Princeton Build Chronology Complete and in Cab

[Ed_Chambley]

I have been promising to show some of my builds.  Here the the cab.  Tweed, laquor, Honey pine, 8 coats cut 4 to 1 with alcohol.

[Ed_Chambley]

Back of cab showing speakers.  One built to vox style, the other is a smooth paper cone, Marshall style.  1.151 paper.  The complete turret board.  Another photo of the board showing the extra area for an additional bias.  It will be a dual bias vary tremolo.

[tubenit]

Very impressive!   Thanks for sharing it.

with respect, Tubenit

[Willabe]

Very, very nice Ed!      

(You posted Curl bias board for the bias board pic)


                  Brad    

[bnwitt]

Looking good Ed.  Man I love pumkin tweed and oxblood grill cloth.

[Fresh_Start]

Cab looks fabulous! That's gonna be one loud Princeton with two 10" speakers.

Is the circuit stock AA1164?

Cheers,
Chip

[Ed_Chambley]

I am using AA1164 with bias vary tremolo.  I have some very nice Teflon wire in solid core and stranded I plan to use.  I don't know if it makes a difference as I have never built a fender style amp and not used pushback wire.  I used some of it in a high gain area of my last build and it cured some noise.

I made the chassis and just got it back from the chrome shop.  It is just like a blackface, but with a few more holes in the back.  I am using a Classictone Deluxe PT with a bias tap and plan dual bias as Slucky said for Ah effect.  I just want to do it.  Dual intensity pot.  I got a Mercury OT for a Deluxe as well except it has taps for 4-8-16.  It will allow me to add extra cabs.  I have a 2 12's I love.  It is a JD design cab with Weber Alnico Silver Bell and a Blue dog.  It may be loud for a princeton, but what I am wanting is a quieter Fender Twin.  I play lead country mostly when gigging.
I'll have some more photos coming soon so you will get the chance to see me do the stupid stuff.  I ordered a brown faceplate in metal and they made a mistake and made it plastic.  I am sending it back.

When complete it will be pumpkin tweed, oxblood, brownface, brown chickenhead knobs with blackface circuit.  I don't know about the cabinet.  I used Pine and just sort of enlarged the sides.  Fingerjointed.  The baffle is birch which I am not sure about yet.  All 3/4" #1 ply and solid pine I got from a friend who collects old wood.  He ran it through a belt sander and almost kept me from putting the tweed on it.

More to come.  Thanks for your interest and please knock me in the head if you see me going astray.  I am building what I hope to be my main gigging amp.

[HotBluePlates]

I am using AA1164 with bias vary tremolo.  I have some very nice Teflon wire in solid core and stranded I plan to use.  I don't know if it makes a difference as I have never built a fender style amp and not used pushback wire.  I used some of it in a high gain area of my last build and it cured some noise.

The main difference is it will be a bit more of a pain to install than the pushback wire you've used before, but you don't have to worry about singeing the cloth when you solder.

But I like the stuff too every now and then. Just used it in my last build.

[Fresh_Start]

The 2 problems with Teflon insulated wire are COST and stripping the darned stuff.  You need really sharp strippers, adjusted just right.  When I'm done with the Teflon coated wire I stocked up on based on mania on 18-Watt.com and AX84, I'm buying old-fashioned PVC coated solid wire. 

If nothing else, that'll make me more careful with the soldering iron...

Cheers,

Chip

[Ed_Chambley]

The 2 problems with Teflon insulated wire are COST and stripping the darned stuff.  You need really sharp strippers, adjusted just right.  When I'm done with the Teflon coated wire I stocked up on based on mania on 18-Watt.com and AX84, I'm buying old-fashioned PVC coated solid wire. 

If nothing else, that'll make me more careful with the soldering iron...

