• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Is there a 'Gainclone' Of the tube world?

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PHilgeman

PHilgeman

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Joined 2003
nomad-audio.com
#1
I dont mean to offend with the title, but I am curious.

Good performance, from a handlful of parts. Reasonable cost and a trusted, well published design?

So... $150 for a stereo amplifier excluding connectors and chassis.
About 5-10W
Less than 20 parts per channel

Thanks,
Paul Hilgeman
 
#2
PHilgeman said:
I dont mean to offend with the title, but I am curious.

Good performance, from a handlful of parts. Reasonable cost and a trusted, well published design?

So... $150 for a stereo amplifier excluding connectors and chassis.
About 5-10W
Less than 20 parts per channel

Thanks,
Paul Hilgeman
Click to expand...

You can build a Decware Zen amp clone for about $150 if you buy one of those old Single Ended EL84 console amps on Ebay. The output transformers aren't much to brag about but they sound pretty good.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=73369&item=5710861477&rd=1
 
#3
I am aware that "Gainclone" refers to a dirt simple audio amp using a chip and just a few discrete components on a heatsink of your choice that has become popular for some reason that escapes me, but the name makes absolutely no sense to me. Can anyone explain this?

Maybe they should have called it "Gainsurprise" because after all the negative feedback necessary to make the solid state thing linear enough to actually listen to, when they found that they still had some gain from a single chip they were surprised. 😱

Why not call a simplified one tube audio amp "amp in a bottle", "tone in a bottle",..... anything but that other name.
 
#5
rcavictim said:
......but the name makes absolutely no sense to me. Can anyone explain this?
Click to expand...

It's a clone of a commercial product called a Gaincard.

DougL said:
Here is a simple Tube amp. Two tubes.
Click to expand...

Still too complex! How about a Mullard 3-3: single ended, two stages, one capacitor in line? There are also a few one-tube amps floating around.
Re: the original post, I don't know if there really is a true equivalent to the Gaincard/clone concept floating around. It would require a small, complex, tube-fueled generic gain block surrounded by a handful of components. The closest I would think are the triode/pentode dual tubes designed as driver/output pairs.
 
#7
The simplest valve amplifier i have come across is based on the 6S45PE (6C45piE in cyrillic) triode for a whopping 1400mW(!) of power. I know this is a rather, no VERY limited in SS circuitry but some of the most expensive, rare and coveted valves only produce about that much power single ended. Fortunately this valve isn't rare and can be had pretty cheaply. See http://digilander.libero.it/paeng/projects_frame.htm and click on ST-AMP under the power amplifiers heading in the left frame. I have attached the schematic to the amplifier below... the red circled bit is the signal circuitry - 6 parts! - I believe this is less than most of the the gaincard/gainclone amplifiers. More power can be had by paralleling these valves, or arranging them in push-pull (more complicated) - I had some schematics for these... i will post them later when i find them.

A more complicated iteration can be found here http://www.valvediy.com/kugelispg1.html and may or may not yield better results - (is simpler always better?)

Anyways, valve circuits aren't usually terribly complicated or containing too many parts - particularly the single ended ones. The 6S45PE valve is actually often used as input/driver valve for more powerful valves. So, anyone who built the amp above could probably reuse the valve and some of the parts in a new amp for more power by adding another more powerful valve behind it.

Here is a circuit using it to drive a 2A3 for 3-4W of power http://home.earthlink.net/~jeremyepstein/freelunch.htm It probably uses about 10 parts in the signal circuitry - haven't counted. Most 2A3 circuits don't use such a high power supply voltage (B+) but this one 'stacks' the power supply for both valves, using the idle current from the output valve (2A3) to supply the input valve (6S45PE), and also uses direct coupling (no capacitors between valves)

For even more power, one can use a transmitting valve such as the 211, although these require horrendously high voltages (sometimes more than 1kV) - see the SE211-6C45 under the power amplifiers heading from the first link in this post.

:att'n: This being said, all valve circuits use high voltages (much more than the +/35V for an LM3875!) and hence extreme care must be taken. Using 500V or 1000V in the higher powered circuits i mentioned really has to be left to people experienced and confident with high voltages. Death is very permanent and electrocution is a horrible way to get there. Sorry to be so morbid but it's the truth.:att'n:
 
#9
But I must 2n`t that. The 6c45pi is a sweet , sweet tube (true it`s construction, using a titanium plate and a platium grid is a little different, but it sure sounds good!!!) Read that again, Titanium plate and Platimun grid..... I just wish it had a big brother!

Woody
 
#10
Konnichiwa,

PHilgeman said:
I dont mean to offend with the title, but I am curious.

