My experience with the First Watt F7

@roxy54

Congratulations on acquiring the Canary.. This American brand flies beneath the radar but they make very good products.

Charles

Great thread!

Been a tube guy for almost 30 years. Only recently been looking into SS. And as a diy person, I’ve built a couple of them over the past year or so. Built an amp cam amp for a friend, along with a “version” of the ACA using boards from AliExpress. It uses 4 amp boards wired in parallel (two boards per channel), and was built specifically for 4 ohm speakers. It was also built for a friend. Built the Pass VFet kit which I was fortunate enough to get access to buying via the DIYAudio lottery. Only 180 kits were made available and a lottery was held in order to make the buying of one more fair.

Been wanting to build one of the F6 kits from the DIYAudio store, but decided to build a Hiraga Super 30w class A instead. Was looking for something to drive my ESL57’s with and it came highly recommended. 
 

Your feelings on the F7 just confirms that what works for one person in their set up,  won’t necessarily work for someone else. So many variables to consider. But your observations are not surprising. Especially with the first watt F series. Highly “specialized” amps like those will have a very specific system and end user in mind. 
 

My natural inclination tends towards single ended tubes, but sometimes, when you want to change up speaker options, you just need more power than they can provide.

Recently built some small, sealed coax speakers using Seas drivers in a small (5 liter) sealed enclosure. They are not very efficient, under 84db and are rated at 4ohm, so I picked up an adcom 545 so I could put some more power into them to see what they sound like with some decent power. The 545 is also a Pass design. I find it to be a bit dark for my tastes, but it has its own thing going on which works with some speakers. Not a fantastic amp by any stretch, but for the 300CDN I paid for it, well worth the money. Especially as a tool to be able to push some more power to inefficient speakers.

The single ended EL84 amp I built (around 3 watts?), which is going into some small full range speakers I also built (4 inch driver in approx 8ltr enclosure?) has some magic that the Seas coax speakers, with 100w of SS power, is missing.

The Coax speakers can play waaaaay louder, are much more “precise” sounding and have significantly more dynamic punch, but the simple little 3w amp, with the single FR speaker, just sound more musical. 
 

Would love to build some Altec Voice of the theatre speakers and run them with a 2A3, but sometimes you just don’t have room for a 300liter Enclosure :)
 

It’s all a learning experience, and thank you for sharing your experience with the F7. Going to keep trying, and look at some other SS amp builds, not quite ready to abandon SS yet…

Another Vote for OTL Amplifiers especially the Atma-Sphere amplifiers. Iv compared them to a number of Tube Amps, Kept going back to the OTL.

The major aspect of paring OTL amps are the speaker should present a easy load and anything from 8ohms to 16ohms will work like a charm.

4 Ohm speakers just dont sound right with OTL

No, the pre was a good match which I checked before buying the F7.

First Watt seems to be mostly a vehicle for Mr. Pass’s experimentations, which is allegedly why there are so many variations despite similar power outputs. It’s my understanding that none of them were intended to be great all-rounders, rather, they each have unique characteristics that Nelson finds alluring in the right context.

I’ve only heard the First Watt J2. To my ears it didn’t have any blatant weaknesses driving single-driver speakers. Maybe there’s good reason it’s one of the favorites among First-Watt fans. 
 

I own the Pass XA25, and other than it being slightly darker in sound than my departed Benchmark AHB2, it’s possibly the best amplifier I’ve owned. 

I was running a couple of no-name 300B SET amps for quite a while, and when the Ukraine invasion drove the tube market into a frenzy, I put my First Watt F-8 back on line and haven't changed it since.  I'm running it with an AR LS27 preamp and Zu Soul Supreme speakers.  I do have one of the impedance lowering/matching resistors across the output terminals of the speakers - as it's been well documented that the FW amps sometimes don't like the high impedance of the Zu speakers.  I still want to find a SIT-3 to have, but the F-8 is audio bliss for me.  With good recordings the speakers disappear and the combo I'm running just sounds perfect to my ears.  I've never heard the F-7, but agree that some of the reviews weren't crazy positive in every respect so I didn't bite on that one.  I owned a J-2 a while back and it was nice, but the F-8 is sort of the Mk. II of the J-2.  Similar topography but improved in some aspects, according to NP.   I don't find the F-8 to be solid state sounding at all, similar to the 300B amps I was running but a firmer grasp on the lower end.  

