Vox to Rocket conversion??

[Markusv]

Hi Folks!

A friend of mine has a 2000 Vox AC30 TB/6. He is considering asking me to remove all circuitry and convert the amp to a Rocket. This is following me building him a Liverpool and he says the 'pool made him lose his passion for the AC30.
It doesn't have the punch he thought it had until he got the trainwreck.

SOOO... here is the thing
I don't want to promise him things I can't deliver.

Question 1)
If I use the existing Vox iron but Rocket circuitry including the Power supply changes. - Will we see much of a difference?

Question 2)
Is it preferable to use at least a Heybour wreck OT?

Question 3)
How readily can I adjust the voltages with existing Iron?

I'm sure there will be many more questions, but if someone could please respond to these I would appreciate it greatly

Markus

[nickt]

A personal view based on doing dumb things to my own AC30 in the 1970's... that rendered it MUCH less valuable...

1. If your friend wants a Rocket but doesn't like the AC30 then he may find he doesn't like the Rocket either.

2. If the dude wants a rocket then sell the AC30 and use the cash to build a Rocket.

3. If you do do something make sure it's reversable or done 'in place' - don't junk the AC30 and start again.

Just my opinion...

[steviea55]

Funny, I had just been asking myself the same thing. How would Vox AC30 iron match up with a Rocket build that I am concidering? There has been talk lately about Triode offering TW type specs. using MC Tranny's. Triode also offers Vox AC30 replacement Trannys. So back to Markus"s question #1

[M Fowler]

Markusv,

Your friend knows that the Rocket doesn't have the gain his Liverpool has right? Not sure what the voltages of his AC30 are but from what I have seen they are usually around 290-0-290 secondary PT. That would work well for a Rocket in my opinion, but slightly higher then what is generally used.

The AC30 OT probably is around 4k which is correct.

So other than finding out what your current AC30 voltage is and OT spec is you should be good to go. It would be a waste to have to buy different iron if the set you have will work.

Mark

[Zippy]

Hi Folks!

A friend of mine has a 2000 Vox AC30 TB/6. He is considering asking me to remove all circuitry and convert the amp to a Rocket. This is following me building him a Liverpool and he says the 'pool made him lose his passion for the AC30.
It doesn't have the punch he thought it had until he got the trainwreck.

SOOO... here is the thing
I don't want to promise him things I can't deliver.

Have you compared the two schematics? That's a good starting place to see what you're about.

Or is he asking that you gut the amp and replace the board?

The Rocket is inately a benignly stable amp and not so sensitive to layout as the Liverpool. You might tweak your way from AC30 to Rocket and learn something along the way.

Trannies should work fine.

[Markusv]

Thanks all for the replies

......and sorry for the slow response. I was unexpectedly busy with working late nights.

So to some of the questions/comments:
Yes- what he wants me to do is to remove all current circuitry intact and put a Rocket board in. We keep the current circuitry for if he ever wants to sell and it can simply be placed back.

Re the issue of gain. Yes- he is aware that the Rocket is not as gainy as the Liverpool.

My concern is this: People RAVE about the Rocket.
People love AC30's
But what is it REALLY that makes the Rocket so special? Is it that different?
Sure I can do what my friend wants but he may end up with what he had.:- An AC30
When I look at the schematics (TB channel) I see very little difference- exept:
1) Transformers
2) Power supply Filtering (This may be it though)
3) possible variations in terms of cathode bypassing on second stage
4) what else ?????

SO: do we love Rockets because we love what KF had left us as a legacy and because we love building them,or do we love Rockets because there's something there that AC30's just don't have?

Thanks!

Markus V

[Reeltarded]

It's a stripped AC30 with just the TB channel.

If he wants something very cool, rebuild it as a non-TB model, and add TB.

Whole different monkey. Ook. THE one to have. Added TB is way more umph than the later standard TB. I am surprised noboy around here has TB'd a Rocket with a milder front end.

[Markusv]

Reeltarded

OK this is getting interesting
Can you give a little more details as in (where the TB gets added etc)
Do you mean add the TB as a stage after the first ? Where would tone shaping go ect?

Not sure how to understand?

Markus

[Markusv]

Reeltarded

I had a look at schematics and it seems you meanthat I build an EF86 first stage ("normal channel") and then follow that with 12ax7 second stage?

Markus V

[Reeltarded]

I am trying to have the same thing done with a Marshall BB combo. We have a non-TB AC-30 with factory added TB and it screams like a banshee. It's more Brian May than Marshall Crenshaw.

On these amps, the cut control is on the control panel, and the B/T controls are on the back of the amp. The sound is reliant on how much the bass and treble are opened up. With them set low, it's mild like a normal AC30, around 3 or 4 for a Rocket kind of thing, and then HELL YES! from there on up. I am of the HELL YES! crowd.

Look up the schematic for '63-'64 AC30, and the schematic for Vox Top Boost. The TB circuit plainly shows where to connect it into the amp. Easier than me making a mess here.

You can buy a set of reconed original alnicos right out of England for about $300, or load it with Celestion green backs for a truly fantastic amp... and it is.

[Markusv]

Hi RT

I had a look and unless I am missing something I see no real differnce in the non top boost with added TB circuit, -and the later years' integrated TB channel

I see that the filtering in the PS is stiffer in the TB channel amps than it was in the 60's

Again- Am I missing something?


BTW I have the guy's Vox with me now and I'm telling him that he should think very carefully before we tweak. This is a hell of a sweet sounding amp

Markus V

[Reeltarded]

If you think it's a good one, I wouldn't do a thing to it..

There is a difference, I haven't taken our apart to look at what it has going on, just to clean it up. This one does have a couple changes, but nothing crazy. It's in the TB, all teh tweaking.

I should get pictures, but I can't promise a time. I have people in and out for the next couple few weeks.

If that amp sounds great, try and talk him into another amp.

[Markusv]

We have decided to go minimalist on this one.
I will install some premium caps and resistors and perhaps see if we could play with cathode bypass on stage 2 as well as switchable slope resistors
All fully reversible

I have never owned an AC30 but played some AC 15's
This thing made me drool.
Even the Vibrato channel. not the trem so much

[Reeltarded]

I never use any channel but the Brilliant on an AC30. I always find something else that does the other stuff better, but if you get one that actually sounds like an AC30, it's damned hard to beat.

I have to work on my patching this morning, if I get a chance I will open up the AC and see what cooks in there. I don't have time, but I can't wait.. ya know?

I need more coffee. Lots more.

[nickt]

BTW I have the guy's Vox with me now and I'm telling him that he should think very carefully before we tweak. This is a hell of a sweet sounding amp

Hi Markus,

If it's already a sweet amp and this guy doesn't like it then I suggest you change the guy not the amp AC30's aren't for everyone. I was always complimented for my tone back in the day but everyone hated playing through my vox go figure...

Regarding the TB vs the older non-top boost with added top boost and extreme collectability - they're identical (well except for the voodoo and fairy dust).

Happy Easter
N