First build: AB763

[Nisto]

Hi All,

After reading a few posts I have been encouraged enough to have a go at my first amp. My first degree was in electronics, although that was 20 years ago and it's been that long since I built up a circuit. I have no real experience of working with valves or audio grade components, so there will be a lot to learn!

I'm based in the UK and looking of a supplier of good quality components in the UK or EU. I had thought I might choose Mercury Magnetics transformers and Sozo caps having heard good things about both companies. I'm hoping I won't need to import them from the US, is there a UK source? I'd like to go for a straight AB763 deluxe build but with good quality components.

Further on down the road, and assuming I get the amp to work, I'll be looking for a deluxe sized combo cab.

I'm interested in any recommendations you can send my way for components and suppliers. I'm sure I'll be asking for a but if help and advice along the way.

Regards

Nick

[Tillydog]

Hi Nick,

An excellent source of parts is Ampmaker in the UK. They have a link to someone who makes cabinets, too.

For a wider choice of transformers Living In The Past, also in the UK.

You can get Hammond parts and others from Bluebell Audio in the UK. or Tubetown in Germany.

No connections to any of them, but I've used them all at various times without any problems (I've spoken to Bluebell & Ampmaker (Barry) and they were both very helpful).

Someone I have only come across recently (but haven't used) is BLS Electronics who make transformers for various amplifier manufacturers and will wind custom transformerss at a reasonable price.

Two bits of unsolicited advice (sorry!):

1) Try not to get caught up in 'mojo' - I don't doubt that MM make very good transformers, but they are expensive (more so due to import costs in the UK), and other high quality transformers are available. There are *many* other sources of capacitors.

2) I know you have a degree in electronics, but if you haven't actually been building stuff, have a go at something like the WF-55 Tweed kit from Ampmaker to get a feel for how to make a good job of putting things together before embarking on your 'magnum opus'. It's not like PCBs!

/patronising git

Good luck, anyway.

Andy

[Nisto]

Thanks Andy, that is exactly the advice I need. I did think abut starting with a 5e3 circuit, maybe that would be a good place to begin. I owned a Tungsten Crema Wheat for a while and it sounded pretty good when it was cranked up but too loud for the house. The bass response was a bit more defined this an the straight 5e3 amps I have heard. It never sounded as good with pedals for the drive. The attraction of the black face deluxe circuit is the reverb and a bit more clean headroom but I can see it is a good bit more complicated.

I'll check out your links to suppliers and am happy to go with alternatives if you think that will be as good.

I'm thinking I might be able to write up the process as a total novice building a first amp.

Cheers

Nick

[Bob S]

Welcome to TAG Nick.
Great advice from Andy - start simple & be safe.
It's addictive so beware.
Bob

[Blindog]

Welcome aboard Nick!

+1, get your feet wet with the 5E3. Like Bob said, this is habit forming

Mark

[lord preset]

As a recent newbie builder I have a different perspective. For my 1st build I started with the amp I wanted to play rather than one that would be easy to build. In my case that was a D'Lite 44 which I built from scratch (not the kit). It's not a terribly simple amp. What made it practical was not whether the circuit was complex but how much documentation was available for the build - layouts, build pics, schematics, etc. I. I chose the D'Lite because there is extensive info available on that design including a build guide. While I haven't researched the AB763 circuit it is a classic design that has been documented and studied to death. I would think with a little research you would find a wealth of detailed layout and build information. So there is nothing wrong with starting with a simple design but it is not the only way to get there.

[rp]

An other option for Fender styles, Allen offers damn good trannies, and husky options for each. I'm guessing they are Heyboers but can't say for sure. They sound authentic and I've been thrilled w/ the ones I've use, couldn't find anything to object to, which is thrilling to me. He doesn't ship overseas, so you'd need a USA buddy.

http://www.allenamps.com/

Transformers are 100 year old technology, I doubt Mercury knows something Heyboer, MC, Hammond doesn't. They use a plastic bobbin to get a vintage sound - hooray. At best Mercury carefully blueprinted all the vintage types and sweats the details on their clones, more than anyone else, I hope that at least. I recently found a Hammond pdf that states their 1700 guitar line uses paper bobbins. I was amazed by that from a global manufacturer, showed they actually cared somewhat. I never liked their 1600 series for guitar amps (too good?) but I'll rethink their 1700 line now that I have some evidence they might be vintage accurate.

For a 5E3 I find the Mission as good as the original.

[pdf64]

The Allen stuff looks nice but their power transformers only support USA / Canadian line supply (120V 60Hz); there's a specific warning not to use them at 50Hz.
So no good for UK / EU etc residents such as Nick.

AB763 is a different circuit and parts list for each amp model and includes non-reverb variants.

There can be a lot of gain available and good build practices and lead dress are beneficial in avoiding oscillation, which may not be audibly obvious. Hence reluctance to recommend an AB763 reverb amp as a first build.
Lead dress etc may have far more potential to affect tone than snake oil components. Treat sales hyperbole with extreme scepticism - specification and verifiable useful performance characteristics are what matters.
Same goes for reports from users who implement several changes to an amp, maybe even a repair and then attribute the resulting improvement to the cap brand that they used.

I suggest trying to build a pedal at a great starting point, plenty of kit suppliers out there.

