Tube Amps / Music Electronics
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|12/31/2003 2:06 PM|
||PV Delta Blues Advice...|
I was wondering if anyone could make any recommendations as to tubes,(I've read quite a lot about the JJ's), and simple mods for the PV Delta Blues. I'm looking for a good loud clean sound, and perhaps a better reverb. In essence, more Fender-like.
Thanks in advance, and Happy New Year...
|12/31/2003 5:14 PM|
I have a Classic 30........same amp minus tremolo and 15" speaker basically. The stock amp is compressed and somewhat muddy and lacks harmonic richness to some extent. What i did to mine sounds great to my ear. Others might thing i'm crazy, but after trying out a bunch of high end boutique amps at a store a while back, i passed on them all because i decided the peavey sounds better to my ear overall. Thats not to say it sounds better in every way. For example, the Dr z amps i played had a clean the peavey couldn't come close to. But the overall amp to my ear is more usefull and better sounding in many ways than a lot of those high end amps sounded to me. Heres what i've done to make the amp sound much better and bring out natural tube qualities and cut out that compresses sound in a nice vintage sorta way.
JJ output tubes....better, tho not a huge improvement by any stretch over the EH, tho if yours has sovteks it'll be a more pronounced improvement.
cathode bias mod........this one made a drastic improvement to my ear in that it really livened up the amp.
fenerized the input, tone stack caps, changed C4...i can't really say how much diff the first 2 of these made, tho i do know changing C4 to an 820 pf seemed to help clean up the dirt channel a good bit so that it has a bit less gain and compression. (in a good vintage sorta way)
All-tone speaker........this speaker from reverend was only $59 and turned out to be probably my favorite speaker of all time. It improved the amp considerably. Many raving reviews i found online made me try it.(put dummy plug in ext. spkr. jack to switch tranny to 8 ohms...all-tone not available in 16)
presence control........added some high end in a range that the treble control lacked.
Now for the latest mod which i believe may be a major improvement. i'll have a chance to try it at a new years eve party tonite, but so far at home it sounds great....possibly one of the best things you can do to this amp as far as mods go. First, i removed the presence because after this mod you won't need it. You may have seen my other post about removing the NFL (negitive feedback loop)just recently. Well, i realized it brightens things up a lot, but probably way too much at stage volumes. But it to added a lot of richness to the tone and was like the proverbial "taking the blanket off" the amp. So i added a 1 meg pot to vary the NFL anywhere from stock to where it's at 1 meg resistance, which gave the same sound as removing it totally. All you have to do for this mod is to lift one end of R57 and attach the hot and ground of a shielded cable to the end of the resistor and to it's former connection to the circuit board, then put the other end to the middle and left terminal (looking from back of pot) of the 1 meg pot. Now you can dial in just the right amount. The amp with NFL attached sounds real dark and muddy, and removed it sound very bright but with a richer tone. This allows the perfect balance.
To sum up, i would suggest the following because i think these things alone will make the amp great....
3)-change C4 to a 820pf cap
4)-as i just described, add a 1 meg pot to vary the amount of NFL
Those are the things i feel made the biggest improvements. The other things i've done i believe could be left stock without hearing any great difference. By the way, i did some other components swaps that i didn't list because cannot recall them at the moment, but didn't make any real difference i could hear. But the above 4 things all made a considerable difference and together made the amp IMO about 2-3 times better. I love this thing now, and i've had my share of great classic amps. This one is now in the same league to my ear. YMMV....hey, we all expect different things from our amps.
|1/21/2004 12:25 AM|
how did you do the cathode bias mod? can you post a link or something. i could not find it on Blue Guitar.
|1/21/2004 2:28 AM|
||here ya go John......|
If you do this mod, use a 100 ohm 5 watt in place of the 60 ohm 5 watt shown. I read Enzo's take on this mod and he said a 100 is a better choice, and i checked the bias and found that to be true. Otherwise follow it just as it shows. I would also strongly suggest that along with the cathode bias mod you also change C4 to an 820 PF cap. That seemed to be a major improvement in making the distortion channel sound more vintage and less processed/compressed. To my ear it was essential. That and the cathode bias mod made a lot of difference in mine, and by adding JJ outputs and an all-tone speaker the amp now sounds far better than stock. Live it sounds friggin great and unlike a lot of amps it retains the sweetness and rich tone thru the mix of the band.
|1/21/2004 2:47 AM|
||a few more things i shoulda mentioned....|
In my original reply i talked about removing the NFL, but said i can't be sure if it'll sound as good live.......well, i tried it at a gig and found it to be too bright. I now think it's only real use is as an extra treble boost, but the amp doesn't need that once the other mods i mentioned are done. In fact, at this point i don't think it's near as good as i first thought and wouldn't bother with doing it.
The cathode bias mod, changing C4, all-tone speaker, and JJ tubes are definatly all great mods that i have time tested and shown to be well worth the trouble/cost without a shadow of a doubt. I think fenderizing the input via steves schematic may also be a necessity if you use boost pedals. I can't say for sure thats what did it and not the other mods, but i never found the C 30 to be good at all when it comes to boosting the input with pedals till i did the mods. now it works great with them. So while i can't say for sure if it's the fenderizing of the input that did it, while you have the amp apart you may as well do that since it's a simple swap of a few resistors and caps.
One more thing...if you haven't opened the amp yet you should know that there are 3 circuit boards that are attached to each other as far as circuit connections with about 70-100 little solid core wire jumpers. The middle board and one of the others is also secured together with some L brackets with screws. But the other board is held only by the jumpers, and when you work on the circuit the they bend and weaken. They will often break and aren't always visually obvious in thier breakage. Even if they don't break they may fracture 1/2 way thru and break all the way at a later time such as at a gig ! So be carefull to try not to bend the board back and fourth too much, and be absolutly sure to inspect each and every jumper before re-assembly. I had them break at a gig a few times rendering the amp useless and had to run thru the PA with the amp models in my processor. (not pretty !) What i finally did to stop this from happening was to solder 1/2" lengths of stranded with in parallel with every jumper ! About a 2 hour job, but the amp is now bulletproof in that regard. By the way, those jumpers will sometimes even break due to the vibration during transport even if you never opened the amp to mod it ! i know because it happened to me with my 1st C30 before i ever opened it. (i've owned 4 of them)It's a stupid design in an otherwise nice amp.
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