2 L-Pad (Ken Fisher type) attenuators for a ~40W 5E7

[dr.barlo]

Hi all,

I love the 5e7 clone (head) recently finished. I am not into the whole 10 inch speaker thingy, rather prefer it with a v30 (Mesa type) and G12-65. That said, the tone and compression is simply great and it became one of my favorite amps right away. The gain is there, afterall 3 gain stages... And very tasty compression.

I've used new Tung Sol 5881's and NOS Sylvania 5751 in V1 and V2 and NOS Jan Phillips 12AT7 in V3 (PI).

Here is a short clip for whatever it's worth:

https://www.instagram.com/p/BsyAh5Th2PA/?hl=en

It is loud tho. 40W's...

I want to lower the wattage to sorta 15-20W levels...

That is why I made myself 2 attenuators, both with 100W resistors. The first with a 22Ohm parallel and 4.7Ohm series L-Pad. The second, with 33Ohm parallel and 2.2Ohm series. The second will be a bit louder.



I am gonna check them today and see which one would be a better fit. I'll let you know if interested. (Can share the details of the L-Pad as well, just let me know.)

B

PS. BTW the guitar is a Heritage fake ES335 with Duncan Seth Lovers and the cab is a Marshall 1960B with V30's (Marshall type).

[jeremy]

Re: 2 L-Pad (Ken Fisher type) attenuators for a ~40W 5E7

5e7 is 40w? i thought they were more like 30w. i have a clone that scott built me a decade ago, love it! curious what you think of the lpads.

[dr.barlo]

Re: 2 L-Pad (Ken Fisher type) attenuators for a ~40W 5E7

Hi Jeremy. It might be. I've used Classic Tone's OT which I like a lot. So it might very well be like 30+... I biased it to 44mA with a plate voltage of 380V using 5881. So the "bias" setting is as you say, sorta 32W...

I am gonna check the lpads today and I hope they won't cause some ot saturation while being enough to cutoff some wattage. I'll report about the lpads...

B

[dr.barlo]

Re: 2 L-Pad (Ken Fisher type) attenuators for a ~40W 5E7

The l-pad I've done with 22Ohm parallel and 4.7Ohm series was a just a bit more effective than the one with 33Ohm parallel and 2.2Ohm series. But with the 22, the OT saturation (not the musical one) was getting started at high vols with the neck position (Heritage fake ES335 ... I don't remember the number Heritage assigns to them whatever) which has a Seth Lover HB. It is like a very mild tremolo very subtle but still there. It starts when I hit the string and lasts like 2 3 second before vanishing. With 33, the vol is a bit higher, but that OT saturation thing is not there.

BTW somehow Marshall's can take a lot of ohmage in the series compartment. Dr.Z.'s values (if I am not wrong) in the Brake Lite were like 25Ohm in parallel and 25 or 50 Ohm in series. And Marshall's don't seem to get affected by those. It has to be someting about the particular OT. 5e3 is sensitive and so is this 5e7, both of which have OT's from Classic Tone that I like a lot. There is always talk that when it comes to tweeds, one of the most important parts of the tone is the OT saturating... And maybe adding a bit resistors into the equation distorts the tone as I have described above...

Anyways, 33 seemed to be the better one and the vol drop is quite noticeable and useable.

B

[dr.barlo]

Re: 2 L-Pad (Ken Fisher type) attenuators for a ~40W 5E7



FYI, here is the layout of that l-pad... I did it with 100W resistors and it is to be used with amps upto 50W. x2 for a safe buffer... So if you are gonna use it with an amp say 22W Deluxe Reverb, 50W would suffice...

Put this into a metal enclosure and use nice wires (it's gonna be quite hot inside) and thermal grease between the aluminum casing of the resistors and the enclosure (for better heat transfer) and switchcraft open but sturdy jacks. The top of the enclosure is gonna be quite a hot plate...

B

[dr.barlo]

Re: 2 L-Pad (Ken Fisher type) attenuators for a ~40W 5E7

And here is how it sounds...

B

[jeremy]

Re: 2 L-Pad (Ken Fisher type) attenuators for a ~40W 5E7

sounds good man! noticed much tonal difference between with attenuator and without?

[dr.barlo]

Re: 2 L-Pad (Ken Fisher type) attenuators for a ~40W 5E7

Thanks.

Regarding the difference... Nope... And that's a good thing

Actually, I think I am getting more tonal differences by reducing the same amount of vol with post pi master vol (I forgot mine, I think mine was Ken Fisher's). I's say punchiness is what's gone with master vol when compared with the same level of reduction using this subtle l-pad. I am basing this on a 1987 clone (metal panel values) with this post pi master vol.

B