How do you know when you add distortion, etc. via tubes what exactly is responsible for the change in sound you perceive? Is it the slew rate, the phase shift? the added distortion? Some combination?
Because of my experience with several types of tubes in several applications. And analyzing the complete audio chain.
I can write a book about what phase shift and slewrate does with the perception of music.
But i have no formula for the best sound.
But most important is to learn what sound you like. And that you can only achive by listen to as much as different setups and start building your own equipment. This proces i am doing now for 45 years and still learning, what a great hobby.
I can write a book about what phase shift and slewrate does with the perception of music.
But i have no formula for the best sound.
But most important is to learn what sound you like. And that you can only achive by listen to as much as different setups and start building your own equipment. This proces i am doing now for 45 years and still learning, what a great hobby.
@Koifarm, thank you for the great work!
we finally finished the pcb build and been listening for few days, we like the sound very much, thank you again.
the 5687 does get hot a bit, with 250v psu i think its almost at it's threshold, is there possibility to use lower V ?
would you be interested to design the buffer with DHT tubes such as 2A3/300B/45?
we finally finished the pcb build and been listening for few days, we like the sound very much, thank you again.
the 5687 does get hot a bit, with 250v psu i think its almost at it's threshold, is there possibility to use lower V ?
would you be interested to design the buffer with DHT tubes such as 2A3/300B/45?
I have three PCB's for the unbuffered input board to share. Just for the shippingcost. If interested send me a PM.
https://www.diyaudio.com/community/...urifi-1et400a-amps.379211/page-2#post-6981958
https://www.diyaudio.com/community/...urifi-1et400a-amps.379211/page-2#post-6981958
Attachments
You can use jack to rca adapter when using the neutrik ncj6fah chasis part. Or connect shield to pin 1 and 3 and signal to pin 2.
About humm.
I had no humm issues when using smps for anode and heater voltage with ground joint together. I used the mu follower topology.
Also opamp buffers have no humm or noise.
About humm.
I had no humm issues when using smps for anode and heater voltage with ground joint together. I used the mu follower topology.
Also opamp buffers have no humm or noise.
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Question to you cognocienti. Purify says that you can use their front end with an unbalanced single ended (aka RCA) input - just connect XLR input pin 2 to RCA hot, and both XLR 3 and Gnd to RCA Gnd. We discussed above, but this is another issue.
If you do that, and run it through LTspice*, you'll see that the level at the non-inverting output of the buffer is about twice the amplitude of the inverting buf output.
Of course, the pk-pk amplitude is the same independent of the connection, provided the input level remains the same.
But. Let us assume that the actual Purify power amp consists of two modules, driven in antiphase and bridge-driving the speaker.
In the case of the RCA input, one module gets double the input level than the other which means that it will clip much earlier than the other.
The total output amplitude, unclipped, is thus much lower than when driven through the balanced XLR input.
Of course, if the Purify power stage is truly differential, it wouldn't matter. But I dunno ...
Thoughts?
Jan
*In the attached sim, two situations: both inputs at 0.5V, or one input at 1V and the other at 0V.
If you do that, and run it through LTspice*, you'll see that the level at the non-inverting output of the buffer is about twice the amplitude of the inverting buf output.
Of course, the pk-pk amplitude is the same independent of the connection, provided the input level remains the same.
But. Let us assume that the actual Purify power amp consists of two modules, driven in antiphase and bridge-driving the speaker.
In the case of the RCA input, one module gets double the input level than the other which means that it will clip much earlier than the other.
The total output amplitude, unclipped, is thus much lower than when driven through the balanced XLR input.
Of course, if the Purify power stage is truly differential, it wouldn't matter. But I dunno ...
Thoughts?
Jan
*In the attached sim, two situations: both inputs at 0.5V, or one input at 1V and the other at 0V.
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