[jmimac351]

You could do this but it would significantly change the sound characteristics since what makes this amp interesting is the dominant second harmonic distortion component. Running two in a balanced configuration would cancel the majority of the even harmonics.

Thank you for sharing that.

[poseidonsvoice]

. As good as the chip amps are, the new NelsonPass F5m i posted above is really special and that can be built for under $500. I’d put it against just about any class A amp I’ve heard.

Very significant given the amps you have already heard, thanks for reporting!

Best,
Anand.

[BrandonB]

After going thru a bunch of DACs, having the Ayre AX-7e integrated (under $1500 used, and awesome), hearing the difference a proper crossover makes (and that the best way to get this is by NOT buying a retail speaker)... and then being parked in front of Danny's "Chip Amps" when I was there recently for a listen... I am quickly realizing that you can spend a fraction of the money you think you have to spend to have the best sound.  I think you can spend a ton of money to have good sound, but it's unnecessary.

I suspect many people have a hard time getting over that mental hump. 

Oh... and I saw those chip amps and started asking Danny about them... He mentioned they were a Folsom chip amp (maybe Folsom EC7293?) that someone did some other work to.  60w/8ohm... 120w/4ohm.  They were effortless with the NX-Treme. 

I am going to be listing a lot of gear for sale soon.

I know you are a big Ayre guy.  I have heard Danny’s system but have never heard Ayre gear.  How does it compare? 

[tom739]

The Pass F5m looks interesting. I'm not a diy amp builder, but maybe???   Any change to your opinion after more use? Thanks mkrawcz.

[mkrawcz]

The Pass F5m looks interesting. I'm not a diy amp builder, but maybe???   Any change to your opinion after more use? Thanks mkrawcz.

Yea, it got better. This is the perfect amp to get into diy due to its simplicity and price. It also happens to be a true giant killer.

[Jaytor]

Yea, it got better. This is the perfect amp to get into diy due to its simplicity and price. It also happens to be a true giant killer.

I'm looking forward to getting mine finished. I had knee replacement surgery last month which unfortunately got in the way of my electronics projects. I did a second rev of my PCBs to fix a problem with a relay footprint and improve the DC servo design, and finished assembling one channel this past weekend. It seems to work well (checking on the scope), but the proof will be getting two channels hooked up to some speakers.

I'm building two stereo amps to be able to use them to try bi-amping my Line Forces with active crossovers.

[mkrawcz]

I'm looking forward to getting mine finished. I had knee replacement surgery last month which unfortunately got in the way of my electronics projects. I did a second rev of my PCBs to fix a problem with a relay footprint and improve the DC servo design, and finished assembling one channel this past weekend. It seems to work well (checking on the scope), but the proof will be getting two channels hooked up to some speakers.

I'm building two stereo amps to be able to use them to try bi-amping my Line Forces with active crossovers.

Jay, hopefully your recovery is going well and those F5m's are going to light those Line Forces up.

[BrandonB]

I just read that LTA has come out with a tube DAC called the Aero.  It cost $3600.

[mkrawcz]

Here is my reworked F5M in a smaller chassis with a Diyaudio universal power supply. I have the amp bias all the way up and it sounds great.

[mkrawcz]

And here is the AlephJ which will become an M2X this weekend if all my parts get delivered. For SS DIY, I can’t imagine anyone not loving them on something like NX-Oticas.

[KTS]

And here is the AlephJ which will become an M2X this weekend if all my parts get delivered. For SS DIY, I can’t imagine anyone not loving them on something like NX-Oticas.

Really nice build!!
I just finished the M2X Sunday and it sounds really good with the Mt View daughter card on the NX Studios, super fun build!

[BrandonB]

These builds are really nice.......

[mkrawcz]

I just finished the M2X Sunday and it sounds really good with the Mt View daughter card on the NX Studios, super fun build!

I just got my M2X up and running. Your choice to build it was wise. 

[KTS]

I just got my M2X up and running. Your choice to build it was wise. 

As was yours! Very cool amp, and I love the way you can change the characteristics by changing the input daughter cards. It is definitely an outstanding amp! I highly recommend!

[BrandonB]

And here is the AlephJ which will become an M2X this weekend if all my parts get delivered. For SS DIY, I can’t imagine anyone not loving them on something like NX-Oticas.

You and Jaytor do a bunch of DIY amps.  What are. you guys using for Preamps?

