[BigTony]

Well after a further 20+ hours burn-in i can say the humm has all but gone - i was going to try the 'turn amp off and listen to hum' but found virtually no hum! I found myself listening to tape-hiss on the recording over the amp noise. Good to know - 50-100 hours to burn amp in .
Just need to fix gain and we're golden.

Btw - the amp sounds brilliant! will write-up a review tomorrow..... unless the suns out!

 

[Audict123]

BigTony: you're apparently ahead of me with burn-in. After about 60 hours (didn't clock it), I'm excited to find that indeed suddenly there is very little hum left! Burn in really seems to do the trick, I'm not fully there yet though, but even if it stays like this I won't bother too much, because....

.. the sound gets better and better. Still I prefer a less thick and more tight bass - wonder what the 403B will bring there. It's of course all about synergy: the HD650 are quite bass heavy. Maybe I should get some Ulyanovsk 6S19P-V tubes too; the Svetlana's I use now are reported to be the warmer ones in the 3322 .

If the 403B's are better in the highs and mids too, how good does it get? The highs as they are now with the dirt cheap russian EF95 analogues are detailed yet smooth - even in the beginning, there was nothing really annoying about it (unlike the burn of the 3322 in reported by Godkin and others). What I like most is the PRaT and transparancy. Foot tapping all the time. A sound I can listen to for hours. Verrrry happy with this 332s.

NB: 50 pounds for rca attenuators is indeed way too much. I was lucky and bought mine for 10. But they are quite simple to make I think: you just need some plugs with some space to fit in two high quality resistors per channel. I can measure the values of the resistors if you want. -14 db works fine for me. -20 might be even better.

 

[deltaspirit]

I have less then 10 hours on mine

 

[BigTony]

Ok, I got some attenuators from the bay - so I should get them in a few days and then I'll be able to reset my rig properly.
Might be an idea to build a cable with a built in attenuator, once I know if its going to work.
For some odd reason my left-channel started back to humming lastnight...

 

[Mullet]

Hey guys/gals,

What kind of hours are you typically getting out your tubes, especially the signal tubes, before you have to replace them? I've talked to an old school tube guy and he says some amps can go through tubes pretty easily depending on how efficient the amp is. What's your take on the 332s/c amps and tube longevity?

~mullet

 

[Audict123]

Quote:

Originally Posted by BigTony /img/forum/go_quote.gif For some odd reason my left-channel started back to humming lastnight...

Even more odd - I noticed the same, and it's also in the left channel! I wonder: I left the amp on all day yesterday with no headphone connected for burn in. Then when I did put the phone in the hum was almost gone. After 2 hours with the headphone the hum had clearly gone up again. Coincidence? I'll set up an experiment on it this week.

 

[BigTony]

Quote:

Originally Posted by Mullet /img/forum/go_quote.gif Hey guys/gals, What kind of hours are you typically getting out your tubes, especially the signal tubes, before you have to replace them? I've talked to an old school tube guy and he says some amps can go through tubes pretty easily depending on how efficient the amp is. What's your take on the 332s/c amps and tube longevity? ~mullet

I guess it depends upon the tube/amp combination, but I've not had to replace tubes due to them reaching the end of their working life - normally I'm switching tube due to rolling in some new combinations. I tend to have my amp on 5-6 hours each day - so thats 1,800 hours per year - tubes can last 3,000-10,000 hours .. I always have backups, just in case.

 

[Audict123]

Left on the 332S without phones connected for the day and indeed - no hum whatsoever when I plug in the phones. Half an hour later with the phones in: the hum is back. My hopes are that this is an intermediate state and that more burn in will get rid of it permanently.

 

[BigTony]

Ah .. goodnews on the 403B's - where did you get them from? I've not seen many around in tne EU for sensible prices.
I've got recieved some Mullard CV4010 today .. will try them later.

 

[Mullet]

I've seen the WE403Bs on eBay for ≈$50. Also, I have local guy here in NYC that has 'em for the same price. He's trying to get $80 for the Ericsson 403Bs. Deals can be had though. I just won 3 unmatched WE403Bs for .99 + shipping. I've read that you don't need to have your tubes matched with the Darkvoice/La Figaro products. I'm not sure if this is true or not, but I'm giving it a go.

Regarding DACs I'm looking at the Gamma 2 (y2) for its price/performance. To have one built is a little more than a Pico DAC, but the quality of the components and the amount of I/O you get surpasses the Pico DAC. I'm also considering the uDAC because it has a lot of bang for the buck. Currently, I'm using a LOD out of my iPhone because it is simply better than going straight out of my MacBook Pro. Am I getting the best quality sound out of the iPhone? I'm sure not. However, the amp still sounds excellent with the stock tubes. I'm probably about 40-50 hrs burn in and things are sounding better than ever. I'll do another post with my comparisons thus far with a variety of headphones... Any thoughts on decent small space DACs that are sub $400?

 

[Audict123]

Quote:

Originally Posted by BigTony /img/forum/go_quote.gif Ah .. goodnews on the 403B's - where did you get them from? I've not seen many around in tne EU for sensible prices. I've got recieved some Mullard CV4010 today .. will try them later.

I deleted (rewrote into hum update) my post on these 403B's - was on here 5mins max, you were quick to read! Yes, I got two from Ebay but they are not equivalent (one black plate, one silver, and the black plate is very microphonic and ). I just informed the seller that I'm not happy... Don't think this pair will be representative of what 403B can bring.

 

[BigTony]

Quote:

Originally Posted by arie123 /img/forum/go_quote.gif I deleted (rewrote into hum update) my post on these 403B's - was on here 5mins max, you were quick to read! Yes, I got two from Ebay but they are not equivalent (one black plate, one silver, and the black plate is very microphonic and ). I just informed the seller that I'm not happy... Don't think this pair will be representative of what 403B can bring.

Bummer about the tubes, I've been avoiding e-bay tubes as much as possible, but the place I buy most of my tubes from in the UK doesn't stock the 403B tubes.

The hum on my amp is getting worse, and seems to be going back to both channels .. going to leave the amp on as much as possible over the week/weekend and see if this problem dies away. Great sounding amp, but the hum is just too annoying for me to be able to sit back and really enjoy it.

 

[BigTony]

I recieved the -10db Rothwell attenuators this morning - had to pop them in over lunch. Just the ticket - now I can leave my digital output at 100% (bit perfect), which is good.

They are expensive new (£39) but I got these used at half that price (and they look new - even in the presentation box).

 

[Audict123]

Quote:

Originally Posted by BigTony /img/forum/go_quote.gif I recieved the -10db Rothwell attenuators this morning

Good!

The Ebay guy I bought the 403B's from offered to take them back for a full refund. It pays off to have a tube tester. I sent back 6dj8 tubes for my preamp a month ago because they measured very poorly. Also there, I got a full refund. I bought a russian L3-3 recently - incredible tester. There are some on Ebay, the prices are very sensible if you see what you get for that.

 

[ogygia]

anyone conduct my test?