Patrol the Border, choke on a filter!

Hi

How much would one expect to pay for a good condition s/h BP valve-rectified, choke-input-filter power supply (standard and MB versions)?

Are they all they're cracked out to be in reviews (i.e very good) when used with most valve amps (in my case a Canary 301mkii)?

 

Hi,

I have seen these go for around £200 to £350 2nd hand. They do make a difference to sound quality. Choke input is a very good way of providing good voltage regulation. It also offers good filtering of ac noise. This will give you 'stiff' power supply to your amp. The voltage stays stable.

This should give your a tighter sound with better dynamics, bass and separation. You notice this more when the music gets going. The less muddle to the sound. The bigger supply is even more of the advantages.

Well worth the upgrade.

SCIDB

 

I'll second that. I used to have a Audio Note Oto (EL84-based integrated) and added a standard BP. At £600 the price hurt, but it was worth every penny - I got all of the improvements mentioned by SCIBD, not to mention more punch and clarity.

No guarantee it will do the same for your Canary, of course, but my experience was entirely positive. Oh yes, reliability was excellent, too. The only 'problem' I ever had was the valve went after about 5 years.

 

B,

Living Voice used to do 3 versions of your amp - with varying degrees of modification.

There were reviews in hifi +.

The mods involved the BP power supply and other component changes too.

Hifi + thought the changes were very beneficial.

The changes were expensive, and I'm sure you could save doing the same thing DIY.

Ive seen second hand BP power supplies from time to time. You can use either, and the bigger the better.

 

So can you basically put a choke filtered power supply on any valve amp?

Regards
Steve

 

build your own!

Hammond 378X £66.43
Hammond 193M £30.78

Chassis, suitable caps and a GZ37

Should be good for 320V@ up to 250ma

Higher HT needs a different transformer and maybe voltage doubler.

http://www.bluebellaudio.com

rgds,

murray

 

Am waiting to hear back from Canary whether doing the mod will invalidate their 3-year warrany, as amp is only a few week old.



Strange how Definitive chose to use the Canary 301 with the BP supply, as the 301 has solid state rectification.

 

not strange at all. Valve rectifier & choke input filter sounds much much nicer than silicon rectifiers

 

Do you think that moving the trannies off the main board contributes to the effect?

Regards
Steve

 

Hi Steve,

Yes. Most power supplies are capacitor input. You can alter a capacitor input supply to a choke input but you need to be aware of the extra voltage drop. You may need to change the mains transformer.

SCIDB

 

Canary say that fitting the BP will indeed void the 3-year warranty but then go on to mention that I probably will never need to use the warranty because the amp is well-built and shouldn't give me any problems.

So, the choice is mine. Would have to get a UK dealer or expert to do the mod, though, as not DIY inclined.

 

I'm sure Kevin at Definitive Audio Nott'm would do it.
If anything it'll make the amp last longer. Gentler switch on and less strain on mains transformer.

SCIDB Aside from the voltage drop just taking the input cap out will increase hum. Also the choke used has to be intended for a CIF. Much more ac hits it and a normal choke will buzz.

CLC filters are quieter. LC generally gives better regulation ie stiffer but you can make an LC as quiet by changing values of caps and the choke.

 

I emailed Kevin asking him if adding a BP supply would substantially improve the Canary 301 and he replied saying that he didn't think adding the BP would be the best thing to do, though it would provide a benefit. Before doing this he would change the coupling capacitors for Hovland film and foil, change the metal oxide resistors and shunt all of the power supply electrolytics. This work would be involved but also of substantial benefit.

I'd imagine 'involved' probably means expensive but I haven't asked the price yet . But the 301 is sounding excellent stock and I believe it already has a beefy 3-stage power supply, which is why I bought it. The Tannoys, although efficient, are true studio main monitors and need some control down below IMO. On the subject of mains power, will probably add a Trichord Powerblock 500 exclusively for the Canary at a later date.

 

Give the money you intend to spend on the power block to Kevin. The rewards will be greater.

 

like I said before, he does the work in stages 1,2, and 3.

If you can find out what he does in each stage you could no doubt pay someone a lot less famous to do it for less if you wanted.

 

No doubt and that will indeed be tempting...but he's recently given me some very good advice and then I've gone and bought the same stuff elsewhere more cheaply instead of from him, not intentionally but that's just the way it's worked out. Easy to do when funds are dwindling and you come across an item for far less, perhaps from abroad. Am greatful for his guidance, though.

 

You may be right.. but I fear we are opening a can of worms here. Some would say cleaner mains is worthwhile and some wouldn't, and the Trichord/Duncan stuff has been recommended on this very site. But, true, it would be expensive just to power the Canary (£400 or more). So, second-hand would be better.

 

I thinkwhat Kevin does is simply replace components with ones he prefers the sound of (at a price), so Hovland Caps, some brand of carbon resistors, by-passing reservoir caps etc. The power supply would also make a difference. Ideally you need both.

I heard some big Jadis amps they'd done which were transformed from how they were previously.