Jump to content

First Watt


JMON
 Share

Recommended Posts

Currently the F3 and J2,  both using JFET power transistors. Even producing less power,  15 vs 25 watts, and having less gain I’m leaning to the F3. It’s a damn special amp and like Rich said, very much a single ended signature but  more so than the J2 to my ears. A short period with the M2 but for me it was nothing special. 

  • Like 1
Link to comment
Share on other sites

  • 2 weeks later...
On 2/27/2021 at 9:40 AM, richieb said:

Currently the F3 and J2,  both using JFET power transistors. Even producing less power,  15 vs 25 watts, and having less gain I’m leaning to the F3. It’s a damn special amp and like Rich said, very much a single ended signature but  more so than the J2 to my ears. A short period with the M2 but for me it was nothing special. 


I have been fortunate to find another of the scarce F3’s so the F3 vs J2 comparison has come to an end. The J2 was sold to a forum member and the two F3 are being run as monoblocks. Very satisfied with the outcome and being able to prove my ambition to 

run monoblock F3’s with special thanks to Nelson Pass and Forum buddy MikeB. 

  • Like 2
Link to comment
Share on other sites

  • 1 month later...

I think a First Watt thread is a great idea for Klipsch forum.  I have a Pass labs xa 25 and I’d love to learn peoples impressions of First Watt.  I’d love to try one.

Link to comment
Share on other sites

1 hour ago, VDS said:

I think a First Watt thread is a great idea for Klipsch forum.  I have a Pass labs xa 25 and I’d love to learn peoples impressions of First Watt.  I’d love to try one.


As you may have noted I’m a fan of FW, the F3 in particular. I actually sold the XA25 in favor of the F3. For the money invested I enjoyed the F3 over the XA and sold while they were the latest and greatest from Pass. Fast forward to today and I sold a FW J2 after finding a second F3 to run as monoblocks. I did own an M2 for a short time and found it too didn’t live up to the F3. All my opinion of course - 

Link to comment
Share on other sites

From what I’ve read in several places, the F3 sounds like a stand out.  I’ll be looking for one from now on.  I notice the F3, J2, and F8 are all jfets.  That may be too simplistic of a connection on my part.

Anybody have experience with the F8? Supposedly a “updated J2” according to NP. 

Link to comment
Share on other sites

  • 5 months later...
On 5/2/2021 at 8:26 PM, richieb said:


As you may have noted I’m a fan of FW, the F3 in particular. I actually sold the XA25 in favor of the F3. For the money invested I enjoyed the F3 over the XA and sold while they were the latest and greatest from Pass. Fast forward to today and I sold a FW J2 after finding a second F3 to run as monoblocks. I did own an M2 for a short time and found it too didn’t live up to the F3. All my opinion of course - 

Yes I would agree I would take the F3 over the Xa25.  Think that since the 402 horns increase separation and are so dynamic themselves, maybe the f8 would take away the last remaining “edginess” I have.  Nelson talkes about the high dose of 2nd order harmonics in the f8 and the Xa25 being more 3rd order, not sure where F3 lands.

Link to comment
Share on other sites

The Burning Amp Festival for 2021 happened over the weekend. It was a virtual event via Zoom featuring some very talented people. Nelson Pass' session is online now on youtube.  A few new projects one being a very small Amp Camp requiring no case or expensive PS section the biggest cost of a Class A amplifier. I know there are many on this forum that have an Amp Camp amplifier and are very pleased with it. Check the video out. 

 

  • Like 3
Link to comment
Share on other sites

Thanks for posting this.  The distortion reduction with dc thing on fullrangers was interesting...  Actually, Nelson is always at least interesting and an enabler for audio experimentation.  This latest little amp, coupled with what he's talking about with Jason at diyA for modularity, might finally get me over the edge. 

Link to comment
Share on other sites

  • 2 weeks later...

I do not own a specific First Watt model but after Nelson made his static induction transistor amps and talked about them at the burning amp festival I had to try one.

 

Very simple design with only 4 giant Mosfets for both channels and an input transformer. Two Mosfets per channel, one acting as a constant current source load for the other it is a single ended arrangement with "Schade" feedback. This drain to gate feedback lowers output impedance and gives a triode like output characteristic. The 1:2 input transformer processes the feedback in a boot strap fashion in order to increase input impedance instead of lowering it making it much easier to drive with normal sources and preamps. It can produce up to 50 watts before clipping but distortion is high at that power level but at 20 watts it is around 1% THD.

 

It may not be as magical as some real SET amps I have had but it is darn close and much more power vs 2A3 and 45 amps which is attractive to many. Big heat sinks are needed as the Mosfets are biased around 3 amps ~85 watts dissipation. Not your average SS amplifier by any means :D

 

I found they were a great pair with Klipsch speakers, currently running on Reference Bookshelf's but I really liked them on my Cornwalls. Also great on my La Scala's but they hardly ever go above 1 watt and only for dynamic transients so I run actual triodes with them.

 

I am surprised more Klipsch owners do not use Pass amps. I am very new here so maybe I could be wrong.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...