (this is important), the only other bypass caps are after bridges 4.7 BG N). The choice of components depends on chasssis and PS.
The chassis play major role, so try to built something small and non-resonant. Use better materials if possible. If used with Patek chassis, this is so far the best I've made.
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So, those are the components and if built this way, it sounds pretty good. If you build it any other way, it will be your amp, not mine.😉
The PS consists of four 12 V/7.2 Ah Panasonic batteries and there are 1000u/50 BG N caps on ea. channel's rail. If you decide not to use batteries, use at least 400VA/22V AC toroid and double MUR860 bridges. The umbilical cord consists of 8 Cardas hook up wires (this is important), the only other bypass caps are after bridges 4.7 BG N). The choice of components depends on chasssis and PS.
The chassis play major role, so try to built something small and non-resonant. Use better materials if possible. If used with Patek chassis, this is so far the best I've made.
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Do you have any DC offset problems with this layout Peter? How do you get away without using any caps outside the power supply?
Cheers,
Zach
Cheers,
Zach
It seems like a new and maybe improved schematic appears almost bi-monthly. I think the above one is probably pretty good. See the latest issue of www.tubecad.com
My source is AC coupled and the usual offset from the amp isn't more than 30mV, which is fine.
In my latest amp I'm not using neither coupling cap nor pot as TVC (transformers) take care of attenuation.
In case I didn't have transformers, I would be using a switched volume control in vicinity of the amp with source selection option. I have an idea for an amp platform, which would have volume and switching circuit built in.
In my latest amp I'm not using neither coupling cap nor pot as TVC (transformers) take care of attenuation.
In case I didn't have transformers, I would be using a switched volume control in vicinity of the amp with source selection option. I have an idea for an amp platform, which would have volume and switching circuit built in.
The chassis play major role, so try to built something small and non-resonant. Use better materials if possible. If used with Patek chassis, this is so far the best I've made.
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Peter
I am planning one; what is the Patek chasis?
I am thinking of dual mono in thick cast Al case with 4mm copper plate heat sink.
Seems to me that adding a coupling cap or a tube stage will 'colour' the sound.
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Peter
I am planning one; what is the Patek chasis?
I am thinking of dual mono in thick cast Al case with 4mm copper plate heat sink.
Seems to me that adding a coupling cap or a tube stage will 'colour' the sound.
Thanks, Peter and friends
Thanks Peter and friends for the suggestions. Sure Peter, I understand what you mean by "if you change something.. it is your amp.."
My goal is not just to "copy" your amp, but rather to start with a design that's the addition of other's experience. I could not afford to build the Reichert amp anyway.. so, I built the Fi Primer 300B using Bartoluccis trannies. I love this amp.
For the Gainclone, a few questions. I sure understand that the choice of materials do have an effect on an amp's signature. As a piano tuner, I can verify that daily.. a Yamaha ain't a Chickering.. different choices along the way give different results.
As for your "Patek" amp (it looks gorgeous, a nice balance of organic/metal materials..) the diagram you do include, am I wrong or it is no longer an "inverted" GC? and if so, why?
The transformer volume control seems a great idea, I'll try that later and will concentrate on a decent power amp GC for now.
Battery operation seems cheaper than buying big power trannies right? since GC operates on +24 0 -24v, does this mean "four" 12V batteries per channel?
About the tubed buffered GC, yes, this seems a nice solution to try eventually in a later project..
I use a Counterpoint preamp (tube) how do I do to know if it is "ac" or "dc" coupled?
I'll do my best to end up with something decent and musical, so our mentor, Peter, can be proud of his pupils.. hehe..
I'll keep you posted.
Thanks Peter and friends for the suggestions. Sure Peter, I understand what you mean by "if you change something.. it is your amp.."
My goal is not just to "copy" your amp, but rather to start with a design that's the addition of other's experience. I could not afford to build the Reichert amp anyway.. so, I built the Fi Primer 300B using Bartoluccis trannies. I love this amp.
For the Gainclone, a few questions. I sure understand that the choice of materials do have an effect on an amp's signature. As a piano tuner, I can verify that daily.. a Yamaha ain't a Chickering.. different choices along the way give different results.
As for your "Patek" amp (it looks gorgeous, a nice balance of organic/metal materials..) the diagram you do include, am I wrong or it is no longer an "inverted" GC? and if so, why?
The transformer volume control seems a great idea, I'll try that later and will concentrate on a decent power amp GC for now.
Battery operation seems cheaper than buying big power trannies right? since GC operates on +24 0 -24v, does this mean "four" 12V batteries per channel?
About the tubed buffered GC, yes, this seems a nice solution to try eventually in a later project..
I use a Counterpoint preamp (tube) how do I do to know if it is "ac" or "dc" coupled?
I'll do my best to end up with something decent and musical, so our mentor, Peter, can be proud of his pupils.. hehe..
I'll keep you posted.
It is no longer inverted, as some recent comparisons indicated that NI configuration provides better sound. Especially depth of soundstage in a stereo amp is increased and somehow the detail is better too. Inverted amp, OTOH, feels somehow veiled or mushy.
