OT: Show us your DIY tube amps

[alancohen]

Done!

Click the watch at just over 4 hours including 1/2 hour for lunch.



If you can build a Lego set and make a decent solder joint, you can build this kit. The step by step instructions are superb.

[RonSSS]

I bought the low cost line for my 300B monoblocks. I need 8 total so $300 ea was not in the cards for me for the primos. The HiFi ones look pretty good construction-wise:

To quote the designer of my amps: Fully 99% of the sonic characteristics reside in the design. Circuit topology controls everything. The designer manipulates inter-stage impedances, time constants, signal headroom, feedback and many other parameters to achieve a desired result.

I tend to agree with this. I'm not a believer in designer caps, argon treated wire or any other audio hocus-pocus. I believe in a well designed circuit that will perform properly with a reasonable range of component tolerances.

I got matched quads for my new project, but he says that's not even necessary.

But you haven't tried them out yet correct?

FWIW, I'm the designer of my amps. I'd post the schematic, but I wouldn't be able to bear the ridecule....... :-)

Ron

[alancohen]

But you haven't tried them out yet correct?

FWIW, I'm the designer of my amps. I'd post the schematic, but I wouldn't be able to bear the ridecule....... :-)

Nope. I just got an email from Bruce with a tracking number. They're on the way. I have serial # 000000001.

And I aspire to one day know enough to laugh at your designs, although i'm impressed by anyone that tries. I just got a combo scope, signal generator and DC PS. I want to start learning.

[Alien_Shore]

This is great - thanks for sharing all the advice, experience, and opinions. One of the better threads we've had in a while.

By the way, I agree with you Alan - I do have an electronics background ( a few classes, but nothing like an EE degree or anything), but hardly know enough yet to design my own amps...I too hope to get there one day. Hell, I hope to be able to alter some of the stock kit designs without blowing stuff up or killing myself.

[RonSSS]

And I aspire to one day know enough to laugh at your designs,

Note that I've not bragged about the sound, etc, just that it's my design. Nothing revolutanary to be done with tube circuits. I kept them simple. was more thinking about Low Ohms coming back on here and commenting about too complicated of a signal path, bypassed cathode resistors and lack of detail due to the parts I chose....you know.

I'll look into thos PSvane 300B, and the JJ as well.

[Old Guy]

I have a very poor opinion of Low Ohms...I consider him a dead short...

[zelgall]

You're cracking me up.
Lo-mu or Low ohms, wherever he goes stirs up controversy. That's his gig. He claims to be open to personal experience but only if it coincides with his.
I think that he has a problem with the obvious.

[alancohen]

At last, my OTL 300B kit has arrived.

As far as I know this is the first time an OTL circuit has been designed for the 300B triode. It's a very tricky circuit since with a 300B tube, the cathode IS the filament. Using it in an OTL amp places the filament in direct contact with the speaker, since there is no coupling transformer. The filament is A/C heated which opens up the possibility of filament hum directly to the speaker.

While the hum was very slight, and most would not have bothered, the issue was virtually eliminated by a dedicated filament power supply that converts 60Hz A/C to 25Hz. So there is still a slight hum, but it now resides below the capacity of almost all systems to reproduce it. For all intents and purposes, the amp is now dead quiet. Pretty cool.

So maybe all hasn't been done in tube amps just yet...or maybe now it has

Here's the filament supply parts waiting for my coffee to be ready.

[alancohen]

PSU is almost done and I'm working on the left channel amp. Populated the chassis last night and now working on wiring it up..



Yes, that's (4) 300B sockets...and that's just the left side.

[LowOhms]

Done!

Click the watch at just over 4 hours including 1/2 hour for lunch.



If you can build a Lego set and make a decent solder joint, you can build this kit. The step by step instructions are superb.

Alan,

Cut those tie wraps that are bundling the wires together, and discard them. Tie wrap bundling of wires is a no - no, unit will sound slightly better when wires are unbundled, floating in free space.

Also, where the board goes front to back on the left side, change that totally to individual high quality wire paths spanning directly from the rear of the preamp to the front of the preamp.

You get two benefits, first, you eliminate two unnecessary solder joints ( ugh, in lowest-level input circuitry), and you get REAL wire to carry the signal, rather than a crummy PC board trace that, to one degree or another, degrades the input signal.

A high quality audio wire run is always better sounding than a PC board trace. Alan, since you are newbie on a budget, learn to use Kimber Kable TCSS, retails at $1.20 a foot, fairly neutral.

I got a kick out of you guys speculating about "me". That is pretty funny !!

Hey Ron SSS, et. all, I see you mentioning MDs and Lipitor. There is a great book I'd like to suggest you order from Amazon and read...it will resolve many medical problems. " Eat To Live " by Joel Furhrman, MD. Last time I checked, a while back, it was in the number ONE position on the NY Times best seller list, Non Fiction, and it had been on the list for 66 weeks.

THAT book will be a great answer for many of us older people. Check it out.

Low Ohms