Thinking of building my first tube amp. Suitable projects?

[Erik Johansson]

I would like some help to choose a suitable tube to build as my first tube amp project. I´m not a complete newbie in electronics ie I´ve been soldering for 6 years (electric powered model airplanes) so it doesn have to be EXTREMELY simple but instead i want to build a good amp that lasts a long time.

I would like to spend not more than US $300-400.

I would prefere an integrated amp but I understand there aren´t that many around so of course a preamp / poweramp is ok too. I would then probably build the poweramp first and use the pre-out jacks of my Harman/Kardon HK3370 receiver.

I just got my first HIFI system last week when I turned 18 consisting of: Harman/Kardon HK3370 receiver, Harman/Kardon HD750 cd-player and a pair of very nice QLN 604 speakers. I might build a ProAc Response 1SC clone if I build this tube amp).

As you´ve probably already understood I´ve been busy for the last month studying everything I can find about this lovely hobby and speaker/amp building as I love DIY stuff. I´ve been into model airplanes for 8 years and now i consider HIFI to be a fun new challenge.

/Erik

[Erik Johansson]

I´ve been looking at this integrated amp: http://httpd.chello.nl/~j.deckers05/tg84en.htm

It looks pretty straight forward and especially the psu looks really simple.

/Erik

[Erik Johansson]

Although as stated above. If there is a suitable preamp/poweramp combo that can be built for less than US $600 I´m very interested as it gives me more flexibility later.

/Erik

[Freddie]

Andrea Ciufolli has some nice tube amps, however they might be quite expensive to build.
http://www.geocities.com/ResearchTriangle/8231/

/Freddie

[dice45]

Originally posted by Erik Johansson




[B]I´ve been looking at this integrated amp: http://httpd.chello.nl/~j.deckers05/tg84en.htm

Erik,




looked at the schematics; this is way below what can be achieved with those components, apart from that, where do you get the output trannies from?









Too simple. Hurts Einsteins "make things as simple as possible, ........ but not simpler".









If i would be you, i would




1st




let the 300-400$ limit go




2nd




build a separate preamp (line preamp) and power amp. You will learn a lot more







And i would stick with the EL84 as power output tube, preferably triode wired. Sonically the best indirectly heated output tube i know.







Please scan the other threads here, there are some serious hints for line preamps from ultra cheap to simple/superexpensive (5687/Shilton trannie). Look at Manfred Huber's homepage http://home.t-online.de/home/MHuber/ ; Manfred's designs all work incredibly good (currently i have a preamp and power amp borrowed from him and seriously doubt my designs wiil reach this level; no retail devices did so far). There also are hints for chaepskates

[Mohan Varkey]

Erik,

It feels nice to see younger folks come on to the tube arena. This forum must be doing something right.

What is the sensitivity of your speakers? I mean how much (Sound Pressure Level) SPL per watt at 1 metre? This will help to determine your power requirement.

I guess that being in Sweden, you may become an unfriendly neighbour if you play your system too loud. Perhaps 100dB should be the peak level that you could consider. Here in Australia, I have a 6.5metre long and 5.5metre wide room. My normal listening level at 3.5metres from speaker is about 83dB.

Let us say that your speakers are specified as having a sensitivity of 86dB/1W/1m. Then for every 3dB you need to double your power requirement as follows.
1W - 86dB
2W - 89dB
4W - 92dB
8W - 95dB
16W - 98dB
32W - 101dB
64W - 104dB
128W-107dB
Once you determine your power requirements, then your choice of amp project becomes easy.
I gather from your comments that you want to make just one amplifier for life and then perhaps, pass it on to your grandson. Yes, valve amps can be handed over from generation to generation. This is the way most of us started in this field.

For a start, do not worry about your budget limitations. I am sure that there are some good Samaritans in this forum (in Sweden) from whom you may be able to borrow or purchase output transformers. Tube fanatics always have unwanted parts lying around!

Welcome once again.

Mohan

[PassFan]

Erik:
Try this link http://gabevee.tripod.com. He has a 15 watt push pull that has an integrated preamp built in or you can buy it without. His kits come with all hardware mounted and the transformers wired. I just built his 6L6GC sinple ended amp and man what a sound. Gabe took real good care of me and he answers e-mails quick. Good Luck

P.S. I have been flying gas powered for about 4 years

[Erik Johansson]

Originally posted by Mohan Varkey
Erik,

It feels nice to see younger folks come on to the tube arena. This forum must be doing something right.

What is the sensitivity of your speakers? I mean how much (Sound Pressure Level) SPL per watt at 1 metre? This will help to determine your power requirement.

I guess that being in Sweden, you may become an unfriendly neighbour if you play your system too loud. Perhaps 100dB should be the peak level that you could consider. Here in Australia, I have a 6.5metre long and 5.5metre wide room. My normal listening level at 3.5metres from speaker is about 83dB.

Let us say that your speakers are specified as having a sensitivity of 86dB/1W/1m. Then for every 3dB you need to double your power requirement as follows.
1W - 86dB
2W - 89dB
4W - 92dB
8W - 95dB
16W - 98dB
32W - 101dB
64W - 104dB
128W-107dB
Once you determine your power requirements, then your choice of amp project becomes easy.
I gather from your comments that you want to make just one amplifier for life and then perhaps, pass it on to your grandson. Yes, valve amps can be handed over from generation to generation. This is the way most of us started in this field.

For a start, do not worry about your budget limitations. I am sure that there are some good Samaritans in this forum (in Sweden) from whom you may be able to borrow or purchase output transformers. Tube fanatics always have unwanted parts lying around!

Welcome once again.

Mohan

Yeah it´s the transformers that are expensive! The best ECC83 tubes a Swedish store had (from Ruby tubes) was only $14. I though a tube would cost like $50

The best EL84 from the same company was also $14 so the tubes for the integrated amp i linked to above would only vost mer $84 here in Sweden.

I don´t want to build an amp that lasts a lifetime. Just a GOOD one that doesn´t need to changed in like 6 months because it doesn´t sound "that" good.

I´m sure I´ll build many more and try to design some in the future as I love this kind of project.

/Erik

[planet10]

Originally posted by Erik Johansson
I´ve been looking at this integrated amp: http://httpd.chello.nl/~j.deckers05/tg84en.htm

This one salvages OPTs from a Dyna SCA 35 -- if you go the salvage route, a Scott LK48 (or the factory-assembled 299?) is a better place to start for about the same money -- better OPTs, a nice aluminum chassis, and point-to-point wiring.

dave

[J Epstein]

Erik,

Bob Danielak designed a low-powered amp called the "Darling" that has been an ideal first project for many people. I revised the design and now there is a "family" of related amps, all of which should probably fit your price range.

My Darling page is here, with links to Bob Danielak's and an article I wrote for Sound Practices just as it ceased publication:

http://home.earthlink.net/~ellenoler/darling.html

These amps are about 1.5 watts per channel maximum and are recommended for use with efficient speakers. I'd be happy to answer questions on them as best I can.

-j