[BrandonB]

I'm looking forward to getting mine finished. I had knee replacement surgery last month which unfortunately got in the way of my electronics projects. I did a second rev of my PCBs to fix a problem with a relay footprint and improve the DC servo design, and finished assembling one channel this past weekend. It seems to work well (checking on the scope), but the proof will be getting two channels hooked up to some speakers.

I'm building two stereo amps to be able to use them to try bi-amping my Line Forces with active crossovers.

I might have asked previously but what are you using as a preamp?

[Jaytor]

I might have asked previously but what are you using as a preamp?

I'm currently using a DIY solid state preamp that uses a pair of AMB.org A20 line amplifiers in a balanced configured, powered by Salas UBIB shunt regulators. A balanced Khozmo stepped attenuator is used for volume control.






I am working on two new preamps. The first has gone through several iterations, and I'm almost done wrapping it up. It uses a balanced stepped attenuator using the AMB.org relay boards with my own Ardunio processor and code for control. The line stage uses a shunt regulated power supply (my own PCBs with a circuit based on the Salas SSHV2) and two 6SN7s in a parallel long tail pair (for each channel) with a cathode current source and a Lundahl balanced line output transformer.  I originally started out using an Aikido design but decided I liked my design better.



The second is a two chassis design loosely based on the Vacuum State RTP3D. I've finished the power supply (which also has the Arduino control). I've fabricated the line stage PCBs (which include the input selection, stepped attenuator, and line stage circuitry) but haven't started the build yet.





The second chassis will use two of these boards with a pair of shunt regulator boards in between.

[jmimac351]

Earlier in the month I bought an Ayre KX-R Twenty preamp.  I am extremely happy with it.  I had the KX-5 Twenty prior to this, and a friend talked me into selling it to him.  It is also excellent.

Ayre has what they call a Variable Gain Transimpedance setup.  There are individual resistors for every step of volume.  And the gain varies along the way, so the signal to noise ratio stays at it maximum, throughout the volume range.  The KX-5 Twenty has a very similar setup, with the difference being parts like $7 resistors... and 400 of them.

Here is a video of how the volume control works.  It's like having a little dude in there hardwiring each volume change.

https://youtu.be/8ma3dwRDIPk?si=s3SrI1JTAVO-rvMk

[BrandonB]

I'm currently using a DIY solid state preamp that uses a pair of AMB.org A20 line amplifiers in a balanced configured, powered by Salas UBIB shunt regulators. A balanced Khozmo stepped attenuator is used for volume control.






I am working on two new preamps. The first has gone through several iterations, and I'm almost done wrapping it up. It uses a balanced stepped attenuator using the AMB.org relay boards with my own Ardunio processor and code for control. The line stage uses a shunt regulated power supply (my own PCBs with a circuit based on the Salas SSHV2) and two 6SN7s in a parallel long tail pair (for each channel) with a cathode current source and a Lundahl balanced line output transformer.  I originally started out using an Aikido design but decided I liked my design better.



The second is a two chassis design loosely based on the Vacuum State RTP3D. I've finished the power supply (which also has the Arduino control). I've fabricated the line stage PCBs (which include the input selection, stepped attenuator, and line stage circuitry) but haven't started the build yet.





The second chassis will use two of these boards with a pair of shunt regulator boards in between.

WOW.  You lost me at this is what I'm building....lol. The first looks nice but the second looks very stout.  WOW.  You lost me at this is what I'm building....lol. The first looks nice but the second looks very stout.  Is that Attenuator in the second picture a really high end attenuator?  It is the same that is used in a preamp I'm looking at purchasing.

[BrandonB]

Earlier in the month I bought an Ayre KX-R Twenty preamp.  I am extremely happy with it.  I had the KX-5 Twenty prior to this, and a friend talked me into selling it to him.  It is also excellent.

Ayre has what they call a Variable Gain Transimpedance setup.  There are individual resistors for every step of volume.  And the gain varies along the way, so the signal to noise ratio stays at it maximum, throughout the volume range.  The KX-5 Twenty has a very similar setup, with the difference being parts like $7 resistors... and 400 of them.

Here is a video of how the volume control works.  It's like having a little dude in there hardwiring each volume change.

https://youtu.be/8ma3dwRDIPk?si=s3SrI1JTAVO-rvMk

Did you notice an improvement from your other preamp?  It is one of the nicest preamps I have seen.