Deville amp
I just unpacked my Hot rod deville. It's pretty old , from July 97 ACcording to the sticker, but seems to be in mint condition. All original. I haven't plugged a mic into it yet, but I powered it up and while it is generally very quiet I did notice a strange crackle come in for a while, which disappeared after a couple of minutes. I'm speculating that the amp is probably due for some attention to capacitors, as it is 15 years old and reportedly done very little work the last 10 years. Anyway, it is heading to the workshop this week for some mods as per Aki's recent submission. I'd love to get some before and after recordings so think I will do that and post links as we go.
I also have some mods in mind which were suggested by Mark Burness. These also appear promising.
The changes Val King made to Aki's amp involve some tube swaps. Mark's suggestions to some extent involve modifications which enable the original tube complement to be retained. Aside from this mark also suggests changing C1 which I think should fatten up the bass, and R9 to tame the volume control. Although I expect I may find a 12AU7 in V1 will tame the volume control quite a lot on its own.
Anyway, I ll get on with it and report back
Thanks for the update Dave. There's nothing like having ' that' tone for your amp!
Cheers Hank!
Thinking back on the test session, its really quite amazing the difference it made having this big amp. I usually use a 30 watt valve amp with single 12" and have it at the screaming edge of feedback and playing the harp at full volume with my hottest mic, and can barely hear it. This amp; yes sometimes it was a little hard to hear but usually no problem and i could back off the harp volume, which of itself made a huge difference to my playing. But also, the fact the amp had that capacity meant I could get some variation of tone, from clean to dirty, rather than just the one flat- out dirty sound I had available before, if I wanted to be heard.
AND these speakers don't break up in the sudden farty way the twelve in my other amp does. These are the stock eminence speakers and I think they are pretty good for the harp.
Anyway, these are the mods. They are not expensive; I like that too :)
Changes made to stock 4 x 10" HotRod DeVille
As described by Val King in Aki's submission
R3 from 1meg to 4.7meg
R4 and R11 to 120k.
I haven't done any tube swaps. Instead:
Preamp voltage dropped to around 170 volts by increasing R75 to 50K.
R9 to 820K
C1 to 220uf.
upgraded power rating of V3 plate resistors to 1 watt
Rebiased power tubes 10-15mA per tube.
rewired speakers to 2 ohm parallel, and used the 2 ohm tap from the OT
I am using the original complement of 12AX7s in V1,2 and 3. May yet try a 5751 in V1 to see if I can get a bit more sweep on the volume control, but I really like the sound with the 12AX7. Also may try the 12AT7 in the PI. Mark B told me this could give greater clarity, but at the cost of some bass.
I envy guys like you with the techie know how and ability. Not having that ability nor knowledge I end up going the dollar route, which at this stage of my life, I'm fortunate to be able to do! I leave the choice of speakers and tubes up to the experts who design and build the custom amps. I'm so happy with the tone I get that there's no temptation to tweak other than the occasional addition of a pedal like the LoneWolf Delay.
Reading about your modifications and those on the videos by people like Aki and Mark is helping me understand the impact of tubes and speakers. Love it!!!
I think you are smart Hank. I have had a win with the DeVille, thanks to some good advice from some knowledgable and generous people. It has been a long road though, littered with not so successful adventures. My Filmosound is the best example of trying for a cheap amp which has turned out very expensive and unfortunately still not finished after a year of frustration and expense. Won't ever be legal and probably unsaleable. May sound good when complete, but really just a middle sized old curiosity which will probably need a lot of attention forever. A folly really. My silverface Princeton reverb is a real ballsy little guitar amp and I love it, but I found i don't have much use for it at the moment. It's nice and will hold its value at least.
