New at runoffgroove.com: The English Channel

[B Tremblay]

The English Channel is a FET emulation of the Vox AC-30 Top Boost amp. Check it out!

Article, schematic, and perfboard layout: http://runoffgroove.com/englishchannel.html
Sound clip: http://runoffgroove.com/salvo.html#english

[Fret Wire]

Oh no...not again!  Awsome! Thanks once again! Loved the soundclip. I forgot what IC's look like :lol:

Besides the nice sound of your emulation boxes, the second best part is the easily obtainable components. No Ge matching, or obsolete parts. A beginner can start with the Fetzer Valve, graduate up to the other circuits, and learn perf at the same time. As well as learning some insight into how their favorite amp works. Your work is accomplishing alot more than just building nice sounding boxes.

Hats off to Ya!

[aaronkessman]

man that sounds REALLY REALLY good.

i agree with fretwire. parts are easy. those perfboard layouts are just awesome too.

[PB Wilson]

Do you guys have stock in FETs or something? :wink:

[Arno van der Heijden]

Very cool!!!  But I have some questions/remarks about your design.

-Why did you use a 1 meg pot for the gain control as opposed to the vox, which has a 500k pot?

-The first stage of the ac30 has a shared cathode configuration. Wouldn't it be better to model it with a 3k and 10u source resistor/cap?

-You state that "the Normal input can be simulated by changing the 470pF cap to 47nF". But if I'm right, the normal channel has only has one gain stage and no tone controls before the phase splitter.  :?

[Nasse]

:shock: Anyone got link to that old Roland virtual guitar amp ad pic that had cool looking bastard amp, you know Fender Marshall Vox etc. Frankenstein mutant... I maybe buy some cheap trimmer pots

[spongebob]

Do you guys have stock in FETs or something? :wink:

lol, I was about to make a similar comment...  :lol:

Anyway, outstanding work! My order for more J201s went out today...  :wink:

[B Tremblay]

Why did you use a 1 meg pot for the gain control as opposed to the vox, which has a 500k pot?

That's simply a typo on the schematic (now fixed), though some reissue AC-30 schematics use a 1M.

The first stage of the ac30 has a shared cathode configuration. Wouldn't it be better to model it with a 3k and 10u source resistor/cap?

We based the circuit on this schematic: http://www.firebottle.com/ampage/schems/vtbpre.gif

You state that "the Normal input can be simulated by changing the 470pF cap to 47nF". But if I'm right, the normal channel has only has one gain stage and no tone controls before the phase splitter?

True, only increasing the cap is a crude approximation of the added bass of the Normal channel.  For true replication, the builder would need to use a DPDT to switch out the first stage output cap, second gain stage, buffer, and tonestack.   We chose to mention using a larger cap as a simplifed option for less experienced builders.

[Marcus Dahl]

All of this amp sim stuff is very cool. I really like the 18 and the Supereaux. My only question is how well it works in front of your favorite amp? They sound great going direct, but in order for the end user to get it to sound right through a live gig rig, I believe yu would have to do some extra tweeking...., Or bypass the preamp section on your amp and go straight to the power amp section with that particular pedal to optimize the actual tone. It's been my experience with the POD that it works best in that since. Going to the power amp section directly. A lot of people don't do that.

Very good work. I'm very impressed.

[Gary]

My clips are recorded through an old Randall SS amp, not direct. I go through the front end using the clean channel, with all tone controls set at max for the flattest response.  I do not overdrive the amp at all with the circuits.  I put the mic ball against the grille cloth.  The mic is directly in line with the axis of the speaker, at the edge of the cone.  Pretty standard fare.  No off axis mic, etc.  The mic is an old Audio Technica cardioid dynamic.  It has no presence peak like a Shure.  The circuits actually sound a little brighter than the clips reflect.  I suppose I could mic closer to the center of the cone...

Only the Thunderchief clip was recorded direct.  I may redo it someday when I have time.

Running these into a cleaner amp sounds best to my ears, but a dirty amp may work just as well for you.  There is certainly no need to bypass the front end of your usual amp.  It does sound best to me to get it as flat sounding as possible, though.