Then consider SE5 5 watt ampmaker kit, both as a learning exercise and as producing an amp that may be usable in a domestic scenario (due to the various VB+ options).
Whereas a 5E3 tends to be far too loud / difficult to control in most domestic scenarios but not loud enough to keep up with most bass / drums (even with efficient speaker arrays).
It's a little more complex but I've been tempted by the Double 6 ampmaker kit, for testing various power valve types, if nothing else http://www.ampmaker.com/store/Double-Si ... ifier.html
Pete

[Nisto]

Thanks for all of the advice so far.

I understand that there is a lot of hype and marketing involved in amp building. Some of my favourite amps at the minute, such as 65 Amps and Morgan seem to use Mercury Magnetics for their transformers but I'm happy to go with another make if the consensus is that there are good quality transformers made in the UK.

I checked out Ampmaker, unfortunately he doesn't do a 5e3 kit, but at some point it might be up for one of his Marshall 18 watters.

After spending a bit of time looking at www.fenderguru.com I'm certain that I want to get to an AB763 deluxe, but I'm going to use a 5e3 as a stepping stone.

So far this website http://www.el34world.com/Hoffman/AB763Parts.htm has been useful to get a layout, circuit diagram and a parts list.

I've also picked up some general knowledge on valves from here http://www.300guitars.com/articles/arti ... -inverter/

In terms of output transformers, is it better to get one with a 16 ohm instead of an 8 or 4? Does the extra winding have more influence on the tone?

Do you guys stick to well known brands for pots, switches and jacks?

Would an amp built from components from Mapljns or RS sound bad?

Cheers

Nick


Nick

[Gaz]

In terms of output transformers, is it better to get one with a 16 ohm instead of an 8 or 4? Does the extra winding have more influence on the tone?

Don't worry, this is a total myth perpetuated by Gerald Weber.

[pdf64]

Do you guys stick to well known brands for pots, switches and jacks?

Hotrox has a lot of useful guitar amp parts, with good prices and service http://www.hotroxuk.com/
Maplin don't sell many parts suitable for use in a guitar amp, maybe jack sockets and some pots.
RS have some useful components but Farnell tend to have a bigger range with more stuff for this application.
When selecting components, bear in mind the voltage rating of resistors (always check it's suitable, even if it means going back to the manufacturer's data sheet) and consider all conditions, not just the static one, eg switch on voltage peaks and current surges.
Why a 5E3? They have a quirky user interface (to put it mildly) and as mentioned, have no obvious application. The Double 6 seems a way more useful and flexible amp to me.
Pete

[lord preset]

Thanks for all of the advice so far.

I understand that there is a lot of hype and marketing involved in amp building. Some of my favourite amps at the minute, such as 65 Amps and Morgan seem to use Mercury Magnetics for their transformers but I'm happy to go with another make if the consensus is that there are good quality transformers made in the UK.

Can't comment on UK transformers but regarding Mercury Magnetics you have to keep in mind that MM heavily discounts their products for builders so they are not paying the very high retail prices the hobbyist/upgrade market pays. If I were an established builder like 65 Amps or Morgan I might use them too. As a builder you would benefit from all the $ Mercury spends on advertising to validate your claims to your customers that you use premium quality/ high mojo components.

[rogb]

Hi there!
I built an AB763 with MM iron but no reverb in a 17x8 chassis I had.
While it is expensive, I have liked the sound of this amp with MMs from day one and so has everyone else. I played it out last Thursday as I had modded the PI more towards the Dumble UltraPhonix style. The Vibrato channel is stock, though.

I would follow the Fender layout and schematic if I were you. Definitely put the caps in the "dog house" as per Fender. I put mine in the chassis and it is TIGHT in there!

It is not a hard build, I would say, if you can read a schemo and can solder properly.

I would learn how to put a Mouser order together. It is free shipping over £50. I wouldn't bother with Maplins or most UK suppliers.

JMI Music in Texas can do a good price on Mercury, or go with Classictone from Triode.
Antique Electronic Supplies is good to deal with. Watts Audio for boards etc.

TBH I usually source 100% of my parts from the USA where there is a wide choice available and great service too! I just suck up the shipping, duty and VAT along with the Parcelforce handling charge...

Some of my AB763 stuff for your reference!

https://tubeamparchive.com/viewtopic.ph ... sc&start=0

https://tubeamparchive.com/viewtopic.ph ... sc&start=0

https://tubeamparchive.com/viewtopic.ph ... c&start=15

https://tubeamparchive.com/viewtopic.ph ... ht=#201791

[Nisto]

Hi Rog,

Thanks for the links, I had read through some of your threads already, they are partly what convinced me to have a go at an AB763 circuit.

I have had a look at this YouTube video http://youtu.be/-i8lXJ7nSR8

Whoever made the video didn't make a fair comparison as they swapped the transformers and the speakers so I'm not sure if it is possible to draw a conclusion, but I did find myself liking the tone of the stock speaker and transformers just as much as the upgraded version. They upgraded amp is different but not necessarily better.

[rogb]

Mate I don't think I would spend £300 on xfrmrs based on that YouTube video!

I am sure you will get an amazing sound from ClassicTone - I'm just ordering a 100w set. I have my MM amp and I love it but it might sound the same with a set of ClassicTone! I dunno as I am not about to re-equip it

This transformer stuff is one of the biggest repositories of snake oil in amp building.

Along with pots, wire, caps, tubes, resistors.....