It means 4 x 12V batteries per channel, although in my current setup the batteries are shared by both channels (only 4 altogether). With casual listening they last about 4-5 days.
It is also my impression that adding a coupling cap or a tube stage will 'colour' the sound. However in some setups it may actually "fix" the brightness or coloration of other stages.
If your source doesn't present any DC offset (you can check it with a meter), it usually means it's AC coupled.
Also the choice of components worked in my setup, but in yours it can be diferent. You noticed the series 220 ohm (Vishay S102)resistor at the input. In some circuits not having that resistors cause big offset jump (around 150mV) when pot is full open. Also, it adds a bit of softness to the effect that Caddock creates as feedback resistor ( Caddocks can somtimes sound a bit harsh) so overall balance is more neutral. Itried few different resitors for 680 ohm and Riken seemed the best. It opens the highs and adds more air. The last one, 22k, is necessary there, as without it the offset will increase too (depending on volume position). Another Riken didn't work here as things became too bright and soundstage decresed (interesting?). You could use another Caddock, but I found that Vishay VTA55 sounds very neutral. BTW, although this is only a shunt resitor, its effect on sound signature is very strong.
Optimally the cables from PS to the amp should be very short. I noticed big improvement in monobloks, where PS is integrated with the amp. The cables alone, make same effect as interconnects between stages. Initiallt we were using Kimber speaker cable (8 strands) as it comes in nice package and is easy to terminate, but eventually we settled on Cardas, which produces much better sound (less flat and less lean, although slightly colored).
The amp doesn't need much in heatsinking requirements, so don't overblow it in this department😉
It means 4 x 12V batteries per channel, although in my current setup the batteries are shared by both channels (only 4 altogether). With casual listening they last about 4-5 days.
It is also my impression that adding a coupling cap or a tube stage will 'colour' the sound. However in some setups it may actually "fix" the brightness or coloration of other stages.
If your source doesn't present any DC offset (you can check it with a meter), it usually means it's AC coupled.
Also the choice of components worked in my setup, but in yours it can be diferent. You noticed the series 220 ohm (Vishay S102)resistor at the input. In some circuits not having that resistors cause big offset jump (around 150mV) when pot is full open. Also, it adds a bit of softness to the effect that Caddock creates as feedback resistor ( Caddocks can somtimes sound a bit harsh) so overall balance is more neutral. Itried few different resitors for 680 ohm and Riken seemed the best. It opens the highs and adds more air. The last one, 22k, is necessary there, as without it the offset will increase too (depending on volume position). Another Riken didn't work here as things became too bright and soundstage decresed (interesting?). You could use another Caddock, but I found that Vishay VTA55 sounds very neutral. BTW, although this is only a shunt resitor, its effect on sound signature is very strong.
Optimally the cables from PS to the amp should be very short. I noticed big improvement in monobloks, where PS is integrated with the amp. The cables alone, make same effect as interconnects between stages. Initiallt we were using Kimber speaker cable (8 strands) as it comes in nice package and is easy to terminate, but eventually we settled on Cardas, which produces much better sound (less flat and less lean, although slightly colored).
The amp doesn't need much in heatsinking requirements, so don't overblow it in this department😉
Alot of people have moved to the non-inverted topology lately, not just Peter, it was odd how hardly anyone tried it for so long and everyone was praising the inverted way... Just goes to show that you CAN think on your own and not be wrong.
But I agree that the non-inverted topology is the better way of doing it. I hear a difference between the two, and the non-inverted design allows for a higher input impedence and lower feedback resistors, both of which are good things. The schematic Peter posted looks good, and obviously has worked great for him. But you CAN change the values of those resistors, if you want more or less gain, go for it, or if you prefer a difference input impedance. What Peter prefers maybe won't be what you prefer, it's a matter of taste.
Don't bother trying to bias these chips in Class-A and if you can omit the input capacitor. But something that is indeed worthwhile is to checkout the new LM47xx series of chips, they might suprise you.
But I agree that the non-inverted topology is the better way of doing it. I hear a difference between the two, and the non-inverted design allows for a higher input impedence and lower feedback resistors, both of which are good things. The schematic Peter posted looks good, and obviously has worked great for him. But you CAN change the values of those resistors, if you want more or less gain, go for it, or if you prefer a difference input impedance. What Peter prefers maybe won't be what you prefer, it's a matter of taste.
Don't bother trying to bias these chips in Class-A and if you can omit the input capacitor. But something that is indeed worthwhile is to checkout the new LM47xx series of chips, they might suprise you.
JoeBob said:
Actually this is copied from Gaincard. I didn't had a chance to find my preference yet. And since GainCard seems to be a proven design, I don't think I will be investigating those values in a near future😉
Thanks Peter for explaining your choices. It gives me a better understanding of what makes what. For some reason, I find tube more builder friendly. ;-)
About battery types, have you got different results from different types?
I know that lead-acid batteries (Yuasa I think) are easily obtanaible here (Maddison) as well some "gel" type ? is the type important?
