Forum Vibe: lack of warmth

[poorboy]

Hi all
after some troubles solved (tnx Lonewolf and Redhouse) i finished my Forum Vibe...
I think is great and sound very well,  expecially after the Redhouse gain mod...
But i feel like is not so warm like the other vibe i heard.. and,  i think,  lack of deep...
Could i ask what tests should I do and what components to check to "solve"  this lack and improve the sound?
I hope someone can halp me
.. tnx very much...

[Liquitone]

Two things I can think of are;

1.Is that Redhouse gain mod a higher impedance resistor or is it the jfet stage? The 47k from the input resistor to ground in an original Uni-Vibe steals a lot of highs from your signal but you could also call that warmth.

2.There should be a sweet-spot somewhere when you set the trimmer of the lamp-driver's transistor where it sounds pronounced enough but also has enough of the dark/chewy low-end. 
   I noticed when I turn up the lamp too bright the sound also becomes brighter and more choppy,. more like a tremolo, less like a phaser.

[poorboy]

Two things I can think of are;

1.Is that Redhouse gain mod a higher impedance resistor or is it the jfet stage? The 47k from the input resistor to ground in an original Uni-Vibe steals a lot of highs from your signal but you could also call that warmth.

2.There should be a sweet-spot somewhere when you set the trimmer of the lamp-driver's transistor where it sounds pronounced enough but also has enough of the dark/chewy low-end. 
   I noticed when I turn up the lamp too bright the sound also becomes brighter and more choppy,. more like a tremolo, less like a phaser.

Hi Liquitone,  i thank you very much for the answer..
I put a 1M resistence,  but the lack of warm is earlier this change..
I worked hard with trimmers,  but i cant find a sweet spot... more deep.. more choppy.. sigh

[lonewolf]

did you do the bulb offset trimmer mod? if so what type of trimmer did you use? I found that a multi turn type trimmer worked best to fine tune the bulb offset..that is what will eliminate the choppyness..not the mix trimmer.the single turn type woked best for the mix.also the speed pot will affect the depth..the 24mm dual pot from small bear worked best for me..I used 2 3904 transistors to make the bulb driver with a 250k multi turn trimmer.turn it very slow until the choppyness fades out...I tried the red house version with the self contained darlington but the 2 3904's sounded better to me..

[Jaicen_solo]

I'm wondering what you're playing into the vibe, and what the vibe is plugged into??

I built a Univibe that can sound very bright, especially with a fuzz in front. However, plugging it into an amp that's already cooking will help to tame some of the high end.

The bulb offset will make a massive difference to getting 'THE' sound in my opinion, as will using the correct bulb and LDR combos. I couldn't get anywhere near the correct sound until I swapped out the bulb for the Small Bear bulb. I also swapped out my LDR's for the Small Bear LDR's, which improved things a again though not by as much.

I'm actually considering adding a low-pass tone control to make the vibe darker when I use my FF with it, perhaps that's an idea you could try?

[lonewolf]

where you place a fuzz or distortion with a univibe makes a huge difference in sound.as well as WHAT fuzz or distortion circuit you use.robin trower used them in front and back of the univibe..you can tell when he steps on the fuzz in front ..thats when he gets that wicked growl in conjunction with a wah pedal..page also gets that sound on custard pie..but the univibe sounds smoothest with a fuzz after it..

[Liquitone]

I'm wondering what you're playing into the vibe, and what the vibe is plugged into??

I built a Univibe that can sound very bright, especially with a fuzz in front. However, plugging it into an amp that's already cooking will help to tame some of the high end.

The bulb offset will make a massive difference to getting 'THE' sound in my opinion, as will using the correct bulb and LDR combos. I couldn't get anywhere near the correct sound until I swapped out the bulb for the Small Bear bulb. I also swapped out my LDR's for the Small Bear LDR's, which improved things a again though not by as much.

I'm actually considering adding a low-pass tone control to make the vibe darker when I use my FF with it, perhaps that's an idea you could try?

The type of bulb/ldr do indeed make a huge difference in my opinion.
In my previous build I used a 'matched ldr /bulb-set' I bought online.
I'm a bit suspicious about this set, cause I never got to get the thing sound right, but in that build the offset-mod proved very use full in tuning it somewhat right.
In my latest build however I got it to sound right from the start without any mods, just the stock uni-vibe schematic. And I really think it's due to the choice of LDR's and bulb I made this time.
I measured and sorted a whole bunch of LDR's untill I had 4 that where all exactely the same (in this case 11k/500k) and used a quite large size 24v bulb ( I used a much smaller 12v in my previous build)
The only thing I really had to tune was the 1k trim-pot on the lamp-driver's emitter to get it sound right.
(I did btw, used transistor pairs of equal HFE values in the phase stages, but I'm not sure if that really made a difference, since my previous build also had that but didn't sound right at all with the wrong ldr's and bulb)

Others might disagree, but in my experience it's best to start with trying different LDR's and bulbs before trying to get it right with mods while using way out of spec ldr's and bulbs.

