NAD + Need some opinions on tube swapping

[fhn_lopes]

some things to consider;.

"Some other weird things I noticed: When I turn on the standby switch the sound fades away whilst playing like it's supposed to, but when I turn the amp off and keep on strumming there is silence followed by a slowly building up sound of my playing coming out of the speakers again before it fades (with the amp in standby"

This is normal, my marshall does the same thing, it's your capacitors discharging the remaining current.

About fizz: It can be several things (and many times combined).
1) V30's are a bit harsh in the high end but it usually disapears in band situation. Have you tried it with a full band?
2) Is your cabinet standing in front of a clean wall, with a distance smaller than 2m?
3) preamp tubes: go NOS. If you want to get rid of fizz, maybe some old green label siemens would be a nice shot. Stay away from blue label GEs (but they work NICE as phase inverters - v5). Also look and OLD tung sol, RSD...
4) power tubes: GO NOS!! I use RFT EL34s and comparing to my old JJs, they KILL... more punch and less harsh high end, and my amp distorts the power section a lot. Also consider KT66s, 6550s or 5881s (as they can fit 6L6s with bias adjustment) other than 6L6. I'd go with 5881s for warm mids or KT66/6550's for more punch/clarity. RFT, Siemens, Sylvania, RSD, GE, Raytheon, RCA, Tung Sol, Phillips... A lot of good brands to look at...
5) Where is your master volume at? Many amps cut the fizz when you make the power tubes work, maybe that's your case... try to make it louder (like 5 or 6) and see wha happends...

I have never seen the JCA 50H schem, but from what you say, it has a lot more to do with the JCM800 than it's tone  :lol:.. JCM's can be harsh and fizzy at times, but usually you can fix this without modding your amp.

[GuitarIv]

Well, after a long and busy week I'm finally back with results. Borrowed my mates Engl cab with em V30s in it and surprise: it made everything better. The fizz of the JCA50 is still there, but not to the huge extent it was before and pairing the cab with my Valveking it even resolved the excessive highs I had after the tube change. (The Power Tubes in the VK where changed to Tube Town 6L6GCs, took a look inside).

It seems that the major factor contributing to the ugly sound I have is the Laney Cab, or rather the Seventy 80's in it. Now I'm going to keep the Jet City (although I still was quite unsure about it until recently) and swap out the preamp tubes (same with my Valveking) and the power amp tubes either on my own or get em swapped. I'm too much of a DIY and modding freak to give up any piece of equipment.

Next thing I'm going to get is the Palmer 212 with V30s for home use and then when I have the cash order some new speakers, I really wanna try out the G12T75 and V30 X-Pattern combination in the Laney Cab.  :D


fhn:

1.) Didn't try it in a full band context yet but playing it side by side with my bass player the fizz wasn't hearable anymore. I'm sure it will work splendid in a full mix. I'm sure as well it has something to do with the volume too, the more I dial the Master back to bedroom levels, the more noticeable the fizz gets.

2.) Nope. Our rehearsal room is small but I have it placed in the corner facing towards the other corner of the room (with my bass players rig and himself standing there 90% of the time)

3.) and 4.) yeah that's the next thing to do. Experiment with different tubes.  :D

5.) As said higher volume levels work. Unfortunately my bassist is a sissy and always tells me to turn the volume down (don't worry about my ears I always wear earplugs when going to 11)  :lol:



I'll keep coming back with results as time passes. Thanks guys, you all have been very helpful.  :)

p.s.: I attached the JCA50 schematic

Cheers!

[dave_mc]

Don't get the palmer cabinet, it's not plywood. The harley benton g212vintage is plywood and good on the cheap if you want v30s.

glad to hear the speakers helped, though. :)

[GuitarIv]

I just looked up the Palmer Cab, it says it's made out of MDF. Then I looked up MDF versus Plywood... well I guess I could still get the Jet City 24S 2*12 (even cheaper than the Harley Benton and made out of Plywood as well, it seems like prices on the whole Jet City range are being dropped like crazy) and that would leave me with their Eminence Speakers. I could always experiment with that and order Vintage 30's if I decide the stock speakers don't suit me.  :lol:

[Dave Sloven]

I dare say those Eminence speakers will be a big step up from Seventy 80s

[GuitarIv]

I'm sure they will be. They are said to be based on the Legend Series, either the V128 or the M12 (don't remember exactly which one right now). In the worst case I can still open it up and swap em out + the cab has the option of choosing between open and closed back.

