• 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.

2.3 watt x 4 or 5 watt x2 SET amplifier using DECWARE Zkit1 and Zkit4 schematics

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hello tube/valve geniuses,

I am I would say a novice in the area of tube amplifiers and am extremely interested in them as I built my own working DECWARE Zkit1 SET amp about a year ago. I love how it sounds on my marantz speaker setup and I recently series bridged it to mono and power my JBL L-100T cabinets with it, achieving shockingly good results for the little thing. :) This among other things started an idea in my head about making a larger set amp out of two of the Zkit1's so I could have 4, 2.3 watt channels or if I series bridged each side, 2, 5 watt channels. If my one Zkit1 could power both my JBl's to a great sounding conversation volume, then if I had this big amp with essentially a bridged Zkit1 going to each individual JBl cab I would have an amp to power them to nice loud awesome volumes. I then said to myself what the hell, while Im at it I want to add a phono pre-amp stage (Zkit4) so I can listen to my turntable in tube stereo awesomeness.

So far my idea will have me building an amp with two large power transformers, one smaller one for the pre-amp, and four nice big output transformers, which means $$$. I just wanted to post on here to maybe get some feedback on the thought, and to see if Im just being plain stupid or not. I would love to know any way of upgrading these amps and making them even better as well. I have drawn up my own schematics to show you all what is in my head, and I will post the DECWARE kit pages below. The kit pages have full parts lists for Mouser.

Zkit1 - Zen Triode SET kit amplifier model ZKIT1
Zkit4 - ZKIT4

Thanks for any input no matter good or bad!!
 

Attachments

  • Amp powersupply.pdf
    304.4 KB · Views: 220
  • Amp section.pdf
    564.5 KB · Views: 262
  • Pre-amp selector and powersupply.pdf
    292.7 KB · Views: 172
That does make sense, I should have thought of that. What if the pre-amp stage is on the line in and then the two sides of the amp pull from the right out and left out of the pre- amp respectively? I dont know what to do for a phono input then, but would that work? Im open to any ideas, I just think it would make it easier to look nice using the Zkit circuit boards DECWARE has available. My first amp I didnt buy the board and tried point to point. I ended up with a rats nest of sorts, but it still works and is only a little bit noisy. Like I said if this is just a plain bad idea just tell me to drop it, but do you know of anything that might be like the concept?
 
Just don't do it...

It is a waste of money to have all these $$$ transformers if you want to acheive just this simple thing. Just make a single ended amplifier with a more powerful tube like KT77, 6L6, KT88

Also transformers and tubes are not perfectly matched, when you bridge them it is not optimum.. Better have one amplifier per ooutput.

And, this Zen kit schematic is pretty horrible in my opinion. Lots of better schematics in here if you search.....
 
Ok so scratch the original bad idea. So what Ive gathered here so far is to look for a
design that uses KT77, 6L6, or KT88. The only one of those tubes Ive experinced so far is the 6L6, and that was in an old peavy guitar amp.

So my next question is which of those tubes will yield a better amp. I know "better" being relative, but is there a strongest one? Do the KT tubes have similar characteristics? Any of them have better bass response than the others?
 
All KT's are different, they have rough equivalents in other output tubes

KT66=6L6
KT77=EL34=6CA7
KT88=6550

Of these, KT7/EL34 are easiest to drive, and KT88/6550 are the most powerful
You can find a lot of schematics for all of them in here and with google

Bass response is in the transformer and the circuit...
 
Look at the Tubelab SSE, Depending on tube choice you could have anywhere from 3W to 14W power. I went with all Edcor transformers. The CSXE outpot transformers are spendy at 80 something each but cheaper than the equivalent Hammond and they sound INCREDIBLE. Running my SSE with KT88's right now and switchable from Triode to UL. Also can switch CFB in and out and select SS or Tube rectification. It's an easy build and the Forum here has plenty of help available. Check it out.
Paul
 
Thanks Paul, this design looks promising as well thanks for the information. As for the transformers I know now that its better to wait and save up for the nicer ones so I wont be worrying about the cost there, Ill make it happen. On yours do you have a preference of tube rectification or solid state?
 
Looking back at your first post it looks like you may expect a 5W amp to play a lot louder than a 2.3 W amp. This isn't so. Volume is in a log-metric scale which means doubling the power will only give you 3db more output which is usually regarded as just noticeable. To seem twice as loud you need an amp that has 10 times the power.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.