#40 resistor choice

[ChopSauce]

I couldn't comment on the resistor choice but I second the choice of #40 as a circuit and the choice of the tweed as a cover ...

I look foward to read your comments about the OD entrance and : "longue vie aux électrons libres" ...
(nice work, by the way)

[talbany]

only my 2, i found pihers too dark sounding, will be interesting how this amp will behave..i quit using brown pihers because of that and also of too big price for not desired effect. although i have wide colections still somewhere

bepone
IMO The 1 watt Pihers are a bit darker than the 1/2 watters. Given his 2nd and 3rd generation amps tend to be brighter (pseudo- Skyliner) and raw-er and a more (boxier) focused midrange (especially in OD). Great for cutting through the mix. The Pihers IMO help to smooth the edges, which makes it a good match for these early ODS's

BTW. If you run across any of those Pihers you think are too dark. I have a great place for them

Tony

[fred.violleau]

Hey ChopSauce, thanks for the kind words!

@talbany, I will build a bread board ODS size, I feel like there are so many combinations and I don't build that many amps to explore as much as I would wish. On my build list for 2022, I plan something like this in order to play with caps orientation and resistor types to prototype the build without having to solder and desolder stuff all the time.

FB_IMG_1639400676319.jpg

@bepone you know what they say, one man's trash is another man's treasure

Quick question on cabinet building: do you insulate the top of the cab with some aluminum tape? Thin Aluminum plate? I did use some tape on this build although I am not sure it makes a big difference. What's your take ont his?

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Fred.

[fred.violleau]

Drilling completed, let the fun begin!

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Fred.

[Richard1001]

Quick question on cabinet building: do you insulate the top of the cab with some aluminum tape? Thin Aluminum plate? I did use some tape on this build although I am not sure it makes a big difference. What's your take ont his?

PXL_20220101_170455761.jpg

Fred.

For this i use a 0.5 mm aluminium plate. You can cut it to size with a good pair of normal scissor and nail it in. Aluminium tape could also work, but i like one solid sheet.

[fred.violleau]

Hey Richard1001, thanks for your feedback.
I bought an aluminum sheet that I cut with a small sawblade, it was a nightmare to do, took forever, result was not super clean...
I tried to put it on top of the a running amp and hear if there was any difference, but could not tell. is it only to isolate from RF or is there another purpose ?

I have attached to the chassis all the pieces but the transformers.

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A few questions :

I usually like to have to brightness flavors, one for the strat and another for the LP types. I ran out of 2 pos. switch so that will be one. Is this amp rather dark or bright ? I tend to live around 220pf for a LP on the bright switch with Lollar Imperial Low winds. 500 pf seems a lot, but again if the amp is dark... that may help. What is your take ?

Also, will add a Mid switch instead of the deep switch. Whenever I have added a deep switch, I don't use it. But I always find use for a mid switch on the footswitch I have had good result with the pair 390pf/4,7M resistor. I have seen another layout with 680pf/4.7M. Where would that leave the mid bump ? higher in frequencies ? Usually the mid switch adds a little, but it is not in your face type of change. Increasing the cap value would have what kind of effect?

And grounding for the NFB/PI is done throught the jack for the FX loops right?

Thanks for your valuable feedback and help,

Cheers!

Fred.

[ChopSauce]

I bought an aluminum sheet that I cut with a small sawblade, it was a nightmare to do...

Next time you do have to do it, you may want to try cutting it between two thicker boards. That's not an economy. Otherwise it takes a "grignoteuse" to do that. I don't remember the english word for that tool, sorry.

Keep pushing!

[Richard1001]

Hey Richard1001, thanks for your feedback.
I bought an aluminum sheet that I cut with a small sawblade, it was a nightmare to do, took forever, result was not super clean...
I tried to put it on top of the a running amp and hear if there was any difference, but could not tell. is it only to isolate from RF or is there another purpose ?

It is a shield for all electro magnetic interference. With the shield in place you create a Faraday cage.

Laying the sheet on top of a working amp does nothing, but if you have a working open chassis on your bench you will notice hum if you put your hand near the preamp / inputs. When you put the sheet on top, closing the amp for interference, it will no longer hum if you put your hand over it.

It shields for RF, but also mains hum (on stage there are a lot more cables, lights, etc) and other interference. For instance when you lay an effect unit on top of your amp.

With a Marshall style amp (open side down) without shield i even had interference from the speakers once.

[fred.violleau]

@ChopSauce, thanks for the reference, I did not know there was a tool for aluminum sheets. They call it "grignoteuse" in Quebec as well, but the English word is nibbler.

@Richard1001, thanks for the info ! Does the thickness of the aluminum sheet matters? Would the aluminum tape and 0.5mm aluminum sheet behave the same in terms of protection ?

Fred.

[martin manning]

Does the thickness of the aluminum sheet matters? Would the aluminum tape and 0.5mm aluminum sheet behave the same in terms of protection ?

Kitchen foil will work, but it needs to be electrically connected to the chassis. That's probably why your experiment didn't produce results.

[talbany]

gnd foil.jpg

Tony

[bepone]

IMO The 1 watt Pihers are a bit darker than the 1/2 watters. Given his 2nd and 3rd generation amps tend to be brighter (pseudo- Skyliner) and raw-er and a more (boxier) focused midrange (especially in OD). Great for cutting through the mix. The Pihers IMO help to smooth the edges, which makes it a good match for these early ODS's
BTW. If you run across any of those Pihers you think are too dark. I have a great place for them

for some MK3 resistors I might consider to change or some US made anode MF res.. i think mine are 100k 2W very big resistors , great for anode, i have some bag somewhere

@bepone you know what they say, one man's trash is another man's treasure

yes thats why im keeping the old stuff, but WAF factor is limiting my scrapping places

[Richard1001]

Does the thickness of the aluminum sheet matters? Would the aluminum tape and 0.5mm aluminum sheet behave the same in terms of protection ?

Kitchen foil will work, but it needs to be electrically connected to the chassis. That's probably why your experiment didn't produce results.

Yes, tape or foil will also work, but i have seen a lot of older amps where the foil was ripped and pieces got torn off by taking the chassis in and out of the cabinet. I don't like that.

[fred.violleau]

@Martin, @Richard1001 thanks for the clarification
.
@tony an IMG is worth a thousand words, and maybe more if it is a pic of Mr Dumble's work

@bepone, name a price

Got the RG59 in place, enjoying every bit of it!

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Fred.

[fred.violleau]

Moving in slowly... I have a question about the use of a 3 lug terminal for the live and neutral connections.

Is there any code, precaution, I should follow beside the obvious?
Do I need to raise the terminal so it is further from the chassis? Do I need to isolate it from the chassis?

I have seen this kind of connection on some two rocks and trainwrecks.

A picture may help understand what I am talking about.

PXL_20220106_224100944.jpg

EDIT: I am talking about the red and blue wire connected onto the terminal lug. These are feeding the PT for the relays, and I would connect the power transformer for the amp here as well. It would help make the maintenance (change of transformer) easier. If needed.

Thanks for your advice;

Fred.