B3 and 147 troubles

[Sweet Pete]

enor is right,under no circumstances plug a 147 into a 122 outlet.Let's out the magic smoke.

Run a pair of leads from the B3/147 outlet box(pins 1+6) to your A100 (G and ground) to test your 147 if you already have a 'known good' A100!
Then you can determine what's needed to get the B3 up to snuff!
Awkward to control tremelo but you'll hear what the 147 is supposed to sound like if that's not the issue.
Easier to determine the issues with a 'known good' unit to compare.

If I read enor correctly,all of his rigs are 'plug and play' and interchangeable.
Same here,except I use mainly 147's.

[PGR]

Thank you Enor. So if I wanted to test the 147 with the a100 then I would need to wire up a new Amphenol in the A100 to handle the 147 - dropping the B+ and using just one G and the Amp Ground. DO I need to hook in a tremolo switch to start?


OR

OK Pete Do I understand you correctly. to test the 147 on the A100 I should run leads to the b3/147 pins 1 and 6( in my case fat reds) at the outlet box to the 147 from the A100 pre amp Red G and Ground Brn

Basically borrowing the signal from the a100 This will tell me if the B3 pre amp is the problem (great volume in the 147 -strong a100 signal -signal from B3 sucks) ......or if the sound is the same volume it would be the 147 as the problem ( not producing)

[Sweet Pete]

To test an amp in a Leslie you don't really need a tremelo switch.You don't need a new amphenol.
Some test leads that will reach your A100 preamp from your B3 outlet box will get it done.My last post above^ has the pin #'s......
Once you've heard how the 147 is supposed to sound,assuming that's not the issue,you'll better zero in on the B3 preamp issues if they exist.
Good thing you've got an A100 that works? Great way to eliminate issues.

[geoffbrown]

The C3 signal is hooked up to the 147 using a guitar cable using the one G and ground method, the 147 amp is powered via a AC mains plug into the wall, speed switching has its own three wire cable, no relay is used this gives slow, stop and fast. This is a non standard set up as there is no six pin connectors or leslie kit used.
147 was modified when I got it, it works well apart from less volume due to the one G hookup

I'm talking about my C3 /147 of course

[Sweet Pete]

The C3 signal is hooked up to the 147 using a guitar cable using the one G and ground method, the 147 amp is powered via a AC mains plug into the wall, speed switching has its own three wire cable, no relay is used this gives slow, stop and fast. This is a non standard set up as there is no six pin connectors or leslie kit used.
147 was modified when I got it, it works well apart from less volume due to the one G hookup

Similar situation here 25 years ago.No kit for my A100/147 so I built my own.Still in use.Full time 'ensemble' with no volume drops.
Mind you,still have the stock cable and 6 pin sockets in use.
Same with R1 on the MT. No volume drop on perc/normal.
Other than that? Stock.

One leg of the G-G's still works OK,just not balanced on the AO28 end. 147 doesn't actually 'see' balanced,but will run it.

[geoffbrown]

Yes Peter I'm in full agreement with you, I've seen the pics of your rig which have been posted previously, I intend to do something similar with ultimate aim being to be able to plug any organ into any leslie.

Back to PGR's problem it initially appeared to me that he had two G's wired into the 147 which would require modification to the 147 input,but this is not the case

[PGR]

So Pete and Geoffbrown

Do I need to de soldier the fat red leads from the B3 pre amp? in order to run the leads from the a100 to the 147 and not have multiple signals show up on the 147. Or is the only way that could happen is if I was playing both organs at the same time ?

[enor]

So Pete and Geoffbrown

Do I need to de soldier the fat red leads from the B3 pre amp? in order to run the leads from the a100 to the 147 and not have multiple signals show up on the 147. Or is the only way that could happen is if I was playing both organs at the same time ?

De-solder those wires and run them temporarily to one G and ground in the A-100. Power up both organs and play the A-100. That's your test rig right there.

[PGR]

Hi y'all

Did the test as prescribed and here is what I got. placed the 147 beside the 122 - eventually , because it was hard to hear the 147 . Then I balanced the volume out control first at 5 on both and the 122 buried the 147 - then at three ( it was easier to hear the difference at 3. ) Then in order to hear both and distinguish the source clearly I had to drop the 122 to 2.25 while leaving the 147 at the 3. At higher volume levels the difference in volume is more significant and also harder to quantify, But it is there and real, I think Sweet Pete said he felt my issue would be in both amps 147 and pre amp and the place to start was the pre amp. Now I agree. In fact with this test done My guess is that if I have the pre amp gone over I would be hard pressed to hear the difference in volume do to anything other than the single G signal and the balanced signal G G

I got both signals because I used alligator clips on the a100 without un soldiering anything. That meant I could un plug the 122 to hear just the 147 with a unbalanced G and Ground and plug it in to get both leslies .

for all the tests I pulled the first 4 bars on the upper to 8's only sometimes I tried the percussion on and then off. My a100 is very much more brilliant than the B3 due in part to the over haul I did numerous years ago and the amp rebuild - I also peaked the TWG so it has a lot of attack. I could hear the difference of this brilliance in the a100 when played through the 122 vs the 147 the 147 was more muted (maybe only due to one signal and ground) and definitely less volume as above. and lots less volume as you push up the dial.


