BE channel of BE-100 (2016) vs. BE of JJ
- Thread starter idnotbe
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technomancer
Well-known member
CrazyNutz":3bh592bl said:
Pretty sure the latest BE has an additional resistor added to the 10k / 4.7k pair
You can see it in this photo
technomancer
Well-known member
CrazyNutz":2nbidfqj said:
Yeah not sure what the value is, but it is definitely there. It's an earlier BE100 updated to the 2016 spec so it may not be doubled up on the "new" version.
The photos are from this thread
https://www.thegearpage.net/board/index ... s.1788729/
lowmantotempole
Well-known member
I’d be seriously surprised if Dave comments on this thread.
technomancer
Well-known member
lowmantotempole":3mu3qj8m said:
Dave can comment or not as he sees fit, none of this is secret or rocket science or anything negative about him or his company. Hell I've owned a BE100 and still own a JJ, they're great sounding amps which is why they're interesting to talk about.
scottosan
Well-known member
Dave has always been a standup guy and even openly discussed the design on other forums until people started attacking him.technomancer":wi91hcxb said:lowmantotempole":wi91hcxb said:
Dave can comment or not as he sees fit, none of this is secret or rocket science or anything negative about him or his company. Hell I've owned a BE100 and still own a JJ, they're great sounding amps which is why they're interesting to talk about.
technomancer
Well-known member
scottosan":2xduphrs said:Dave has always been a standup guy and even openly discussed the design on other forums until people started attacking him.technomancer":2xduphrs said:lowmantotempole":2xduphrs said:
Dave can comment or not as he sees fit, none of this is secret or rocket science or anything negative about him or his company. Hell I've owned a BE100 and still own a JJ, they're great sounding amps which is why they're interesting to talk about.
Yep nothing but respect for Dave and his work here
psychodave
Well-known member
scottosan":2oqqwpg1 said:I just wired up a 3 way switch for my NFB
Left - stock BE
Center - Cameronesque
Right - JJ
The Friedman NFB is pretty dark when using the SAT. The center position now with SAT.... oh my........
How about wiring an adjustable NFB pot and putting different caps (or maybe an additional resistor
) on a 3 way switch...
technomancer
Well-known member
scottosan":23izn72q said:I just wired up a 3 way switch for my NFB
Left - stock BE
Center - Cameronesque
Right - JJ
The Friedman NFB is pretty dark when using the SAT. The center position now with SAT.... oh my........
Come on now you're just teasing, values for the middle position
I've got a couple schems for this stuff but they're supposedly all wrong lolI'm thinking what I'm going to do if I get around to my build is replace the 220k with a 1M pot and have the 2.7nf cap on a switch (so basically the Thump from the Slax, but with the extra cap switchable) so at 1/4 on the pot and switch off you have the stock BE but also have some options. Might also replace the 47k with a pot and resistor in series.
scottosan
Well-known member
I have a beta tester thats gonna try it before we talk specificstechnomancer":2twp0yqp said:scottosan":2twp0yqp said:I just wired up a 3 way switch for my NFB
Left - stock BE
Center - Cameronesque
Right - JJ
The Friedman NFB is pretty dark when using the SAT. The center position now with SAT.... oh my........
Come on now you're just teasing, values for the middle position
I'm thinking what I'm going to do if I get around to my build is replace the 220k with a 1M pot and have the 2.7nf cap on a switch (so basically the Thump from the Slax, but with the extra cap switchable) so at 1/4 on the pot and switch off you have the stock BE but also have some options. Might also replace the 47k with a pot and resistor in series.
. But the CCV clone still sounds better. This mod would just give some MC sauce 
technomancer
Well-known member
scottosan":9v6w7zdv said:I have a beta tester thats gonna try it before we talk specificstechnomancer":9v6w7zdv said:scottosan":9v6w7zdv said:I just wired up a 3 way switch for my NFB
Left - stock BE
Center - Cameronesque
Right - JJ
The Friedman NFB is pretty dark when using the SAT. The center position now with SAT.... oh my........
Come on now you're just teasing, values for the middle position
I'm thinking what I'm going to do if I get around to my build is replace the 220k with a 1M pot and have the 2.7nf cap on a switch (so basically the Thump from the Slax, but with the extra cap switchable) so at 1/4 on the pot and switch off you have the stock BE but also have some options. Might also replace the 47k with a pot and resistor in series.
