bluesfendermanblues wrote:I fully agree with Gil regarding not to dampen the OD channel's highs with a treble bleed cap.
The only damping I like, stem from the dumbleator and I even compensate by having the 68p cap on the master to regain brightness. My amps are not bright in an unpleasant way.
@ 'jazzyjoepass' a new amp is usually bright and a bit edgy. However, this will change after some burn-in time. You can speed up the burn-in process by attaching a CD player to the amp input and play music or even better 'pink noise'. Let it play non stop for about 1-2 weeks and voilá ...you got a very different amp that is not as edgy, but bright in an pleasant manner. This is not theory but facts.
It doesn't have to be loud and you can put a dummy load resistor on the speaker out.
I wouldnt do any tricks or mods to any amp before it has been played/burned-in properly.
My #102 Build.
Moderators: pompeiisneaks, Colossal
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jazzyjoepass
- Posts: 192
- Joined: Wed Feb 15, 2006 4:23 am
Re: My #102 Build.
Looks like I've got use for my RTA (puts out pink/white noise) and my Two Notes digital loadbox.
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jazzyjoepass
- Posts: 192
- Joined: Wed Feb 15, 2006 4:23 am
Re: My #102 Build.
I understand #102 with high plates at 220k and 150k, HAD was trying to get clipping earlier, all the way from the clean channel to the OD channel.
With higher plates resistors, there is more voltage drop across the plates and the dropping string has to drop lesser voltage to get to the gospel 200V mark.
But with 220k and 150k, it's impossible to get the plate voltages of the twin triodes to be equal (unless you use unmatched triodes). My dropping resistors have changed to something like 500R, 12K and 2.2k.
My approximate plate voltages are
448V 6L6 Plates/Screens
280V/278V PI
198V/203V V2
198V/203V V1
I've got Tunsgram ECC83 in there and I notice certain tubes draw less current and the plate voltages go up by about 10V.
So the 2.2k/22k/2.2k dropping resistors are hardly gospel. What about you guys? What tubes do you use and what dropping resistors have you got? Is it high plate #102 or low plate #124 ????
With higher plates resistors, there is more voltage drop across the plates and the dropping string has to drop lesser voltage to get to the gospel 200V mark.
But with 220k and 150k, it's impossible to get the plate voltages of the twin triodes to be equal (unless you use unmatched triodes). My dropping resistors have changed to something like 500R, 12K and 2.2k.
My approximate plate voltages are
448V 6L6 Plates/Screens
280V/278V PI
198V/203V V2
198V/203V V1
I've got Tunsgram ECC83 in there and I notice certain tubes draw less current and the plate voltages go up by about 10V.
So the 2.2k/22k/2.2k dropping resistors are hardly gospel. What about you guys? What tubes do you use and what dropping resistors have you got? Is it high plate #102 or low plate #124 ????