It seems to me that if one has issues with a First Watt or Pass products performance it might be worth a shot to send Nelson an email (or Pass Labs) and discuss SQ expectations to determine whether or not the amplifier is sounding out of character. 

Good thread, enjoy the viewpoints, both positive and negative.  I believe Steve Guttenberg put it best when he said the First Watt amps don't always hit, even when you have a good match on paper, but when they do, they hit really hard.

I've owned 4 different First Watts and currently use the SIT-3, and I wholeheartedly agree with Steve.

I’ve used an F3 on a pair of Crites Cornscalas for a while. Around 100db efficiency I think. It sounded very good on the top and upper mids but had very little authority in the lower end. My friend is currently using it on the top end of an active crossover speaker and he says it sounds excellent. Fwiw, I had no other complaints about the amp. Also, it does make a pretty good heater in the winter months 

I run Pass Aleph 1.2 monos and the mids and highs are absolutely addictive.

Hi All. I'm using an F7 with an Einstein preamp and restored Klipsch Forte 2 speakers. The system sounds wonderful to my ears.

I'm using a F7 with an Audio By Van Alstine FET Valve CF preamp to drive my Cornwall IVs.  I absolutely love it!  I've tried a McIntosh MC275 VI, Rogue Stereo 100 with Dark upgrades, Van Alstine 600R (I own), and a Enleum 23R (I own).  The F7 is in a league by itself compared to the others that I've tried in my system. 

The very slight greyish harshness in the Cornwall's midrange is completely gone with the F7.  Soundstage is noticeably larger in width and depth.  Bass is well defined and tight.  Imaging is the best I've heard in this system.  This system is musically engaging.  Digital components in my system are an Aurender W20SE sourcing a Holo May KTE and for analog I have Rega P10 with a Luxman EQ-500 phono stage.  Unlike Roxy54, I love how the F7 in my system does horns and guitars.

@smatsui 

Unlike Roxy54, I love how the F7 in my system does horns and guitars.

Your positive outcome is as real as roxy54’s negative outcome with the F7 amplifier. Either scenario is understandable. Different listeners ears/taste/audio system and so on.

Charles 

I agree with Charles of course, there’s room for every preference. I know that many love the amp, and the positive consumer and professional reviews were the reason I had wanted to try one for years.

What was surprising to me was that my speakers have always been easily revealing of the sound of amps, cables etc. without a lot of editorializing, and within my system, the F7 had such an unnatural sound, so far removed from what I had expected or previously experienced.

If it had been additive or subtractive in a pleasant euphonic way, I would probably have liked it a lot more, but it seemed to be attempting to "reconstruct" the music rather than letting it flow naturally. I understand that this isn’t what most people hear.

@roxy54, none of your components are the same as mine, as well as differences in our listening rooms and our preferences, so it’s not surprising our opinions of the F7 are different.  In your original post you asked for other user experiences with the F7 and that’s what I’ve provided.  You and I heard the same amp in two completely different systems, listening rooms, and ears and we have opposing opinions of the amp.  If I heard the F7 in your system chances are I wouldn’t have liked it.  If you heard the F7 in my system you might like it, and then again you might not.  My main system has Harbeth M40.1 speakers that are warm and organic sounding to my preference.  If you heard it, you might think it sounds like muck.  Different strokes for different folks.

I bought my F7 from Mark at Reno HiFi.  When I called him, my intentions were to buy the First Watt F8 or a XA25.   TBH, I had never even given the F7 a thought.  After telling him about my system and my preferences, he strongly recommended the F7.  Mark told me he was a big fan of Klipsch speakers, and that his listening preference priorities were the same as mine while recommending the F7.  I think his recommendation hit the nail squarely on the head.  

