LoeD
Joined: Feb 29, 2012
Posts: 310
Germany
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Posted on Oct 02 2012 03:59 PM
Hi there,
i was just dialing arround the knobs of my DIY tube reverb unit when I figured out something that seems a bit strange to me, or let´s say - what I meant not have had before:
When turning the mixer knob down towards 1 the signal not only gets cleaner (less reverb) but also more bassy and a lot louder.
Is this normal behavoir? or did I wreck anything by kicking the tank during time?
I tried to record a mixer sweep:
changing tubes (small ones only, don´t have a spare 6K6) did not change anything. reverb sounds good still. and when i bypass the tank with a looper the tank with mixer at 1 is a bit louder than bypass and a bit more trebly, like a treble booster set quite low.
Thanks for reading!
any help would be appreciated
cheers
LoeD
— here comes the WEST SAMOA SURFER LEAGUE
Last edited: Oct 02, 2012 16:06:03
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tubeswell
Joined: Sep 24, 2011
Posts: 1424
Wellington, NZ
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Posted on Oct 03 2012 02:09 AM
Normal. The signal from the sole recovery stage on the wet side is sourced from a feeble signal from the pan's output transducer, whereas the gain on the dry side is 'unity' about .98 of the signal from the geetars p'ups. What's more the dry side is a CF so it has a lot higher output current and can drive the load of the output cable to the main amp a lot easier than the wet side stage, which is a normal 'inverting' gain stage and looses more signal in the AC-loading on the output.
— He who dies with the most tubes... wins
Surf Daddies
Last edited: Oct 03, 2012 02:12:07
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sonni
Joined: Nov 08, 2006
Posts: 80
Vienna, Austria
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Posted on Oct 03 2012 02:57 PM
It's the return of that old... here I found the old thread:
http://surfguitar101.com/forums/topic/7860
tubeswell even suggested a mod that maybe would solve the problem - Thanks btw! Unfortunately I am quite a noob on electronics, so I didn't try that...
Last edited: Oct 03, 2012 14:58:25
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LoeD
Joined: Feb 29, 2012
Posts: 310
Germany
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Posted on Oct 03 2012 03:25 PM
got it!
a member of the german tube amp builders forum tubetwown had the idea to check the impedance of the following stage after the tank and guess what? that was it! yersterday i had my tank connected to a line in jack of a mixer.
today i hooked it in front of the T-Rex tremolo on my floor board as usual. and it sounds perfect again. little dry sound boost compard to hard bypassed tank. and this volume increase stays when dialing in the reverb. the reverberated signal has now more power then before as it must not fight against the following stage.
So it is like tubeswell wrote above. The inverting amplifier stage after the pan has not enough power to drive the low impedance input of the mixer.
so guys if you have aproblem with too low reverberated signal: check the impedance of the following stage!
lesson learned!
thanks for your help
LoeD
— here comes the WEST SAMOA SURFER LEAGUE
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