• 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.

The best valve amp!

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#21
aLLoU said:
Are you absolutely sure that for this kind of speakers 5W is enough???

They seem a bit low and weak...

Unfortunately i'm not wealthy, so i don't want it to be very expensive.
Click to expand...

Go for 25w per channel max and do push pull. The circuit will be cheaper to build and you will get a better power out to power in ratio..

The output transformers will be cheaper as well! 🙂


Regards
M. Gregg
 
#22
Post a value in money you expect to spend on components.

Then members will be able to give you more help!
Also they will suggest circuits for you to build..

What about a baby huey amp....

Are you expecting to build a top flight amp or just a very good sounding amp?
Audiophile grade megga bucks or Mid Fi....what kind of source are you going to use?

Regards
M. Gregg
 
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#23
When you ask the question (the best)

It depends on music type and you...some people like SE some like PP some like PPP some like OTL....

The topology of the circuit will depend upon many things...Are you going to play classical music...rock or soul...Volume level ...club ear bending...small room piano....jazz......it goes on!

You need to provide more information...

Regards
M. Gregg
 
#25
There are many ways to build great sounding amplifiers, based on creativity, money and skill. IF you want a PCB based amp that is easy to build with 20 to 125 watts/channel there is Pete's big red board. There are numerous ST70 type clones and kits, ST35 PCB kits and more point to point options to make your head swim.....
I consider the most important choice is the output transformer and them match output tubes and power transformer to it. Attached are a few photos of home designed PCB based amps made from the toner transfer etch method, one is 6550 based ( UL and triode) with Hammond 6.6k outputs and the other is a 6LB6 based ( triode) with Hammond 6.6k outputs.
Also there is a ST70 clone, at least that is where it started. The only ST70 parts in it now are the bias adjusting pots, everything else is modified. 1/2 PCB like the St70, but 6SN7 for the first gain stage with a LTP and constant current sink for the 2nd stage, 1/2 point to point wiring like the ST70.
If you do not want to do wood work, sheet metal work you can buy a complete kit, just some assembly required, or a complete white page everything from scratch. It doesn't really matter what you do as long as you learn and have fun while doing it. The enjoyment lasts for yrs as you enjoy the sound stage and clarity that a tube amp presents.
 

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#26
aLLoU,

What ever you build it will be great fun as long as you or someone is with you that know electronics and the voltages involved..

As above you can have some great fun building these projects..the main thing is don't give up...

Make a list of what size room you are using it in and music type..an idea of buget..and you will get loads of help..

Nice pics roline... 🙂

Have a look in the Photo Gallery..... all sorts in there..just remember this is a journey.....we all start somewhere....and we don't know what you have done before 🙂

Regards
M. Gregg
 
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#28
The room is about 28m2 or 301f2.

I play mosty classic rock (not the sh*t that is produced nowadays), pop, house and greek music.

I want to have respectable power (but not too much, i guess 25wpc will do the job), and music quality in the whole frequency range.

The source is a pc with hundreds of flacs and high quality mp3s.

For the amp i believe that PP or PPP suits for me, but i'm a bity confused about the differences between class A, AB and B.

About the maximum cost, i would prefer it if it doesn't exceed 400-450€ or 550$.
 
#29
Hi alloU, a nice article to read about usable power of any amplifier is nicely explained by S. Deckert of Decware audio... a must read article!
Please check this site: http://www.decware.com/newsite/paper110.htm

I would personally recommend a OTL amp or maybe 300B SE amp with mono-block power supply configuration...

Some time ago I thought 300B amp was the best in the world until I heard 2A3 SE & later OTL amp's side by side, but 2A3 SE want's at least 90db+ sensitivity from your speakers...

And, this is my example of 300B with active high-voltage regulation ( 2x6550 as pass tube per channel ) which was working very nicely with Rogers LS3/5a speakers ( 11 Ohm, 82,5 db )...

Max
 

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#30
Very tight budget at $550 max, not really in the territory of 25W per channel unless you are very careful. You might get there with Pete Millett's red board design - google for the details here. I think on that budget this is your only hope. Note that if you are willing to acquire the bits and pieces over a longer time much more ambitious projects are possible.
 
