Peavey Royal 8 valves and mods

[mark h]

I've just bought a Peavey Royal 8. It's a SE 5 watter. The previous owner has already swapped the original speaker for a Celestion Super 8. Swapping the valves/tubes are the next obvious change. I was also thinking about changing the values of some components. I've also got a OT from a Gibson skylark that I could put in it, but that is getting towards increasingly serious surgery.
What brand on tube have others used? Can anyone suggest possible mods.
I'd like to get some more life out of the clean tones which don't really ring and clean up the distortion when settings are on full. I am aiming for a classic vintage sound for country and blues and rockabilly type sounds.
Any advice would be great.

[mark h]

I just thought I'd add that while there are plenty of mods to be found online for the Epi VJ and the Fender Champion 600, far fewer seem to exist for the Peavey.
I imagine you could adapt what has been suggested for them but I'm not experienced enough to work it out for myself yet.
How do they compare?

[mark h]

Here are some mod suggestions made on another site, but not to get the sort of changes I'm after. I hope they may be of some use:

"some things to look at, although they might not float your boat

I'd lower c1 to 2.2u or even 1u
mess about with R5, lower values = more crunch
c2 - bump that right up to 1000u
r8 - increase to 270 to run the power tube a bit cooler

maybe mess about with the tonestack, although if you like the tone control after mods then just leave as is"

Does it follow that higher values for R5 will reduce "crunch"?

[tubeswell]

Hi Mark

In terms of tube swapping, the Royal 8 uses 1 x 12AX7 and 1 x EL84. In most cases any EL84 will sound much like any other one in that amp with the stock setup. You will probably notice more difference experimenting with swapping the 12AX7 out for other types (like a 5751, 12AY7, a JJECC832 or 823, 12DW7 etc) which change the gain structure and will have more of an effect on tone - whether you like the changes or not is a personal thing.

If you want to get into tweaking the circuit, remember that tweaks will void any remaining warranty and that mucking about with tube amps is quite risky. Meantime, the tips at the bottom of this page offer a simple explanation of tweaking pre-amp gain stages, which I found useful in the past:

Tube Terminology for Dummies

[mark h]

Thanks tubeswell. I had seen people talk about changing the Sovteks for JJs etc and I wondered how much difference a change of brand would actually make.
Also what about changing the EL84 for a 6V6? What difference would that make? Then the amp would need re-biasing too wouldn't it? Is that more effort than it's worth?

[tubeswell]

I like the brightness of Sovteks, JJs are a wee bit rounder, but lots of peeps like'em. As for 6V6s, a typical 6V6 running Class A in a single-ended amp runs well at between 340-360VDC on the plate (with screen about 60V below this), and biased with a 5W 470R cathode resistor (bypassed with a 63V 22-25uF cap) - to give about 18-20V bias, and likes a primary load resistance of 8k (from the output transformer). This is typically somewhat different from a single EL84, so there are a few things you need to tweak (plus the octal socket of course)

[mark h]

Given what has been written here * would changing the EL84 really have that much effect (for the effort needed to convert the circuit) ? Maybe I would be better off concentrating on the pre-amp and tone sections.

* http://music-electronics-forum.com/t13507/

[reverendbk]

You said you wanted more punch and clean. Changing to a 6v6 is a lot of work compared to other options.

I'd say do what everybody did with their epiphone valve juniors (me too): find a Hammond SE OT. A 125DSE or 125ESE runs about $40-50 brand new (I used the DSE).
Stock the amp had no clarity when playing distorted chords, very "blatty", muffled.
With the bigger OT it sounded much more detailed, punchy in the bass, and no longer muffled in the highs. It had that nice SE "zip".
Eventually I switched to a 12AV7 instead of a 12AX7 for less gain.

Increasing the EL84 bias resistor will make the amp sound less driven and compressed, but going too far with this will make it sound grainy and unresponsive.

[mark h]

I've been thinking about going in a similar direction. I've also got lots of information and advice from sewatt.com

Lots of VJ mods are applicable to this amp and indeed most 5w SE amps

[CSPRINGER]

PEAVEY ROYAL 8 + with cheese

Hi Mark and all,
I have a Royal 8. No experience with other tube amps, I am a breadboarder by inclination and have done some cool pedals. I have nice pics of ROYAL PCB and notice that it appears quite diff from the Valve Jr and the schematics are different - I would not assume the mods would have similiar impact unless you rread schemey's well. The manufacture looks like they come from the same prod line although the PCB board composition ans circuit is different.

