Presentation of my SE EL34 tube amplifier
Hello to all forum members, I am writing my first post so please be understanding! I would like to present my amplifier and get your opinion on the appearance and used lamps and other components.
The amplifier is a typical Single Ended based on EL34 tubes in the power stage operating in triode and pentode mode (change with a switch) and ECC82 in the preamplifier working as a white follower, EM84 as a drive indicator and one EAA91 as a signal rectifier for EM84 tubes. The amplifier has a semiconductor bridge rectifying to the anode voltage and it is the only semiconductor used in it. I decided to use a CLC filter for the power amplifier and a CLCRC filter for the preamplifier. The total capacity of the capacitors for the anode voltage is 362 uF. The capacity is sufficient because the only hum comes from the magnetic coupling between the loudspeaker and mains transformers (I checked). The choke has 8.1H and 140mA of allowable current, 20mA reserve. The anode voltage at the first electrolyte is 270V and about 245V at the EL34 anode. Ug1 = -14.5V.
Initially, it was powered by an Elpo stabilized power supply, and then from a network transformer scrolled on request, its power was about 100VA, Ua = 230V, Uż = 6.3V, measured under load. A loudspeaker from Telto, I had tubes.
The amplifier worked from the first start:
- hum is a single mV
- no excitation at low and above acoustic frequencies, measured with an oscilloscope
I did not measure the power and I will not say about the sound because it is the first tube amplifier I have ever heard, but it satisfies me (a bit weak bass but without exaggeration)
Here are photos from the completed project:
And here are photos from the formation and others:
And here are the diagrams from which I was based, but I changed them a bit (e.g. adding a triode / pentode switch)
If you have any questions, write to us.
woda400 wrote 63 posts with
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Live in city Tarchały Małe.
Been with us since 2009 year.
Comments
And another DIY lamp looks interesting. Did you have any fun with finding the optimal weight during startup? What are the costs of its implementation? [Read more]
The gain stage is not a duplicate, but a WK with an active load. [Read more]
When it comes to looks, it's not a revelation. I would do something like this myself, but I don't have time. Why did you choose the ECC82 in this configuration? I keep wondering what to put in... [Read more]
Saying "I would do it myself, I just don't have time" reminds me a bit of the old Soviet saying at a party meeting in a factory: "we would make canned food if we had meat, but we did not have a tin."... [Read more]
Speaking of the appearance, I am not so proud of myself, but I wanted to do something on the tubes, I chose the ECC82 because I have several of them, and besides, I read that in this configuration you... [Read more]
Hello. Congratulations on the committed amplifier. What does the colleague drive with this system and in what room? Regards nitros66 [Read more]
I would like to add that I do not have one EM84 lamp, as you can see in the photos, I have to buy it someday, but when you put it on the other side, it also works properly. Added after 6 [minutes]:... [Read more]
Basically ok, but you might have thought about a different layout of the elements on the carrier board - those scattered capacitors spoil the look. You could have placed them on the side of the transformer... [Read more]
Mark II admits my mistake this configuration is actually WK with active load, I confused these two configuration names. I am waiting for further opinions and questions. Regards, Woda400! Added... [Read more]
Hello I would like to know where you obtained / where did you buy a choke from the power supply (in older descriptions it was an ordinary mains transformer with the primary winding used) because apart... [Read more]
The choke comes from the school's type 2 anode power supply, here is the photo of this power supply: http://obrazki.elektroda.net/5_1289333797_thumb.jpg As for the network transformer in its... [Read more]
in my opinion, the stickers on the front panel do not fit a bit, but overall a good job ;) [Read more]
Hello, you came out with a very nice amplifier, a simple simple circuit (in my opinion the best, especially when it comes to tube designs), instead of stickers on the front panel, make this panel on your... [Read more]
I know that the stickers came out lame and in addition they came off, so I peeled them off and I'll think something about it. Yes, you are right, the equalizer is Unitra FS 032, age-old, which fits... [Read more]
The amplifier is almost nice, but it almost makes a big difference. Can anyone answer the question why almost all tube amplifiers are mounted on a "spider" and almost always unsightly? [Read more]
And where do you see the "spider" mount here? This is a traditional spatial assembly on connectors, next to turrets, the best way to build lamp devices. [Read more]
You know, this is only my first larger project, you have to learn everything one by one to get to the practice. Only then can something look like a factory product. I'll try more for the future, but... [Read more]