Nuuk said:
Carlos, same question to you as I asked Protos - how long are your interconnects between preamp and power amps? And what sort of cables are they, ie how much capacitance?
And thank you to Portugal this morning for allowing the UK some of the sunshine
Nuuk, you'll be surprized, because I was describing an ideal situation for a Gainclone, which is not what I have right now.
It's more as you have, as I see on your other note.
Maby I'll sort this out by putting my GC on a middle position between the two speakers, because it's now on a 5-tier Target rack that's near the right speaker, where the whole system is installed.
Here it goes:
Pream -> Gainclone: 0.5m UTP Cat.5 interconnect (Diy).
Gainclone -> speakers: Kimber 4TC, 5 meters left, 3.5m right channel.
Tut tut Carlos
unequal length speaker cables!It's as I thought, nobody using GC monoblocks seems to be using them very close to the amps, ie with long interconnects. If the interconnects are in the feedback loop as stated somewhere else on this forum, then it may be that a buffer is needed on the input of the amp, as well as an active preamp.
My connections between stepped attenuator and GC's are about 0.5 metres and there is no problem at all with driving them, or the GCs passively. I think that the only objection to passive preamps is when you have to drive longer interconnects.
As somebody who has had his power amps situated right next to the speakers for four years, it would take a lot to convince me that long interconnects/very short speaker cables isn't the best solution.
BUT the GC set up that I have running now, with no active preamp, makes me question if this short interconnects/long speaker cables set up could be bettered by the extra circuitry of an active preamp!
As I am building a valve preamp, it will be an interesting experiment to see if I can run the GC monoblocks at a distance of a couple of metres from the preamp!
Buaaaaah!
My main system is in my living room, I have no other choice.
Anyway, Nuuk, during the weekend I've been listening, and I can tell you my new preamp kicks an impressive performance.
It's not finished yet, the boards and pot are on the floor, without a box.
But I made also a headphone amp to include on my pre, with OPA2132 and BUF634 and it delivers a performance I have never heard from my Beyerdynamic headphones.
Oh yes, it drives them like there's no tomorrow.
Nuuk said:
Tut tut Carlos
My main system is in my living room, I have no other choice.
Anyway, Nuuk, during the weekend I've been listening, and I can tell you my new preamp kicks an impressive performance.
It's not finished yet, the boards and pot are on the floor, without a box.
But I made also a headphone amp to include on my pre, with OPA2132 and BUF634 and it delivers a performance I have never heard from my Beyerdynamic headphones.
Oh yes, it drives them like there's no tomorrow.
Fedde, don't be silly! He's Portuguese
Seriously, I was going to ask the same question.
So Carlos, you are saying that the GCs sound better with your active preamp than with just a pot? That is very interesting. How frustrating that we can't listen to each others systems over the internet!
Come on Mr Gates, get a move on and sort that one out quickly 
My new integrated GC with buffer etc isn't coming along at all well! Carlos has sent us too much sun
and I prefer to be out on my bike.Re: Re: Buaaaaah!
Kimber 4TC is an expen$ive cable, at least for me, because we're talking big distances.
Anyway, I like so much their performance I completely forgot I will ever need to change speaker cables again.
And the difference in size doesn't make an audible difference, at least with this cable.
I have to live with the constraints I have, or else I would take all the furniture out of my living room and do the things my way.
But my wife wouldn't like it.
If I one day put my GC in a central position then I'll buy a 2m pair of 4TC.
Or maby I make two monoblocks and use 0.5m speaker cable.
But for now it's going to be this way.
fedde said:
What about using two 5 m cables ???=>
...
Fedde /
Kimber 4TC is an expen$ive cable, at least for me, because we're talking big distances.
Anyway, I like so much their performance I completely forgot I will ever need to change speaker cables again.
And the difference in size doesn't make an audible difference, at least with this cable.
I have to live with the constraints I have, or else I would take all the furniture out of my living room and do the things my way.
But my wife wouldn't like it.
If I one day put my GC in a central position then I'll buy a 2m pair of 4TC.
Or maby I make two monoblocks and use 0.5m speaker cable.
But for now it's going to be this way.
Nuuk said:
No, I can't assure that, because I didn't test with just a pot.
My GC is a power amp, and I like it that way.
What I'm saying is that I have now such a dynamics and definition
that I have doubts you could get with just a pot, and worst still a separate passive pre.
You could ultimately have a little bit more detail with just a pot.
As I said, I need a separate preamp.
I have many sources connected to my system, not just one or two.
I'm talking very high quality active components here.
Not crappy op-amps that muck up the sound.
What a pitty we can't hear other people's systems...
Nuuk, come on, you're invited.
Come in and hear my bunch of wires (the pre) singing.
Hi Guys
Take the Hybrid-Tube Gainclone to the Max, as in Max Power.