My Royal:
Have replaced stock tubes with JJ's
Replaced stock speaker with WEBER Blue PuP 8 inch British Series.

My observations:
JJ's: I have not spent any time specificially identifying the impact of Only tube replacement - hence so comment.

Weber Blue PUP: This speaker is definately warmer and the treble is noticeably less harsh although the BP treble does not seem muffled at all. The Bass (perhaps some Mids too) are definately better (more + more defined) and I think this gives it a definately WARMER - less harsh - less raspy feeling when focusing on the Gain sound. As for SPL/speaker sensitivity - I do not know the Sensitivity rating of the BP - nor the mfr or specs of the stocker. When A/B'd it seems that the stocker may seem a hair louder at same knob settings - the difference is very subtle and most wouldn't notice it at all. I feel it is due to the BP being a bit less harsh and it may also have a bit less raspy breakup. The BP to my ears is a definate improvement - a keeper.

I kept the stock tubes and speaker and they live in a closet. I have a 30 Watt Yamaha 30-112 SS amp and never really liked it. Since getting the Royal I am playing lots more and really enjoying it. I play mostly 70's punk - but don't hold that against me as I REALLY am not an irresponsible pimple popper! .

I play mostly at home with a CD player and use an old 70's Strat > BOSS ( pedal knobs about 09:00 o clock position) > ROYAL Gain #1, Tone 10:30 o'clock , Master #3 - #4. I play lots of THE CLASH / PISTOLS/ETC and similiar era punkrock ( geeze I hate that lable).

I really like this amp, it is incredibly loud for it's dimunitive size, and it weighs nothing, where was this amp years agi when I bough the YAMAHA? . I think using a pedal for effect is better / more controllable than using the amp, seems to be concensus from the net for most amps. I am not really big on Gain but I do like OD! The amp seems very touch sensitive and using the guitar vol to control OD is very effective, it is like having a remote control at your pick site to control effect level. I have yet to try playing with a drummer but at home I have not been able to play this amp + pedal at FULL ON. I like my ears!

Well I could go on and on but the sun is up and time to go outside any play.
Web info on the PEAVEY is non existant, so I thought I would try to get it started here. Sorry for the lengthy post but I recall someone asked.

[jimi_t]

Are the tube sockets on the PCB?

I'm a complete newb when it comes to amps but I do know that tubes mounted to PCBs are not looked at favorably. Looking at the PCB pic above, it looks like v1 and v2 are the tube sockets. Is that correct?

[CSPRINGER]

Tube sox

Hi JIMI,
Yes I believe you are correct, yes they are mounted directly to the PCB. Interestingly my power transformer and output transformer never seem to get beyond warm and the cage that houses the tubes (in the middle pic) never gets past warm either.

Just for grins I used my laser temp sensor to get a temp reading on the tubes and they never read hot either - I dont recal the numbers but I think roung 100.

CS

[jimi_t]

Thanks. Since you didn't mention anthing, I assume you had no issues making your mods. I'd love to find one of these to try locally before getting one, even if I probably would mod it. For the price, they are hard to pass up.

[CSPRINGER]

Simple...

Jimi,
The speaker and tube changes are quite simple. What city are you in? You might want to post on a PEAVEY board as if someone lives in your city they might be a good resource to hear it. You are welcome to swing by and hear mine...

What kind of music do you like to play?

Here is a clip of this amp with a Marshall Guvnor 2 Plus pedal (unfamiliar with this pedal). Sounds like a HEAVY Gain pedal. Not my cup of tea at tall. Thought you might be interested in the clip if it's your style.
http://acapella.harmony-central.com/....php?t=2452043

I bet this guy will post after his speaker change. For your sake maybe he will post a clip without pedals. This amp can do nice cleans by the way.

Good luck

CSP

[CSPRINGER]

Temperatures edit

Sorry,
I just measured with a digital laser and the tubes glass portion at the base socket of the larger tube read about 290 - 300 degrees. However the safety cage remains barely warm...certainly not hot.