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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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In Reply to: I can hardly wait to hear the explanation posted by Soundmind on September 1, 2006 at 04:55:52:
Hi.Who needs you here if you can't come up with an answer to my dV/dt question instead of trolling along. This is a technical discussion, not a soap talk show.
How the heck you THINK you know Dynaco PS-2 "doesn't have nearly enough gain of its own"???? Speculation again?
If you never touched any Dynaco pre-amps, may I suggest you to check up their specs first before you open you mouth. You are not even "qualified" to comment at all since you sounded ignorant in this topic.
Let me tell you what I did to it to improve the sound so dramatically which beats conventional wisdoms.
(1) I bypassed the entire input programmes selector, a passive sound
blocker.(2( I bypassed the entire tone-control stage, a huge active sonic killer. Who needs tone controls anyway?
I tape the O/P signal direct off the RIAA cap BEFORE the phonstage O/P coupling cap, direct to its stereo volume control, with its existing balance control disengaged entirely. I replaced with its stock volume control pot with an ALPS blue-velvet stereo pot which sounds so much better.
With minor rewiring using the exsiting front panel switchs to accept CD & tape I/Ps, now I rebuilt this vintage stock PAS-2 into a one-of-a-kind phonostage+passive linestage which rewrites the definition of a conventional phono-preamplifier.
I hook up this 'cut-half' PAS-2 pre-amp, with only its RIAA phonostage in function, direct to the stock ST-70, which I upgraded
withOUT rebuilding it with new driver board & tubes like so many did.Never have I encountered any problem with gain to drive the ST-70 which I even trioded the EL-34 UL PP power stage.
I have even gone beyond your imagination & speculation by rewiring the heater circuit of the PAS-2 to accept an outboard battery power supply via its existing AC power outlets at the back panel.
This DIY tube heaters power pack, a 6V5AH sealed lead acid cell rechargeable by a switch mode power module, housed in a small plastic equipment case seated nicely next to the PS-2 pre-amp.
After this 'half-cut' upgrade, without changing any RIAA design or changing any RIAA parts, with its stock Telefunken ECC83s, it sounds so lifelike, dynamic, transparent with proper soundstaging, & NO, repeat no gain problem, I would call it a mission accomplished.
Get a glimpse where I come from? Don't talk big to me. You're not there yet.
c-J
PS: I did this PS-2 upgrade straightly to prove one thing -
there are ways to improve beyond conventional wisdom.
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Follow Ups
- Quit your soapy show now, stroll !!. (long) - cheap-Jack 07:57:44 09/01/06 (3)
- I did a lot of that on mine -- and got a super preamp for 78s! (Part of the trick.) nt - clarkjohnsen 10:35:53 09/01/06 (2)
- Are you talking about passive line control ? (nt) - cheap-Jack 12:47:12 09/01/06 (1)
- Waal... ain't exactly *passive* with tubes... nt - clarkjohnsen 06:58:00 09/02/06 (0)
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