My trial GC was plain non-inverting and I was amazed at how good it sounded. Got much better with time. Just ordinary parts. Not as transparent as my 300B yet, but I imagine that the "Patek" version should beat it, I know.. ;-)
About interconnecting power supply, where does one get Cardas?
I might experiment with multi strand and solid core copper wires too, just for the fun of it.
Joe Bob, you live in my area. Where do you get your parts? it would be fun at some point to make some listening sessions..
Same for you Peter, do you know of good part sources here in Canada? I find that ordering in the u.s. makes things fussier and complex.
I have to gather parts now and make plans..
Got me Think-Thinking..
oh, any idea for a decent potentiometer? ladder type
About battery types, have you got different results from different types?
I know that lead-acid batteries (Yuasa I think) are easily obtanaible here (Maddison) as well some "gel" type ? is the type important?
My trial GC was plain non-inverting and I was amazed at how good it sounded. Got much better with time. Just ordinary parts. Not as transparent as my 300B yet, but I imagine that the "Patek" version should beat it, I know.. ;-)
About interconnecting power supply, where does one get Cardas?
I might experiment with multi strand and solid core copper wires too, just for the fun of it.
Joe Bob, you live in my area. Where do you get your parts? it would be fun at some point to make some listening sessions..
Same for you Peter, do you know of good part sources here in Canada? I find that ordering in the u.s. makes things fussier and complex.
I have to gather parts now and make plans..
Got me Think-Thinking..
oh, any idea for a decent potentiometer? ladder type
For someone with this moniker you seem to know surprisingly little about tube preamps. Of course your Counterpoint is ac coupled, same as practically any other tube preamp and more specifically it's cap coupled.
Regarding the sudden about-turn in GC polarity - it is a mystery to me. More than a year ago i listened to both polarities and prefered the inverted - better low level detail, more delicate highs. Today i confirmed this - the difference is not startling and may well be accounted for by the higher component count in the non-inverting amp but i find it stunning that everyone suddenly prefers the inferior connection. Winter fashion? Of course the non-inverted amp is more practical and that alone is probably a good justification for preference but to state it actually sounds better...
Same as everything else it's very system and component specific and at least it deals with that dreadful buffer.
I usually order my parts online, for I don't know any good local shops. Maddison isn't bad for generic resistors and little things like that (I actually found some nice surplus NEC relays there the other day) but nothing special. Electro-Mike is alright as well for wire, solder and surplus parts, but I wish I knew where I could buy quality passive parts locally.
Usually lead-acid batteries are used since they are rechargable, I'm not sure about the gel types. But I do know bgmicro has some surplus 12vdc 7Ah lead acid batteries for 6 usd part number BAT1019, alot cheaper than those available at maddison.
I really think we should get a quebec city listening session going, for there are some other members on the board from here, and they've got their gatherings out west, why not out here?
Usually lead-acid batteries are used since they are rechargable, I'm not sure about the gel types. But I do know bgmicro has some surplus 12vdc 7Ah lead acid batteries for 6 usd part number BAT1019, alot cheaper than those available at maddison.
I really think we should get a quebec city listening session going, for there are some other members on the board from here, and they've got their gatherings out west, why not out here?
analog_sa said:
I don't think it is inferior connection. We actually bring amps back from US to convert them to NI. Whould we do that if it was inferior?😉
As to the parts, partsconnexion.com is a good source. There is a thread about ladder attenuators currently on a forum. You can also check percyaudio.com for some interestin offers.
Technically, I see how an inverted amplifier "should" preform better. But in the real world, I see the input impedance setting the gain of the amplifier to be nowhere acceptable. A buffer does indeed solve that problem, and I could see that setup being prefered over an IGC alone, but it's much easier to use the opamp in non-inverting config ionstead to begin with.
While I may not agree with some people and their facination of the vibrations of the chip 😉 I do believe there is an audible difference between these two topologies, and if Peter is saying that not only he prefers NI but many others do as well, then I really think there is something there.
And yes, I have compared the two topologies, but since at the moment I have no descent source, I can hear a difference, but I'm not sure which sounds better at the moment. But on the technical side I much prefer the NI setup.
While I may not agree with some people and their facination of the vibrations of the chip 😉 I do believe there is an audible difference between these two topologies, and if Peter is saying that not only he prefers NI but many others do as well, then I really think there is something there.
And yes, I have compared the two topologies, but since at the moment I have no descent source, I can hear a difference, but I'm not sure which sounds better at the moment. But on the technical side I much prefer the NI setup.
It's more relevant here so I'll post it here too.
Not much to it. A pot extra and the PS. I love it. How much simpler can it be. I guess you can put the SM resistors (0805) on the back of the chip and closer to the plastic, but I wanted to keep them visible so that I can experiment with the values. Nicely shielded input also (all the way to the guts of the chip).
Not much to it. A pot extra and the PS. I love it. How much simpler can it be. I guess you can put the SM resistors (0805) on the back of the chip and closer to the plastic, but I wanted to keep them visible so that I can experiment with the values. Nicely shielded input also (all the way to the guts of the chip).
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