[Liquitone]

p.s. Do you happen to know the value of the LDR's you used?
In an earlier build I've used 500r/2M LDR's and that one also sounded either too bright and choppy or too dull and dark depending on the driver- and offset-trimmers settings.

[poorboy]

did you do the bulb offset trimmer mod? if so what type of trimmer did you use? I found that a multi turn type trimmer worked best to fine tune the bulb offset..that is what will eliminate the choppyness..not the mix trimmer.the single turn type woked best for the mix.also the speed pot will affect the depth..the 24mm dual pot from small bear worked best for me..I used 2 3904 transistors to make the bulb driver with a 250k multi turn trimmer.turn it very slow until the choppyness fades out...I tried the red house version with the self contained darlington but the 2 3904's sounded better to me..

tnx Lonewolf... good idea the multi turn..and i'll socket my pcb to use the 3904...

I'm wondering what you're playing into the vibe, and what the vibe is plugged into??

I built a Univibe that can sound very bright, especially with a fuzz in front. However, plugging it into an amp that's already cooking will help to tame some of the high end.

The bulb offset will make a massive difference to getting 'THE' sound in my opinion, as will using the correct bulb and LDR combos. I couldn't get anywhere near the correct sound until I swapped out the bulb for the Small Bear bulb. I also swapped out my LDR's for the Small Bear LDR's, which improved things a again though not by as much.

I'm actually considering adding a low-pass tone control to make the vibe darker when I use my FF with it, perhaps that's an idea you could try?

im put my Vibe in front of my blues deluxe reissue.. low pass.. hum maybe this can be a thing to try,

where you place a fuzz or distortion with a univibe makes a huge difference in sound.as well as WHAT fuzz or distortion circuit you use.robin trower used them in front and back of the univibe..you can tell when he steps on the fuzz in front ..thats when he gets that wicked growl in conjunction with a wah pedal..page also gets that sound on custard pie..but the univibe sounds smoothest with a fuzz after it..

.. and ill try with fuzz and other distorsion pedal after Vibe..

I'm wondering what you're playing into the vibe, and what the vibe is plugged into??

I built a Univibe that can sound very bright, especially with a fuzz in front. However, plugging it into an amp that's already cooking will help to tame some of the high end.

The bulb offset will make a massive difference to getting 'THE' sound in my opinion, as will using the correct bulb and LDR combos. I couldn't get anywhere near the correct sound until I swapped out the bulb for the Small Bear bulb. I also swapped out my LDR's for the Small Bear LDR's, which improved things a again though not by as much.

I'm actually considering adding a low-pass tone control to make the vibe darker when I use my FF with it, perhaps that's an idea you could try?

The type of bulb/ldr do indeed make a huge difference in my opinion.
In my previous build I used a 'matched ldr /bulb-set' I bought online.
I'm a bit suspicious about this set, cause I never got to get the thing sound right, but in that build the offset-mod proved very use full in tuning it somewhat right.
In my latest build however I got it to sound right from the start without any mods, just the stock uni-vibe schematic. And I really think it's due to the choice of LDR's and bulb I made this time.
I measured and sorted a whole bunch of LDR's untill I had 4 that where all exactely the same (in this case 11k/500k) and used a quite large size 24v bulb ( I used a much smaller 12v in my previous build)
The only thing I really had to tune was the 1k trim-pot on the lamp-driver's emitter to get it sound right.
(I did btw, used transistor pairs of equal HFE values in the phase stages, but I'm not sure if that really made a difference, since my previous build also had that but didn't sound right at all with the wrong ldr's and bulb)

Others might disagree, but in my experience it's best to start with trying different LDR's and bulbs before trying to get it right with mods while using way out of spec ldr's and bulbs.

p.s. Do you happen to know the value of the LDR's you used?
In an earlier build I've used 500r/2M LDR's and that one also sounded either too bright and choppy or too dull and dark depending on the driver- and offset-trimmers settings.

actually im using this: http://www.banzaimusic.com/Univibe-Upgrade-Kit.html
but i'd like to try others.. could you link your's?
Late morning ill take the value of my ldr's..
Ps hemm... how can i measure the ldr's value? is  variable..

