300B Class A gorgeousness

[Bigman80]

Would be Quad ESL 57's at Alan's.

For me, you've missed the most vital piece of information which is: what speakers are you using to test this amp? To my ears, and many of my clients, 300b, 845, and 805 amps sound best with no feedback, in the right circuit and driving sensitive, easy load speakers. Of course, difficult loads or insensitive speakers can cause the whole sound to collapse, which is where feedback comes to the rescue.

I've built amps with variable and switchable feedback but, again, with the right speakers and amp circuit the sound always closes up when feedback is switched or dialled in.

Don't get me wrong: I'm not anti feedback and happily run Radfords, Lebens and others to drive my Tannoy Canterburys. It's just that the valves above in the right circuits sound best driving the right type of speakers with no feedback

[AD Audio]

Quad ESL57s sound absolutely gorgeous with my no feedback 300b amps which very happily drive them, so that for me, points at something up circuit-wise.......

[Bigman80]

Quad ESL57s sound absolutely gorgeous with my no feedback 300b amps which very happily drive them, so that for me, points at something up circuit-wise.......

You may well be right. I can't comment, I haven't heard a 300b amp

[Firebottle]

Good to hear other viewpoints but in this instance it is far far better with a little bit of feedback in the circuit.
The circuit is very traditional, 3 common cathode stages with simple resistive anode loads on the first two.
However I have never been a fan of 6922 valves as I think there are far more linear valves to be had. With a small amount of feedback the sound is transformed.

Previously my low output OTL amp trounced the 300B, now they are on a par, extremely lucid with the 300B actually having a better bottom end.

[Primalsea]

I think a 300b amp with no feedback can sound amazing with some speakers but terrible with others. However, a 300b amp with feedback can sound amazing with some speakers but terrible with others.

Its the old chestnut of synergy, but not only that, also what music you listen to. Sometimes coloured, flawed sound is just the ticket but sometimes it just doesn’t work...

[anthonyTD]

It is of course possible to unite a zero feedback amp with a particular type of speaker" that will work exceptionally well with some music, and if that is all that you listen to, then fine, however; if you listen to real world music, from many genre's, and at real world level, then this type of amp, and speaker combination will undoubtedly almost always come up severely short in the listeners expectations.
I have heard many systems over the years that can’ and do indeed excel in certain aspects of chosen musical content, but if I Were asked could I personally live with that type of system, then the answer would be a firm no, as to do so, would probably render most of my music collection unplayable, but again, that’s just my personal view.

[WESTLOWER]

It is of course possible to unite a zero feedback amp with a particular type of speaker" that will work exceptionally well with some music, and if that is all that you listen to, then fine, however; if you listen to real world music, from many genre's, and at real world level, then this type of amp, and speaker combination will undoubtedly almost always come up severely short in the listeners expectations.
I have heard many systems over the years that can’ and do indeed excel in certain aspects of chosen musical content, but if I Were asked could I personally live with that type of system, then the answer would be a firm no, as to do so, would probably render most of my music collection unplayable, but again, that’s just my personal view.

I’ve had zero feedback amps on a few different sets of speakers and they performed wonderfully over a wide range of musical genres. Yes the pairings had to be considered but once put together they certainly wasn’t genre dependent.

[anthonyTD]

Good to hear!

I’ve had zero feedback amps on a few different sets of speakers and they performed wonderfully over a wide range of musical genres. Yes the pairings had to be considered but once put together they certainly wasn’t genre dependent.

[AD Audio]

It is of course possible to unite a zero feedback amp with a particular type of speaker" that will work exceptionally well with some music, and if that is all that you listen to, then fine, however; if you listen to real world music, from many genre's, and at real world level, then this type of amp, and speaker combination will undoubtedly almost always come up severely short in the listeners expectations.
I have heard many systems over the years that can’ and do indeed excel in certain aspects of chosen musical content, but if I Were asked could I personally live with that type of system, then the answer would be a firm no, as to do so, would probably render most of my music collection unplayable, but again, that’s just my personal view.

Unfortunately Anthony your personal view and blanket statement-then this type of amp, and speaker combination will undoubtedly almost always come up severely short in the listeners expectations-is not backed up by fact. My musical tastes range from choral through to dub with everything in between and I'm lucky enough to have a commercial zero feedback 845 amp in my studio-Mastersound 845 mono blocks driving Troels Gravesen speakers-along with a Leben CS1000 driving Tannoy Canterburys in the lounge. Both systems reproduce all types of music beautifully and would not be there if they didn't. This goes for my clients' systems using zero feedback amps too: they all listen to a wide variety of different styles and would not accept an amp that didn't excel with all styles full stop. The majority if not all of them moved from amps using feedback to zero feedback amps.

The speaker /amp match is important and there's many a tale on this Forum of folk changing speakers and ending up changing amps-the name Tannoy springs to mind-and my Mastersounds are not a good fit with my Tannoys but perform wonderfully with the Troels' speakers that are themselves a difficult load.

You are very welcome to stop by and have a listen if near London.

[anthonyTD]

Hi David,
First of all, thank you for your kind invitation, I have to admit, I dont get the need to visit London much these days, but you never know!
Now as I hinted in my earliar posts, when you get the combination of speaker and amp correct, something almost magical can happen, unfortunetly, where zero feedback designs are concerned, and this is all IMHO a lot of folk give up way before they get to that magical combination, also, as I am sure you understand, the type of output valves used, and their configuration play a huge part in how the amp reacts to the speakers varying load, and the difficulty of controling the speaker cone movement etc, this again IMHO is key to getting a zero feedback amp and speaker combination to work. I suspose its posible that I have become Biased and slightly Jaded over the years,from the systems I have heard, and therefore; witnessed first hand, how wrong you can get these type of systems, when proper care and attention hasnt been used to partner things correctly etc, which could indeed contribute to my feelings on Zero feedback designs, and for that I sincerely appologise.

Unfortunately Anthony your personal view and blanket statement-then this type of amp, and speaker combination will undoubtedly almost always come up severely short in the listeners expectations-is not backed up by fact. My musical tastes range from choral through to dub with everything in between and I'm lucky enough to have a commercial zero feedback 845 amp in my studio-Mastersound 845 mono blocks driving Troels Gravesen speakers-along with a Leben CS1000 driving Tannoy Canterburys in the lounge. Both systems reproduce all types of music beautifully and would not be there if they didn't. This goes for my clients' systems using zero feedback amps too: they all listen to a wide variety of different styles and would not accept an amp that didn't excel with all styles full stop. The majority if not all of them moved from amps using feedback to zero feedback amps.

The speaker /amp match is important and there's many a tale on this Forum of folk changing speakers and ending up changing amps-the name Tannoy springs to mind-and my Mastersounds are not a good fit with my Tannoys but perform wonderfully with the Troels' speakers that are themselves a difficult load.

You are very welcome to stop by and have a listen if near London.