I dont get it. My MC100 sounds so good im not even thinking about changing tubes. I find that some of these amp builders tweak the amp around the tubes that they are using. My twinjet was like that. I always hated JJ power tubes, but they sounded great in it. I just dont see the need to even mess with the Wizard at this point. Does anyone know where to set the bias on the new MC100?
What type of tubes are you using in your Modern Classic?
- Thread starter Superunknown
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steve_k
New member
Had a peek under the chassis and found a bias screw (for the quad), which was great to see. Went back with a matched quad of SED Winged C 34's. The JJ's E34L's that were in it were biased pretty hot from the factory at 40mA. I ran the bias down to 30mA for the SED's. I put a Jan-Phillips MIL 12AX7A in V1. Left the JJ EC83's in V2-V4. One reason I think the amp was making more noise than I cared for is because the tubes were biased high. Getting them down in the 70% range really put the muffler on this hiss. And, I like the Jan-Phillips tube in V1 in all my amps, including the Mesa's. You can hear a mouse fart with the volume and gain fairly high.
By the way, the PTP wiring is an awesome sight to behold. Very nice work in there. I also replaced them bastard screws (what are those called?) holding the back on. Luckily I had a 9000 piece socket set that happened to have one of these sockets in it. In the event I got caught out and didn't have the socket, the old phillips head can come to the rescue.
After all that though, it sounds about the same
. Runs a hell of a lot cooler though. Those JJ's were smoking at 40mA.
Steve
By the way, the PTP wiring is an awesome sight to behold. Very nice work in there. I also replaced them bastard screws (what are those called?) holding the back on. Luckily I had a 9000 piece socket set that happened to have one of these sockets in it. In the event I got caught out and didn't have the socket, the old phillips head can come to the rescue.
After all that though, it sounds about the same
. Runs a hell of a lot cooler though. Those JJ's were smoking at 40mA.Steve
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johnnyjellybean
Well-known member
Them bastards are called Roberts head screws..... It's a canuck thing eh?steve_k":1jxj4tz6 said:
Hollywood
Active member
Sounds like you had fun in there changing the tubes, twisting the screws and sneaking a look at the Wizard amp with it's pants down. 
The tubestore is selling those RFT's like a few other stores, TOO HIGH! I know it is supply and demand, but $59.95 for those is being TOO DAMN GREEDY.
The tubestore is selling those RFT's like a few other stores, TOO HIGH! I know it is supply and demand, but $59.95 for those is being TOO DAMN GREEDY.
So besides the amp running cooler you didnt notice any tone improvment? I know these suckers run hot, but I am loving the tone from it as is. I did the whole try this tube try that tube thing a few years back and the only amps I would notice a big difference in were my modded Marshalls.
Hey Steve,
Isnt 30 ma on the SED to low? I would think you can bring them to at least 35. The JJE34L are able to handle a hot setting. I really dont think 40 is running them hot at all. Depending on the plate voltage of the amp I usually run SED EL34 at 35. In my CCV Cameron told me to run the SED at 40.
Isnt 30 ma on the SED to low? I would think you can bring them to at least 35. The JJE34L are able to handle a hot setting. I really dont think 40 is running them hot at all. Depending on the plate voltage of the amp I usually run SED EL34 at 35. In my CCV Cameron told me to run the SED at 40.
Superunknown
Well-known member
I just opened up my new Modern Classic and was very surprised to find four original Mullard 12AX7's in the pre-amp spots.....no wonder this amp rocks.... 
steve_k
New member
parntz145":3uqn8sh0 said:
Maybe so. I always run them around 30 in other amps. Plate voltage measured was about 512V. I didn't calculate the optimum, but give or take a little isn't much of a large deal. The SED's seem to break up a bit quicker than some other tubes. Being it biased as a quad, V5 was set at 30. When I measured V8 it was at 35. My matched quad isn't spot on. So, I kept it from 30-35.
Steve
steve_k
New member
parntz145":3r748bit said:
I agree and it is just to be able to tinker around with your stuff. I think the SED's break quicker than the JJ's, especially at lower volumes. When I cranked it open a bit though, I couldn't tell much difference - other than the background noise. That is mainly what I wanted to get rid of. With the amp on run and making changes to the bias with the old tubes in it, there is a remarkable difference in the amount of hiss when you roll it back to 30 from 40. So, mission accomplished. That and the tube change in V1, or a combination of them got it where I am smiling now
The amp rocks for sure. One more thing, if you guys can swing it, get a 4x12 Wizard cab with the Rock 20's. Man, it made all the difference on this head, as opposed to V30's. Or, a decent Marshall cab or something with Greenbacks, H30's or equivalents really make this amp sing.
Steve
johnnyjellybean
Well-known member
I'll bet Rick is looking for those!!!Superunknown":3ojopyow said:I just opened up my new Modern Classic and was very surprised to find four original Mullard 12AX7's in the pre-amp spots.....no wonder this amp rocks....
steve_k
New member
I guess you would need to confirm which tranny the Wizard had first and see what sort of output you are getting. I measured PV @ 513V on mine. 70% would be 34mA per tube. 40mA is pushing 90% of bias range. For a lower output tranny, like 450V, 70% would be 39mA. Just depends on how hard you want to run the tubes.
With the voltage the trannie puts out, I bet the MC100 could run a quad of 6550's real nicely.
Steve
With the voltage the trannie puts out, I bet the MC100 could run a quad of 6550's real nicely.
Steve
My Metal came with some Marshall branded EL34's in them. Not sure what they are but they sound really great so I'm not gonna mess with em', ...for now.
I've actually always liked the JJ's best in my Wizards. They are a darker sounding tube which works well with the Wizards which can be fairly bright. FYI, the GT E34LS is actually made by JJ. It is basically the JJ E34L with heat sink wings and 30 watts of power vs. 25.
I've actually always liked the JJ's best in my Wizards. They are a darker sounding tube which works well with the Wizards which can be fairly bright. FYI, the GT E34LS is actually made by JJ. It is basically the JJ E34L with heat sink wings and 30 watts of power vs. 25.
Superunknown
Well-known member
johnnyjellybean":2wzixmqy said:I'll bet Rick is looking for those!!!Superunknown":2wzixmqy said:I just opened up my new Modern Classic and was very surprised to find four original Mullard 12AX7's in the pre-amp spots.....no wonder this amp rocks....
steve_k
New member
Decided I didn't like the SED's in the Wiz. Went back to JJ's. Sovtek LPS in V1. Biased back up to around 38. Still much more quiet then before. I think that HG JJ in V1 was a problem. Usually, SED's will kick the bottom up in any other amp. It took away from the Wizard though. Anyway, done tinkering, gonna go make some noise. Already have the level out so my wife can straighten the pictures up.
Oh, checked the fuses while I was there. Wondering why there was an 8 amp mains fuse in it? It says use a 4A. Replaced it and the HT fuse with a 2A as it was not marked.
Steve
Oh, checked the fuses while I was there. Wondering why there was an 8 amp mains fuse in it? It says use a 4A. Replaced it and the HT fuse with a 2A as it was not marked.
Steve