Building 4 x reg's HT PSU's?

simon · Post by **simon** » Fri Dec 27, 2013 11:27 pm

23 chokes - no wonder you stopped lugging your amps down to South Yorkshire

steve s · Post by **steve s** » Sat Dec 28, 2013 11:18 am

Makes the 11 i've got wired up look like i'm being a cheapskate....but its only 2 stages..
Nice to know i'm going in the right direction... At last eh..

Whats holding me back at this point is the fact that i may be better off with 4 separate power supplies, i've been doing a lot of searching and thinking(for what thats worth?) but most of my books are pre 1950 . And they where mono only, so it wasn't such a big deal.

Will · Post by **Will** » Sat Dec 28, 2013 11:56 am

A couple of weeks ago my lad (43) had his pal round who is on a sound recording degree course in Lundon...dad put yer stereo on for Mark.. well after a couple of tracks of SRV we had to scrape him off the floor and brew some sweet tea.
This rekindled my interest..true story

simon · Post by **simon** » Sat Dec 28, 2013 1:46 pm

Welcome back Will

Cressy Snr · Post by **Cressy Snr** » Sat Dec 28, 2013 1:51 pm

Will wrote:A couple of weeks ago my lad (43) had his pal round who is on a sound recording degree course in Lundon...dad put yer stereo on for Mark.. well after a couple of tracks of SRV we had to scrape him off the floor and brew some sweet tea.
This rekindled my interest..true story

It's nice when that happens

Makes it all worthwhile.

Dave the bass · Post by **Dave the bass** » Sat Dec 28, 2013 9:27 pm

Will wrote: well after a couple of tracks of SRV we had to scrape him off the floor and brew some sweet tea.

Aaahhhh! Our-Will is definitely back if 'Tin Pan Alley' is being played again

Still got Muddy Waters Folk Singer by any chance?! Heheheheheheh

DTB

Dave the bass · Post by **Dave the bass** » Sat Dec 28, 2013 10:14 pm

Right, I think I've got a Plan-of-Attack sorted WRT 4 x Reg'd PSU's.

I know what 4 x SS rectified and SS reg'd PSU's sound like, that's what I'm living with at the mo, soooo... lets go out into HollowstateLand with Valve rect and reg'd 2 x ~360V @100mA max Series Pass for the 300B stages and Valve Rect but Valve Shunt Reg'd for the 2 x 150V at ~ 35mA 6C45P stages.

I've bookmarked Prof. Creswells Reg'd PSU's for Dummies thread and have the Merlin B PSU book as reference. Lets see
A)what I can breadboard
B)if it works.

Lastly we'll see if it sounds any good if A + B states are met!

DTB

thomas · Post by **thomas** » Sun Dec 29, 2013 10:36 am

Hi DTB

Go for it!

You'll be needing a trolley, mind!

T

Cressy Snr · Post by **Cressy Snr** » Sun Dec 29, 2013 10:45 am

Aye....get on with it

Paul Barker · Post by **Paul Barker** » Sun Dec 29, 2013 11:01 am

The only consideration I would give, is that as you have separated the first stage power supplies from the second stage, the need to regulate the output stage on behalf of the first stage no longer exists. By all means shunt reg the first stage. Now try choke input on the output stage instead of regulating it. Compare that to your series Reg and let me know the outcome.

little eddy · Post by **little eddy** » Sun Dec 29, 2013 11:11 am

Dave the bass wrote:lets go out into HollowstateLand with Valve rect and reg'd 2 x ~360V @100mA max Series Pass for the 300B stages

I presume Dave you're considering valve regulation so am wondering what further level of improvement might be attributable to valve rectification? Just thinking whether SS rectification & series valve regulation might be an improvement over simple valve rectification for my amp so will watch with interest.

Dave the bass · Post by **Dave the bass** » Sun Dec 29, 2013 12:59 pm

Paul Barker wrote:The only consideration I would give, is that as you have separated the first stage power supplies from the second stage, the need to regulate the output stage on behalf of the first stage no longer exists. By all means shunt reg the first stage. Now try choke input on the output stage instead of regulating it. Compare that to your series Reg and let me know the outcome.

OK, will do, thats quick and easy to do. I'll give that a try.

little eddy wrote:[

I presume Dave you're considering valve regulation so am wondering what further level of improvement might be attributable to valve rectification? Just thinking whether SS rectification & series valve regulation might be an improvement over simple valve rectification for my amp so will watch with interest.

I don't know if it will be an improvement Mike, thats why I thought I'd try it and see. Don't know unless I try.

Something I have noticed since going IR LED cathode bias on the 6C45 (thus increasing anode current) is that in combo with all the SS bench supplies the way the amp 'does' Acoustic Double Bass recordings is awethumne. Ultra tight, no flab, high definition. If I loose that I lose that I wont be happy.

DTB

steve s · Post by **steve s** » Sun Dec 29, 2013 2:33 pm

I think there are two issues i can think of and it will depend on the amp or valves used.
1st the modern production 300 b valves i 've heard seem to benefit from a regulated supply to tighten the bass, thats not really an issue with the old valves ..in my view.
The 2nd is the power supply is modulated by the load, ie the music signal. A stiff power supply ie Lc will reduce that modulation, as will the use of the various types of regulator, the valves types will not prevent it, just reduce it further.
As that modulation is in time with the musical signal load, and in a stereo amp there is a phase difference between the driver and output stage, and differences between the chanels. all the valves are been fed the modulated signal which is the sum of the modulation on the power supply, less any smoothing between the valves ...
Thats when the penny droped for me when i realised the average 2 dc volts drop in my power supplies when playing was actually been turned in to 2 volts ac modulated by the music load.
When you think in terms of the actual ac signal voltage, a couple of volts of mixed channel out of phase modulation added to the driver power supply will have an effect somewhere. As will cross chanel too.
I think dave may need requlated supplies on his 300bs, where as I can get away without on my px25's but to be honest I'm not 100% sure why,

I do wonder if the improvements on say a more simple single power supplied amp when say choke loading or transformer coupled drivers are used could be down to the inductance involved.

Post by **Nick** » Sun Dec 29, 2013 2:51 pm

I think dave may need requlated supplies on his 300bs, where as I can get away without on my px25's but to be honest I'm not 100% sure why,

Assuming a fixed Z power supply, am output stage using a valve with a lower Ra will have a worst PSRR than one with a higher Ra.

But I found (years ago now), that a 45 sounded best with a shunt supply, series supplies and LCLC were much the same. So even with a 45 it still matters.

I have to disagree that old 300b don't show the effect, IMHO (at yours, I dont have any) they do, it just that their other wonderfulness can distract you from noticing the problems in the supply.

steve s · Post by **steve s** » Mon Dec 30, 2013 11:28 am

Nick we are all gullty of hearing what we want to hear at times and disregarding the rest, i consider it a skill...

the regulated supply in your 45 could sound better because the valve sounds better on a regulated supply,
or it could be the lack modulated section of the supply ensuring a clean power to all valves causing the amplifier to perform better... If the latter, separate quality none regulated supplies could possibly end with the same result
But i don't know the answer.. But the latter seems to explains things more logically to me.

The thing for me was daves amp was a step change on the seperate supplies, compared to any thing else i've heard, whilst both your amps and steves amps and a few others really had me thinking over the last few years, i now must do something with my power supplies.

audio-talk

Building 4 x reg's HT PSU's?

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