Fender Deluxe Reverb AB763

[7xa12]

I am building Deluxe and it is my first amp build so any help/advice welcome, I have some components ready to solder.
I have bought some parts from Tube doctor and some from Tube Town. any recommended places in EU.?
TAD have Deluxe kit but I decided to choose more than one source.
1. I am Have TAD bipolar 25V 25mF. Are they ok for the application? anyone used them in Fender deluxe ?
2. PT 291 BEX Hammond transformer (6600 VCT@138mA 6,3 V@3A 5v@3A) any comments?
maybe stupid question - on the primary it has 2 wires black and white ? ( why just not 2 black wires like in AB763 schematic?, it is AC) it is confusing for me
3. Choke- Hammond 194B 4H 90mA
It is bigger and has higher current rating than standard 194A - but after fixing it to chasis I realized that it is very close to PT, (almost touching it) will it work better than 194 A? or should I use smaller choke?

[Mick Bailey]

Where are you in the EU? I'm in the UK so postage comes into it. Depends what you need to complete your build.

1. TAD bipolar caps are OK for cathode caps. Haven't used them myself as there's no benefit due to one end of the cap being grounded in an amp. A polarized cap is more usual in this position. And cheaper.

2. The 291BEX is good for a Deluxe Reverb. Wire colours make no difference - it's just that you know which is the start of the winding (see the Hammond winding diagram). I like Hammond transformers.

3. The value of the choke is the same and it won't work any better, but the improved current handling probably makes it a more durable long term choice. In theory the end-bells of the 194A should offer a little more screening. Have you fixed the position of the choke - is it a commercial chassis? Chokes can be mounted pretty close to a PT. In this case the laminations aren't on the same plane as the PT, which is a better situation.

[7xa12]

thanks Mick
I am in Ireland (ROI) I did not find any parts supplier who specializes in tube amps unfortunately.
I have full set (7) of TAD bipolars 25v/25mF already. so I presume is there no disadvantages if I use them?. I bought the chassis for Deluxe it was pre drilled and seemed to be fine except holes for the choke and reverb transformer. I have all the carbon composition resistors except 10M 3M3 and 2M2 ( would metal film be ok in the place ?) I am not sure about screen grid resistors ( 1Watt or 2watt ? I have seen some people stick with 5 watts cement )but on the other hand I like see them like fuses too, so will "medium" carbon 2wats be fine ? what you think?. I have cloth wires too but they dont look reliable, but i never touch them before, so hard to say.

[Randall]

I have all the carbon composition resistors except 10M 3M3 and 2M2 ( would metal film be ok in the place ?)

Yes, metal film will be fine in those positions. The 10M and 2.2M carry no signal, so you are better off with more stable film resistors. And the 3.3M doesn't pass enough signal to any good having carbons there. IMHO, there are precious few places in that circuit where carbon comps would do more good than harm. Do some searches on the subject, MAYBE they do some sonic sweetness in certain circumstances, but mostly they are noisy, they drift, they are heat and moisture sensitive, and are the source of a lot of an amps creaks and groans. Better quality carbon films are much better, the way I see it. I know, I just built the same amp, and ended up tearing out the 8 or so expensive carbon comps I initially used because right out of the box, the amp sounded like it needed some things replaced... because it did.

[Mick Bailey]

There's no disadvantage to using the caps, but no advantage either. A 25uf bipolar (also referred to as non-polarised and often marked NP) is essentially two 50uf caps in series back-to-back within the same can. They will be fine.

Some suppliers;
Modulus Amplifiers for lots of tube amp specific components. Superb service. Good prices on Belton sockets;
MODULUS AMPLIFICATION

Bluebell Audio. Superb. Philip really knows amps. Hammond transformer specialist and a whole lot more;
Bluebell Audio

Hotrox. Good selection of valves;
Hot Rox UK - Computer Matched Valves Guitar effects pedals Electro harmonix Guitar Strings Hot Rox UK

Your screen resistors don't pull much current. Fender Lists 1W MO FP for the Reissue Deluxe Reverb. I usually use 2W in this position. 2W carbon is fine. Screens don't pull much current - just a few mA - so the voltage drop across the resistor is low and therefore so is the dissipation. Flameproof resistors are increasingly used to meet safety approvals for various markets across the world.

5w is unnecessarily large.

No problems at all with metal film resistors. Technically superior, more stable, more accurate etc. but you need to watch the voltage rating in tube amps, depending where they're being used.

Your cloth covered wire - is it new? the stuff I buy is rated at 600v. Incidentally, if you didn't already know you don't strip it you push back the covering. Makes for quick wiring. To check the quality of what you have take a look at the construction. The coloured fabric outer covering should be woven over a more dense, waxy inner core woven over the wire, usually white.

