A 70's ODS

[talbany]

Late 70's ODS taken from various posts ,comments, layouts and schematics here...The tone stack and pot values fluctuated during this period.. If anyone wants to add feel free..

Tony VVT

[Chad]

Thanks Tony, Nice looking layout.

[Deric]

Tony,

Thanks for sharing!

[super100]

Appreciate the effort and taking the time to share. Thanks.

[butwhatif]

Thanks and nice job Tony, sometimes it makes u wonder how these went on to inspire in their original state.
fortunately some great players were able to twiddle the knobs, and with their playing ability, get the goods-. They were evolving into what we currently hear.

[ToneMerc]

I've been gathering parts for a few months to build a #40 clone. I wish there was a domestic "silver" chassis. I guess I'm going to have to break down and get the Asian one.

Tony, is this done in Visio?

Appreciate it.

TM

[wjdunham]

Tony, thanks for updating that layout, having the posts on the right column is a great idea. Have you built this amp? If so how does it sound? I had to do a bit of tweaking to get the one I built to sound good, OD was really thin and brittle. I wound up with 10uF bypass on the OD (kind of the opposite of a #124 style, 5uF on cleans, 10uf on the OD), and a lot of fiddling with the OD couplers and the feedback values. Otherwise I used basically the same layout.
The only exceptions were that I added the 100K OD volume into a 1M master, I couldn't balance the volume of the clean and OD properly. I also added the PAB relay, this thing is off the hook with PAB engaged in the OD. I have the FET input gain set pretty high (3dB), has anyone ever measured what that setting is in the real thing?

Bill

[Structo]

Another great looking layout Tony!
I wonder how this compares tone wise to the later 80's style ODS?

It has to be a lot fuller sounding with the 25uf bypass caps across the board.

[talbany]

Glad to do it... Feels good to give back!..
I have some used Twin Silverface Iron I want to build a 100 w for grins ... Im sure I will have to make a few changes here and there ....I'll post any changes and do some sound files before and after any tweaks...I plan on voicing the amp using the FET..
Anyone know the origional fET transistor he used?... I have a box full of old FET's doing nothing...It's a white out here in DC...15' so far and still shakin...

I use 3 programs.. Visio is the main one... Canvas X and Photoshop...


Tony

[glasman]

Is there wire from the wiper of the treble control to top of Volume control missing or is it hidden.

Gary

[talbany]

Fixed Thanks!!

[ToneMerc]

Are you going to add the 180k from the cathode tail to the junction of the .01 & 1Meg?

Is 320 the typical NFB value? I believe #40 has a 820 Piher 2W CF and the big 100K is a 2W Piher CF as well.

TM

[ic-racer]

Is 320 the typical NFB value?

Looking back at the earlier, incomplete #40 layout I did, I see I made a typo: 320 instead of 820. I suspect the typo on that older layout got passed along to this one.

[talbany]

IC- Most of the board values were taken from your layout.. The pot values were taken from a hand drawn layout from HAD as well as Marcos post of his amp and Pics of 40... The hand drawn layout is difficult to read so some of those values may be incorrect..best guess..The layout is not intended to be a #40 clone..Updated again..


Tony

[martin manning]

Anyone know the original FET transistor he used?

2N4416? Someone here must know what HAD was using. All I know is in the #124 pictures the FET looks to be a 2N-something. Vishay/Siliconix have current production 2N4416A in TO72 at about $2.50 ea.

MPM