Belton Reverb Brick

[TIMBO]

Hi guys, Anyone have success with using these with a tube circuit???

[John]

Yes. I use the brick like a reverb tank, sandwiching it between 2 halves of a triode, that way you get that wet/dry mix going. IMO it sounds really nice. Not as lush as real spring, but pretty nice. I like either medium or long decay.


I have so far, always had to use either a separate winding, or small 6V tranny to power the 5 volt supply for it, NOT tap into the heater supply. Otherwise, it injects lots of noise into the circuit. It is possible of course that I'm just too simple to do it right. ;)

[silat]

John can you show us a Picture of one you have done with the brick?

Cheers~

Silat

[sluckey]

I've never used one but I've read several success stories, probably here on the forum. Search for belton reverb and see what turns up.

[John]

Hi Silat, here is the schematic. I didn't come up with this reverb circuit on my own, I stole it    off the innerwebs. IIRC, I tinkered with the resistors coming off of, and going into the A side of the valve, and of course the "mixer" resistor (commonly a 3.3M in Fender reverb amps)

[VMS]

here is one thread on the subject:


https://el34world.com/Forum/index.php?topic=6760.0

[TIMBO]

John, your da man.
Wanting to adept to this.

[John]

I suppose it would work just fine after the tone stack. I don't recognize those tubes in your preamp, but I would think the values should be close anyway. And hey, parts is cheep. 

[tubenit]

John,

I am VERY intrigued by your "one tube Belton brick" !

Can you help us out and add some more detail to your schematic, please? 

Can you draw where the hook ups are from the tubes to the brick & then please repost the drawing for us to look at? 

I appreciate your help with this question.

I have so far, always had to use either a separate winding, or small 6V tranny to power the 5 volt supply for it, NOT tap into the heater supply. Otherwise, it injects lots of noise into the circuit. It is possible of course that I'm just too simple to do it right.

IF I am understanding this correctly,  …….. it looks like the Belton Brick still needs a 5v power supply even with the tubes?  Is that correct?  And if so, can you show us what you did for a power supply, please?   

I am wondering IF one could use the Relay power supply that Hoffman sells to power this?   It certainly is quite in my amps regarding the relay switching?

With respect, Tubenit

[Ed_Chambley]

I like the long decay only. I will warn you the brick is not forgiving which makes it great in stiffer amps. Plainly stated, Fender spring verb will make the amp feel open and almost seems to simply continue on all the time and I really notice the attack soften. The brick does not do this. The brick responds to signal changes without any ambient verb hanging around.


The decay can be shortened, but I have found setting up the  amp control pots long decay is fine and preferred.

[Ed_Chambley]

Attached is a reverse schematic on the brick,  i use this to determine how and where to insert.

[tubenit]

IF I am thinking thru this correctly …………………….

Belton Brick $13  +  Hoffman's  5v relay power supply (all parts)  $12 =  $25

vs.

Reverb pan  $33   +   reverb transformer $17.50  =  $50.50

This assumes the 5v relay power supply idea would work and be quiet?    Could be some savings in cost and size?

With respect, Tubenit

[jojokeo]

IF I am thinking thru this correctly …………………….

Belton Brick $13  +  Hoffman's  5v relay power supply (all parts)  $12 =  $25

vs.

Reverb pan  $33   +   reverb transformer $17.50  =  $50.50

This assumes the 5v relay power supply idea would work and be quiet?    Could be some savings in cost and size?

With respect, Tubenit

Also the extra tube stage(s), socket, wiring, etc...  To have reverb with all the space savings and not have the nasty spring noises when moved or bumped... Lots of win wins here....

Boys: need to see the footswitch control also???

[jojokeo]

Attached is a reverse schematic on the brick,  i use this to determine how and where to insert.

Ed, those look more like PT2399s than Belton bricks???

[tubenit]

Q1)   I am wondering IF one could use the Relay power supply that Hoffman sells to power this? 

Q2)   In reply #8:   Does that attachment/drawing/photo on hooking up the tubes, 5v DC power supply and Belton brick look correct?

With respect, Tubenit

[sluckey]

The Hoffman 5V relay power supply is fine. However, use a separate 6.3VAC source. Don't use the existing filament string. The Belton brick negative terminal (pin 5) should connect to chassis ground since guitar signals will be passing through it.

[tubenit]

The Hoffman 5V relay power supply is fine. However, use a separate 6.3VAC source. Don't use the existing filament string. The Belton brick negative terminal (pin 5) should connect to chassis ground since guitar signals will be passing through it.

Thanks Steve!  I always appreciate your help! 

Respectfully, Tubenit

[sluckey]

I just looked at the spec sheet for that brick. Pin 3 also needs to connect to chassis ground.

[TIMBO]

Thanks guys, lots of good info.

