Author Topic: Class A amps? (Read 10733 times)

indysmith · « **Reply #15 on:** November 27, 2005, 01:07:11 PM »

i played the LC15 t'other day and it didn't sound very VOXish at all. Only on low volume on music shop tho, i didnt really get a chance to have a propper go. It didnt sound bad. needed pedals! :P

math2014 · « **Reply #16 on:** November 27, 2005, 01:14:05 PM »

Ok,

LC15/30/50 are more modern than the VC15/30 series.

LC have 1 more preamp valve and 1 more gain stage.

VC series is the one that supposedly sounds like an AC30.

I got no clue if the LC30 is 100% ClassA or ClassA/B, it says ClassA though. I just wonder if i can change power valves without rebiasing (i think i can).

Thats about it.

BTW there is a BIG difference between the LC15R and LC30/50 in build quality. LC30/50 have chassis mounted valves, pots and jacks wired OFF the pcb, whereas the LC15R has them pcb mounted.

Gary · « **Reply #17 on:** November 27, 2005, 02:01:44 PM »

The THD Univalve looks interesting - 15w for under a grand. Anyone tried it?

HJM · « **Reply #18 on:** November 27, 2005, 02:04:44 PM »

Quote from: Gary

The THD Univalve looks interesting - 15w for under a grand. Anyone tried it?

Great sounding amp, a touch noisy but it does sound juicy. I prefer it to the Bivalve and the Flexi 50. The BiValve sounded plain odd when pushed, the Flexi is a bit soft and the bass is a bit tubby for my tastes. Good lead amp though, not for rhythm, at least for me.

HJM · « **Reply #19 on:** November 27, 2005, 02:05:49 PM »

It's probably cathode biased so a swap should be fine.

Floyd Pepper · « **Reply #20 on:** November 27, 2005, 05:12:58 PM »

Quote

Vox have been miss-selling for years

The Ashdown Peacemaker say "Class A" on the front but I've read they're really A/B.

Quote

i can't reccommend enough the cornford Harlequin

Me neither. Only 6W but everyone of them is the best I've heard. Got my Cornford for £350 second hand too. :) If you want a recording or play at home amp then check out a second hand Harlequin.

seancorker · « **Reply #21 on:** December 04, 2005, 07:49:01 PM »

Had a VC 30 for 3 months couln't get rid of it fast enough. The clean channel is good but the dirty side is a horrible muddy mess of a sound. I ended up putting a pedal infront of the clean channel. It then started buzzing and humming for England and the valves kept falling out because of the cr@p holder. Oh yes and the valves are mounted direct onto the PCB board which is not good for the PCB because of the heat generated in class A. The FX loop is unusable because it ruins the tone. My pedals are Keeley so I know they are fine.
For me class A is good for clean but I prefer AB for distorted

Sean

balde · « **Reply #22 on:** December 04, 2005, 09:25:02 PM »

As Hjm said, the Vox ac30 isn´t a true class A amp. But neither are their clones, like the laney lc30 or the vc 30. Matchless amps aren´t true class a, either. Mostly every amp in the market marketed as class a, isn´t.

This is a good definition that i took from the aiken amps webpage:

A push-pull amplifier is defined as operating in class A if, at the full UNDISTORTED output (just prior to clipping), the plate current flows in each tube for a full 360 degrees of the input conduction cycle.. If each side is in cutoff for exactly half the input cycle, it is a class B amplifier. If the amplifier is designed such that the plate current flows for more than half, but appreciably less than a full cycle, it is then a class AB amplifier.

Aiken amps webpage provides a lot of useful info on its page, I believe that we should try to make amp makers start speaking the truth. Still, It´s my opinion, just that.
cheers!

Bird · « **Reply #23 on:** December 04, 2005, 09:41:51 PM »

So what are some good Class A options :?:

Joe Dorcia · « **Reply #24 on:** December 04, 2005, 11:58:47 PM »

I just wanted to pop in. If you want a big meaty sounding distortion. You know the huge sound i mean, more modern with a fuller tone and beefed up lows but still beautifully tube, then go for Class A/B, eg DSL's (head, not combo).

I tested a Matamp 1224 Mk V and that has a class switch. This switches from class A with 1 or 2 valves, to Class A/B with 2 or 4 valves. The distortion sounded best (to me) on the class A/B 4 setting.

It all depends on your style and whether you want tube clean and distortion or tube clean and pedal distortion etc.

The best advice is always test everything and find whats right for YOU. Hopefully you should find tube amps warmer, more harmonically rich and fuller at louder volumes. As well as finding hand wired tube amps even more harmonically rich in comparison with their printed circuitboard tube counterparts.

Hope that helped and confused you. Im good at doin that :)

Best Regards
joe n