The Singing Bush

[AnthonyA]

Pagoda /stepped drill
Or circular hole saw

 

[ggetzoff]

Choky,

Do you have any thoughts on VGS range for the THF-51?

Thanks,

GG

 

[Zen Mod]

regarding sett-ability , no issues , no preferred range

in case that you are outa range og Ugs I did cover with values on board , single resistor change would solve that

 

[elwood625]

ZM - For my THF-51S build, I have a 1000VA, 2X 48v secondaries with 18v and 12v secondaries transformer. 6 - 27,000uF capacitors (3 per channel).

Do you recommend motor run capacitor for each channel? If so, what size?

 

[Zen Mod]

motor-runs are cherry on top

biggest and badder you can squeeze in , connect in parallel with last cap in PSU

practically , don't go under 40uF , more - sky is the limit

is that xformer two separate windings of 48Vac each , or 96Vac center-tapped ?

 

[elwood625]

xformer is two separate windings of 48v each
each channel will have it's own rectifier and CRCRC filter except for the bias circuits

found a pair of cbb60 100uF motor run caps PP film, cheaper then TP on a-zon

 

[Zen Mod]

bingo

my dear Papa's Koan (first of them, F4) is made in similar fashion - had 800VA Donut with 4 secondaries , 18Vac each

then 4 bridges and separate cap bank for each channel

FW case being too sissy to squeeze in motor runs too ....., but- hey , that could be squeezed only in 500mm deep



edit : so , 800VA Donut , sum heat being around 150W , and singing all day long with peaks at (2x) 1W5/16R , in my workshop

but , I've put LED toobz , instead of neon ones

 

[elwood625]

When you mentioned that the Singing Bush had a bias circuit requiring a lower voltage, I found an.ANTEK 1000VA xformer with dual 48v along with 18v and 12v secondaries, I went with it instead of having to find room for multiple xformers.
I'd rather have room for capacitors instead of xformers.
Thanks for listing spec's for PS, I was hoping you'd list your recommendations.

 

[cjfrbw]

Could you post a rough power supply diagram with labels? I know it's a work in progress.

 

[alheiz]

Hi
I want know if is possible use linear amplifier as replacement transformer input JENSEN .
https://www.vishay.com › docsPDF
Designing Linear Amplifiers Using the IL300 Optocoupler - Vishay
ZM is possible in isolation galvanic T and 4N37?

 

[Zen Mod]

Could you post a rough power supply diagram with labels? I know it's a work in progress.

asking elwood , or me?

Hi
I want know if is possible use linear amplifier as replacement transformer input JENSEN .
https://www.vishay.com › docsPDF
Designing Linear Amplifiers Using the IL300 Optocoupler - Vishay
ZM is possible in isolation galvanic T and 4N37?

not possible without major changes in circuit - input xformer is necessary part of Schade feedback loop , doing several things at once ( all explained in Papalecture , linked in first post) - galvanic isolation , Schade feedback , increase of input impedance

if you can find decent 600:600 xformer locally , try it

decent means - declared HiFi use ( 20-20KHz) , not Telephone range

 

[alheiz]

Thanks Dear ZM
��
I go working !!!!slow but sure

 

[pras1170]

Continue selling THF-51S THF-51N TOKIN SIT 2SK182ES 2SK180
2SK180 20 old usedNeed friends, send an email to contact:Email: 378632242@qq.com

 

[Botte]

Well, I guess I have some time for the project.

Here is the first power supply.

22kuF x4 with .11ohms on a 25vac x2 300W toroidal.

74 volts unloaded 68V with about 1 amp load.

 

[Zen Mod]

looking good ........

 

[cubicincher]

to Botte #294

Hello Botte,


very close values like my PSU....


Greets
Dirk

 

[Botte]

I’m hoping with 68v I can use a cap multiplier if there is to much noise for my horns.

I would use the same cap multi as in a zen 9.

I will wait and see.

 

[Zen Mod]

cap multi is for Sissies

 

[danny_66]

Well, I guess I have some time for the project.
Here is the first power supply.

Nice, with LT4320 ideal bridges

 

[Juntuin]

Hi ZM,

Can you tell how those leaky gate SIT's behave with Singing Bush? (2SK182ES). Same DC-offset behavior as with SissySit? I'm just trying to explain myself why I definitely need another project..