• 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.

Thinking of building my first tube amp. Suitable projects?

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
 
Originally posted by Erik Johansson



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 :)
 
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
 
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:D

P.S. I have been flying gas powered for about 4 years
 
Mohan Varkey said:
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
 
Erik Johansson said:
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

Member
2002-02-08 7:24 pm
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
 
J Epstein said:
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

Only 1.5W per channel doesn´t seem like much.

My QLN 604 speakers have a sensitivity of 90db/W. http://www.qln.se/_604/604.html

I will probably build ProAc Response 1SC clones this summer and use whatever amp I build to power them. Then I´ll still have my HK based system powering the QLNs running in another room.

The Darling looks like a great first DIY project but I´d like something that can power less efficiant speakers and I have now decided that I prefere to build separate preamp and poweramp.

/Erik
 
Erik Johansson said:
Here is a list of all the different tubes I can buy at the store:

That is a pretty good list. Even ECLL800s (at $90 CAD -- ouch -- each). Missing some of the more exotic russian tubes like the 6H30, but there are 6N1Ps. Lots of choice. I'd pick the amp 1st and worry about the tubes later.

dave
 
Erik Johansson said:
Only 1.5W per channel doesn´t seem like much.

My QLN 604 speakers have a sensitivity of 90db/W.

Jeremy's speakers are about 89 dB/W and i know he is happy (BTW J how are those exotic Reggae CDs coming ;^)

I just switched in my 1.4 W (max) 5-buck amp in the lab and it plays my 90 dB/W desk monitors fairly loud, so don't write off the low-watt jobs.

[IMGHTTPDEAD]http://www.t-linespeakers.org/tubes/images/5B_front2_tn.jpg[/IMGHTTPDEAD]

I do find that in my much bigger room upstairs that the 4.5W SEP EL84 won't drive my 89 dB/W BD-pipes to really loud levels (my long term solution is 4 amps instead of 2 and eventually more efficient speakers -- i'd love to get my hands on 4 Fostex FE108ESIIs).

dave
 
More Kits

Try worldtubeaudio.com. Go to the "directory" and then to the "tube kit section" and browse at will. About the best list of kit sites I know.

If you go a few hundred more bucks you really get what you pay for. If you want a keeper, as discussed above, think about your platform and the potential for tweaking it. Diyhifisupply.com has two nice sets. They are getting a US distributor soon at diycable.com . Thorsten Loesch (thunderstoneaudio.nav.to) has modded the hell out of one of their basic units (the "Bessie") and you can get all the details at Audio Asylum so you can take advantage of all of his insights for future mods. That is priceless right there.

Also, one of the standards in sets is bottlehead.com. Great support and forum for further mods too. If you look there take a look at Voltseconds mod page which is listed at the Bottlehead site.

I have heard good things about Gabe's too but have never built one.

Have fun!



Have fun.
 
Erik,

I just had a look at your speaker. Although it is 90dB/1W/1m, its nominal impedance is 4 ohms. Maximum power handling is 250W.

I am not familiar with your speakers. However, I suspect that you need a fairly stiff (read as damping factor) amp perhaps in the 20W-30W range. You are not looking at a simple beginners amp here. Perhaps you should be looking at a push-pull 6L6 or KT88 amp for a start. I could be wrong here. Someone else on this forum could comment on this speaker and amp compatibilities.

It is great that everyone on this forum is trying to help you get started. Do you have friends locally, who may be able to come over to your place with their tube amps for an audition or have you already auditioned a tube amp in your system?

I n the mid nineties, I had correspondence with a few friends over your way. But I have lost contact with most of them. This was through the Lowther Club. If you wish, I may be able to go through my old correspondence and dig out a name or two. Lowther people are diehard fanatics. It is rather difficult to get a neutral opinion from them. But they will have tube amps.

Perhaps you may be aware that there was a Swedish electron tube manufacturer. The name escapes me. I think? that this company was taken over by Outoucompu in the mid seventies.

Mohan
 
I would recommend either trying a kit or working on and modifying an existing piece of gear.This gives you a chance to learn as you go and not have to deal with some of the trial and error stuff that usually goes with homebrewed gear.It also allows you to have something to use and listen to,which is really what it's all about anyway.After you become familiar with what's going on inside,then try building something from scratch.