From what I can gather (I'm not an electrical engineer so it mostly goes over my head), the Solina that three delay lines modulated by two LFOs. One LFO was faster and added more of a vibrato/tremolo effect, and the other was slower and more for subtle chorusing.
The signal is split into three with different phase relationships (different sources give different degrees) and modulated at around 6 Hz by one LFO (creating the ensemble effect), with the second LFO at around 0.8 to 1 Hz giving vibrato.
From what I've read, Ken Freeman's (prototype/personal) instrument had three oscillators, but the production Freeman String Symphonizer, built and marketed by Lowrey, had only two.
---
-
- KVRian
- 514 posts since 11 Jun, 2005 from Western Third of the shire of the Horse Bay
And it is as it is and we take as we find / Always next season's buds on the bough / But I'll never find a better time / Hard though it is to allow / I'll never find a better time / To be alive than now
-
- KVRAF
- 3080 posts since 17 Apr, 2005 from S.E. TN
Thanks that sounds correct on the solina chorus generator. I have a set of schematics around here somewhere. Finding them would be another matter entirely.
The freeman I bought, at closeout price, the "end of the line marketing push" can't recall exactly-- 1973? Something like that. Also have the factory schematics for the freeman, which matched the freeman I had as best I could see. Sold it off long ago but liked the old thing.
Maybe some of the freeman's only had two osc banks, dunno. Mine had three banks and it didn't seem an "odd" model, just bought off a stack of identical boxed up closeout freemans at atlanta's rhythm city store.
The factory schematic also shows three osc banks. If a person simply popped the top and looked inside, it would be a natural mistake to assume that the freeman only had two banks, because it only had 24 tunable tank oscillators, which are big and easy to count.
I assumed mine only had two banks for a couple of years until one of the notes developed intermittent static. Same static on the same note in every octave. Both the tank oscillators for that note were fine, so it was a puzzle.
So ordered the schematic and discovered the static was from the "extra" third bank. The silly thing had a top octave generator integrated circuit, which never received any vibrato, then it had two sets of 12 discrete tank circuit top octave oscillators, which were cross wired from a half dozen or so slightly different frequency vibrato lfo's.
That tog chip had already become unavailable, but luckily was able to clear the one note with static in my weak chip, by gluing a big heat sink on the tog chip. It only made the static when hot, and that chip ran rather hot. But used the freeman many years afterward, and luckily the chip never failed or got worse.
The freeman I bought, at closeout price, the "end of the line marketing push" can't recall exactly-- 1973? Something like that. Also have the factory schematics for the freeman, which matched the freeman I had as best I could see. Sold it off long ago but liked the old thing.
Maybe some of the freeman's only had two osc banks, dunno. Mine had three banks and it didn't seem an "odd" model, just bought off a stack of identical boxed up closeout freemans at atlanta's rhythm city store.
The factory schematic also shows three osc banks. If a person simply popped the top and looked inside, it would be a natural mistake to assume that the freeman only had two banks, because it only had 24 tunable tank oscillators, which are big and easy to count.
I assumed mine only had two banks for a couple of years until one of the notes developed intermittent static. Same static on the same note in every octave. Both the tank oscillators for that note were fine, so it was a puzzle.
So ordered the schematic and discovered the static was from the "extra" third bank. The silly thing had a top octave generator integrated circuit, which never received any vibrato, then it had two sets of 12 discrete tank circuit top octave oscillators, which were cross wired from a half dozen or so slightly different frequency vibrato lfo's.
That tog chip had already become unavailable, but luckily was able to clear the one note with static in my weak chip, by gluing a big heat sink on the tog chip. It only made the static when hot, and that chip ran rather hot. But used the freeman many years afterward, and luckily the chip never failed or got worse.
-
- KVRian
- 514 posts since 11 Jun, 2005 from Western Third of the shire of the Horse Bay
Ah, Gordon Reid must've been misinformed -- it was in his intro in the manual for GForce's VSM and I've just noticed it's also mentioned in his SOS article about the String Symphonizer.JCJR wrote:The factory schematic also shows three osc banks. If a person simply popped the top and looked inside, it would be a natural mistake to assume that the freeman only had two banks, because it only had 24 tunable tank oscillators, which are big and easy to count.
I assumed mine only had two banks for a couple of years until one of the notes developed intermittent static. Same static on the same note in every octave. Both the tank oscillators for that note were fine, so it was a puzzle.
So ordered the schematic and discovered the static was from the "extra" third bank. The silly thing had a top octave generator integrated circuit, which never received any vibrato, then it had two sets of 12 discrete tank circuit top octave oscillators, which were cross wired from a half dozen or so slightly different frequency vibrato lfo's.
And it is as it is and we take as we find / Always next season's buds on the bough / But I'll never find a better time / Hard though it is to allow / I'll never find a better time / To be alive than now
-
- KVRAF
- 3080 posts since 17 Apr, 2005 from S.E. TN
I could try to find my freeman schematics if it would help anyone. For anyone with a freeman and curious to look inside, as best I recall the big top board when you pop the top has all the top octave oscillators. There are two rows of 12 "cans with holes in the top" that are the tuning coils for the tank circuits, and if it also has a top octave chip, as best I recall it would be located toward the right of that board, in-between the two rows of coils. But that was a long time ago. What was the first wife's name anyway? Some things are REALLY HARD to remember!! 
The freeman had lots of parts compared to most string machines at the time.
The freeman had lots of parts compared to most string machines at the time.
