James D OB's

[Nick]

Would you care to comment on how they compare with the old 211 amp

Hard to say. The orig 211 I had, worked just great with the 90dB/W ProAc's I had, and I guess I voiced them for those. When I moved to the OB's the 211 (Mk 1)didn't seem to be as good a match, I found that compairing it to the 300b I took to the Doncaster meet, it seemed to lack a little in low level detail, it was as if it was slightly too over powered for the OB's. The other problem, was the mains TX's buzzed at home, because of my crap mains. This avoids some of that by having a 1000v B+ not 1300v, as Paul will tell you, that 300v does make a difference.

The new one seems to have a bit more detail, in a way its a bit more relaxed, but also it has a feeling of restrained power. I remember that Paul mentioned some time ago, that A2 amps have a certain drive to the sound, and I think it does that. I am also thinking of the comment Steve made about reducing the resistance in the output stage helping the dynamics, I think there is truth there as well, and again, thats the case here, as the cathode is at 0v.

It seems to have the standard 211 nice top end and slightly lean midrange (compaided to a 300b that is), but this one I think may have the edge on the last one when it comes to the bottom end.

Iansr heard it the other week, he seemed to think it sounded ok.

I am having to keep the circuit a bit close to my chest, as it started life with someone wanting a 211 to potentially sell, it probably will come to nothing, but if I can get a few quid for it, it will slightly offset the amount I have spent on this hobby. But there is nothing special in there, Paul could probably look at it and sketch most of it out.

And the other big plus, is it will fit on just the one bit of wood

What did slightly worry me, was I built it almost out of spare parts, just pinching heater supplies and OP TX's from the old amp.

Then again, If I heard the old amp again, I might decide that I was wrong, its not as good, who knows

[simon]

Sounds like it should be good Nick. How many stages does this one have, the previous had 5 didn't it? I know you've talked about balancing the harmonics of the 6SN7 with the 211, are there any more that you can reveal?

Respect for building it from spare parts . I did that with the 6EM7, but it's hardly the same...

[iansr]

Iansr heard it the other week, he seemed to think it sounded ok.

Nick is being modest. As I told him, I thought it sounded really very good indeed. I reckon its a cracker.

Ian

[Paul Barker]

Great,

I too find the 211 better bodied at A2 bias, Some people find it too thin usually. Bass damping will probably always be a problem.

Anyway if it is better than your original one it must be great because the old one was such a reliable attendee at gatherings. Where would Whittham 1 have been without all your stuff Nick?

As I type I am in heaven listening to radio 3 beautiful impromptu jazzish stuff. Field coil 8" driver on one baffle with a scanspeak tweeter on top and alnico jensen 14 incher for bass on that side, lowther pm6a on other baffle with both rockwood bass units.

Craisy, cobbled together but it is working out just nice.

Awaiting the aer and the pm7a pair (which the bloke is driving over with on Sunday).

Fortunately various people in Scarborough have been geting very cold so I go the money for my purchases.

[Will]

Good luck those AER's looked good.

This is my first year for winter fuel payment
from Sir Gordon Brown it paid for the VT52's
they now sound more like a beefed up 45
after changing the arm and bits in the, phono and amp.

[Nick]

How many stages does this one have, the previous had 5 didn't it? I know you've talked about balancing the harmonics of the 6SN7 with the 211

No, the previous, was only 3 stage, it just had a lot of supporting stuff. 75 -> 45 -> 211. This one is the same sort of shape as an Ongaku, but using a el84 as the driver.And the voltage amplifiers (6sn7) have a lot more headroom.

Anyway if it is better than your original one it must be great because the old one was such a reliable attendee at gatherings.

As I say, that remains to be seen, but hopefully I can get some more opinions soon. What will be interesting is taking it to Colins, as I was rather shocked just how badly the original 211 handles Colins statics

This is my first year for winter fuel payment from Sir Gordon Brown it paid for the VT52's

Nice one Will, I am not sure why, but that has made me feel much better, there is light at the end of the tunnel

[ed]

but that has made me feel much better, there is light at the end of the tunnel

In your dreams! Its just some bugger with a torch, bringing you more work

[shane]

This is my first year for winter fuel payment
from Sir Gordon Brown it paid for the VT52s.