Cheers,

Chip
[/quote
Chip, I got one of those heat strippers.  You just close them and make a quarter turn and it comes right off and not a single nick in the wire.  The things cost about $150, but I got one at a garage sale for $2.
Check it out
http://www.teledyneinterconnect.com/products/wire_strippers/wirestrip.asp
Most people don't know what they are.  I didn't and have passed by them for years until I saw someone using one one day.  Get a good look and you will begin seeing them in junk shops.

[DummyLoad]

i use solid conductor PTFE jacketed wire and i use these to strip it. absolutely no problems stripping it, and things go together quickly. loathe the push back wire - the stripped ends fur-ball too easily. PVC? - forget it! one mod and that insulation looks like a melted mess. for larger power tube filaments i use stranded PTFE jacketed.

PTFE jacked wire all the way 4 me, just my preference. i wish doug would stock solid PTFE jacketed, E type would suffice, EE type would be better but not essential in either nickel or silver plated copper.

respectfully,

nice looking build ed... keep it rolling. :-)

--DL

[John]

I'll put my vote in for Doug to stock the solid core Teflon. I liked the stranded I got from him just fine except that it's, well, stranded. 

I use Klein strippers from Home Depot, no problems.

[Ed_Chambley]

i use solid conductor PTFE jacketed wire and i use these to strip it. absolutely no problems stripping it, and things go together quickly. loathe the push back wire - the stripped ends fur-ball too easily. PVC? - forget it! one mod and that insulation looks like a melted mess. for larger power tube filaments i use stranded PTFE jacketed.

PTFE jacked wire all the way 4 me, just my preference. i wish doug would stock solid PTFE jacketed, E type would suffice, EE type would be better but not essential in either nickel or silver plated copper.

respectfully,

nice looking build ed... keep it rolling. :-)

--DL

Thanks

Isn't PTFE just the legal way of advertising the same material as Teflon?  That is what the rack I got says on it, PTFE, but the retired Aircraft mechanic I got it from called it Teflon.  Anyway, when you strip it it is silver.  I just got it.  He gave it to me.  It is a huge rack with spools in it and most are full.  It has solid core in 16,18 and 20.  Stranded in 18-24 which is also silver when stripped.  It is 8 rolls wide and 8 rolls tall and made from wood with dowels holding the rolls in place.  I have never seen anything like it, the rack I mean.  Each roll has a tensioned on it so it won't rats nest on you.  He said he was cleaning out, but I think he was just being nice to me.  He is one of the retire guys in my neighborhood and hangs out in my shop.

He has an Oscilloscope, I think he called a techtronic, that he said I could use since he doesn't use it anymore.  I have never use one myself but I hear some of you speak of them often.  Off track, this needs to be a new thread.

[DummyLoad]

Isn't PTFE just the legal way of advertising the same material as Teflon?

PTFE can be Teflon and not all PTFE is Teflon. DuPont owns the trade name Teflon but are no longer the only makers of PTFE.

He has an Oscilloscope, I think he called a techtronic

that is a generous offer. most tektronix gear is well engineered and reliable.

any more progress with the PR? i've been kicking around the idea of a 2pair 6V6 (30W) variant for quite some time... i should get off my lazy duff and at least bread-board it. 

--DL

[Ed_Chambley]

More progress. Lots.  Pix coming soon. Populated the board, but did not solder.  Did not like it, so I reordred a couple of things.  I decided to use the blue sozo up to the power section and Orange Drops as the .1's.  As fate would have it, I should have not drilled the holes in the bottom.  Since I am using a Deluxe PT and OT the holes are going to be in a different place.  So I am going to have a couple of extra holes.   I know it sounds like no big deal, but all the planning and I still missed it.  I am thinking about changing the mounting bracket on the OT and use the stock holes.  The PT does not matter as I am having to cut that anyway.

It will have a Master Volume, I just have not decided what type.  It is really going well.  It is the best one so far I have ever done.

I promise to get you guys some more photos soon.

[Ed_Chambley]

Getting down to the nitty gritty.  On the schematic I did not connect the second hald of the intensity pot.  I am aware of this.