[tubenit]

Hopefully, one last question ………………………..     ON the relay power supply rectifier, it was not truly chassis grounded in the relay system but was sort of a floated pseudo ground to help with the relay switching.

Using that relay power supply rectifier with this Belton brick,  ……….. would the rectifier be "chassis" grounded in this instance?

With respect, Tubenit

[sluckey]

Yes, the power supply "Grnd" terminal needs to connect to chassis. I just realized that pin 3 and 5 are internally connected, so only need to connect pin 5 to chassis ground. Here's some more info...

http://www.accutronicsreverb.com/main/?skin=sub01_05.html

[John]

Sorry it took me a while... So, here's the schematic of the 5V supply, and how I laid it out the first time I tried it, using the H1 brick.The H2 is much smaller.


Ed, I haven't really noticed it being "stiff". It seems to linger a while if I have the level turned up pretty good. Then again, the way I play it don't really matter much. ;)


Sluckey, thanks for the info about the power supply. Now I feel better!


Tubenit, I've though about making a dogbox for the brick and supply on the outside of the chassis to save space inside, but haven't ever tried it yet. Maybe it would be quieter? Maybe not. I know that the quietness of the tube used for the "buffer" matters. I think lead dress is every bit as important using the Brick as it is for the spring.


Hope this helps!

[tubenit]

Steve and John,

Thank you both for helping with this and giving some clarity to it.  I did add information from this thread AND referenced the thread in ARCHIVES (3rd page reply #119)  under "one tube reverb"  Belton Brick.

John, I appreciate your taking the time to show the schematic and layout.

I am understanding that the 6SL7 has a mu = 70.  So, I'm thinking a 5751 (12A_7 type) might work well also?

with respect, Tubenit

[jjasilli]

Checked the Belton site.  They specify a 5V regulated supply.


Signal input is 1.5VAC max.  So  12ax7  cathode drive looks fine. Mu should not matter.

Guess thing sou ds OK???  Seem to be 3 versions re duration of decay: Short, Medium, Long. Any suggestions.

[tubenit]

See Reply #9 on this thread

Ed Chambley prefers the long decay   

I like the long decay only.

[TIMBO]

This has been passed on to me from the supplier of the brick.


I don't think it is an approved circuit from Belton but was given to the supplier as a reference from Belton.
 

[tubenit]

Timbo,

There is a PDF file for that schematic and a photo of that "reverb" amp built on this thread in reply #24.  One of our forum members, Leevi built this.

https://el34world.com/Forum/index.php?topic=6760.msg94327#msg94327

With respect, Tubenit

[TIMBO]

Hi T, I'm going to finish the amp first then fit the reverb to it as I have left some options in the layout.

I'll bread board it first.

[Ed_Chambley]

Attached is a reverse schematic on the brick,  i use this to determine how and where to insert.

Ed, those look more like PT2399s than Belton bricks???

Sorry Joe, it is.


This is what I meant to post.

[jjasilli]

Revising my post above:  Looks like the BDTR-3 now has adjustable decay.  Also, schematics show that tube drive can be either plate or cathode.  This is useful for phase when the wet is recombined with the dry signal.  (in case the Brick doesn't like polarity reversal of it's ground & output terminals)


OTOH, SS drive and recovery is probably OK under the circumstances -- kinda like a guitar pedal circuit inside the amp.

[2deaf]

This has been passed on to me from the supplier of the brick.
I don't think it is an approved circuit from Belton but was given to the supplier as a reference from Belton.

Probably just an old-school thing, but I don't like shorting the output of SS devices.  How about a grid-stopper resistor on V1B with the footswitch connected to the grid?  Maybe even a grid-leak resistor so that you aren't depending on the SS device for the V1B ground reference.

[PRR]

> tube drive can be either plate or cathode.

Note details. The plate-drive form has IIRC 220K in series with a low-Z input, so maybe 22:1 reduction. Against tube gain of 50, it's not-quite unity gain (more, but not >>more).

> I don't like shorting the output of SS devices

It's sometimes safe and fine. It is not usually done. And in this case it does nothing about the hiss of the following tube stage. We might try to short-out reverb after the tube. Or at least throw 1K between chip and switch.

[TIMBO]

Guys, I'm going to do a pedal as a type of breadboard and once working I should be able to graft it into the parallel SE amp.

The trem is just a thought at the moment.

[John]

I believe tapping off the heaters of the 12ax7 for your 5V supply will inject lots of hum.

[TIMBO]

Thanks John, I'll give this a try first and add another transformer if there is a problem.

[John]

Heck yeah, even if it hums it'll let you hear how it sounds. And adding a little 6V tran is no biggie. I had my one amp totally built when I added mine. 

