Gareth, they look like 4 output pairs in parallel to me, and the inductor and the resistor are both part of Zobel network. Right?
You right.
Member
Joined 2009
Paid Member
I'd like to share my contribution to the hybrid amp family: ANUBIS. It was built on what was an all solid state power amplifier PCB, something not unlike Rod Elliot's P3A. With some minor modification and creativity, almost any Lin Topology amplifier PCB can be used.
Click here for more info.
Click here for more info.
Attachments
Hi
I made IOTA-CD few years ago, and tried to measure some characteristics with an USB soundcard (Behringer UCA202; 16bit, 48kHz), but only that i could conclude is that amplifier distortions (phase, harmonic, IMD) was below soundcards level, so it was unmeasurable with that "equipment". Only that i could measure precisely is a frequency response, and it's flat in the measurement range of the sound card (<24kHz).
I can't compare it to the DOGC-MK3, I din't listen DOGC enough and in the same conditions as this amp, but I can tell that IOTA-CD sounds very nice to me, and other people who listened it shares the same experiance.
p.s. sorry for my bad English
I made IOTA-CD few years ago, and tried to measure some characteristics with an USB soundcard (Behringer UCA202; 16bit, 48kHz), but only that i could conclude is that amplifier distortions (phase, harmonic, IMD) was below soundcards level, so it was unmeasurable with that "equipment". Only that i could measure precisely is a frequency response, and it's flat in the measurement range of the sound card (<24kHz).
I can't compare it to the DOGC-MK3, I din't listen DOGC enough and in the same conditions as this amp, but I can tell that IOTA-CD sounds very nice to me, and other people who listened it shares the same experiance.
p.s. sorry for my bad English
Fact is that IOTA-CD sound really marvelous, but I don't think it is because of tubes in LTP, for, DOGC-MK3 and DOGC-H sounds at least equally good. Primarily, difference is in “character” of overall sound and for me it is hard to describe that by words.
>>Just to make a hybrid amp for fun, excercise etc......<<
Frankly, all of that together and also that include challenge and curiosity, but certainly not because I believe tubes are better or that they will bring some superiority regarding sound or anything else.
>>Just to make a hybrid amp for fun, excercise etc......<<
Frankly, all of that together and also that include challenge and curiosity, but certainly not because I believe tubes are better or that they will bring some superiority regarding sound or anything else.
Hi Kacernator,
I'll try to explain. I have designed a number of hybrid amplifiers, involving 12AU7 tubes.
First of all - from engineering point of view.
Most of the amplifiers use NFB, that corrects lots of non-linearities and other unwanted artifacts. However, in order to have the amp as good as possible with NFB loop closed, we need to have it as good as possible with the loop open. Active device(s) at the very input is extremely important.
Some tubes have got a unique combination of characteristics, combined in one part - low noise, high linearity, low input capacitance, unique "soft" behavior when slightly overloaded, resulting in excellent handling of fast transients at the edge of amplitude swing.
See my live measurement results for one of my latest designs >HERE<
Soft clipping, square wave handling, THD, inter-modulation... you would rarely see THD at 1KHz and 20KHz being the same. Outstanding phase response.
Measurements of the whole amp with 8 ohm load, utilizing this front-end is >HERE<
Output stage slows down the whole thing a little as expected, but it is still showing very high performance.
Now, sonically, it results in a very natural sound reproduction. Excellent micro-dynamics, transparency, lots of nuances, comfortable listening.
Can we reach similar qualities without using tubes? Yes - no doubt - we can. With some complications and still with some differences.
The right tube, used the right way, sounds great.
That's why I use them. I don't see any difficulties or stop-factors with regards to using them.
Well, that's my personal view
Cheers,
Valery
P.S. It's definitely not the only way to go, but one of the good ways
Last edited:
It would be nice if you try to describe the difference, because you are propably only one who has listened to both amplifiers. And as both amps are almost the same except the tube/mosfet input stage, we would know what tube can bring in terms of sonics.
Do you think that tube input is worth the effort despite more complex power supplies for tube stage - HV, heaters, delayed-start?
Thank you.
IOTA-CD PCBs
Hi,
I have designed PCB board for IOTA-CD hybrid amplifier in Eagle 6.5.
I have now listened to DOGC-MK3 amplifier and compared to Symasym, DOGC is better in every aspect - airy, 3D, rich, sounds more like music. Now I really wonder what tube input stage could bring to the sound, because now with mosfet input sounds perfect!
Thank you Bora for very good design!
Hi,
I have designed PCB board for IOTA-CD hybrid amplifier in Eagle 6.5.
I have now listened to DOGC-MK3 amplifier and compared to Symasym, DOGC is better in every aspect - airy, 3D, rich, sounds more like music. Now I really wonder what tube input stage could bring to the sound, because now with mosfet input sounds perfect!
Thank you Bora for very good design!
No Stanislav, THANK YOU for such a nice review!
Symasym is way more famous and DOGC is almost unknown to the majority of audio builders. I am glad someone else wrote such impressions because if I have done that, it might easily be seen as immodest and biased statement. IOTA is likely even better!!!
Enjoy!
Symasym is way more famous and DOGC is almost unknown to the majority of audio builders. I am glad someone else wrote such impressions because if I have done that, it might easily be seen as immodest and biased statement. IOTA is likely even better!!!
Enjoy!
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.