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pedals 4 pv
Platinum Member
Canada
1351 Posts |
 Posted - 08/27/2008 : 10:45:23
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I had to change the tubes in the pre-amp in my Classic 30. The only ones available were Groove tubes brand, but I had the choice of three types, the chinese 12ax7, the russian 12ax7, and the Mullard 5751 re-issue.
The Classic 30 uses the two stages of the first tube, V1 for the clean channel, and adds the two stages of V2 between the two stages of V1 for the distortion channel. V3 is the driver for the four EL84 power stage tubes. As the Driver V3 doesn't have as much effect on tone as V1 and V2, I put the chinese in V3 because it has a clean tone. I put the russian in V2, as it is a high gain tube with a more robust distortion sound. I put the Mullard re-issue in V1. The bias is non-adjustable on the classic 30, but the 5751 works fine. I was concerned about the bias at first, but no problem. This brings me to the point of my post, the Groove Tubes 5751 Mullard re-issue. What an excellent tube. It is a low gain tube, and it really, really takes away that harshness that the classic 30 is known for. With the Russian high gain tube between it two stages I get a warm distortion without that harshness. Before, I had a Ruby tube in V1 and JJ Tesla's in V2 and V3 and the tone was much better than the stock Peavey compliment of three chinese 12ax7's, but It was still too harsh. The low gain Mullard 5751 has taken that away completely, I can turn the treble way up now and the boost switch works way better too. I used to use the boost switch only with my cab, and it was good with the cab, but just added noise when I used just the amp. The Mullard 5751 re-issue kicks ass! |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 08/27/2008 : 12:37:04
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Hi pedals as far as i know you don't need to bias the preamp section of a valve amp so you can swap the valves/tubes around... the 5751 i wouldn't be 100% about... i always thought that you should stick with the same 'family' i.e. 12ax7,12au7 etc.. but i could be wrong.... i have 2 amps that run on EL 84'S and i think it's in the L84's nature to be a bit on the treble side anyway,i'm glad your having fun and getting some good sounds and managed to tame the little beast.... .... |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 08/27/2008 : 12:40:08
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Hi pedals 4 pv
This is very interesting experimentation.
Thanks for sharing your findings.
You know I have a soft spot for the Classic 30,
I just can seem to be in the right place to find one.
Regards Dr. Bob |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 08/27/2008 : 15:39:28
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I recently downloaded the mods for the Classic 30 because mine is so harsh it is left to sit in a corner.
Your info is very welcome - maybe a simple tube change will bring it back ino the fold rather than a bunch of mods (and goodness/Dr. Bob knows I'm not currently a fan of tube amp mods!)
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 08/27/2008 : 16:53:23
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quote:
Originally posted by Laurie
I recently downloaded the mods for the Classic 30 because mine is so harsh it is left to sit in a corner.
Your info is very welcome - maybe a simple tube change will bring it back ino the fold rather than a bunch of mods (and goodness/Dr. Bob knows I'm not currently a fan of tube amp mods!)
I know Laurie won't mind me, filling in the other members here:
Laurie is in the middle of a pain in the butt problem with some mods on his new Fender Custom Vibrolux.
We have been banging out heads together  so HARD,
We might actually be getting somewhere, although Laurie might not think so.
I know he's getting somewhere now, because all the name calling (in PM) has now stopped, well --- at least, until he reads this post.  
It appears that the mods on the link that he was given, might not all be documented correctly.
We'll know more when it's finally sorted out... Soon ...
See Laurie a problem shared....
Apologies for going off topic
Regards Dr. Bob
3500
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Edited by - Dr. Bob on 08/27/2008 16:57:22 |
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Dirk
Platinum Member
Netherlands
1309 Posts |
Posted - 08/27/2008 : 17:23:34
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| Nice Pedals 4 PV, I might try that tube as V1 in my JCM800 split channel to clean up the Normal channel a little more. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 08/27/2008 : 18:33:21
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Thanks for the support Dr. Bob. I'm happy knowing that once this amp is sorted a really nice Fender amp will be saved for a life in the cupboard because of it's issues.
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pedals 4 pv
Platinum Member
Canada
1351 Posts |
Posted - 08/28/2008 : 00:44:35
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I found a little write up that says Stevie Ray used to do this in his amp. Here's the blurb;
This new GT 5751 has all the character of a NOS tube. a smooth linear tone with gain equal to 70% of a 12AX7.
It is best as a replacement for the 2nd preamp tube in your classic two channel Fender, the 2nd preamp tube in your Marshall/Tweed Bassman classic style amp, the first preamp tube in your Deville/hotrod or Blues Jr. and the first preamp tube in your Carvin, Peavey, Krank, Mesa, Gibson, Epiphone, Modern Marshall, Vox etc. amp.