[7xa12]

The wires I bought are Vintage Cloth Wire AWG #22 / 0,32 mm² lacquered cotton braid finish brand new ordered from Tube Town - there is no info about voltage rating - no marking on isolation or spool nothing I didnt find the info on The Tube Town page too. The second type I got from them is green color, awg 18 - they look more reliable. (thicker core).
and yes I had tried to strip them, I would never do it again . They are stiff and seemed to be easy to position, (but cotton not woven) are they reliable? they look waxy, inner core is white.
Mick do you know any Irish suppliers or anyone (prices in euro) anyway I might try these you pointed out. thanks.

[7xa12]

thanks Randall, I am researching CC vs metal film. thera are many controversial opinion indeed. your advices are highly respected and welcome, you can save me some trouble and time as well with debugging my build. What is your advice about right order/steps of building and soldering?

[7xa12]

I am using the eyelet board. I have checked all the components with multimeter they are in tolerance . I did simple test on transformers ( not live test)
I got 1760 Hammond OT

[Mick Bailey]

I don't know of any Irish suppliers. Germany is probably your best bet for euro pricing. There's also Banzai over there for some items.

Your wire sounds ok, but if you have any doubt contact the suppler for the exact spec. 22 gauge is used for most of the wiring - sockets, pots, signals, preamp HT. Thicker wire is for heaters and heavier current service. Tube Town sells the same stuff as pretty much everyone else.

[Mick Bailey]

I build in this order;

1. Fit transformers, choke, mains switches + standby (if fitted), pilot light and tube sockets to the chassis.
2. Wire up the mains side of the transformer.
3. Wire the heaters and pilot light.

I usually terminate the B+ and bias wires into a 'chock block' at this stage and test voltages, unless its a repeat build.

4. Build up the board on the bench with enough wire to reach the sockets/pots etc.
5. Fit the pots and input/speaker sockets.
6. Fit the board and wire everything up.
7. Have a break
8. Come back and double check everything
9. Power the amp up with variac/bulb limiter (or just a bulb limiter if that's all you have) without tubes.
10. Check voltages. They will be slightly high due to no load from the tubes.
11. Fit the tubes
12. Connect speaker and fire up (still with limiter)
13. Test with a guitar.
14. If all is well power up directly from the mains.

[7xa12]

Thanks Mick
I Have started building the board,I am soldering components and wires to the board, I have never worked with eyelet board before and I have found out that my soldering Iron I usually use for PCB and small electronics is not great for this job. (small Weller 12 watts ). I have decided to buy better soldering gun. I am not sure what power is the best for working with eyelets board.

[Mick Bailey]

A 12w iron is way too small, as you've found. A larger iron will heat the joint quicker, transmit less heat along component legs, and give better, smoother joints. If you're planning on doing more than just this one amp, then a temperature-controlled station would be best. There are essentially two types, low cost ones that reduce the mains going into the iron (like a lamp dimmer) and ones that have a sensor in the tip to maintain the temperature under different conditions. I prefer the second one, though the first is better than nothing at all. I use an 70w station - a Xytronic 169D and I'm totally happy with it. You can go larger on eyelet boards if you wish.

A higher rated station means you can turn the heat down for delicate jobs, but have the power there for heavier work. Like having a car with a big engine - you can go down to the shops just like in a small car.

[7xa12]

I have a better soldering iron, it is not a soldering station unfortunately, but quite good for this job. I have just finished soldering components on eyelet board, heater wires on power and preamp tubes , and 470 screen and 1K5 resistors across a tube sockets. I have decided to use 470 ohm Metal Oxide 2W on tube socket because CC resistance value changed to much after soldering, rest resistors did not drift significantly so I left them untouched.

[mikepukmel]

I am building Deluxe and it is my first amp build so any help/advice welcome, I have some components ready to solder.
I have bought some parts from Tube doctor and some from Tube Town. any recommended places in EU.?
TAD have Deluxe kit but I decided to choose more than one source.
1. I am Have TAD bipolar 25V 25mF. Are they ok for the application? anyone used them in Fender deluxe ?
2. PT 291 BEX Hammond transformer (6600 VCT@138mA 6,3 V@3A 5v@3A) any comments?
maybe stupid question - on the primary it has 2 wires black and white ? ( why just not 2 black wires like in AB763 schematic?, it is AC) it is confusing for me
3. Choke- Hammond 194B 4H 90mA
It is bigger and has higher current rating than standard 194A - but after fixing it to chasis I realized that it is very close to PT, (almost touching it) will it work better than 194 A? or should I use smaller choke?

Hi 7xa12
It's been a few years, if you're still on the blog, how did your amp come out? How does it sound? Any tips for someone starting very similar project?
Best Regards!
Mike

[Enzo]

Looks like he hasn't logged on since October of 2013.