New Tremolux 5G9 build --> input welcome!

[loudthud]

OK! What kind of tone difference is to be expected? 'like a 5E3'?? More raw/earlier break-up???? To be sure, if you put the extra resistor and cap I assume the connection between pin 3 and 8 should be removed again?

It's usually a fix to cure too much bass with humbucker guitars. Brightens up the tone. Too much bass is usually remedied by changing coupling capacitors from 0.1uF to 0.047uF or 0.022uF. Separate cathode resistor/capacitor networks allow a different voice on each channel.

I am not sure if I understand... You mean that your 6V6 pin 8 is a grounding point now? And that it is used for the bias supply ground and tremolo ground... Maybe you can explain why a pin on a tube can be used as ground? Or should pin 8 be connected to ground?? I feel a bit ignorant.

Since the ground for the bias supply is floating, (not tied to the centertap for the main B+) tying it to the 6V6 cathodes isolates the ground currents to where that block of circuitry is used. Not a big deal really but just done that way instead of tying it to the noisey ground at the minus side of the 20uF caps.

And I am not intending to isolate the trem jack as well. You indicated that then the extra grounding wire is not necessary, but does it hurt? Or similar to the input jacks: also extra wiring for safety (or noise in case of bad connection)?

I just added that wire because you had a question mark next to the jack in your original layout and you didn't say what type of jack it was. Since the jack grounds to the chassis, you can leave the wire off.

What about the diode. For the stock selenium rectifier it goes from + to - . But for the 1N4007 it is the other way around? pnp vs npn?

On old schematics you see plus and minus signs next to diodes. On one really old schematic, I think from the late 40's, the diode symbols were clearly drawn backwards compared to the way we draw them today (arrow points opposite to electron movement). Fender schematics all seem to be draw correctly, ignore the plus and minus signs. In this circuit, the arrow should point to the transformer and the band on the diode should connect to the transformer.

[tubeswell]

Hi klooon, Looking at your most recent layout, I would add - keep the heater wires (going to all the tube sockets) as a twisted pair. I tuck the heater pair into the bottom rear corner of the chassis in tweed style layouts. Others prefer to have the heater pair running 'overhead'.

[klooon]

It's usually a fix to cure too much bass with humbucker guitars. Brightens up the tone. Too much bass is usually remedied by changing coupling capacitors from 0.1uF to 0.047uF or 0.022uF. Separate cathode resistor/capacitor networks allow a different voice on each channel.

Interesting. Nice option for me (I play an SG and an ES-335)! Playing through the Deluxe (my first build; now sold) my tone knobs were always fully open to brighten up things.
Is it just a matter of adding this network with same values or should I change the values of resistor and/or cap?

Since the ground for the bias supply is floating, (not tied to the centertap for the main B+) tying it to the 6V6 cathodes isolates the ground currents to where that block of circuitry is used. Not a big deal really but just done that way instead of tying it to the noisey ground at the minus side of the 20uF caps.

Thanks. Also after reading the article suggested by Tubeswell above, I start to understand grounding a bit better.

I just added that wire because you had a question mark next to the jack in your original layout and you didn't say what type of jack it was. Since the jack grounds to the chassis, you can leave the wire off.

OK, clear! I will remove it.

On old schematics you see plus and minus signs next to diodes. On one really old schematic, I think from the late 40's, the diode symbols were clearly drawn backwards compared to the way we draw them today (arrow points opposite to electron movement). Fender schematics all seem to be draw correctly, ignore the plus and minus signs. In this circuit, the arrow should point to the transformer and the band on the diode should connect to the transformer.

Thanks, also clear! I will remove the signs...

Here is the updated layout v6 and I added a variable resistor 50k in series with a 15k resistor instead of the 56k for a variable bias.

[klooon]

Hi klooon, Looking at your most recent layout, I would add - keep the heater wires (going to all the tube sockets) as a twisted pair. I tuck the heater pair into the bottom rear corner of the chassis in tweed style layouts. Others prefer to have the heater pair running 'overhead'.

In my previous builds I used the twisted overhead option. But I have received now more advice to go for a twisted pair in the bottom of the chassis. I am not sure if the rear corner is the best option, because there also all the wires coming from the board are close?? What do you think? Do you have a picture of this (or post a link?), I can imagine that it is a bit crowded?

Thanks.