Well they'll keep you nice and warm...

[Scottmoose]

In your dreams! Its just some bugger with a torch, bringing you more work

A flamethrower if you're really unlucky. ;^)

[steve s]

nick , i'll be trying to find another stc211 for when you bring that new amp round...

there is something about 211 s and the like ..
sort of mystery about them...

i should really wind the voltage up on the det25 amp and fully drive it.. se how it really works

i can't belive i'm thinking about building a 3 stage 300b amp.. how much more driving does a 211 need than the 300b? bet it not much more..

i was thinking on the lines of 41mp/41mxp/300b the 41 mxp has low resistance.. i've got a feeling to get it right it will need a seperate power supply from the 300b...time will tell..
a single mh41 would drive it but not give full output.. maybe also worth a try.
I starting to like plenty of current in my drivers.. i consider the 2p amp to be about right, the driver is set at 24m/a to deliver the 20 volts needed..
i consider this relationship quite important now, to put the same current/ voltage ratio up a 300b would need some driver..

the px4 would be ok, set at around 250vots 60m/a means it needs only low bias and load resistance (not as low as the 41mxp) and an easy 20 volts up it would be enough to drive the 300b and ensure low distortion when the wick is turned up..

nice choices....
steve

[simon]

Blimey Steve, I'm speechless.

[Cressy Snr]

i can't belive i'm thinking about building a 3 stage 300b amp.. how much more driving does a 211 need than the 300b? bet it not much more..

I was thinking on the lines of 41mp/41mxp/300b the 41 mxp has low resistance.. i've got a feeling to get it right it will need a seperate power supply from the 300b...time will tell..

steve

Hi Steve
I found with the 6AS7 amp, (which needs voltage drive rather than high current) that separate power supplies for each section are a very good investment giving a well-controlled detailed sound. TBH I would design the thing from the outset with a separate driver stage power supply.

Steve

[Paul Barker]

My PM7a's came today bye hand. The man deals in Lowthers.

I learned a few things.

In the alnico range from pm7 upwards they use a cobalt pole piece,

The older alnico motors in the square framed drivers sound better than the modern motors. He is not sure if this is because they were better or because over 50 years they lose 3db and might sound better for it.

The modern cones are better than the square frame days' cones.

the pm4a stabyliser can be fitted to the other units to good effect. It aparently loads the whizzer at the 3khz and prevents that doubling up effect at 3khz. The bullet thing we call a phase plug is useless.

He doesn't buy into the Gernan cones being better, when he recones he buys from Lowther cones assembled complete with spiders and surrounds, and says these are better than the German ones.

I have placed one of the drivers in place of the single pm6a I was using. Initially it was subjectively at least 3db louder. Anyhow with this thing about loading the whizzer on my mind I fashioned a crude stabiliser to follow the whizzer and coated it with loo paper.

This was a significant benefit and higely noticeable effect. The trebble is brighter, appears to go higher, significantly clearer, speach more discernable.

Overall change compared to pm6a, less dull faster attack, 3db louder (subjective human hearing assessment).

Should be good when the supravox woofers arrive.

Slight snag the pm7a's are going to take quite some breaking in.

Your off your head Steve, I have a little 45 amp here, plenty powerful enough for Lowthers of your and mine sensitivity on OB.

I'm probably selling my gm100's to Darren, say goodbye to all that madness.

[Cressy Snr]

I'm probably selling my gm100's to Darren, say goodbye to all that madness.

Don't blame you Paul.
Those Electronluv GM100s at VSAC 98 (I think) looked more Dr Who than Dr Who!
IIRC didn't they also need fencing off with scene of crime tape to keep the punters at a safe distance so they wouldn't either get fried by the volts or sunburned by the glare?

Steve

[Paul Barker]

We were all put out of the room while they were powered up and then let in, but we were also taped off from getting near.

Secondly they had to supplement their power with an extension lead from the next room.

The sound through Josh's woman's private parts lookalike metal horns was hardly any different to the sound I was geting from the 212 at the first eggfest. The signiature of large tungsten filament bottles is lush and powerful. 211's and 845's don't posess it.