My question is more in the layout.  The master used in the layout is setup for control of combined 220 resistors.  Since it will be necessary for me to split those for dual bias and use a dual intensity pot, will them master volume work as it.  I am thinking not, but could be wrong.  I thinking I can use the LarMar master but not sure of that either.

I would prefer to use the one in the layout as it is switchable on/off.  I do not see it working as is with the split.

[sluckey]

The MV in the layout is a crossline MV. I don't like 'em. I bet you won't either. But I think it will probably work as drawn. Try and see. Change to the larmar if you don't like it. Layout shouldn't be affected.

[Willabe]

Nice job on the schemo drawing Ed.

Took me a lot longer to learn the program to be able to do the same.


                            Brad    

[sluckey]

I believe bnwitt drew that schematic and Ed just added his improvements with a graphics editor.

Here's a PR with MV that tubenit drew a while back. It's gives good performance. I probably would lose the 33KΩ resistors and put grid stoppers on the output tubes. You can find the editable sch version in the schematics section.

[Ed_Chambley]

Thanks for the credit Brad.  I did not draw it, However I am a graphic artist by trade.  I can draw layouts, but have big problems with schematics.  That is why I got Merlins 2 books.  I can read schematics, but I do not know tube structure.  I have printed out tube datasheets, about 400 of them.

Here is what is weird, I can open up a chassis and using Adobe Illustrator, draw one where it almost looks like a photo, but it took me about an hour to figure out to change a value of a resistor in Visio, you click on it and it opens an editable text box.

I ordered a windows Laptop yesterday just to be able to use the programs that people in electronics use.  I am all Macintosh, I know Jschem Blah Blah Blah.  If you are gonna do it, do it right.  I have found some software which interfaces the PC to use as Scope and MM along with some other cool features.

Slucky, thanks for the info.  I think I will pass on the Crossline and go straight to the LarMar, I know it and like it.  The main problem with the LarMar is loss of presence, but I have a solution for that.  A cut, also I am adding to the bottom of the chassis 2, 10k liner pots.  One will be for a middle.  I will measure 6.8k and mark that whereas I will always know where stock value is.  Also, I am changing the NFB to a 10, but might add a 4k series resistor to give me the ability of having 4- 14k.  I did a NFB mod on a princeton for a guy a while back and made a mistake and put in a 14k resistor.  It made it have a very voxy chime.  I am using small pots with knobs smack dab between the tubes. Easy access and out of sight.  I am a tweaking fool.  If there is a knob in site, I will turn it.  That's why I am putting them on the bottom.  Out of site, out of mind.

Like Slucky said, it's just a princeton.  I am having a ball with this build.  I dry fit everything yesterday and I could not believe how well the chassis and cabinet fit.  I am great with metal, but awful at wood.  Soon as I decide and wire the MV I will post more photos.

I gonna have a close look at the MV Steve posted.

[Ed_Chambley]

I believe bnwitt drew that schematic and Ed just added his improvements with a graphics editor.

Here's a PR with MV that tubenit drew a while back. It's gives good performance. I probably would lose the 33KΩ resistors and put grid stoppers on the output tubes. You can find the editable sch version in the schematics section.

The MV looks interesting and simple to wire in, but how would you ever be able to have stock values?  I did not take the time to calculate, but it would always be like having 253k grid resistors. Also what is the need for the added .1uf caps prior to the MV.  To keep the possibility of DC off the pot and if that is the case, how could it get DC on the pot anyway?

[Willabe]

Also what is the need for the added .1uf caps prior to the MV.  To keep the possibility of DC off the pot and if that is the case, how could it get DC on the pot anyway?

1'st pair to block the PI's plate and cathode dc voltage.

2'nd pair to block the -bias voltage.


                        Brad    

[Fresh_Start]

+1 on not using the cross line mv in a Princeton Reverb. I put one in my first PR build and didn't like it.  The owner doesn't use it.