Before getting the F7, my Cornwall’s mids and highs couldn’t come close to matching my M40.1.  In particular, string tone didn’t sound as natural, female vocals were a bit harsher, sax didn’t sound as full in comparison to the Harbeths.  The F7 has closed this gap by a substantial amount such that I don’t even think about the differences anymore and now I thoroughly enjoy listening to my Cornwall IVs.

I wonder if there was an impedance mismatch issue or something else weird going on here with some preamps/amp combinations used.  Looking at the different FW amps, most of the latest versions were at least 100k ohm input impedance. The F7 is 10k ohms. Comments anyone?

@decooney, yes I was aware of the F7’s low input impedance. That fact makes matching a preamp (especially a tube preamp) more difficult. When I talked with Mark at Reno HiFi, he told me that many tube preamps don’t match well with the F7. I have a SS and a tube preamp, Holo Serene KTE (SS) and Van Alstine FET Valve CF (tube), so he said that the SS preamp will work well with the F7. I’ve tried both of my preamps with the F7 and I think both sound great but different. I think the Serene KTE has more defined and tighter bass. The Serene sounds faster and more neutral where as the AVA preamp sounds more relaxed.

I use a REL S5 subwoofer with my Cornwall IVs so the bass is not a problem with the tube preamp and the F7 in my system. I think the solid state Serene is a little better than the tube AVA preamp in my system but both sound great. If roxy54 was using a tube preamp it may have caused the bass and musical flow issue that he heard with the F7. My Cornwalls are known for their tight bass because their 15 inch woofer hardly moves at all by design. Other Klipsch speakers may not mate as well to the F7. The F7 is definitely not a universal fit in most systems. Like I mentioned above, you’re more likely to have a positive outcome with the F7 using a solid state pramp because of the F7’s low input impedance.

On the First Watt home page,  Nelson Pass seems quite clear that First Watt in general, and each model specifically, are designed for unique situations, needs, preferences, and not meant as a general amp lineup for everyone...at Mark's suggestion, I used my F7 with Rowland Capri ll preamp and Avalon Ascendant ll speakers, in small/medium room, and sound was awesome...

@decooney 

That difference in impedance is really interesting and could have accounted for what heard. Thanks for the information.

Hi @sns  and ​​​​@roxy54 ,

I have a similar experience to you with SS tube Push Pulls and SETs.

SET sounds most natural, real, transparent and it also gives a good bass when it is well designed and used with height sensitivity speakers.

Once I heard Montana EPS speakers with Plinius class A monoblocks in one dealer room. It was a Diana Krall track with a few instruments but each instrument sounded rhythmically disconnected like musicians don’t hear each other.

Regards,
Alex.

@roxy54 

2 weeks? 
 

should have let hew play, and warm up at least 6 months.

\,,/

You're a real comedian @arcticdeth .

Reading "lifeless" or "disconnected" sound type of comments and references come up once in a while in different amp threads, makes one wonder why. Solid state or tube. I was always curious wondering how this occurred for some, and not for others. Also, I remember trying an older simpleton preamp from the 70s that made the amps I used sound sort lifeless and un-engaging. Never quite figured out why until years after, while coming across threads similar to this one here.

In most cases, eventual information surfacing about how there was a preamp < > amplifier impedance or input/output voltage mismatch, and/sometimes compounded further when a little bit lower efficiency speakers are involved too. When both scenarios are true at the same type, usually ties back to an unhappy listener selling off some gear, trying again.

One sure can appreciate a good preamp and amp specifically designed and tested to go well together, followed by speakers that are well matched to a particular amplifier. Something I learned to appreciate more after lots of trial and error over the years, only to start looking closer at basic in/out specs and paying closer attention to how things actually sound and components interact with each other.

I’m looking to potentially pick up an F7 to use with a pair of Fritz Carbon 7 SE mkii speakers.

Has anyone successfully used an F7 with Fritz speakers?

Was thinking I’d use my Van Alstine RB10 tubed preamp, but not sure that pre/power amp combo would actually be a good match.  Output Impedance is 2kOhms.  F7’s Input Impedance is 10kOhms.  The preamp can be wired to drop it to 47Ohms if I want to send it back to Van Alstine.

May be better to find a tried and true solid state pre.

