Yet another 12B4 line stage, or is the 12B4 better than the Grounded Grid..... - Page 50 - diyAudio
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Old 18th September 2006, 02:40 AM   #491
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Quote:
Originally posted by jasonb84
To pose the question again in case no one picked up on it. I count 1 274B rectifier, 2 12B4A's, 4 OD3 regualtors but I still can't figure out the pair in front. They look to be a similar shape to the OD3 but emit a typical orange glow rather than the unique purple.
Anyone know what they are?
My guess is a 0A3/VR75, since it looks octal.
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Old 18th September 2006, 03:09 AM   #492
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Quote:
Hey Mark, yours doesn't come with the orange glow toobs!!
Actually mine has 4 purple-pink glow toobs plus the two 12B4's. My rectification is also via toob but is contained in the DC bench supply which is seperate. Lets see.... the Stainless Steel top plate adds another $16.00 at Metal Supermarket to my already $200.00 price tag.....

Mark
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Old 21st September 2006, 01:32 PM   #493
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Default transformer out ver

I made mine transformer out with switchable resistor/battery bias. I do like the battery bias best. Haven't seen much on others using Sowter output trannies. Is it cost? Quality? Bad return in this position?

Also, please help with some advice plese, should I have something across the transformer out, resistor and cap in series? This drives long cables to 2A3 monoblocks with 417A driver, input resistance is 1M (value of 417A's grid leak)

Thanks
Dan
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Old 22nd September 2006, 01:04 AM   #494
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So what is all the hoopla about using a tranny on a line stage that has this low of output impedance......? This line stage is pretty hard to beat in a transformerless state!

Mark
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Old 22nd September 2006, 01:50 AM   #495
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Quote:
Originally posted by Mark A. Gulbrandsen
So what is all the hoopla about using a tranny on a line stage that has this low of output impedance......? This line stage is pretty hard to beat in a transformerless state!

Mark

Mark
you still didn't tried choke loaded or parafeed or VOT with 12B4....
I remember that you also were sceptical - regarding few other things earlier
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Old 22nd September 2006, 03:03 AM   #496
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Choky,

My regulated DC supply does have choke feed.... then there's the gas regulators after that. My 12B4 is a trubute to Dr. Gizmo if you know who he is..... The last thing I'd want to do is stick a transformer in my line stage....

Mark
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Old 22nd September 2006, 04:05 AM   #497
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Hi guys,
I've been following this thread for a while and love the extream simplicity of it.

Hi Mark,
If you have not try anything other the R plate, have a go with the choke plate, it's much easier to implement then IT. I had some experiment with plate choke with many of my projects and they never fail to increase the gain and bandwidth.
Have a try and hear for yourself. Moreover, chokes can be comperatively economical experiment.

Cheers
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Old 22nd September 2006, 09:06 AM   #498
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Quote:
Originally posted by Mark A. Gulbrandsen
Choky,

My regulated DC supply does have choke feed.... then there's the gas regulators after that. My 12B4 is a trubute to Dr. Gizmo if you know who he is..... The last thing I'd want to do is stick a transformer in my line stage....

Mark
me:
Quote:
you still didn't tried choke loaded or parafeed or VOT with 12B4
I know that you have choke feed.......
what I say is -try to get rid of resistor anode load
if you have luck,you will have another layer of dynamics and details
Gizmo was my brother
in his style - "don't tell me later that I didn't tell you that before"
Gizmo and ZM have one big common thing -we love our toyz
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Old 22nd September 2006, 12:58 PM   #499
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I have no problem trying a choke in there, thats a sensible thing to try. I also have not tried a solid state regulator at the plate either. Someone had reccomended the IXYS type....

Please reccomend a choke if you would.... No, I won't try an output tranny if you held a .357 to my head!

Mark
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Old 22nd September 2006, 01:14 PM   #500
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Quote:
[i].... No, I won't try an output tranny if you held a .357 to my head!

Mark [/B]
sounds reasonable.

I used a Lundahl choke (LL1668) load on my 417A/2A3 monkey. I like it, but nothing ot compare it to, as this is the only way I built it.

Probably a good choice here.

Dan
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