Tweed Deluxe Reverb Questions

[cboysen]

Hi everyone! I have a couple of questions that hopefully you can answer for me.

I've been lurking in the corners for some time now, and been enjoying the vast amount of knowledge this site brings. So much so, that I've decided to build my very first amp. I have done a few pedals and tweaked a couple of amps in the past.

The build will be based on Sluckey's Tweed Deluxe Reverb and Deluxe Lite; a huge thank you to Steve Luckey for the layout and schematics! http://www.sluckeyamps.com/tdr/tdr.pdf http://sluckeyamps.com/misc/AB763_Deluxe_Lite.pdf

Additional mods will include:
1) A footswitchable Tone Stack lift/boost with a Potentiometer to dial in the amount of boost - I assume that is the raw mod in the layout?

2) A PPIMV - The Trainwreck Type 3, as explained by RobRobinette at his site. Seems very simple, but does it alter the tone, even at full volume? And is the LAMAR that much better?

3) I'm one of those strange people who like the sound of the Deluxe Reverb's normal channel. Will a switch that jumpers  C6 to R23 bypass the Reverb without any problems?

4) Single input, mid pot, and simpler biasing scheme, and ground scheme like Sluckeys Deluxe Lite, no bright switch.

lastly.. Do you float the ground lug above the pots, or solder it to the back across the pots?


Thanks
Christian

[shooter]

C6 to R23 bypass the Reverb without any problems?

it's probably doable, although it might pop.
are you trying to get rid of V3a when verb is off and verb pot is 0?

Do you float the ground lug above the pots, or solder it to the back across the pots?

yup, either works, floating allows for easier pot changes, some of us have the pre ground on the turret board and just run a wire to the input jack.  the key is it's only grounded 1 place and that is at or near the input jack

and simpler biasing scheme,

the one Steve shows IS a good scheme, I'd call it a "best practices" type circuit, something to consider

[cboysen]

C6 to R23 bypass the Reverb without any problems?

it's probably doable, although it might pop.
are you trying to get rid of V3a when verb is off and verb pot is 0?

I'm trying to make a switch between the Deluxe Lite and Deluxe Reverb. I see that the lite version only uses one preamp valve, thus bypassing v3a seems logical - Am I missing something?

Do you float the ground lug above the pots, or solder it to the back across the pots?

yup, either works, floating allows for easier pot changes, some of us have the pre ground on the turret board and just run a wire to the input jack.  the key is it's only grounded 1 place and that is at or near the input jack

Thanks!

and simpler biasing scheme,

the one Steve shows IS a good scheme, I'd call it a "best practices" type circuit, something to consider

I am In no way doubting Steve's expertise, all I meant was to use the Deluxe Lite biasing scheme, and alligator clip to one or the other 1ohm resistor when biasing - instead of making the bias sockets, as per the TDR

I just noticed that it's hard to get your hands on anything sturdier in the right size, than the Hammond 1444-20 alu chassis. Tube-Town sells a 2mm standard 5e3 chassis, but it's 36cm length instead of the 43cm of the hammond. I doubt everything will fit. They also have the steel version of 1444-20, but only in black and grey powder. I was considering screwing a bracket for the Power Transformer, to the roof of the cabinet, to relieve the downward stress. Any other ideas?

Thanks
Christian

[sluckey]

Will a switch that jumpers  C6 to R23 bypass the Reverb without any problems?

Yes, but use a SPDT to totally disconnect C6 from the reverb circuit when in bypass mode.

That Hammond 1444-20 alu chassis is really flimsy. You can actually twist it like a pretzel with your bare hands. I recommend a sturdy chassis such as the Blank Aluminum Chassis 17 x 6.5 x 2.5 that Hoffman sells.

     http://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Chassis&ORDER_ID=!ORDERID!

[cboysen]

Will a switch that jumpers  C6 to R23 bypass the Reverb without any problems?

Yes, but use a SPDT to totally disconnect C6 from the reverb circuit when in bypass mode.

That Hammond 1444-20 alu chassis is really flimsy. You can actually twist it like a pretzel with your bare hands. I recommend a sturdy chassis such as the Blank Aluminum Chassis 17 x 6.5 x 2.5 that Hoffman sells.

     http://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Chassis&ORDER_ID=!ORDERID!

So nice to hear from the man himself!

And thanks for the advice. The SPDT switch, was what I had in mind also. About the flimsy hammond chassis..  Unfortunately I'm from Denmark, and the hoffman chassis would be a very expensive piece of metal in that case. I'll have to check for other chassis around in europe.