Don't worry, I'll be bothering you about the single channel CCV concept once I get some other builds done
My tentative plan assuming laziness doesn't win is two Friedman-esque builds and a build based on a Brad-era Atomica. For the Atomica I'll probably try something like the Punch and Voicing that use caps in parallel with pots in the NFB. So at the rate I move I'll probably be trying to get a hold of you in about a year with CCV questions lol
11blueegyptians
New member
Thanks for the awesome info!CrazyNutz":27obopp2 said:
Is the coupling cap after the first stage the 2.2nF that’s in the BE? It seems to be a candidate for tweaking between models as well.
11blueegyptians
New member
Cool! Thanks!
I’m modding my Marshall Vintage Modern and borrowing from the Small Box. I noticed the divider has the same ratio. Tighter bass with the 2.2 along with the lowered bass shelf in the NFB loop on a JJ makes sense, though.
I’ve been experimenting with different filter networks in that location. Is there a discussion on this?
I’m modding my Marshall Vintage Modern and borrowing from the Small Box. I noticed the divider has the same ratio. Tighter bass with the 2.2 along with the lowered bass shelf in the NFB loop on a JJ makes sense, though.
I’ve been experimenting with different filter networks in that location. Is there a discussion on this?
CornNutz
Well-known member
11blueegyptians":2unzpo66 said:
Well I think the smallbox has 100k/64k (64k to ground) where the JJ has 64k/100k (100k to ground)
you really have to understand these things are tweeked to sound right/good in the total circuit. For example the first coupling cap on the SB is a 4n7, I have a feeling that works better with the low jtm45 style filtering. If you look at the SB it has 3 gain stages, and the CF on a single B+ Node with a single 16uf filter cap.
I just converted a friends 50w plexi to a Dirty Shirly, and it sounded meh until I pulled out the 47uf/10k/47uf preamp filtering, and replaced it with a single 16uf.
the sounds you get are effected by every component, and circuit in the amp. It all needs to be in harmony.
11blueegyptians
New member
The schem I found of the Small Box was 68k series/100k shunt but I trust you.
I agree with you about the meh. I did a Jet City 20W but didn’t mimic the rail filtering; no choke and the junk stock transformers. It’s class A/B with the Friedman NFB and kept the presence control. It doesn’t have the 22n fat cap, so I wouldn’t call it a Pink Taco by any means. I did keep the 4.7n on the cathode bypass though.
I’m quite happy with the plexi-style tone. The issue is the BE stage. I’ve changed the overall voicing from a BE to get what I want when using a TS as a lead boost; but I haven’t fully resolved the spike I’m getting in the treble, though I think part of it is the way I pick. I’ve addressed it by adding two poles of low pass filtering but the clarity is suffering beyond what’s already caused by the mess of a power rail. I like the brown and feel from the stage, but I think biasing it a little warmer might work better on that spike because I think the stage is too current starved.
But the Vintage Modern is coming along pretty well, especially after removing that (IMO horrid) PPIMV. Though I do want to change it from KT66 to EL34 down the line.
I agree with you about the meh. I did a Jet City 20W but didn’t mimic the rail filtering; no choke and the junk stock transformers. It’s class A/B with the Friedman NFB and kept the presence control. It doesn’t have the 22n fat cap, so I wouldn’t call it a Pink Taco by any means. I did keep the 4.7n on the cathode bypass though.
I’m quite happy with the plexi-style tone. The issue is the BE stage. I’ve changed the overall voicing from a BE to get what I want when using a TS as a lead boost; but I haven’t fully resolved the spike I’m getting in the treble, though I think part of it is the way I pick. I’ve addressed it by adding two poles of low pass filtering but the clarity is suffering beyond what’s already caused by the mess of a power rail. I like the brown and feel from the stage, but I think biasing it a little warmer might work better on that spike because I think the stage is too current starved.
But the Vintage Modern is coming along pretty well, especially after removing that (IMO horrid) PPIMV. Though I do want to change it from KT66 to EL34 down the line.
CornNutz
Well-known member
11blueegyptians":1owvlctd said:
Well on that, don't trust me. I have not personally been in a smallbox. I have a scheme that shows it as 100k/64k, mine could be the the one that is wrong
As for the biasing on that first stage, it is critical. Get it wrong and it will sound thin, and fizzy, or bloated. Voltage at the plate should read around 135-145vdc
Play with your dropping resistors to get it in that range. Also keep in mind 135, and 145 sound different so you'll have to play around on that range to get it where it sounds right for your amp.
EDIT: I did a search, and I think I found the SB schem you have, does the schem you have show 16uf/10k/16uf filtering in the pre. If so that is not correct. I think I have the revised schem. The SB has 32 main, 32 screens (on a single can) then 33 (axial) PI, and one 16 (axial) pre. You can see that from gut shots