Output Impedance is 2kOhms. F7’s Input Impedance is 10kOhms. The preamp can be wired to drop it to 47Ohms if I want to send it back to Van Alstine.

Ideally the recommendation for power amp input impedance to preamplifier output impedance is a ratio of 20/1. So a genuine output impedance of 500 ohms and less is preferable. A very low output impedance of 47 ohms shouldn’t present an issue at all.

@roxy54 

thanks for the smile!

I mentioned it,…I prematurely returned a CD player after only a week, I should have listened when Yoda spoke.

Owned many First Watt amplifiers but not f7. I had the best synergy using a tube preamplifier with them. But f7 isn't best used that way. Why it didn't appeal to me. Of all the first-watt amps I owned my F3 seemed to be the one that I enjoyed most.

@J_Andrews, if you decide to go with the F7, then I recommend sending your preamp back to AVA to change the output impedance to 47 ohms.

My Van Alstine FET Valve CF tube preamp has an output impedance of around 100 ohms per Frank Van Alstine.   I called him to discuss pairing this preamp with the F7's low input impedance and his response was no problem.   He  was right, the AVA preamp/F7 pair sound better than the same preamp with several tube amps that I've tried driving my Klipsch Cornwall IVs.

I own the Fritz Carbon 7SE MK2 and use it with the Pass Xa25. I would think they would be great with the F7 as well, even considering the differences between the two amps. 

I believe your issue is the impedance of the AVA preamp. As stated above have Frank reduce the output impedance on it. 

thanks @smatsui & @mesch

Definitely will consider.

As I understand it, apparently what he would do on this particular pre-amp is wire the output of the headphone output to one of the 2 pre-amp out jack pairs on the back of the unit.

This would yield a buffered 47Ohm output.

It would be coming directly off two T.I. LME49600 current buffers which are in turn coming directly off the output of the tube lineage.

Another option is just to find an appropriate pre-amp for the F7.

@mesch , how do you like your Carbon 7SE mk2 with the XA25? What pre are you using there?

I bought my pair directly from Fritz this past summer and think the speakers are pretty outstanding and it’s only very rarely when I’m playing pretty complex maximalist music, do I feel that things are getting a little out of control.  By and large they present as much larger and in-charge than their size would imply.  Also the stereo image and depth is spectacular.  I sometimes wish that the phantom image were a little taller.  Not sure if that's related to the speakers or the amp.  Currently they are on 24" stands.  They are great bandmates with the Alstine gear.

@helomech I agree with your thoughts on the Carbon 7s. I listen to mostly Jazz and light rock (no heavy metal) with them so can't say much regarding their performance on much more complex music. 

I drive my XA25 with a Aric Audio Special 6SN7 tube preamp.  If looking for a tube preamp I can recommend him. Most have output impedance of 300ohms at the highest across frequency range. Hive Aric a call he can confirm this on each of his preamp offerings.

I have an F7 paired with an LTA MZ tube preamp and Ojas speakers. I have found the high end to be thin. Female vocals breaking apart on high notes and trumpet notes feeling almost shrill at times.

@jdillla interesting…. Do you attribute those issues to the F7 or the Ojas speakers?

I know Ojas offers a compression driver add-on to the coax kit.

Have you tried that pre/power amp combo with different speakers?

Are you satisfied with the F7 otherwise?

I had a F8 in the stable to try with my Cornwall IV's and it sounded amazing for a SS amp. As a mateer of fact, best SS I had heard in my system. But I digress...I sold it "wish I would have kept?!?"...because it just didn't have "that sound" I get from my DH WE300B SET. I do miss the different presentation though. As a matter of fact, I'd buy another F8 but may try a couple of the other flavors in the First watt lineup or an XA25?!?

After getting my speakers, Spatial Audio X5s, I went to the house of someone else who owned the same speakers. He had a Cary tube amp and the F7 and we listened to both. The difference was immediate and stark. The F7 sounded thin and shrill. This actually was the beginning of my interest and use of tube amplifiers. 

It's definitely an amp that you need to try in your own system before committing to a purchase. I would say more so than any other amp I've owned or auditioned in my system.