Ok... tnx to all!  youre great!

[lonewolf]

measure resistance in the dark and with light..the amount of light will vary the resistance and I think the up/down times affect it also..the original vibes used hermetically sealed ldrs mounted flat getting mostly reflected light..small bear has the hermetically sealed ldrs..that sounded the best I think

[Liquitone]

that's the kit I used in my previous build as well. I wasn't satisfied by the kit, and found it annoying they don't mention the parts values, so you have to assume it's correct on good faith, which i find annoying. I haven't measured them at the time though.
http://nl.farnell.com/excelitas-tech/vt90n2/ldr-series-vt900/dp/1652637 these are the LDR's I used, they're out of stock sadly but there are lots of different ones with the same values. the rise/fall times on these are 78ms/8ms.
I wish I knew the rise/fall times of the original, but these sounded good.
I used this bulb http://www.okaphone.com/artikel.asp?id=460997
they're not available at banzai sadly. but it was 24v 50Ma 5,7mm diameter, 13mm height.

[poorboy]

ahhh ok Lonewolf... i'll try.. tnx a lot..

[R.G.]

Liquitone is on the right idea. "Lack of warmth" is the same thing as "bass loss" or "treble gain", depending only on how you describe it.

The 47K in front really does load down treble, which causes "warmth" or "bass gain" or "treble loss", again depending on how you describe it.

Another thing to look for is if you happened to get a signal cap the wrong value somewhere, it could cause loss of bass. Most of the series signal caps are 1uF electros, so this is not the usual thing, but it's a good place to check just to be sure.

[poorboy]

Liquitone is on the right idea. "Lack of warmth" is the same thing as "bass loss" or "treble gain", depending only on how you describe it.

The 47K in front really does load down treble, which causes "warmth" or "bass gain" or "treble loss", again depending on how you describe it.

Another thing to look for is if you happened to get a signal cap the wrong value somewhere, it could cause loss of bass. Most of the series signal caps are 1uF electros, so this is not the usual thing, but it's a good place to check just to be sure.

Oh tnx R.G.  im checking all the componets... maybe some wrong cap is driving me crazy... i let you know
Great boys.. tnx

[poorboy]

that's the kit I used in my previous build as well. I wasn't satisfied by the kit, and found it annoying they don't mention the parts values, so you have to assume it's correct on good faith, which i find annoying. I haven't measured them at the time though.
http://nl.farnell.com/excelitas-tech/vt90n2/ldr-series-vt900/dp/1652637 these are the LDR's I used, they're out of stock sadly but there are lots of different ones with the same values. the rise/fall times on these are 78ms/8ms.
I wish I knew the rise/fall times of the original, but these sounded good.
I used this bulb http://www.okaphone.com/artikel.asp?id=460997
they're not available at banzai sadly. but it was 24v 50Ma 5,7mm diameter, 13mm height.

Great Liquitone!  tnx.... i will search for ldr's and new bulb....
this night ill upload a little demo of my vibe.. so you can heard how it sounds... bye and tnx again...
tnx to all boys

[Jaicen_solo]

Also forgot, make sure you're using a proper light shield. It' will never sound right without one.

[poorboy]

Also forgot, make sure you're using a proper light shield. It' will never sound right without one.

Oh tnx Jaicen_solo...i use a black cup to shield...but i want to try a copper one..if i find one...

[poorboy]

ok, this is how my Forum Vibe Redhouse mods sounds..
http://www.mediafire.com/?xk6mwawe161l8lg

and this is how i would like to sound..is great
http://www.mrdwab.com/john/neo-vibe1.mp3

the difference is only the brightness?...
If so..i can try with the RedHouse  KR Megavibe and remove R2 altogether and increase R1 to well over 100k to approach the  K&R mega-vibeTM input mod...
Or change R2 from 1M (the gain mod) to 500K or less...
After i will search for new LDR's and Bulb, some bad value cap and i want to try differents shield and LDRs orientation...
ah..diy is so hard 

[Brossman]

Sorry to revive an old thread, but I've been having the same problem, just wanted to see if poorboy ever figured this out. Ill start with the input resistors and see what Ive got...

[poorboy]

Hi,  the lack of warm was the bad eq in my amp...
This vibe sounds better if you add more mids in amp eq...
Pups made difference,  my Tele with texas special sounds better than my strato with tex mex...I hope this helps...