I'm still wondering about that master volume. I'm opting for PPIMV to include phase inverter distortion, but you use a Pre Phase inverter Master - Why? I'm concerned how it will alter the tone when the master is maxed - Even though the pot bypasses all resistance internally, will a true bypass via push/pull be better?

Kind regards
Christian

[sluckey]

I used the pre PI master as a fix to my design problem, not because I wanted a MV. This quote is from my webpage for the TDR...

The Strat is plugged in and I'm having fun. Something is not quite right though. Sounds like the gain is turned way way up even at a minimal setting. This one took a couple hours to find, mainly because I had to strongly suspect a wiring error or bad component. I danced all around the problem for some time before realizing that the error lay with my rendition of the original AB763 schematic. The vibrato channel has an extra gain stage due to the loading effect of the reverb and tremolo circuit. The tremolo pot puts a 50K resistance on the signal path just prior to the mixing resistors that feed the PI. I had totally omitted this resistor! Gator clipped a resistor in and everything quieted down. The final fix is a 100K pot for a master volume control. I'll just give up the 'Middle' tone control.

R13 and R14 on the Deluxe Lite schematic accomplish the same thing as the MV on the TDR.

[cboysen]

I used the pre PI master as a fix to my design problem, not because I wanted a MV. This quote is from my webpage for the TDR...

The Strat is plugged in and I'm having fun. Something is not quite right though. Sounds like the gain is turned way way up even at a minimal setting. This one took a couple hours to find, mainly because I had to strongly suspect a wiring error or bad component. I danced all around the problem for some time before realizing that the error lay with my rendition of the original AB763 schematic. The vibrato channel has an extra gain stage due to the loading effect of the reverb and tremolo circuit. The tremolo pot puts a 50K resistance on the signal path just prior to the mixing resistors that feed the PI. I had totally omitted this resistor! Gator clipped a resistor in and everything quieted down. The final fix is a 100K pot for a master volume control. I'll just give up the 'Middle' tone control.

R13 and R14 on the Deluxe Lite schematic accomplish the same thing as the MV on the TDR.

Thanks Steve!

I've read through your website quite a few times, and thoroughly enjoyed the read. :)

[dunner84]

I have built both the single channel with reverb, and the lite version. The type 2 is by far the best sounding (to my ears) MV for these amps. The lite also really needs the bright cap. For the raw control, I have a 10k wired to a 250k pot, so all the way off, it has 10k of mid... I thought about a setup utilizing a switch, but I found that at gig volumes I set it at around 3 on the dial, and leave it there. Its like having a boost always on. Great srv ish tones, and clean up with volume control on the guitar.

I recently added a soldano slo as a second channel to the lite, and I don't use the raw control live anymore, only when messing around at home.

[cboysen]

I have built both the single channel with reverb, and the lite version. The type 2 is by far the best sounding (to my ears) MV for these amps. The lite also really needs the bright cap. For the raw control, I have a 10k wired to a 250k pot, so all the way off, it has 10k of mid... I thought about a setup utilizing a switch, but I found that at gig volumes I set it at around 3 on the dial, and leave it there. Its like having a boost always on. Great srv ish tones, and clean up with volume control on the guitar.

I recently added a soldano slo as a second channel to the lite, and I don't use the raw control live anymore, only when messing around at home.

Interesting stuff Dunner84! Thanks!

Is the type2 Fischer/Lamar the same as the Trainwreck/Lamar from the metro forums?

To make a neat grab'n'go no pedals amp, using a push/pull 250k in series with the 10k pot, will make for a nice on/off solo boost pot. To go even further, you could wire a capacitor in parallel and even a footswitch, to make it a footswitchable treble boost!

I've never been friends with bright caps though, but I'll think about it.

kind regards

[cboysen]

A few new questions have arised, after crudely numbering Sluckeys layout, corrosponding to the schematic.

Sluckey seems to have wired the bias resistors directly to pin8 of the power amp tubes. Other layouts solder pin1 and pin8 together. Does it matter?

If the bus bar isn't soldered to the back of the pots, does that mean the signal flows through the chassis via the pot washers? - Wouldn't this cause potential issues? Also, do you solder the ground lug of the pots, to the back of the pots, like on guitars?

Sorry if this seems very obvious to some of you, but I'm still learning.

Thank you!

[sluckey]

Sluckey seems to have wired the bias resistors directly to pin8 of the power amp tubes. Other layouts solder pin1 and pin8 together. Does it matter?

You cannot connect pin 1 and pin 8 together if you follow my layout. Doing so will quickly burn up your output tubes, maybe even some transformers. I have a 1.5K grid resistor mounted between pin 1 and pin 5 just like the original Deluxe Reverb. See this layout...

     http://el34world.com/charts/Schematics/files/fender/Fender_Deluxe-Reverb-AB763-layout.pdf

If the bus bar isn't soldered to the back of the pots, does that mean the signal flows through the chassis via the pot washers?