Cheers,
Chip

[Ed_Chambley]

Also what is the need for the added .1uf caps prior to the MV.  To keep the possibility of DC off the pot and if that is the case, how could it get DC on the pot anyway?

1'st pair to block the PI's plate and cathode dc voltage.

2'nd pair to block the -bias voltage.


                        Brad    

Thanks Brad, makes perfect sense.  My mind drifts to blocking DC from the pot, didn't consider signal path.  Have you used this master?  How do you like it?

[Willabe]

No, I haven't but plan to some day.

From what I've read posted here the guys love this MV, very highly rated.


                Brad     

[Fresh_Start]

Here's a useful discussion of master volumes:

http://www.el34world.com/Forum/index.php?topic=3496.0

Cheers,
Chip

[Ed_Chambley]

Here's a useful discussion of master volumes:

http://www.el34world.com/Forum/index.php?topic=3496.0

Cheers,
Chip

Chip, thanks for the link.  I have tried most and even a few not listed.  I spent one whole Saturday with the Trainwreck pages MV.  I normally end up with the LarMar and ground the shields like Slucky said.  The main problem with the LarMar is the dual pot.  I have 6 linear dual 250k Alpha's and not a single one is even close to the same ohm at a specific rotation.  I have one that at half turn that is 23k and 120k.  Everyone of them is over 250 at full turn.  I had so much trouble with a 5f4 that I finally spent $38 plus shipping to Digikey and got a PEC.  Problem solved.  The one Bruce Collins came up with is ok, but you still have to get it up in volume.

I have used power scaling in both ways, whole b+ and just the power tubes.  I find it muddy in either case.  I have been searching high and low for a dual 250k pot which is accurate.  I put PEC's in my 5f4 and jtm 45 with the LarMar setup and it is simply the best for me.  Everyone likes a different tone.  The Gain and Volume setup in the Fargen 800 is the single wire and it works great.  I've got a super clean build going.  I have a bunch of alpha pot I am going to test.  If I get lucky (I did with a bassman) I will use the alpha, if not I guess it will be another PEC.  Wiring the LarMar correctly takes time and takes lots of space.  This time if I do it to my current build, it will run under the board where I can keep the lead dress looking professional.

My big question is could you ground the shield wires to the main cap ground.  I don't know if there would be any problems with doing this, but since I have dual bias the the 220k resistors are only about 1 inch from the ground on the large cap.  It would be very neat and I would not have the shield wires out of sight and only shrink wrapped connections at the dual pot with the 2m8 resistors.

I really like the master on the Egnater amps, but I cannot get my hands on a schematic.  I called them and they ain't tellin.  I have a tweaker combo I practice with.  I am getting ready to take it apart.

[Fresh_Start]

Ed - Thanks for that info on the dual-ganged pots.

Cheers,

Chip

[tubenit]

I have 6 linear dual 250k Alpha's and not a single one is even close to the same ohm at a specific rotation.

I am familiar with that problem.  What I have done is used is different resistors in parallel from wiper to side on the PPIMV setting that I use the most.

For example, if I am using a 500k dual gang pot ...................... I might parallel with a 470k & a 510k to get very similar values from "5-7".
That seems to work out well for me.

(Don't lock on to the particulars of the example. I just used them to illustrate the point.)

With respect, Tubenit

[Ed_Chambley]

I have 6 linear dual 250k Alpha's and not a single one is even close to the same ohm at a specific rotation.

I am familiar with that problem.  What I have done is used is different resistors in parallel from wiper to side on the PPIMV setting that I use the most.

For example, if I am using a 500k dual gang pot ...................... I might parallel with a 470k & a 510k to get very similar values from "5-7".
That seems to work out well for me.

(Don't lock on to the particulars of the example. I just used them to illustrate the point.)

With respect, Tubenit

I understand.  What you are saying is you get your master set where you like it and balance the pot as most of the time you keep your master close to the same rotation.