I think I would have saved money and a lot of mucking about and have more space in my house if I just bought a double trouble or an HG50 in the first place, but hopefully I have at least learned something from all this, even if it's only that I should learn to take advice from those who have been there already
I just picked up a 410 deville too a couple of days ago. Got it for 450$ figured was a good deal considering I live in Hawaii and any amp that big is gonna be crazy expensive too ship. Your power tubes you got them at 10-15 mA. What's the mV numbers you set it at ? I'm using a multimeter . I watched the vid that tube depot and -60 mV or something like that is the factory set. Is yours set to -40? Dont have the skills or money right now to do the resistor stuff gonna just play around with the preamp tubes and the bias. Hopefully I can get some good tone from that. I did plug my old 1953 McGohan pa head in it and that sounded warm and fat. I figured I can use it as a cab if anything.
Gday Brian. I believe the number is likely to be about 30 Mv at the test point. But I am not sure of EXACTLY which point Barry has set the bias.
Barry Young is the guy who has done the work on this. I think I asked him to bias around the upper end of that range. I dont recall exactly. I have not seen him since I collected the amp, and didn't actually see him then. So there has been no real discussion. Although we did discuss in detail prior to modification.
The video on biasing the 6L6 tubes in the bassman chronicles is quite illustrative I think.
I have not heard a guitar through the amp post mod, but I think it would sound less than good! Great for the harp though.
Good luck with your project. I was wary about the plate resistors for V3 even though I stayed with a 12ax 7 in both V 3 and V1, just because they seem to have a history of failure in these amps. But mark said he thought it was ok to use a 12at7 in V3.
I have left my amp in the jam room and haven't been near it for a month. Now I am keen to fire it up again. It's a great sounding thing. I really am happy with it but it's definitely a gigging and gig volume jam amp.
Anyway, about 30 millivolts I think is where I went. Much colder than the tube depot guy runs his.
Let me know how you get on with it.
Cheers, Dave
Ps your comment about the speakers seems to line up with my experience. I think if you paid 450 you are on a good thing even if you only use it for a speaker cab.
Thanks Dave, i set the the bias at the test point at 35 right now, sounds better than the factory setting. gonna try the 30mv as you got yours at. i got a 5751 jan phillips in v1 now, gonna throw a 12at7 in the v3 i got a couple of vintage ones laying around. i also tried to put new tung sol 6l6gc str tubes in but the bias wouldnt go lower than 80 and went up to like 140mv at test point , weird, so just went with the stockers. gonna ask skip about that. shoots,Brian
Howzit Dave, I set the bias to 32mV. Got a harp tone plus pedal cause i didnt really want to do the resistor changes, plus i got other amps i can use the pedal with. The pedal definetly fattened the tone up. I was supprised at how well it kept the feedback down, the room i tried it in was 20' b.y 20' and i got it up to 6 on the volume on the amp. I was running the pedal through the #2 input and i have all 12ax7 tubes back in, used jt30 with a hot cr element. I cant see any band drowning this amp out, as you said this amp is loud. I didnt have time to really play around with all the settings on the amp and pedal, but what i did play sounded good to me. The best part of the pedal is i can use it with all my other amps. So all i got to do now is keep practicing, you know what they say, as you get better the gear sounds better too :)
Hey Brian, good to hear. Yeah, I've been using input 2 also. I tried the amp with my LW Octave pedal, but I think I prefer it's natural sound. Did you get more bass with the Harp Tone+ pedal?
Yea the pedal definitely adds bass. It's not boomy or sloppy. More of a tight compressed sound, I think it sounds good.
DeVille came back from the workshop and into the band room yesterday. This is now definitely officially my number 1 amp. It's heavy, but that's the only thing not to like. Loud, good bass, with a lone wolf delay it's round and mellow, with the lone wolf octave I can get that paper tearing tone. So what I'm saying is its versatile. And big sound that will cut through. I have dialled the mid right out and I like that tone, surprised at how much treble I can put in, up to 8. reverb is very powerful, just on 1 is plenty. Or none. I'll detail the mods later. Very happy with this amp though.