No, just the opposite. The ground path would be through the bus bar to the chassis (Usually near the input jacks). Then through the chassis to wherever you have the HT center tap of the PT connected (usually near the PT).

Also, do you solder the ground lug of the pots, to the back of the pots, like on guitars?

That's how Fender did it. See the layout above. I don't advise doing that. I connect the pot ground lugs to the ground bus that floats above the pots and has one end connected to the input jacks ground, which provides connection to the chassis.

[cboysen]

Sluckey seems to have wired the bias resistors directly to pin8 of the power amp tubes. Other layouts solder pin1 and pin8 together. Does it matter?

You cannot connect pin 1 and pin 8 together if you follow my layout. Doing so will quickly burn up your output tubes, maybe even some transformers. I have a 1.5K grid resistor mounted between pin 1 and pin 5 just like the original Deluxe Reverb. See this layout...

     http://el34world.com/charts/Schematics/files/fender/Fender_Deluxe-Reverb-AB763-layout.pdf

If the bus bar isn't soldered to the back of the pots, does that mean the signal flows through the chassis via the pot washers?

No, just the opposite. The ground path would be through the bus bar to the chassis (Usually near the input jacks). Then through the chassis to wherever you have the HT center tap of the PT connected (usually near the PT).

Also, do you solder the ground lug of the pots, to the back of the pots, like on guitars?

That's how Fender did it. See the layout above. I don't advise doing that. I connect the pot ground lugs to the ground bus that floats above the pots and has one end connected to the input jacks ground, which provides connection to the chassis.

Thank you Sluckey, that makes sense! Still trying to wrap my head around electron flow, reading RobRobinettes pages, and watching Doug's youtube videos.. Good stuff!

I'll make a parts list next week and order everything. Looking forward to it all.

kind regards.
Christian

[cboysen]

Hi again!

I'm trying to figure out the best practice of grounding / wiring the RCA sockets for the reverb. It looks like a pretty sensitive area for hum, even on original deluxe reverbs. Hoffman's way looks very neat, but sluckey does it somewhat differently in the TDR. I've tried to make the connections in paint. I don't intend on using a reverb switch.

First of all the 220k resistor to ground is connected to the sleeve of the Reverb switch or RCA OUT in most cases. Sluckey has it connected to the board ground. I guess it doesn't matter?

Whether it's TRS or TS plug seems pretty subjective too..?

Also the black ground wire of the reverb transformer goes to the RCA OUT on Hoffman's design, but RCA IN on others. Matter of preference?

So what's best practice? I see people making steel frames around reverb tanks and isolating jacks, wiring the ground to input jacks etc.

In any case, is my TDR layout additions correct? Should I use TS plugs only - Move the 220k resistor to the plugs and ground the transformer to RCA OUT - as per hoffman designs?

Thanks again for the help, patience and understanding - It's deeply appreciated.

[sluckey]

There are no TRS jacks in the reverb circuit of my amp. All jacks are simple RCA jacks, center pin and shell (connected to chassis). The only reason I put the 220K resistor on the board is because of the space limitations I had with that narrow chassis. I would have mounted the 220K on the jacks just like Fender and Hoffman did if space had not been so tight. Don't forget to remove the 220K on the board and just run a short wire directly from the jack to V3 pin 7.

[cboysen]

There are no TRS jacks in the reverb circuit of my amp. All jacks are simple RCA jacks, center pin and shell (connected to chassis). The only reason I put the 220K resistor on the board is because of the space limitations I had with that narrow chassis. I would have mounted the 220K on the jacks just like Fender and Hoffman did if space had not been so tight. Don't forget to remove the 220K on the board and just run a short wire directly from the jack to V3 pin 7.

Nice! So I take that as my scribbles are correct?  - I'll just do it the hoffman-way then, since that looks stellar. And yes, RCA OUT will go straight to V3 pin 7.

I assume the reason for using TRS connectors on the switch, would be to have the reverb working without having the footswitch plugged in.

[sluckey]

I assume the reason for using TRS connectors on the switch, would be to have the reverb working without having the footswitch plugged in.

TRS means Tip, Ring, Sleeve such as a stereo jack. Again, there are no such jacks in my TDR amp or any of Hoffman's AB763 amps.

This reverb circuit will operate without a footswitch connected. The footswitch is used to kill the reverb, not enable it.

[cboysen]

I assume the reason for using TRS connectors on the switch, would be to have the reverb working without having the footswitch plugged in.