[tristanc]

I just stumbled across this thread. Over on diyaudio I have a thread going along similar lines - wanting to add, basically, the inners of a reverb pedal to an amp. Thought it would be worth sharing what I've come up with. Schematic attached.

Briefly:

• A solid-state loop (to save space & current) using LND150s for buffer and recovery
• Lots of input on how to bias the LND150s and set attenuation / gain for unity across the loop
• Reverb circuit added after the return input, using the newer Belton BTDR-3, borrowed from the Rub-a-dub deluxe
• Reverb bypass switch
• Power supply taken from 6.3V or 5V taps, doubled then regulated

I hope to make a small PCB (or two) with all this on. For the reverb I'd ideally like to use trimpots for all but the reverb mix which would go on the front panel - to keep things simple. The effects send pot would be on the rear panel along with the bypass switch.

The schematic may be overly complex and, yes, I could buy ready-made boards but where's the fun in that?

I'd appreciate any further input / warnings etc!

[TIMBO]

Guys, we have success.
I think it needs a bit of tweaking by using a 12DW7 as the 12AX7 drives it a bit hard.
I tried a 12AU7 and there is a much better boing, so using the AU7 side for the driver and the AX7 side for the recovery should work well.

Rewired the half wave rectifier on the 6.3v side as the output volts only reached 4.5v and there was some distortion in the decaying notes.

[TIMBO]

Hi guys, The TREMOVERB is born.



I cut the ground wire with the thought of adding a GROUND switch, but had another think and it's probably not a good idea

Doug described the spring reverb as "vintage splash and drip"
The brick is more like a crash and linger, with a bit of bite when you dig in.
Sounds great

The tremolo also sounds great, so I'll leave it at that.

[John]

Good stuff!!

[PRR]

What happens when you turn the Reverb knob all the way down? Looks like all signal is lost.

[TIMBO]

Hey PRR, reverb stops but dry signal still passes.

[sluckey]

Hey PRR, reverb stops but dry signal still passes.

Really? According to that schematic the output jack would be grounded. Nothing goes out.

[TIMBO]

I'll check 

[davidwpack]

I'm interested in how this turns out. I hadn't heard of a reverb brick until recently. I wonder if a tremolo brick is a future plan?

[Ed_Chambley]

Sorry it took me a while... So, here's the schematic of the 5V supply, and how I laid it out the first time I tried it, using the H1 brick.The H2 is much smaller.


Ed, I haven't really noticed it being "stiff". It seems to linger a while if I have the level turned up pretty good. Then again, the way I play it don't really matter much. ;)


Sluckey, thanks for the info about the power supply. Now I feel better!


Tubenit, I've though about making a dogbox for the brick and supply on the outside of the chassis to save space inside, but haven't ever tried it yet. Maybe it would be quieter? Maybe not. I know that the quietness of the tube used for the "buffer" matters. I think lead dress is every bit as important using the Brick as it is for the spring.


Hope this helps!

John,
I did not say the verb itself was stiff.  I guess I was not very clear.  So, let me clear it up.  On a Dumble type, or any amp deriving the most of its tone from the preamp, generally the outout section is tight and not forgiving.  FUCHS made a Overdrive Dumble clone and I had a 50 watt version at my house for a little while.  The amp is super responsive and nice soundinfg too.  Andy Fuchs used a brick in this amp.  When playing the reverb is present, but quickly dampen the strings and the Reverb will immediately stop.


I couldn't get it to act like a spring reverb until Brick 3.  You know, you bump a fender and hear reverb and the speakers over the tank would have to wiggle the spring some.  I am just saying it is a little different is all.  Good sounding reverb and probably better for recording.


I still prefer plate reverb.  I made one of these, https://hackaday.com/2018/03/23/building-a-plate-reverb-on-the-cheap/


Since I did not have room for a full size plate, I made one of these but covered.  Works really well.

[John]

When playing the reverb is present, but quickly dampen the strings and the Reverb will immediately stop.

Ah hah, now I know what you mean!

[TIMBO]

Hey John, going to fit a brick to the parallel Se amp this weekend.
Trying the BTDR 1 long delay, I'm keen to hear it.

[TIMBO]

Sluckey/PRR, are right, the signal is lost when the "reverb" is turned to "0"

Another observation is the trem strength is weak when the "reverb" pot is on 1-2 one the reverb dial, so it's a bit of tweaking of the dials to get enough trem without getting heaps of reverb.

I might try connecting the trem to V1a cathode?

Just had a thought of a 220k resistor off the wiper of the reverb pot as a mixer, will that let the signal pass?

[sluckey]

I've never seen a tremolo signal applied only to the reverb signal. Applying the trem to V1A should be much better. However, I've never seen tremolo applied prior to the reverb circuit either. Curious to hear how you like that.

Adding another mix resistor should fix the "no signal" issue. Like this...