Expert: Cleggsan - 2/18/2010

Question
QUESTION: Hello! I am interested in building my own tube amplifier from a kit. I would also like to build a receiver. I am looking to spend between $400-$500 for both. Do you have any suggestions? (I am knowledgeable in electronics). What else would I need besides an amp, a receiver and speakers? A pre-amp? I'm sorry there are so many questions. You can answer what of them you wish if it makes it easier. Thank you!

ANSWER: One of the best sites for system configuration and hookup guidelines is www.crutchfield.com or others like unto it. Yamaha, for example, has similar hookup pages.

http://www.crutchfield.com/S-fnwhs15sphV/

http://columbiaisax.googlepages.com/audio_stereo_hookup.htm

http://www.audioc.com/library1/connect.htm

Above are just starting points.

What you must decide is what kind of system you are reaching for:  Just high fidelity audio playback?  Audio and Video for dvd and high fidelity audio?  HD or high definition video as well?  Are you going to be playing just CDs or do you also have a collection of LPs?  78s?  Disco?  Etc.

The loudspeaker system will be the most critical component in the chain of events. It is often best to start with the kind/type/quality of acoustic reproduction then match the power amps and preamps and players to optimize the system performance.

There are tons of web pages to help you sort through this maze of information.  Are you a member of the Audio Engineering Society?  Have you built/designed audio circuits previously?  Or, do you intend to work from other designs?  There are few "kits" around anymore but plenty of Internet readings of tube amps and preamps.  

Are you an audio enthusiast or a music enthusiast?  There are two kinds of vacuum tube users:  One who enjoys the electronics aspect of them or : On who is a music and sound purist and does not believe transistor sound is as perfect as vacuum tubes.  You must decide about that.

There are many places to find tube stuff:

http://diyaudioprojects.com/Tubes/tubes.htm

is only one; google around and you can find many.

Some of the primitive tube amps from Dynaco are very much in demand now days but hard to find.  Early EICO and Heathkits are still in demand as well, both companies have been out of business for many years.  For the high end Velleman and Futterman are still talked about - and so on.

You tell me where you are going and we can discuss further.  But, for now you must do some homework to gets your focus and target more refined.  Best wishes.



---------- FOLLOW-UP ----------

QUESTION: High fidelity audio playback. I will only need two inputs: a phono for a turntable and a stereo for a cd player (which will really be an mp3 player of some sort). The speakers that will be powered are a pair of Polk Audio Monitor 70s. I'm only interested in personal stereo entertainment. I intend to work from other designs, but what I was hoping you could do is recommend a kit (as there is a lack of readily available tube equipment presently) that would modestly fit a music enthusiast's needs. I would like to remove any solid state circuitry from my system. The music will be primarily rock. I am not a member of the AES, but I have worked with circuitry before and have knowledge of soldering and diagrams. I do not believe that a pure sound can be created from solid-state equipment. Thanks for your help.

Answer
Let me not discourage you from wanting to go vacuum tube.  But, from a purely scientific point of view transistor amplification is much more accurate or higher fidelity than are vacuum tubes; especially this is true of vacuum tube amps using iron core output transformers.  Some like the distortion that is produced by vacuum tubes and that is just fine with me.  But, if you want the best performance, from a purely objective, lab measured perspective, transistors are better.

HOWEVER: that being said any good amplifier is an order of magnitude more pure than even the better loudspeakers.  Therefore, the weakest link in a sound reproduction system will always be the loudspeaker system and the acoustic space in which it is working into.

Thus, if you go to tube amp you will want to choose the transformerless design if you wish to stay away from transformer non-linearity  distortion.

And, if you are using a magnetic or moving coil cartridge in the TT you will need an RIAA preamp circuit for proper equalization. Not many tube designs around anymore for that.

I do not make specific equipment recommendations because there are so many subjective issues involved in the choosing process.   Especially this is so with amplifiers for the reasons stated above.

Unless you can design your own circuitry you are stuck with building the circuitry designed by someone else.  Tube amps are more black magic than they are engineering marvels.  Most golden ear "experts" like certain tube amps due to their sound; that is because they all sound a little different whereas good transistor based amps have very little sound differences because they are more pure to begin with.  Therefore, tube amps tend to have a "following" and opinions rage from person to person and magazine reviewer to magazine reviewer based on these "sound quality" characteristics they claim to be able to hear.  If you are a believer in laboratory measurements and properly conducted AB or ABC listening tests tube amps don't come out so hot..... Sorry to say.  So, you will have to make your own choice.  Enough of that; I will get off the soap box.

Hope this is helpful to you.  Best wishes.