Post pics of your builds....
Oct 23, 2015 at 1:00 AM Post #9,736 of 9,811
Didn't know that Rod can custom his boards...I got a few boards from him too, for my 45 and 300B projects.  Did you consider to include 45 into the mix (OPT may need switching for correct impedance)?  Truly nice work on the P2Ps; my P2Ps look like a spider web.
Oct 23, 2015 at 1:34 AM Post #9,737 of 9,811
I don't know whether the board was custom. He may just have included the additional dropping resistor for R2.

And yeah, the primary impedance for the OPT is 3.5K. Not suited for the 45. And trying to build for three distinct output tube is a bit too difficult. Note that I am also switching the secondaries of the power transformer with a high voltage relay. In order to dial in appropriate operating points for each output tubes.

I do plan to use the 45 in my next build: a D3a/45 DRD headphone amp, pretty much a copy of the one you made a few months ago. :D
Oct 23, 2015 at 4:37 AM Post #9,738 of 9,811
Finally I would like to thank some audio masters...

@ Kolyas:  Nice project... you could have mentioned that you also obviously took inspiration from my C3G SET amp 

No pun intended.
Oct 23, 2015 at 10:25 AM Post #9,739 of 9,811
Both D3a and C3g are fine tubes.  Let us know how you like your 45 DRD.  My 45 DRD drives the HD800 beautifully; probably the best I've heard from the HD800.
Thinking about doing a 300b DRD but the heat through that bottom cathode resistor gonna be horrendous.
Oct 23, 2015 at 11:09 PM Post #9,741 of 9,811
Finally finished up my second LM3886 Chipamp build. My objective was to create a solid state amp that didn't look like a solid state amp, to get away from that idea that SS amps are just big black blocks with heatsinks. In this case I hid the heatsinks on the inside and positioned the toroids out of the main chassis to give a more vintage, tube-amp like look. Chipamp PCBs, DIYAudio Soft Start board, and Cardas wire and connectors are used throughout. Kilo knobs adorn the front, and Antek torroids and torroid shields sit on top. The chassis is made by Horace Atkinson of, VERY solid .125mm aluminum with figured maple wood accents. I opted to finish the maple my typical red stain, but with a glossy finish this time (took quite a few coats). The chassis and shields are powdercoated for a nice durable finish. 
Additional parts include 100uF Clarity Caps w Sonicap bypasses, Elna Silmic electrolytics, Nichicon power filter caps, Wima PP film caps, Audio Note Tantalum and  Takman film resistors.


Ended up being a nice tight build with little wasted space. Features 5 inputs and subwoofer output, the wattage output is (I believe) ~68 watts. Sounds very nice, a bit more refined and "present" than my previous attempt. I'm sure the film caps and separate power supplies have something to do with that. Still presents a mildly warm, natural sound with a bit of emphasis on the top end. Compared to my everyday integrated, a Manley Stingray with upgraded tubes, the sound is a bit less emotional and loses some midrange liquidity, but is more crisp and detailed with a bit more force. We'll see if anything changes with burn-in. I'd still recommend this as a nice SS to try for people who usually only listen to tube amps, as it doesn't have that clinical sound that some SS amps possess. 
Nov 10, 2015 at 12:46 PM Post #9,745 of 9,811
Picked up a whole bunch of NOS Western Electric (including some becoming-harder-to-find NOS KS13385L1 WE16GA & WE14GA recently praised by Jeff day: ), some Beldin 8402 for interconnects and other misc NOS the last few weeks!
DIY headphone cables, PCs and speaker cables to come!


I'm excited! 

Dec 21, 2015 at 6:01 AM Post #9,746 of 9,811
Here's a little amp. It's very simple: external 30vdc wallwart, regulated down to 24vdc. Opa134 in unity gain with a class A buffer in the loop followed by transformers set for a voltage gain of 2. All cased up in an old NAS box (I still have to find a nice frontplate, so no external pictures)
Not really suitable for low impedance cans (because of the output transformers, the impedance seen by the power stage is divided by 4) but it works well into high impedance cans. If I wasn't lazy, I could add a switch to change the transformer from 1:2 to 2:1 as wanted.


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