#31
aLLoU said:
About the maximum cost, i would prefer it if it doesn't exceed 400-450€ or 550$.
Click to expand...

new products

35watts per channel, $555 + 25 shipping in the U.S.

That's about the best you're gonna do unless it's completely DIY with parts found at a Hamfest.

It doesn't sound like you live in the U.S. If that's the case then you need to be a heck of a lot more specific about that. If you're in Europe, I don't have a clue what's available. You're probably better off buying something old and fixing it up in that case. I'm sure European kits are going to be more expensive than this one.
 
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#33
Thank you all for your advice, but i want to do it form scratch,

more specifically, i want to search the local market for parts and build the amp from zero,

based on a good schematic which could be either from a famous brand or a good diy design.

I don't want to buy any ready diy kit.
 
#34
dirkwright said:
new products

35watts per channel, $555 + 25 shipping in the U.S.

That's about the best you're gonna do unless it's completely DIY with parts found at a Hamfest.

It doesn't sound like you live in the U.S. If that's the case then you need to be a heck of a lot more specific about that. If you're in Europe, I don't have a clue what's available. You're probably better off buying something old and fixing it up in that case. I'm sure European kits are going to be more expensive than this one.
Click to expand...

Dirk, this amp is 17 wpc
 
#35
Here's what I did.

I bought an old Magnavox mono console from the want ads for $50.
I scored the matching mono amp from eBay for $35 plus shipping. (~80 total)

Now I have two big output trannies, tube sockets, tubes etc.

I mounted both amps into one cake pan. One power transformer was strong enough, because it also powered a seperate tubed tuner and lights.

I bought a resistor and capacitor kit from "Just Radios", I think around $100 or so for both. I have lot's left over for other projects.

All-in, I have less then $250 in my 6V6 PPPamp. (Push-Pull Parallel.) I say it's 20wpc just to be conservative because I really don' t know, I'd have to do the math. I've been told it's more like 30wpc.

As a general rule of thumb 15wpc will be the same volume as a LIVE show.

Have fun
AL
 
#36
Its time for you to do some research..

On this forum e.g This is not my build just the title of a thread

http://www.diyaudio.com/forums/tubes-valves/158322-my-kt88-williamson-amp-build.html

You need to collect information about cost of output transformers and any power transformers chokes....

then a list of components like volume controls...and binding posts for speakers input supply sockets etc...

When you have something within your buget then get the Iron first this is the most cost...tube sockets etc..


The above is just an example...if the cost is to high then go for lower power and ease of build..search this forum for baby huey amp look at the diy projects forum as well!
http://www.diyaudio.com/forums/tubes-valves/72536-el84-amp-baby-huey.html

Here is an example of how one of my small projects happened ..read the thread just to get an idea how it all happens (10w per channel sounds great)
http://www.diyaudio.com/forums/tubes-valves/179200-any-thoughts-circuit-11.html <<<if you want I can post the schematic


Regards
M. Gregg
 
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#37
one way to keep costs down is to salvage parts - for example, an old solid state stereo amplifier might be a good source for a metal box with power switch, connectors and volume control already in place. Look for Russian equivalents to the tubes you want and get them from ebay including tube sockets and russian PIO capacitors, consider 6V6 as the output tube as it's readily available and well regarded, Hammond and Edcor for transformers depending on shipping costs etc. (Hammond make some nice DIY tube chasis too)
 
#38
Bigun said:
one way to keep costs down is to salvage parts - for example, an old solid state stereo amplifier might be a good source for a metal box with power switch, connectors and volume control already in place. Look for Russian equivalents to the tubes you want and get them from ebay including tube sockets and russian PIO capacitors, consider 6V6 as the output tube as it's readily available and well regarded, Hammond and Edcor for transformers depending on shipping costs etc. (Hammond make some nice DIY tube chasis too)
Click to expand...

Good tips I'd say, however shipping from Carlsbad, NM to Europe might be expensive enough that a local vendor could beat Edcor on price, although I have to say I am pretty pleased with the custom power transformers they have made for me.
 
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