Reverb cables...the missing link

[Normster]

I just got new reverb cables today from Antique Electronics. Nice fat cables with 90 degree ends. The real surprise, however, was the effect on tone. Mind you, the old RS cables weren't bad, just not as good as these. I'd complained to Scott that my Bassman ODS was harsh after trying the RN65 resistors. Well, with the new cable in everything sounds sweeter than ever. Much better top end and no harshness!

[Bob-I]

I just got new reverb cables today from Antique Electronics. Nice fat cables with 90 degree ends. The real surprise, however, was the effect on tone. Mind you, the old RS cables weren't bad, just not as good as these. I'd complained to Scott that my Bassman ODS was harsh after trying the RN65 resistors. Well, with the new cable in everything sounds sweeter than ever. Much better top end and no harshness!

Good news Norm. My build has some issues with noise and loss of tone with the reverb engaged. I've been suspecting cables all along and my plan is to go to a stereo shop and buy high quality cables.

Are your reverb jacks isolated from the chassis?

[Normster]

The jacks aren't insulated, but I didn't pick up any noise so I left it as is. (I insulated the jacks on Loren's amp but didn't notice any change.) I really need to get a new multimeter with a capacitance checker. I suspect that the old cables had very high capacitance. After swapping the cables, the Bassman has nearly the same top end chirp as my Dumble repro. The only real difference between the amps now (aside from the reverb) is the Bassman is very thick and meaty sounding while the Dumble far more articulate and crunchy.

[sgp]

Hi,
First off, It's great to find this site, my hats off to all of you guys for your dedication and willingness to help others.
Just to clarify Normster, Is this the single tube reverb that is shown on your layout diagram?
I'm embarking on my first dumble (Hybrid-A), but I haven't decided to go with the single tube, the rev-a-loop, or just worry about it some other day. I'm leaning towards the revaloop, cause the dumbleator is an appealling feature, but the parts count on the single tube version is becoming more appealing, especially after what you just said.
any insight is really appreciated.
thanks,
Garth
PS I was just up your way at the arco arena today, took my daughter to see the Wiggles concert. We almost got stuck in the baby-mosh-pit.

[Normster]

Yep, that's the single tube reverb. My favorite build to date is my Dumble "relic" based on a '70s schematic. I just run reverb and delay pedals in the loop. (Passive loop, not a Dumblelator.) That said, I'm currently working on a '90s style 100 watt with reverb, post OD tone stack, and EL34s.

[tonelab2]

Hi Normster, what changes (improvements) have you made to the 70's ckt. Did you use the vishay/dale resistors on the plates? Is that the amp used on the Engl screamer clip?
Sorry for so many questions, I have a '70s chassis and an '80s as well. Thought I'd give the '70s a go first before tackling the '80s (with reverb).
Thanks
.

[Normster]

Hi Normster, what changes (improvements) have you made to the 70's ckt. Did you use the vishay/dale resistors on the plates? Is that the amp used on the Engl screamer clip?
Sorry for so many questions, I have a '70s chassis and an '80s as well. Thought I'd give the '70s a go first before tackling the '80s (with reverb).
Thanks
.

The '70s amp is built to be as close to a Dumble as my resources would allow. I tried to keep the layout accurate, but I didn't use Mepco resistors or carbon comps. (I did use PS series caps.) Most resistors are 1W Xicon carbon film. On this build I haven't tried the RN65s yet.

I installed internal 100K trimmers for OD2 treble bleed and OD level. (I use the OD level on the front panel as a master volume.) I also added a 1K resistor feeding the accent switch which makes the effect more subtle. The only other change I plan to make is maybe adding a boost relay.

The Engl clip was the '70s repro with rock, bright, deep, and accent switches ON, treble and bass at 2:00 and mid at 11:00. My "normal" settings are rock, deep, and accent ON with all tone controls at 12:00. This gets me pretty close to early Carlton, but with a bit more blues crunch.

[pedro]

Hi Normster,

thanks for the clip - I like that a lot , great stuff.

I'd like to know more about effects in the passive loop - I have Boss Reverb RV-5 and Boss Delay DSD-2 which I like using with my amp but havent built in a passive send/return.

How well do your pedals interface with the passive send return ?

I'm building up an external dumbleator because I coundnt get mine working well in my ODS build ( it was an afterthought ). It would be nice to use pedals in the loop but Id assumed ( maybe wrongly ) that they wouldnt work well with the passive send return . Do you have to make a "passive loop" rather than just use the "pre out/power amp in" ?

Let me know when you get chance.

TIA
Pete C

[mlp-mx6]

I believe there would be 2 possible issues w/ a passive loop and pedals. First - the level will likely be too hot for the pedal. Second, the impedance would not be correct. Two potential side-effects, then. From the first - overdriving the input of the pedal. From the second - high-freq attenuation. IOW, your tone would SUCK! (grin )

[Normster]

Do you have to make a "passive loop" rather than just use the "pre out/power amp in" ?

"Passive loop" may have sounded confusing. Pre-out/power-in is what I meant. I use the pre-out/power-in setup with my reverb/delay pedals and they work just fine. I keep my pedals on top of the amp and connect with very short cables so maybe that's got something to do with it.

I may be shot for saying it, but I prefer the digital reverb pedal over the spring reverb in my other amp.

[pedro]

Hi again guys

so, if there is signal to spare ( too hot ) then would a simple voltage divider work. Would it be possible for this to act as impedance bufer as well ?

cheers
Pete

[dogears]

Hey Norm,

Do me a fave and edit out your post.....

Thanks!!!

[tonelab2]

Thanks Normster.