Many thanks X!
In this moment I will start listening. Had a short delay because of a defective internal signal cable, I thought it's the amp, but luckily everything is fine now.
Hi Anand, man thanks! I very much stick to the industrial design for whatever reason@Plott
Absolutely superb execution and industrial design Plott, I love it! 2 BIG thumbs UP!
More pics please!
Best,
Anand.
- glad you like it 
Pics will follow next week - I have to change both switches... The output selector switch was broken after switching 5 times... I have now ordered two new switches, they will arrive next week. And I will take puctures.
First impression after just a few songs: WOW!
This amp sounds gorgeous
Period. It's very dynamic but at the same time very relaxed, not strained, not exaggerated.It creates a huge soundstage with depth and width and height, the instruments are placed very well. Singing - beautiful. Chantal Chamberland stands in front of me, her voice is completely natural, the s-sounds are perfect. Goosebumps.
All these comments concern the tube output.
I’m glad you are happy. More people need to know how good this preamp sounds. It’s one of the reasons the EP600.2SE sounds so good. The LSA HyperDrive-2 headphone amp uses the same tube buffer topology.
Enjoy your beautiful creation - now you can go through your music collection all over again.
Enjoy your beautiful creation - now you can go through your music collection all over again.
Returned on my bench for several days, but finished this afternoon : my Audio Research SP3A1 from 1974...
The gain difference between both channels L and R - in any input mode and at any volume level - is less than 0.1dB at 1kHz sinus, now. All the other controls are also well L-R balanced also.
What I still have to refine is the RIAA of the phono section, where I measured gaps up to 2dB at the extremes, due to unexpected R or C drift values : the parts will be ordered soon...
T
The gain difference between both channels L and R - in any input mode and at any volume level - is less than 0.1dB at 1kHz sinus, now. All the other controls are also well L-R balanced also.
What I still have to refine is the RIAA of the phono section, where I measured gaps up to 2dB at the extremes, due to unexpected R or C drift values : the parts will be ordered soon...
T
On the bench tonight is the rev B of the Line Noise Black Hole. I have reduced it down to two CMC’s in a 5th order Chebyshev filter the achieves a predicted -55dB at 100kHz and -47dB at 60kHz. I tested it at 60kHz and measured 2.8mV out of 508mV for -45dB, close to -47dB.
Good for 10A of current at 110 to 230vac. Built in triple MOV/GDI lightning suppressors for protection of your equipment from HV spikes. It’s a very compact and robust package now.
Good for 10A of current at 110 to 230vac. Built in triple MOV/GDI lightning suppressors for protection of your equipment from HV spikes. It’s a very compact and robust package now.
Hi Tubelectron,
Thanks! I really use it all the time - it’s as integral as my Fluke multimeters where I use this type of instrument/meter on a daily basis. It has a built in function generator so makes for a perfect one unit testing solution.
I love your vintage preamp - that is a nice looking piece of gear. Very cool to have a bit of history when listening.
Thanks! I really use it all the time - it’s as integral as my Fluke multimeters where I use this type of instrument/meter on a daily basis. It has a built in function generator so makes for a perfect one unit testing solution.
I love your vintage preamp - that is a nice looking piece of gear. Very cool to have a bit of history when listening.
Thank you @xrk971 and @poseidonsvoice !
I think that I will offer me one as a complement for my current bench (below) as a compact, portable checking tool...
T
I think that I will offer me one as a complement for my current bench (below) as a compact, portable checking tool...
T
In the bench tonight is the Desktop Diamond Plus (DDP) Headphone Amp designed by Jhofland. It is similar to the Desktop Diamond Buffer HPA but has a built in AC/DC PSU with a filter and low dropout voltage regulators. Plus a solid state relay headphone output protection with turn on delay to prevent turn on thunp, and instant off to prevent turn off thump. Also includes a 3 way selector for 0/6/12dB Gain.
I am using a 1kHz Akitika oscillator and Focusrite 4i4 audio interface.
Max power before clipping into 33ohms is 7.0vrms. That’s about 1.5Wrms.
The THD is 0.011% at max power.
At a more reasonable power level of 1.00Vrms (30mW into 33ohms) the THD is 0.0013% and FFT is all second and third harmonic with dominant second:
The noise floor measures 850nV rms. The 60Hz mains peak is at 5uV rms. This means that the amp is absolutely silent with no music playing.
But if I increase the gain in the input output of the Focusrite by about 15dB to fully utilize the dynamic range, the THD is now only 0.00064%:
Here is the test setup:
Amp:
I am using a 1kHz Akitika oscillator and Focusrite 4i4 audio interface.
Max power before clipping into 33ohms is 7.0vrms. That’s about 1.5Wrms.
The THD is 0.011% at max power.
At a more reasonable power level of 1.00Vrms (30mW into 33ohms) the THD is 0.0013% and FFT is all second and third harmonic with dominant second:
The noise floor measures 850nV rms. The 60Hz mains peak is at 5uV rms. This means that the amp is absolutely silent with no music playing.
But if I increase the gain in the input output of the Focusrite by about 15dB to fully utilize the dynamic range, the THD is now only 0.00064%:
Here is the test setup:
Amp:
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