1. The recommended Tx is the Jensen JT-11P-1 Line Tx (used by Rowland in some of his amps). I also have a
locally made Quad-filar wound Tx available, which I will be using. Also one of the Lundahls should be a good
choice. Whatever the choice, it must be a premium quality and 1:1 ratio.
2. Use LM3886 as they are generally rated at 7A rather than the 4A of LM3876. This is really more of a 'muscle
amp.'
3. The Trimpots shown is likely to be 333K when adjusted for lowest DC Offset.
4. Here the 0R22 resistors are more important than usually. My simulations strongly indicate major failure
possible without, so don't think they can be omitted this time.
5. The 390p cap must be tweeked for best audio performance.
6. Front-End Power Supply as suggested earlier.
7. The Main Power Supply, I would use heat-sinked TO-220 Schottky diodes, made into discrete bridges. The
Power Tx 500VA min and about 10.000uF x 2. Paralled Panasonic FC types recommended, for ultra-low ESR.
This could require fourty of them.
8. Can easily be configured for Balanced Input. Add additional buffer and feed to grounded part of the Tx.
The projected power is 120W into 8 Ohm and somewhat more into 4 Ohm. This can only be finally confirmed
after it's been built. Also about ten times the current capability of a standard LM3876 IGC before the SPIKE
'thermal limiting' circuitry sets in. Use big heatsinks.
So now YOU can make your own 'muscle amp.'
Any Comments?
Joe Rasmussen
Take the Hybrid-Tube Gainclone to the Max, as in Max Power.
An externally hosted image should be here but it was not working when we last tested it.
1. The recommended Tx is the Jensen JT-11P-1 Line Tx (used by Rowland in some of his amps). I also have a
locally made Quad-filar wound Tx available, which I will be using. Also one of the Lundahls should be a good
choice. Whatever the choice, it must be a premium quality and 1:1 ratio.
2. Use LM3886 as they are generally rated at 7A rather than the 4A of LM3876. This is really more of a 'muscle
amp.'
3. The Trimpots shown is likely to be 333K when adjusted for lowest DC Offset.
4. Here the 0R22 resistors are more important than usually. My simulations strongly indicate major failure
possible without, so don't think they can be omitted this time.
5. The 390p cap must be tweeked for best audio performance.
6. Front-End Power Supply as suggested earlier.
7. The Main Power Supply, I would use heat-sinked TO-220 Schottky diodes, made into discrete bridges. The
Power Tx 500VA min and about 10.000uF x 2. Paralled Panasonic FC types recommended, for ultra-low ESR.
This could require fourty of them.
8. Can easily be configured for Balanced Input. Add additional buffer and feed to grounded part of the Tx.
The projected power is 120W into 8 Ohm and somewhat more into 4 Ohm. This can only be finally confirmed
after it's been built. Also about ten times the current capability of a standard LM3876 IGC before the SPIKE
'thermal limiting' circuitry sets in. Use big heatsinks.
So now YOU can make your own 'muscle amp.'
Any Comments?
Joe Rasmussen
Nuuk said:
Yeah - shouldn't you be in bed!
It's only 10.45PM here, this is Ozstralia mate!
Looks good to me but I don't really need that sort of power. I bet there are loads who do though!
Me neither. But I'm doing this project for a friend whose speakers, and I didn't necessarily approve of them, do need a lot of muscle. Rather than see him blow a cool wad of $$$ on such a beast, I thought, being a good friend (and probably a dumb one at that) I'd save his bacon. Besides, it appeals to me as a challenge.
Joe Rasmussen
Hi,
The idea of balancing the input is quite appealing.
It wouldn't require a great deal of money to do so and would be quite interesting to compare to the SE version.
I had the idea of putting the buffer stage in a separate case so it could easily be preceded by a source selector and volctrl.
It could than be used to drive longer lengths of IC without perceivable attenuation at HF and you could build the amps as monoblocks and put them closer to the LS.
Is this a sound (no pun intended) concept?
Cheers,
The idea of balancing the input is quite appealing.
It wouldn't require a great deal of money to do so and would be quite interesting to compare to the SE version.
I had the idea of putting the buffer stage in a separate case so it could easily be preceded by a source selector and volctrl.
It could than be used to drive longer lengths of IC without perceivable attenuation at HF and you could build the amps as monoblocks and put them closer to the LS.
Is this a sound (no pun intended) concept?
Cheers,
Mad_K said:wow! must be something wrong with my eyes
No, I am in Trondheim...
You are almost neighbours! Well... I did say almost.
Actually I fixed it, the file sits on my web site in a folder, noticed the problem almost straight away and got in there quick enough to fix it... whew.
It's now 11.48PM and I'm about to hit the sack. This is a DIY forum and yet in the last hour it's been working in, like, realtime.
I'm going to bed!
JR
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