My deal is I do not use a MV to get lots of distortion, it is mainly the added sustain which can be achieved.  In other words, I never max the gain and turn up the MV.  This just loses everything IMO.  I like the interaction between controlling the power section separate from the preamp.  I am the same as you I guess in regard to setting the master.  I find I am either at a little over half turn or completely off.

If you remember I asked you about using 2 separate pots and you said some people try to get a SE in this way.  I was asking because I was thinking about finding 2/250k alpha pots that were a good match.  It adds another hole, but I put the master on the back or the underside.   I tried it and made a round sticker with lines where the pots are very close to the same ohm reading.  It is a lot of trouble, but it works and doesn't cost $38.00.  I will say this tho, the imbalance of the dual pot will make some weird tones but you can turn it a little more and weird turns to cool.

The reason I am spending soooo much time on this is because of the bias vary tremolo.  I think if I get an imbalance to large it will show up vividly in the tremolo.  Who knows tho, it may sound like a leslie.

Do you see any problem with grounding the shield to the main cap ground, or would it be better to chassis ground.  It would be the same wouldn't it?

[Willabe]

Do you see any problem with grounding the shield to the main cap ground, or would it be better to chassis ground.  It would be the same wouldn't it?

Maybe.    

It has the most B+ ripple still left, so it's also the noisiest B+ ground node in the amp and it has the most current flowing to ground.

If this ripple/noise/modulated ground current couples to the center wire from the shield it could be a problem.

I'd try to ground the shields at the screen grid nodes ground.

You might be able to just twist (tightly) the 2 wires that go from the bias pots to the 220K grid return R's together.

 
                               Brad    

[Willabe]

Here's how I'm going to wire and ground my output tube bias vary tremolo with dual bias, bias balance and bias range.

It's a 5G9.

This way it's 2 pots instead of 3, including the dual pot that might not track right. Less space, less $$, no tracking problem. Just my $0.02.

(The schemo for Ed's build is in reply #15.)


                        Brad      

[Ed_Chambley]

So you plan a range resistor instead of a pot and use a bias balance.  1 pot.  The other pot is a dual 1meg.  I like the idea of a bias balance.  Good food for thought.  Did detect a little sarcasm tho?

Thanks for the shemo.

[Willabe]

So you plan a range resistor instead of a pot and use a bias balance. 1 pot.

No, 2 pots.

25KL bias balance pot and 25KL bias range pot. Look at the schemo agine, there both there. (There marked as 22KL, they should work also.)

The other pot is a dual 1meg.

There are no dual pots in the schemo drawing.

Did detect a little sarcasm tho?

No, I ment none.


                          Brad          

[Willabe]

Here's the dual bias version, I got both from KOC TUT books.


                              Brad     

[Ed_Chambley]

Good Stuff.  I am reviewing.  How do you plan to do the layout?

[Willabe]

I have to fix a few things in the layout drawing, when done I'll post it in my 5G9 Tremolator new build thread.

http://www.el34world.com/Forum/index.php?topic=13912.0


                      Brad      

[Ed_Chambley]

More Progress.  Chassis is nice.  Didn't plan in advance for the large cap so I had to make it larger.  Got a couple holes to drill for 10k pots for NFB and a Middle control.  Other than that, I a waiting on time and a couple of parts.  Very close to start the lead dress.

[Ed_Chambley]

Little more photo.

[Willabe]

Looks real good Ed.


                  Brad        

[Ed_Chambley]

Looks real good Ed.


                  Brad        

Thanks man.  I it is haven't decided on bias/balance or dual bias yet.  So I am changing a dual setup to bias/balance in my frankenamp first.  I have a Plexi build I test stuff with.  It is nothing more than a 20 x 12 x 4 inch chassis with modular pieces.  Room for days.

I will tell you this, I made a mistake in making the cabinet baffle.  I should have placed the top speaker on the left looking at it from the front.  It would have given me much clearance for my transformers.  I would just flip it over, but it is not a traditional install.  The baffle is fitted and the grill cloth is a separate so I can change it.  I used velcro to attach the grill cloth frame. I am having some embroidered material of 2 different designs so I can change it.  Grill cloth frame, great idea.  Baffle stupid.  It is going to work out fine, but would be better if I had reversed the baffle.