This is the tube that Stevie Ray Vaughan discovered as a way to get cleaner headroom from his Fender amps.
It is a great sounding, great looking high quality tube open for lots of experiments and designs.
(wonderful as a cathode follower for designers)
Taken from;
http://www.torresengineering.com/nenewgrtu57.html
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Edited by - pedals 4 pv on 08/28/2008 01:54:45 |
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FRANZONI
Double Platinum Member
Ireland
3543 Posts |
Posted - 08/28/2008 : 01:57:19
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Nice one.... i think i will try this in the marshall as the musicman has a solid state preamp and only uses the 12ax7 as a splittter and the people on the musicman pages recommended the 12ax7 in that position bercause of the high voltages that musicman used in their amps....... the selmer is so old it uses 9 or 10 valves in all .some of the strange ones like EF 86's along with the usual suspects EL84's,12ax7 etc.... good topic pedals.....you learn something new every day....
P.S if it's any use to you i found that the 25 watt greenbacks i changed in place of the vintage 30's sound a little smoother especially with overdrive with the marshall running the EL84'S in the power section...i can get a really fat sound with the neck pickup on the strat and the bridge isn't as spikey anymore,but they didn't drop the volume much even with opening up the back of the cab...... |
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pedals 4 pv
Platinum Member
Canada
1351 Posts |
Posted - 08/28/2008 : 08:57:59
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I was going to change the Peavey Blue Marvel for a Celestion V 30. When our Dollar went up in relation to the American Dollar, it worked out real good for me. I got a new cab with a V30 for the same price as the music store (a large canadian chain, L&M)wanted for just the speaker ON SALE!!! And I paid shipping. I don't have any plans to change speakers now as the Blue Marvel sounds pretty good paired with the Celestion in the cab and of course the 5751 Mullard Re-issue
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 08/28/2008 : 16:46:01
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quote:
Originally posted by pedals 4 pv
I was going to change the Peavey Blue Marvel for a Celestion V 30. When our Dollar went up in relation to the American Dollar, it worked out real good for me. I got a new cab with a V30 for the same price as the music store (a large canadian chain, L&M)wanted for just the speaker ON SALE!!! And I paid shipping. I don't have any plans to change speakers now as the Blue Marvel sounds pretty good paired with the Celestion in the cab and of course the 5751 Mullard Re-issue
Hi pedals 4 pv
My GP advised me to inform you, that you are giving me seriously crippling GAS pains.
The only known recommendation & cure is to get a Tweed Classic 30.
I did a heap of gigs back in 96, with a guy that had one of these with the mods, and just an MXR dyna type clone, & a home made simple LPB-1 type signal booster.
I can still hear his creamy sustaining lead sounds.
This guy "HAD" the tone I have been searching for, & was always praised by the other muso's in the crowd, as well as the crowd.
Regards Dr. Bob
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Edited by - Dr. Bob on 08/28/2008 16:46:48 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 08/30/2008 : 20:34:48
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| Just bought the Mullard 5751 re-issue tube for my Classic 30 - will try it later this weekend |
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DarrinPA
Silver Member
USA
221 Posts |
Posted - 08/31/2008 : 00:05:06
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| I have a Crate Blue Voodoo 120watt that gets distorted on the clean channel when it's turned up loud. I have to roll back the volume knob to make sound clean. Would one of these 5751 in the preamp help make my clean channel stay clean? Is this something I could do on my own? |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 08/31/2008 : 00:45:22
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quote:
Originally posted by DarrinPA
I have a Crate Blue Voodoo 120watt that gets distorted on the clean channel when it's turned up loud. I have to roll back the volume knob to make sound clean. Would one of these 5751 in the preamp help make my clean channel stay clean? Is this something I could do on my own?
It might help... Does the amp have a 12AX7 as "V1" (the first tube in the chain - it SHOULD be a 12AX7, but need to check)?
Lower gain in the pre-amp might settle it down. And yes, easy to do yourself. Buy the tube and unlpug the old one then plug in the new one. Wipe off your fingerpints then power it up.
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Edited by - Laurie on 08/31/2008 00:46:34 |
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pedals 4 pv
Platinum Member
Canada
1351 Posts |
Posted - 09/01/2008 : 03:24:09
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quote:
Originally posted by Laurie
Just bought the Mullard 5751 re-issue tube for my Classic 30 - will try it later this weekend
C'mon Laurie! Try the tube I need to know what you think!! |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 09/01/2008 : 04:37:30
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quote:
Originally posted by pedals 4 pv
quote:
Originally posted by Laurie
Just bought the Mullard 5751 re-issue tube for my Classic 30 - will try it later this weekend
C'mon Laurie! Try the tube I need to know what you think!!
It's coming... too many family things today. Will get to it tomorrow |
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5751 for 12ax7
