I think I've figured out what I want

[rake]

Okay, old fart newbie here so please cut me some slack! 

I'm pretty much settled on two channels foot switchable.
The "normal" channel is pretty much the Blackface deluxe's reverb channel with some tweaks.
The "lead" channel would be a similar circuit but with more of a Marshall tonestack and maybe a bit more gain.
The reverb would function on both channels. (I like that Dick Dale Surf Sound) (hey, I'm OLD)

My thought was to use Doug's DPDT relay setup to switch between channels and simultaneously ground out the
unused side. Basically the relay would act like the stock grounding input sockets.

The amp would only have one input socket.

All pro's, con's and suggestions are of course welcome!
thanks in Advance!

TJ

[sluckey]

Have you put you ideas on paper?

[rake]

Only hand written as of yet. still trying to figure out the drawing programs.

[tubenit]

What about this? And then using an AB/Y box.

[rake]

Thanks, that's a good start to what I was thinking.

[tubenit]

OK, I reread your first post about relay switching and more gain .................   and then looked to see if I had saved anything in my files that is closer to that and found this schematic.

This uses Hoffman's relay switching and adds a "hotswitch" to the Marshallish channel for more gain.  Maybe it's closer to what you have in mind?

Since you've declared being somewhat new to this forum,  here is a link to LOTS of info about relay switching.  Hoffman carries excellent relay switching components.  I think you probably don't need relay #2 and that you could just use relay 1 & 3.

http://el34world.com/Forum/index.php?topic=14348.0

Attached is an editable ExpressSCH schematic.  This is a very easy program to use and is very intuitive to figure out. The download for it is here:
https://www.expresspcb.com/expresssch/

With respect, Tubenit

[rake]

Thanks, this will work nicely.
Yeah that second relay seems unnecessary.

Time to get crackin! 

Thanks again!

TJ

[tubenit]

Do you know how to draw up layouts? 

IF you are genuinely serious about the amp ..............  edit what changes you want in the schematic and I would be willing to help you with the layout if you are OK with paralleled turrets similar to Vox or HiWatt. If I help draw up the layout, it does NOT obligate you to build it of course.  You can edit the GIF schematic with Windows Paint or use the ExpressSCH program to edit it (which makes more sense to me.)

Having said that, if you're not sure what you want, then I'll let you figure it out and work out a layout on your own.

With respect, Tubenit

[rake]

Thanks

I downloaded ExpressSCH and will try and edit that schematic to suit my ideas.
Of course I'll gladly accept help and advice. Once I have my ideas in a schematic
I'll post it up and will hopefully get some feedback. (no pun intended)

Come layout time I'll definitely be giving you a shout.

It's better to have others who have built amps give advice than to have to build this multiple times!   

I worked as a repair tech in a good sized music store back in the 90's but
most of my experience was on the instruments themselves.

[tubenit]

Look forward to your edited schematic.   

Once you've done it in ExpressSCH then you take these steps to post a GIF  file for others to see (who don't use ExpressSCH).

Go to "file" at the top left of the SCH schematic drawing page and click on  "export schematic image". 

This will save it as a bitmap file.   Open the bitmap file with Windows Paint and resave it as a GIF file.  Very easy to do.

Once in a GIF file format, then you "resize it"  using Windows Paint to 55% of the original size and resave as GIF.  Very easy to do.

I just experimented with this on a schematic and it took me 73 seconds to go from ExpressSCH format to a resized GIF format.   

With respect,  Tubenit

[tubenit]

Regarding ExpressSCH .....................

You just click on to a component to change it's values.

You can copy a component and repost it someplace else in the schematic.

I create a favorites file by using the "drop down box" of Library of components.  I simply click on a resistor, cap, electrolytic cap, diode, transformer, pot, etc....... out of the Library of components and then save/move them into my favorites.

Hoffman has already created a library of tube amp components and the link is listed in this post/thread:
http://el34world.com/Forum/index.php?topic=590.0

You can click on to entire sections and save them as a "custom component".  For example,  I have a Dumblish overdrive section "custom" component,  I have a one tube reverb component,  I have a Fender style reverb component,  I have an active FX component,  I have a vibrato component for 6G16 Fender, I have a one triode vibrato component,  I have an LTPI section,  I have a PPIMV section,  I have a mosfet cathode biased section,  I have an input section, I have a paralled triode ............................

Then later when I want to mod a schematic or create one, it doesn't take me very long at all.   And there is an ExpressSCH library of 100's of schematics and layouts that you can pull up and edit into whatever you want.

With respect, Tubenit

 

[rake]

Okay I got to mess around with the schematic and try to create what I was thinking.
I moved the boost circuit to before the channel switch in the hope I can get a lead boost
regardless of which channel I'm using. Sort of a two amps in one idea.

Please let me know what y'all think.
Thanks in advance!

[turtle441]

Holy cow!!  Clearly I need to dig around this forum more.  Pretty sure you just posted up a schematic for my dream amp!!  Anyone build one of these deluxe bassman's before?

[rake]

Holy cow!!  Clearly I need to dig around this forum more.  Pretty sure you just posted up a schematic for my dream amp!!  Anyone build one of these deluxe bassman's before?

