OK, I watched this video in that thread you posted:
http://www.theinside.net/Wreckbeginnings.MPG
And that's *exactly* the same feedback I was getting when I had the dial at about 10 o'clock. I had a little more variety with it when I was at 12 or 1 o'clock, but for the most part my guitar and amp just seems to grab the b string and make it sing.
I thought that was not right because it was only one note...I figured if the amp was "tuned", I'd be able to pull all sorts of finger controlled feedback.
Am I wrong in thinking this? Or am I expecting too much?
Sorry to thread jack...just an interesting tangent we are on that's somewhat related to microphonics and feedback.
Sensitivty of V1
Moderators: pompeiisneaks, Colossal
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Lonely Raven
- Posts: 878
- Joined: Fri Nov 16, 2007 4:09 am
- Location: Bolingbrook, IL
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Re: Sensitivty of V1
Jack of all Trades,
Master of None
Master of None
Re: Sensitivty of V1
Tubetwang, you are welcome! I was VERY frustrated with the same problem.Tubetwang wrote: gcenker...you are the man!!!...
i've been wanting to stop a radio broadcast on my new Express build for a few days now...searching for a cure...reading like crazy...
That 33K one watt trick worked for me. No more radio!!!!!!!!!
I can honestly say that this Wreck is an amazing amp. Ken knew what he was doing.
Starting a Liverpool tomorrow.
Thanks again...
-Greg
Re: Sensitivty of V1
Good advice that just solved my 5E3 oscillation issue.gcenker wrote:The standard value for virtually every other amp on the planet is 68k but 33k seems to work just fine and does NOT suck the tone out of the amp ...
Just my 2 cents ....
More info can be found here:
http://www.aikenamps.com/
Go to TECH INFO then "Grid Resistors - Why Are They Used?"
One nit: if you look at the "standard" hi/lo two jack input on marshalls/fenders/voxes/etc you'll find that there are two 68K resistors and when using the hi channel those two guys are in parallel giving 34K (or close enough to 33K not to matter!).
BTW has anyone ever used the lo input except to jumper brite and normal channels?
Regarding Microphonic V1
I tried a number of tubes including Ruby, JJ, EH, and I found that only quality NOS tubes worked the best. I my case I settled on an Amperex Bugle Boy 12AX7 for V1 and Voila! Zero Microphonics and noticeable tone improvement.
My $0.02.
I realize that Bugle Boys are not in everyone's budget, but I had about 6 of them just given to me a couple of years ago and was sitting on them for just the right build.
-Steve
My $0.02.
I realize that Bugle Boys are not in everyone's budget, but I had about 6 of them just given to me a couple of years ago and was sitting on them for just the right build.
-Steve
Re: Sensitivty of V1
I have had 3 gigs now and 2 out of them I could use my xpress clone with 2x6V6. I installed Penta labs ax7 to the V1 position (mullard reissue V2 and balanced sovtek ax7 V3). It worked the first gig. I have master and a half power switch also. Amp was on half power and master at 3 o'clock (could not turn it up more- small stage). At rehearsals (half power volume max) it started to oscillate or gave me some quite constant humming tone but by choosing my position I could somehow manage with it. The second gig was a place without grounding system and the amp hummed very loud. Had to switch quickly to DSL. Last friday had a gig with a larger stage and running full with 2x6V6 it started to oscillate again uncontrollably and tried the Jan Philips AT7 at V1 and the oscillation was gone 
I dont have any current production at7 at hand to test if it was the NOS quality or the lower gain factor that helped in my case. If possible maybe will try some current prod AX7 with siliconrings around them.
I dont have any current production at7 at hand to test if it was the NOS quality or the lower gain factor that helped in my case. If possible maybe will try some current prod AX7 with siliconrings around them.-
skyboltone
- Posts: 2287
- Joined: Wed May 10, 2006 7:02 pm
- Location: Sparks, NV, where nowhere looks like home.
Re: Sensitivty of V1
I honestly haven't had this runaway amp syndrome at all with the two hole liverpool build. Not that I haven't had it before. It's an old nemisis. The amp is not sensitive to V1 at all. I think I've got a new old stock RCA grey plate in there now but I've had sovtec and just about anything else you can imagine in there.
the only time I had runaway was when my NFB reisistor was glued under the board and the wire ran parallel to the power tube grids for about four inches. The amp won't runaway at all unless the guitar is plugged in. Then you better mute all the strings when you got 'er cranked. At 1 o'clock on the volume dial and the guitar on full it's just a monster. Wish I played well enough to really get the most out of it.
I can dime the volume control and it still won't run away with no input.
Dan
the only time I had runaway was when my NFB reisistor was glued under the board and the wire ran parallel to the power tube grids for about four inches. The amp won't runaway at all unless the guitar is plugged in. Then you better mute all the strings when you got 'er cranked. At 1 o'clock on the volume dial and the guitar on full it's just a monster. Wish I played well enough to really get the most out of it.
I can dime the volume control and it still won't run away with no input.
Dan
The Last of the World's Great Human Beings
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
for the newbies (like me)
just thought id revive this thread theres some great wiring tips for the express. BUMP
Live , Love , Learn