[klooon]

Good news. I received the cabinet!! I will post some pictures later.

Further, I was talking about my wish to add some kind of attenuation. I have found the attenuation method used in the new Fender EC series. It seems like it is a pure resistive load --> by two high power resistors on the back side of the chassis, next to the transformers. I found this on YouTube: Fender Tremolux EC - YouTube


I have made a few (resistive load) attenuators. Quite satisfied using them, especially at lower attenuation settings, so I might add the two resistors and a switch to knock off a few decibels... I can use the obsolete ground switch of the 5F4 chassis for this purpose.

[tubeswell]

I to go for a twisted pair in the bottom of the chassis. ...Do you have a picture of this (or post a link?).

Not difficult at all. Takes hardly any real estate

[tubeswell]

FWIW I personally prefer a .047uF coupling cap on the bright channel of the 5G9, together with a 2.2uF bypass cap on V1, but I still think you should build it stock first and then tweak from there.

[klooon]

Not difficult at all. Takes hardly any real estate

Good to see. I misunderstood 'rear'. I thought that you meant by rear the side of where the board is and then it gets crowded, but this is fine of course!

[klooon]

Pictures 5G9 cabinet

Here are the pics of the 5G9 cabinet I will be using... Custom made by a specialist in the UK.

[Bruce / Mission Amps]

Who is this cabinet builder? I have lots of customers in the UK that are looking for a decent cabinet maker...

[klooon]

Who is this cabinet builder? I have lots of customers in the UK that are looking for a decent cabinet maker...

Ebay seller: doublenickels_55. Great guy to deal with.

If somebody wants more info, please send a private message to me.

[klooon]

Attenuator added to layout

I added the two 10W resistors and DPDT for the attenuator to the layout (version 7) and I rearranged the heater wires.


I think I will go for the half power option (50%) to knock off 3dB, but I am considering also a bit more attenuation. Here are the calculations. Total speaker load is aimed at as close as possible to 8 Ohm.


As always, comments are welcome

[klooon]

well the 5f4 chassis already has a standby switch hole
btw, you could put a single 40uF cap instead of two parallel (leftmost) caps on your layout, probably save some space

I am about to order (amongst others) the electrolytic caps. The only 20uF (and 40uF) are the Sprague Atoms (22mm diameter) at almost 10 euro each and I read somewhere that 2x20uF is better than 1x40uF (lower ESR values - does it matter??????), so 20-20-20-20, wil set me back 40 euros. Alternative for me is to use 4x22uF F&T caps at 3 euro's each (F&T 40uF not available) - 18mm diameter. Any comments on the Spragues in term of 'superior' quality? What is the "consensus" here? Worth the extra money? 20uF vs 22uF probably doesn't matter? Any advice?

For the rest I am going to stock up for the future to save on shipping costs. I need quite some 16uF, but I see F&T 15uF/450V @1.30 euro/piece versus F&T 16uF/450V @ 7 euros/piece (or Sprague at again a bit under 10 euros). I assume the 15uF versus 16uF doesn't matter too much as well? Let me know your thoughts!

[loudthud]

There are many horror stories about Sprague Atom caps. A persistent one is that when you cut the cap open, you find another smaller cap inside. Another one is that if you shake the cap, you can hear the smaller cap inside rattling around. They are probably made by an outside vendor and just re-sold by Sprague (Vishay). Given the high price, I would buy something else.

[klooon]

There are many horror stories about Sprague Atom caps. A persistent one is that when you cut the cap open, you find another smaller cap inside. Another one is that if you shake the cap, you can hear the smaller cap inside rattling around. They are probably made by an outside vendor and just re-sold by Sprague (Vishay). Given the high price, I would buy something else.

That doesn't look good... Thanks, then I will stick to the F&Ts. Hopefully the smaller/cheaper 25uF/25V caps from Sprague Atom are okay(?), I see they are hard to get in other brands or again, should a F&T 22uF/100V do the job? e.g. F+T Bipolar 22uF, 100V :: Bipolar Capacitors :: F+T Capacitors :: Electrolytics :: Capacitors :: Passive Components :: Electronic Parts :: Banzai Music
I have no good feeling what all these 'small' differences in cap values will do? Any thoughts? (8uF vs 10uF, 15uF vs. 16uF, 20 vs 22uF, 22uF vs. 25uF???)