TRS means Tip, Ring, Sleeve such as a stereo jack. Again, there are no such jacks in my TDR amp or any of Hoffman's AB763 amps.

This reverb circuit will operate without a footswitch connected. The footswitch is used to kill the reverb, not enable it.

Alright, that was also my previous understanding, I guess I had read some false information on another forum then. I get the TRS abbrevation, it's just that Weber and RobRobinette seems to be using a socket with 3 connectors, T G and S, like the input jacks, which confused me a bit, as to why.

Thanks for the clarification.

EDIT: Ah, I have also mixed up G and S, mistaking G for Ground and S for sleeve, instead of G for sleeve and S for switch. Makes a whole lot more sense now.

[sluckey]

    Now you're cookin'!

[cboysen]

   Now you're cookin'!

I sure hope so! You and the rest of the forum have been a great help.

kind regards

EDIT: Oh forgot to ask - assuming the rectifier tube can handle the power filtering, would you recommend 5U4(GB) or the GZ34 for this build?

[sluckey]

I don't use 5U4s. I replaced every one I had with GZ34s. I love the fact that a cold GZ34 takes about 20 seconds to warm up enough to start putting out B+.

[lego4040]

You can never go wrong with a Sluckey build

[cboysen]

I hope you aren't completely tired of my endless stream of questions, but here goes again!

1) Do you really need a standby switch? - ValveWizard says no, most people say "don't mess with an old design..", but we sure are past that point now aren't we? The ValveWizard pages even goes on about how a standby switch may even be harmful to an amp. My question then is, if omitting the standby switch, would you run into any difficulties testing the amp - Biasing or otherwise. Negative Grid bias is running even when the switch is in standby. So how come you (sluckey) have included it in your design?

2) I seem to find discrepencies between The Deluxe Lite, Tweed Deluxe Reverb schemateic and Tweed Deluxe Reverb Layout. Sluckey speaks of accidently omitting the tremolo/reverb circuits loading resistor of 50kOhm, leading to an increase in gain, and as such has included a 47kOhm resistor in the layout. This is later on replaced by a 100kOhm master volume pot. This runs just before the 220k resistor, just as per original design. Oddly enough, in the Deluxe lite schematic and layout, this 220k resistor is BEFORE the loading resistor of 270kOhm (50k/100k pot). Why 270kOhm, and why before,  and not AFTER as the original design? Increasing the value restrics the signal to ground, and increases gain. 270kOhm is gainer than 50k right?

If I am to use an SPDT switch between C6 and C9/R?, what should the value be? Should I include a 200kOhm resistor after the SPDT lug bypassing the reverb setion.

Sorry for the long message

Kind regards
Christian

[sluckey]

So how come you (sluckey) have included it in your design?

I absolutely can't live without a standby switch on my Tweed Deluxe Reverb.

I seem to find discrepencies between The Deluxe Lite, Tweed Deluxe Reverb schemateic and Tweed Deluxe Reverb Layout.

Nobody is perfect. Discrepancies between the TDR schematic and layout are errors on my part. Sorry. But there can be no discrepancies between the TDR and the Deluxe Lite because they ain't the same amp. The TDR is the reverb channel. The Lite is the normal channel. This also explains the differences you see with those resistors that are slightly different. If you study the original Deluxe Reverb schematic hard enough, you'll see why those resistors are slightly different.

If I am to use an SPDT switch between C6 and C9/R?, what should the value be? Should I include a 200kOhm resistor after the SPDT lug bypassing the reverb setion.

I don't know what you're talking about. Please explain.

You are building an amp based on my TDR and Deluxe Lite (two similar but different amps) and you're also adding some Rob mods. It would be nice if you provide a schematic showing exactly what you are building.

[cboysen]

Sorry for the confusion, after looking through the schematics of the original ab763, I see why the 220k resistor is before and after the load depending on the channel, and why its 270k to ground (50k+220k). I didn't mean to point out any errors or mistakes, I just didn't understand it.

I have made a drawing of how I would wire up the a dpdt or an spdt to remove the reverb from the circuit, although I still need to figure out how to incooporate the differences of the channels into the switch, if possible.

I'll look into the Visio program, and try to learn how to use that.

Kind regards
Christian

[sluckey]

Maybe you would like a stock two channel DR.

[cboysen]

Maybe you would like a stock two channel DR.

A good friend of mine has an original 65 Blackface DR, and is mainly the reason for this "quest". Although it costs $3000+ in Denmark.

The tweed cabinet looks gorgeous, and I'm not a big user of tremolo. I like the challange, so I'm going to stick to this build.

Kind regards
Christian