Tubenit posted a schematic for me to consider and I used it as the basis for the one I posted.
Don't know if anyone ever built the original version but my version was drawn earlier this evening.

It's most likely what I'm gonna build. It's my wish amp!   

[tubenit]

I love creativity and innovative ideas! And I am impressed with enthusiasm and how quickly you jumped in and figured out expressSCH.  That's great!  And I like it that you have a sense of the kind of tone that you're looking for.

I think you should build the amp that you want and fully support that.

With respect, Tubenit

[tubenit]

You asked for feedback on the design and I will offer some for your consideration. 

The "dual channel" amps seem to fall into two channels that parallel each other where one is switched into the LTPI while the other is taken out of the circuit.  The other "dual channel" type amp seems to be a clean circuit that is fed in series into more gain stages which are the overdrive stages (Dumble amps would be an example of this).

I have some experience with four gain stage amps in that I've built the Tweed Overdrive Special, the Tweed BluezMeister,  the D'Mars Overdrive Special and the Carolina Overdrive Special.

1)  four gain stage amps like Dumble, Bad Cat, Cornford, and some Mesa Boogie amps have very low value cathode caps or no cathode caps on
     some gain stages.  Instead of 22uf they may be 5uf or less.

2)  four gain stage amps tend to have smaller value coupling caps between the overdrive stages.  So instead of .1 or .047,  one might see values
     of something like  .01 down to .002       IF you build a four stage gain amp with larger coupling cap values and larger cathode cap values
     then you will have an amp that is very muddy sounding and not transparent in tone and articulation, IMO.

3)  the crossline master volume is my least favorite master volume of all that I have tried. The typical pre-LTPI master volume like on Marshall
     sound good to me and then the PPIMV (post phase invertor master volume) also called the Lar-Mar master volume sound good to me.

4)  with four gain stages, the layout and lead dress is critical.  It is very easy to end up with an unusable noisy amp with hum, floor noise and
     oscillation if not done well

5)  relay one is not drawn correctly

With respect, Tubenit

[tubenit]

I will say again, I think you should build what you want.  And I will offer this for your thoughts and consideration.

Knowing you want a master volume, I drew a PPIMV for you.

IF you use a PT that is a stand up variety (given how much room you'll need for the larger turret board) and a PT that has 300-0-300 with 150ma,  you could make it cathode biased and simply switch between 6V6's or 5881/6L6 by just swapping tubes and not needing to re-bias.
IF you use a 100uf/50v cap for the power tubes, it will give a tone heading towards fixed biased with good bass response.

A 300-0-300 PT with allow you around 330v on the power tube plates with 5Y3GT,  360v with 5V4 or 5U4GT or 390v with GZ34 or 420v with plug in solid state rectifier.  Lots of options tone wise.  150ma allows 5881 or 6V6.

IF you went with a Dumblish style tone stack and had a mid-boost and a PAB (preamp boost), you can get an incredible boost in gain/overdrive without having to have 4 gain stages on the Fenderish channel.   This would allow you a hotswitch boost on the Marshallish side giving you boost features on both the Marshallish side and Fenderish channel.   Honestly, the PAB and midboost both engaged at the same time is about the same boost in gain as a 4th triode gain stage.

Note that the second and 3rd gain stages on the Fenderish channel have 5uf cathode caps.

Just thoughts for you to ponder ..............

With respect, Tubenit

[rake]

I really appreciate any and all help, assistance and suggestions.
I'm here to learn and get a kick ass amp or thirty three in the process.
If you know how to "build a better mousetrap" then I'm all ears!

I shall study your drawing and proceed with tweaking the design.

Rome wasn't built in a day they always say. 

[Tony Bones]

> If you know how to "build a better mousetrap" then I'm all ears!

The secret is simple: build amps one after the other for one hundred years. Each one different from all the others. Tweak each one until you can't stand it any more. At the end of your training, you will be able to build better amps than anyone on the planet.

[tubenit]

I was trying to think thru the number of tubes and how I might draw the layout board and thought it might be useful to use a mosfet cathode follower on the Marshallish side to cut down tube count.

I am NOT pushing this idea, just trying to offer something to consider based on your original post and response.

With respect, Tubenit

[rake]

Had a thought.
I've got a nice pair of vintage Jensen 12" speakers.
If I went 2 12's with a longer cabinet and a "super reverb size chassis
there should possibly be enough room to go all tube.
I worked on the drawing a bit and took in your last drawing's values.
Let me know what y'all think.
Thanks much!

[tubenit]

Please take some time and study the values of the coupling caps and cathode caps (& cathode resistors) on the following amp designs that have 4 gain stages:

Dumble
Cornford
Bad Cat
Jim Kelly
Mesa Boogie
Bogner Ectasy preamp

Most if not all of those will be in Doug's Library of schematics. If not, you can google them.

To give you an example of how critical the values are ................      On one of my amps after the 4th gain stage, I have a .0047 cap.  When I tried .0068 there, it sounded muddy and with grit.  Your schematic has a .1 cap after the 4th gain stage.

With respect, Tubenit