Good performance, from a handlful of parts. Reasonable cost and a trusted, well published design?

So... $150 for a stereo amplifier excluding connectors and chassis.
About 5-10W Less than 20 parts per channel
Click to expand...

Not quite there, but close would be a "El Cheapo" version of the Maurits be Mr. Van Der Veen. You can use fairly inexpensive Mains torroid as output transformers with good results (not the least because of the low anode impedance of the 6AS7) as well as a simple mains insulation transformer and a simple LT transformer or two LT Transformers back to back to generate the Supply Voltages. Part count is fairly low too.

I have been idely working on a modified design with a few neat tricks and reduced parts count, to be build and published eventually, when I get enough time....

In the meantime:

http://www.diyaudio.com/forums/showthread.php?postid=351756#post351756

http://www.triodeguy.com/6as7_pp.htm

Maybe this will get you going?

Using a pair of pretty high powered 12V+12V secondary mains transformers, one to give heating (6AS7 Heaters in series) and the second transformer "back to back" to give around 230V AC stepped back up from the 12V+12V and you have your supply sorted. If you buy surplus mains transformers you should be well within your budget.

Sayonara
 
#12
The simplest valve amplifier i have come across is based on the 6S45PE (6C45piE in cyrillic) triode for a whopping 1400mW(!) of power. I know this is a rather, no VERY limited in SS circuitry but some of the most expensive, rare and coveted valves only produce about that much power single ended. Fortunately this valve isn't rare and can be had pretty cheaply.
Click to expand...

Where is this valve available. I can't seem to find any reference to it at any of the usual sources in the U.S..

Thanks.
Mike L.
 
#14
audiousername said:
The simplest valve amplifier i have come across is based on the 6S45PE (6C45piE in cyrillic) triode for a whopping 1400mW(!) of power. I know this is a rather, no VERY limited in SS circuitry but some of the most expensive, rare and coveted valves only produce about that much power single ended. Fortunately this valve isn't rare and can be had pretty cheaply. See http://digilander.libero.it/paeng/projects_frame.htm and click on ST-AMP under the power amplifiers heading in the left frame. I have attached the schematic to the amplifier below... the red circled bit is the signal circuitry - 6 parts! - I believe this is less than most of the the gaincard/gainclone amplifiers. More power can be had by paralleling these valves, or arranging them in push-pull (more complicated) - I had some schematics for these... i will post them later when i find them.
Click to expand...

Interesting little amp. If you were to build this thing, would you use separate LC stages for each channel? Looks like one PS for both channels in his schematic.

Sheldon
 
#16
Brian Clark said:
For a similar amp - and one that has been tried and tested by several people around the world - see

The Great El Spuddo!

My last iteration used Mundorf Supreme caps in place of the Russian paper items.

BTW The Krklec OPT referred to is no longer available. I would now recommend a 2k5 or 3k5 unit, the lower impedance seems to give a sweeter sound.

Brian.
Click to expand...

Cool, even more ideas.

Thanks,
Sheldon
 
#18
Is there a decent tube design that gives about 20-30w, and isn't too difficult for a first time tube DIYer?

Is this design any good?
http://www.lundahl.se/claus_b.html

Or for a lower powered design:
http://www.lundahl.se/claus_b_se.html

I know very little about tube amps, but want to build one to compare. The above amps were the first one I stumbled on through google.

Also, the above amplifiers use output transformers. The SE one is specified as 8w/8 ohm. Will this cause problems if my speakers are 4 ohm? The output transformer doesn't appear to have a 4 ohm tap.

--
Brian
 
#19
Hi Brian. Gonna try some tubes huh? You should have no problem from what I have seen of your SS amps. I have a SE EL34 that I built and I could send you the schematic. Actually it's probably on this site. The big question is do you have the sensitive speakers that are required for low power tube amps. If not you may have to do a PP amp which is a little more complex but certainly should be no problem for you to build either. Decide on the minimum power requirments for the speakers you have and go from there.
 
#20
This one is also fairly simple ... 6 parts + a tube + OPT per channel plus powersupply...

http://www.t-linespeakers.org/tubes/SEP_50EH5.html

a whopping 1.4 W ... not much bass with the tiny OPTs (but someone did build the $405 version -- ie add $400 of Lundahl iron, and reported that it sounded very good).

You could get the parts count down to 4 or 5 parts if wired in triode... maybe even 3 if you lost the cathode bi-pass (but now you are down to 500 mW or so). Maybe even lose the grid stopper... now its 2 resistors per channel ... i think i'll have to try that :^)

An externally hosted image should be here but it was not working when we last tested it.


dave
 
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