[Ed_Chambley]

I believe bnwitt drew that schematic and Ed just added his improvements with a graphics editor.

Here's a PR with MV that tubenit drew a while back. It's gives good performance. I probably would lose the 33KΩ resistors and put grid stoppers on the output tubes. You can find the editable sch version in the schematics section.

In using this master volume, are the .1 caps pit inline with the dual pot?

[sluckey]

Just wire it like the schematic.

[Ed_Chambley]

Just wire it like the schematic.

I hear you Steve.  You are direct at times.  Just wiring it like the schematic is why I got a great deal on a 66 Blackface bandmaster head.  Someone drilled a hole right through the word Bandmaster and installed a master volume.  It took me a while, but I found an original faceplate, welded the hole in the chassis.  I know this is not what you are suggesting as I would think you give folks more credit than that.

It is how to lay it out is what I am considering.  Where I am going to put the MV and add the caps which were not preplanned on my board layout. I prefer to keep the face as is with the controls the same as a stock princeton.  Master will go in the back, but the back already has lots of things going on  there.  I do have a good place for it.

Here is what I see when looking at the schematic.  Maybe you can help.  I see a Dual 1m pot with terminal 2 (cancel the resistor) hooked to a .1uf cap and then connected to the 220k, x2 because it is a dual pot.  On the upper portion I see a .1uf cap connected to terminal 1 of one of the pots, lets say the inside pot, and the lower portion connected to terminal 3 of the outer pot.  I don't think it would be that way.  So I assume both .1uf caps prior attach to terminal 1 front and back of the dual pot and terminal 2 controls attach front and back and terminal 3 are both grounded.

Also, A lot of times I see mods where people just hang a cap from a wiper, but if I add a couple of turrets above the 220k I should be able to put the caps on the board which in my opinion will make for a better layout.

I have a question though.  What kind of effect is the MV going to have on the tremolo considering it connects to the the intensity of the tremolo.  Will it just increase and decrease the volume only or will it have some interaction on the intensity strength?  I am thinking not since the tremolo is bias vary and the MV would not affect the bias.

[sluckey]

Does this drawing help? I modified Tubenit's drawing. I labeled the pot lugs, removed the 33Ks, and put in the 1.5K grid stoppers. I can't advise you on the layout. I know you have the board done and probably have a spot chosen for the pots. The extra .1µF caps are the only other things you have to figure out where to physically locate. I'd probably mount them on the pot and avoid modifying the board layout.

I can't say how it may affect the trem. I've never seen this circuit on paper, let alone heard it. You tell us.

OTOH, I kinda like Willabe's ideas for the dual bias, or the bias range/balance.

[Ed_Chambley]

Does this drawing help? I modified Tubenit's drawing. I labeled the pot lugs, removed the 33Ks, and put in the 1.5K grid stoppers. I can't advise you on the layout. I know you have the board done and probably have a spot chosen for the pots. The extra .1µF caps are the only other things you have to figure out where to physically locate. I'd probably mount them on the pot and avoid modifying the board layout.

I can't say how it may affect the trem. I've never seen this circuit on paper, let alone heard it. You tell us.

OTOH, I kinda like Willabe's ideas for the dual bias, or the bias range/balance.

I did exactly this a while ago except I did add 1 turret above each of the 220k resistors. I assumed the ground would be common to both pots or the dual pot would work opposite.  Plenty of room there and will be within about 1.5 inches of the MV pot.  It will not hurt the layout as I intend to use the extra turrets even if I end up with a different MV.  Even with the LarMar MV, I do not wire it like the layout floating around.  Putting all that shielded wire and resistors on the pot makes a mess.  And a 2m2 resistor is not correct.  It may be technically the closest to 220K, but that is the most the circuit will ever see. If I change to the LarMar, I use the extra turrets to experiment with resistors which are usually on the pot.  I first put one on a JTM-45 and the pot ran into a wall at about 1/2 turn and choked the overall volume.  I forget what I ended up with now, but the resistors are not 2m2.  They are smaller values and the one on the 5f4 I do remember.  It has 1m.  It will give you a full turn and remove the blanket.  The amp will really open up but it seems there no "set" value for any amp.