Also found those two comparison vids:

http://www.youtube.com/watch?v=W0PVnHz77cw

http://www.youtube.com/watch?v=fB7Y48QYLL0


The stock speakers sound inferior in both samples to my ears but not bad.

[Dave Sloven]

I don't know as if I'd say that they are inferior to either.  To me they sounded pretty good in that cab, nice and clear.  The V12 Legends sounded a little muffled to me under gain and the V30s have their characteristic rasp. The stock speakers sound like they might have a broader tonal palette than either loaded in that cab.

Put them in a heavy 412 closed back cab and it might be a different story, but I say go for it, they will be much better than the Seventy 80s.  I've never heard a Seventy 80 cab that impressed me.

[GuitarIv]

Will do. The cab sells for 150 bucks at Thomann right now. That is a steal  :D

[dave_mc]

I just looked up the Palmer Cab, it says it's made out of MDF. Then I looked up MDF versus Plywood... well I guess I could still get the Jet City 24S 2*12 (even cheaper than the Harley Benton and made out of Plywood as well, it seems like prices on the whole Jet City range are being dropped like crazy) and that would leave me with their Eminence Speakers. I could always experiment with that and order Vintage 30's if I decide the stock speakers don't suit me.  :lol:

it's far cheaper to just get the harley benton cab with the v30s. the jet city speakers are not bad for oem-type speakers, but i didn't think they were anywhere near as good as name-brand speakers, either.

alternatively you can get the HB cab with HB speakers (cr@p) for less than the jet city cab. And as I said below, it may be my imagination but I wouldn't be surprised if the HB actually is the better-sounding cab. and then you can pop v12s into it.

I don't know as if I'd say that they are inferior to either. 

They are. If you ask me. They're a bit harsh and tinny- better than most OEMs I've tried, but not great either.

Now... I didn't give them the best try. I didn't break them in or anything, since I already had v12s sitting waiting and was kinda chomping at the bit to get the jet city speakers out and the v12s in. :lol: But even out of the box, I thought the v12s were better.

I also fancy the HB cab might sound better than the jet city, but that might just be in my head (that was my feeling, I didn't get to do a head-to-head). The HB is slightly bigger and I fancy sounds slightly bigger. Granted the jet city has the option of open-backed or closed-backed operation, which I guess is handy, but the way the back's been designed, you have to take the whole back off to remove the little removable panel. Which is daft, it makes it "set and forget". I have other cabs where all I have to do is remove 4 screws.

[GuitarIv]

Dave, I see what you're saying but I still think I'll go for the Jet City Cab. I like matching stuff and having that rather vintage looking combination on stage whilst playing face ripping metal with it has it's own charm hahaha  :lol:

Regarding the speakers I'm sure the HB Cab does it's job well, read quite a few reviews and heard some samples where the only downside to it was being branded as "Harley Benton". I'm not a brand whore so no issue for me. (And you can always remove the logo). Anyway I'm still not sure if I will really go for Vintage 30's so having the JC 24s with the stock speakers will give me a good idea in what direction to go. Apart from the Jet City and my Valveking sounding bright my guitars aren't really dark either so it may very well be that I will go for something a bit darker speakerwise. If the JC speakers sound anything like the Eminence Legends that should give me an idea how Eminence speakers sound in general as I've been only using Celestions so far.

I guess G12T75s aren't a solution due to the fizziness, Vintage 30's are good so far but still a bit raspy. I might just go your route and follow Toe-Knees recommendation, buy a set of V12s and pop em in. Will see  :D

Cheers!

[dave_mc]

Yeah I went for the jet city cab because it matched, too. :lol: No worries there. :D

when they're broken-in, v30s sounded pretty good with the jet city, I thought. But I still preferred v12s. So yeah if you get the jet city cab with the intention of eventually swapping them with v12s, that would be fine (of course if you like the stock speakers, that's even better- mine weren't broken-in but i thought they sounded closer to v30s than to v12s... not that there's a *massive* difference between either, but the v12s were a fair bit darker/smoother, I thought).

[GuitarIv]

Yeah as said I'll just go with the stock speakers and see how I like em. Will of course report back with results as soon as the cab arrives. I'm kinda anxious right now as I'm approaching the point where I'm finally "done" with my rig. After the Cab all that's left to get are a few pedals as addition to my board together with the Carl Martin Octaswitch and the Fuel Tank Chameleon, then I'm through with my list. Stoked!  :D

[dave_mc]

nice :D good luck :)