[Marcus Dahl]

My clips are recorded through an old Randall SS amp, not direct. I go through the front end using the clean channel, with all tone controls set at max for the flattest response.  

Only the Thunderchief clip was recorded direct.  I may redo it someday when I have time.

Running these into a cleaner amp sounds best to my ears, but a dirty amp may work just as well for you.  

Well, I'm even more impressed. Thanks for the answer to my question Gary, and again very good job.

[Doug H]

My clips are recorded through an old Randall SS amp, not direct. I go through the front end using the clean channel, with all tone controls set at max for the flattest response.  

Only the Thunderchief clip was recorded direct.  I may redo it someday when I have time.

Running these into a cleaner amp sounds best to my ears, but a dirty amp may work just as well for you.  

Well, I'm even more impressed. Thanks for the answer to my question Gary, and again very good job.

I have found my Meteor and other amp emulators I have played with can be kind of finicky about the amp I use. This kind of stuff seems to like my SS amp with flat-EQ.

BTW: The English Channel looks and sounds great.

Doug

[Peter Snowberg]

You guys are great!

In fact I'm getting carpal tunnel in the process of taking my hat off to you guys so much. I think I'm just going to stop wearing hats!

Another job well done!

Take care,
-Peter

[Bill Bergman]

Might have to dust off my soldering iron for this one. I redrew the layout already for pcb construction. You know me ..... only pcb

[RDV]

I'm starting to think about building this one as the front end of a DIY SS amp. My Marshall is so very picky about what I put in front of it that I've got a huge drawer of unusable pedals. The only things my amp really likes are my Boss SD-1/808 and my dual mosfet booster.

Does anyone have any ideas about a good SS amp design? I'd love to build about a 60 to 100 watt one or so and use the English channel as the front end. If there's a link to a decent SS power-amp design, I'd appeciate a 'head's up'.

Thanks

RDV

[Paul Marossy]

You guys are something else.  

As a rule, I keep my amp on the clean channel all the time and use my distortion pedals to get distortion tones. It seems to work out pretty well that way.

[Lonestarjohnny]

I'm also like Peter, I'm gonna have to buy a new hat,  
And after testing a few of these pedal's , you Guy's deserve it ! I played the 18 and the Professor through my Peavey classic 50, these pedal's are unbelievable, Now my Old Peavey is worth more money to me now, and they sound very good through other amp's I own, the Traynor really respond's well, and even my Super said it was O.K., But the Cleaner the amp, the better the realistic tone.
Thank's for another ONE,
JD

[ErikMiller]

I'm starting to think about building this one as the front end of a DIY SS amp. My Marshall is so very picky about what I put in front of it that I've got a huge drawer of unusable pedals. The only things my amp really likes are my Boss SD-1/808 and my dual mosfet booster.

Does anyone have any ideas about a good SS amp design? I'd love to build about a 60 to 100 watt one or so and use the English channel as the front end. If there's a link to a decent SS power-amp design, I'd appeciate a 'head's up'.

How about a hybrid, with a SS preamp and tube power amp? I've recently had in my shop for repair a couple of Music Man HD-212 One-thirty amplifiers, and once I cured them of their (not unexpected at their age) ills, these were some GREAT sounding amplifiers.

These were the early Music Man design, with the 12AX7 inverter and 4 EL34 output section.

The preamp is an opamp design, but with the Master volume down and the preamp volume cranked, they rock. Kind of a "China Grove" vibe.

So my suggestion is to take an AX84.com design and graft the English Channel on right before the power amp section.

[Peter Snowberg]

... So my suggestion is to take an AX84.com design and graft the English Channel on right before the power amp section.

I've been wondering how long it would take that idea to surface here.

A good clean power section with a long tailed phase inverter (all tube of course) coupled to a switchable preamp would be the cat's pajamas!

take care,
-Peter

[Jason Stout]

Peter S.

.......coupled to a switchable preamp would be the cat's pajamas!

Ahoy!!! I think so too.

Edit
Although I'd never say anything was "the cat's pajamas."  :wink: