Difference in sound BV (BCV) vs B3

[AndyPanda]

I have had a BCV for years and love it. I've never owned a 3 series before (played a bandmates M3 back in the 70's but memory fades).

I just acquired a C3 and have got everything working now and set them up side by side with each connected to its own 122 style leslie cabinet (both with P15LL woofers).

I was very surprised to see that the Vibrato/Chorus sounds very much the same between the two - the Chorus mix is much lower on the BCV (I read about a resistor change to bring the Chorus mix up in intensity) so that Chorus3 on the BCV is just a hair more intense than Chorus2 on the C3. Vibrato compares about equal between them - so I think it's just the mix on the chorus that is different.

In the upper registers, the two organs sound VERY similar (again I was surprised) but in the lower registers they sound worlds apart with the C3 having a growl and completely different sound to the bass notes and the BCV having more of a sine wave quality to the bass sounds (complex tonewheel is responsible for this I assume?). The BCV doesn't foldback the bass notes, they go all the way down - but the C3 seems to be MUCH more bassy and much louder bass. I haven't rebuilt the preamp on either and I suspect that a preamp rebuild on the BCV would likely bring that bass volume up (a fresh cathode bypass resistor **EDIT: I meant capacitor** on the output stage would probably help). But I'm curious if others who have a BV or BC or BCV series have opinions of how the bass sounds compared to the models with complex tonewheels. In a way (other than the lower volume of the bass) I really like the rounder sound of the BCV bass -- and in other ways I really like the growl of the bass on the C3 -- they are very different sounding from each other and depending on the type of tune I'm playing, one or the other seems to fit better.

Would it be of value to anyone if I were to record both organs and post the sound differences?

I was also surprised by the keys -- I had thought the newer keys were going to be A LOT more rounded than my old BC keys (who knows, maybe someone has replaced or modified my BCV keys before I got it) but they are very similar. I do like the newer keys better but the old ones are not that much sharper edged. (I can take pictures if anyone is interested in the comparison). The key click is MUCH more pronounced on the old BCV compared to the C3 ... and I've gotten in the habit of using the keyclick as a rhythmic element when I'm writing a song idea.

[David Anderson]

I haven't rebuilt the preamp on either and I suspect that a preamp rebuild on the BCV would likely bring that bass volume up (a fresh cathode bypass resistor on the output stage would probably help).

There is actually no cathode bypass capacitor (I assume you meant capacitor) in the Vibrato preamp. It was built without any electrolytic capacitors. The output stage is a push-pull 6SN7. That said, uneven push-pull signals to this output stage will result in diminished bass. (The 6J7 is triode-wired as a cathodyne phase inverter.)

I've often been surprised by how bright BCs and CVs still sound, and there is somewhat more tone-shaping going on in the 2- and 3-series preamps. I haven't investigated it, but I wouldn't be surprised if part of the tonal difference you're describing has to do with greater high-frequency response in the early preamps. Remember that Laurens Hammond considered key click to be a fault. In other words, the question of more or less bass is sometimes a question of the overall frequency balance.

And do check where the tone pots on both preamps are set.

[Guest]

Two separate leslie's in different locations need to be taken into account as well. Remember, the room and placement of the speakers is one of the biggest things that can effect the sound. If the amplifiers and crossovers have not been rebuilt, that can be a factor too.

[AndyPanda]

Thanks for the replies ....

Yes I meant capacitor (thanks for reading my thoughts :-)) So there isn't one? There goes that idea.

Regarding the two leslies - I've swapped back and forth with same results so leslie position isn't the factor - both fresh rebuilds.

I just dug up the schematic and see what you mean .. wouldn't a cathode bypass cap be a good thing to have there? Thanks for the tip on the uneven push/pull - probably high time that preamp got a rebuild anyway.

I'll take a look at the tone controls and see where they are set.

[johnny b3]

Wow, Nathan! Been a while...

Andy if you've got mics set up....recordings wouldn't hurt!

[dunderola]

As seen in my novachord thread...Keys!
Some pics..
1. Model A "the sharped edged ones"
2. S6/B3ish "rounded smooth ones"
3. Novaschord "extreme rounded ones". And as service manual states: Molded of bakelite and PLASKON.

[David Anderson]

I just dug up the schematic and see what you mean .. wouldn't a cathode bypass cap be a good thing to have there? Thanks for the tip on the uneven push/pull - probably high time that preamp got a rebuild anyway.

The output stage of the Vibrato preamp is almost certainly running in Class A, push-pull, so I doubt that a cathode bypass capacitor would do very much, but you could easily try it if you wanted to. If the stage is well-balanced, the AC signal at the cathodes should be close to zero anyway. You generally don't push stages like this into Class AB1, which is the point at which a cathode bypass would start to have an effect.

On the other hand, since that cathode voltage is also used to elevate the heaters, you might get some noise reduction benefit, though the 8V positive voltage isn't quite as high as it should be for optimal heater noise reduction. Needs to be close to 10.5V to be entirely effective.

[enor]

I haven't investigated it, but I wouldn't be surprised if part of the tonal difference you're describing has to do with greater high-frequency response in the early preamps.

I suspect the lack of tapering in the manuals of the old organs is the main factor in them staying bright ... I have a BC which now has -3series parts after the manuals (matching transformer and preamp) and it is VERY bright. But it also has strong bass, on the other hand.

[AndyPanda]

Well I finally got a chance to break away from work and take another look at these. Both of them have the tone control set exactly midway. So I tested for a bit and discovered that when I turn the tone down on the BCV and then turn up the volume of the amp to compensate I was able to get it to where the BCV has very nearly the same balance as the C3. Thanks for the suggestion, I wouldn't have thought that tone control would make such a difference.

The C3 still has more of a growl to it while the BCV has a smoothness to it - that difference stands out most when you get down to the bottom two octaves - in the rest of the range they sound very similar.

[AndyPanda]

I don't have proper mics setup - and the organ is still in my garage until I find three strong guys to help me get it upstairs. But I recorded this with a little tascam hand held with built in mics - sound quality isn't great but you can hear the general sound of the two organs. I didn't use any percussion since I don't have perc on the BCV.

0-7sec= C3 888 lower and 666 upper
8-14 = same thing on BCV

14-21= C3 888 lower and 666 upper Chorus2
21-28= same thing on BCV

28-35 = C3 same clip as before chorus2
36-43 = BCV on chorus3

43-47 = C3 888
47-51 = BCV 888

52-57 = C3 888 lower and 666 upper
58-1:04 = same on BCV

Final series is alternating stacked fourths on C3 then BCV and back again alternating between organs going low to high with all drawbars out

[AndyPanda]

I just added a 32K resistor across lugs 17 and 20 on the vibrato line box on the BCV and that brought the chorus depth up to the same level as the C3. All in all, I'm pretty impressed with how good the old BCV sounds. But I am also really enjoying having the C3 with perc and the split vibrato and smooth drawbars - it'll be a whole new learning experience.

[Tim_at_Jonas]

The C3 is too dirty, and the BCV is a little mellow. I'd take the latter I think.

[AndyPanda]

The organs are still in my garage - so not the best recording acoustics - but I put a couple of damping panels around and setup a pair of condenser mics aimed at either corner of the horn and a ribbon mic about 6 inches in front of the lower rotor (and kept everything on slow motor). No processing at all ... the two chorus comparisons are with expression pedal on full and leslie amp about 4 for the C3 and about 7 for the BCV (BCV has much lower output) ... the bass comparison has the expression pedal at about 1/3 and the leslie amp around 6-7 for the C3 and 9 for the BCV. I did this because the bass difference shows up much more with expression backed off. This may be a function of how the two different types of expression work - but I suspect it's more to do with the complex tonewheels and foldback on the C3 while the BCV goes all the way down and has more sine wave sounding tonewheels.

I've modified the BCV with a 50 ohm resistor between lug 17-20 on the line box to get the chorus up about the same level as the C3 - I also had to turn the tone on the BCV preamp down to about 1/4 (it was midway and was much brighter - the C3 is still midway)

In each recording the C3 goes first and then the BCV follows. Both are set 848 on lower manual for left hand bass and 666 on upper manual for right hand chords.

[AndyPanda]

Also ... for those of you who have wondered what the BC or BCV sounds like with the second generator with detuned tonewheels --- here is a clip where I first play a chord without and then engage the chorus generator - it adds some shimmer and a little extra motion.