That is why I put the turrets on the board.  Couple gater clips, turn the master wide open and stub in resistors.  When you get in the ballpark the amp will get louder, cleaner and have that punch a Non-MV amp has.  That was the intention of that style of MV.

With the MV simply controlling a volume control for the power tubes I wouldn't think the intensity will be affected any more than turning down the volume.  I do not know for sure, that is why I asked all those questions on how bias vary tremolo works.  By the nature of the design, it has to be affected by the volume to some extent.  The harder you run the power tubes the more potential of intensity you have.

I am not locked into dual bias and.or bias balance.  I am going to do the dual first because Willaby is doing the other.  It should give us some feedback of which is best.  I am thinking the bias/balance will be the winner.  I am using 25lk pots for bias so I can convert to bias/balance easily.  I like the idea as well, but I do have a dual pot for the intensity which is exact in rotation.

I built a SS rectifier.  470K-.01cap-Diode, 3 down and 2 across.  I am sure you have seen this before.  I don't remember where I learned it.  I think I did one like it for a guy I converted a Showman to Fender twin.  DPST switch for the reds to switch back and fourth.  So it will be a dual rectifier.  SS rectifiers seem to do the Country twaang real better.

I don't know exactly what I am eventually going to end up with, but I know I can always have a Princeton Reverb.  I have never had one, but always wanted one.  I just cannot bring myself to buy a Blackface Princeton for $2000 when I know in a few years the price on them will drop like Beenie Babys.

[Ed_Chambley]

New stages complete.  Heaters in with amphenol sockets for power tubes.  I checked 10 7c5 and everyone match at 375 volts.  Hulled out the chassis to fit in a dual pec pot for intensity.  I have a hole for the old ground switch where the MV will be.

Question, if I have dual rectifier, can I attach a separate bias range resistor for the SS and another for the tube, but have both of them on the board.  Then when I flip the switch it will use a smaller resistor for the tube.  If so, will I need a diode prior to the resistors?

Also, if I connect a diode from pin 5 to 6 and 3 to 4 and hook p to 3 and 5 to protect the rectifier tube?   I have some mullard rectifiers, 34's or should I simply use a 5u4.  I want the SS rectifier to eliminate sag as I want the quick punch for tele.

I hate it Brad's bias/balance did not work, so it is back to my original plan.  Couple more wires and I will post some more photos.  All my parts are here.  Not a single resistor, pot or cap which doesn't measure correctly so we know it will not sound like an old blackface.

[Willabe]

I hate it Brad's bias/balance did not work, so it is back to my original plan.

That's only for a bias-vary trem. amp.

With a BF it should be fine. BF trem is injected in a different part of the circuit, so bias/balance wont be alterd by the trem.


                              Brad     

[Ed_Chambley]

I hate it Brad's bias/balance did not work, so it is back to my original plan.

That's only for a bias-vary trem. amp.

With a BF it should be fine. BF trem is injected in a different part of the circuit, so bias/balance wont be alterd by the trem.


                              Brad     

I am adding a bias vary tremolo.  I do not understand.  Could you please elaborate.  I do not have the schematic to post as it is on another computer which is currently undergoing a rebuild.  Above, I believe there is an incomplete schematic where I have not connected both of the intensity (dual intensity pot) back to the 1 meg resistor.  Going from memory here, but I think you get the idea.

[Willabe]

I am adding a bias vary tremolo.

Sorry,my fault Ed, that's the trem the bias/balance wont work with.

I forgot you were going with a bias-very trem.

(But sluckey's working on something that I'd bet will work.)

                             Brad