The other thing I noticed much to my surprise is the current level of brightness in the B3 ( not as bad as I thought) It could be better but for now its ok.

[geoffbrown]

Just for comparison purposes my 122 is hooked up to the C3 using a conventional leslie kit including MEE switch, the 147 is hooked up using the one G and ground, method I usually have the 122 on volume 5 the 147 has to be set on 9 or 10 to match the 122.
I'm sure there is nothing wrong with my 147 it sounds great and is loud enough for me.
Yes your on the right track with your fault finding, use a process of elimination

[PGR]

Hi GeoffBrown

Yes I would say that my 147 and 122 volume difference ( same as your situation ) would be comparable When I ran the 122 at say 5 on its volume dial The 147 would need to push at 9 easily maybe even as high as 11-12 but I didn't test this hign - just too hard to hear.



So my plan is to pull the Pre amp again and go back to replacing all the resisters and caps that have been provided in the kit. I did the cap cans and a few really big caps then tested the amp which seemed OK . The reason I think I should go back is because when I tested volts and amps etc at all the stages of the amp IT seemed I was always running just a little colder than spec - so maybe I can with the replacements bring it back into spec and get the amp to produce a cleaner brighter signal ....without touching the TWG :)


Thanks to everyone for the incredible assistance . THis forum and all its participants are just amazing.

[enor]

I could hear the difference of this brilliance in the a100 when played through the 122 vs the 147 the 147 was more muted (maybe only due to one signal and ground) and definitely less volume as above. and lots less volume as you push up the dial.

"Muted" as in "less brilliance"?

If anything, a healthy 147 should sound brighter than a 122.

[PGR]

Hi Enor,

Definitely less brilliant If I said put ear muffs on when you listen to the 147 and take them off when you listen to the 122 that is what I mean. The volume was less but the tone was muted (not as brilliant ) a lot softer rounded sound. Hope this makes sense.
What your suggesting means the 147 is not producing well enough too. besides putting in resisters and caps in the 147, I did change the 12au7 because the old one was microphonic but the one I put in was from the 122 change over So it is definitely 50+ years old but also has not seen a lot of use over most of those years. Any way are you suggesting that the 147 is suspect ?

[Sweet Pete]

All things equal with a 122 and 147 there should be more 'headroom' on trebles before 'breakup' on the 147.
A proper 147 should not only be as loud as a 122,it should have more pre 'breakup' gain.
In my experience a 122 sounds great until they have no more 'headroom'.
They 'compress' rather than 'distort'. The 147 doesn't 'compress' as much and will have more audio bandwidth than a 122.
Most noteable on the treble end. Maybe the balanced input load of the 122 limits the amount of 'over the top' gain that the 147 is so famous for.

If your 147 isn't at least as loud as your 122 it likely has an issue. Check your plate voltages on those 6550's.
Maybe time for a new 470 ohm resistor under there?
Having more than one of each gives me a comparison test and that's how I narrow down my issues.

I have a really clean all original 1966 Leslie 122 amp (from the pristine 222) I will drop into a 41" or 33" cab from time to time.
My 'go to' studio or jazz chassis.Sounds beautiful with less headroom.
It can't keep up to the 147 set on the 'open' ohm selector dial!

So Gord,you have a known decent AO28 in the A100,and likely a good working 122 as well.
Easier to spruce up the 147 chassis using the A100 at this point.
Once you have a proper 147 locating the B3 preamp issues will be easier.
The B3/147 should be as loud at least, as the A100/122, if not a lot more.
My B2/147 can't keep up to my A100/147 for overall gain.

[PGR]

Ok so it would be easier to do a partial and permanent hookup from the A100 to the 147 then trouble shoot the 147 to get it working right - when that's done walk back to the ao-28 . the only part which I Am confused about right now is the long term hookup on the tremolo switch so it can work the 147 and the 122
Don't need it now but soon . in the mean time put in the 6 pin on the a100 specifc for the 147 and then pull the 147 and start to work trough it

IF y think different let me know - cause tomorrow I can start the a100 conversion and then get the 147 up an on the work bench live.