♫♪ My little cheap Circlophone© ♫♪

[aditya]

As Minek mentioned, R23 and R are the only resistors you need to modify to alter the gain/sensitivity.
To keep the simulation happy, you might find that other tweaks are required, but they could prove disastrous in the real world

I am confused now sorry earlier you mentioned R12 and above you said R23 so do you mean the feedback series and R are the ones I could tweak,

So I shouldn’t touch the 22 Ohm Vas emitter resistor.

 

[Elvee]

If you change the B-E resistors of the drivers (for whatever reason), you also need to make a change elsewhere, but the best option is to change nothing, except the gain changing resistors if you want to modify the sensitivity.

 

[oscargolf]

Hello Circlophone friends, I recently met up with my
friend Stallion the other day and he asked why Q5 and Q6
have to be types 2N3019 or KSC3503 ?
He said it must also work with BD139 or maybe MJE340G?
My friend Stallion is more a developer of preamplifiers and digital technology.

 

[Elvee]

Q5 and Q6 need to have a sufficient transition frequency (like 100MHz) and a low enough feedback capacitance (10~15pF)

 

[oscargolf]

Thanks Elvee !! Have a nice Day !

 

[auriga2001in]

Happy New Year Elvee, minek, ...
My circlophones have been performing great for 3 years, and I was wondering if it's time for preventive maintenance. What should I be looking for?
Thanks again

 

[Elvee]

Happy new year everyone!
Unless an E-cap is close to a heat source, no maintenance is required: no adjustment that can drift, no component wear, etc. It should be good for another 30 year

 

[aditya]

A very Happy New Year to all - I will be joining the Circlophone gang shortly with my board, did want to make it a stereo board but its mono for now..

 

[oscargolf]

Allen Circlophone-Anhängern ein frohes neues Jahr.
hoffe ihr hattet alle einen guten Start ins neue Jahr.
Hier ist eine neue PCB-Version von mir und Stallion.
Hengst, mein Freund, wollte eine Version mit Sicherungen und im Format 100*100mm.
Er möchte jedoch nicht, dass diese Version im freien Open Source landet.
Bei Interesse schreiben Sie mich direkt an.
Danke OSGO

 

[aditya]

Allen Circlophone-Anhängern ein frohes neues Jahr.
hoffe ihr hattet alle einen guten Start ins neue Jahr.
Hier ist eine neue PCB-Version von mir und Stallion.
Hengst, mein Freund, wollte eine Version mit Sicherungen und im Format 100*100mm.
Er möchte jedoch nicht, dass diese Version im freien Open Source landet.
Bei Interesse schreiben Sie mich direkt an.
Danke OSGO
View attachment 1125233

Hi Oscar,

A very Happy New Year, Congratulation on the new board.

Have you tried this board testedin practial. how does it perform.

what is the dc offset you get with this setup along with the Quiesent current?

 

[aditya]

working on my Drafft board layout done in SMD with board size of 100mm x 65mm.
Driver and Output Transistors are accomodated below the board for a monolith assembly on heatsink construction.
all SMD capacitors are COG/NPO type rated at 100Volt

 

[oscargolf]

Hello Aditya,
Your board looks very good too. It's just that I'm not so good with SMD. But the board looks good.

Yes of course I have tested it and my DC-OFFSET is
< 2.5 mV.

 

[aditya]

Hello Aditya,
Your board looks very good too. It's just that I'm not so good with SMD. But the board looks good.

Yes of course I have tested it and my DC-OFFSET is
< 2.5 mV.

Thank you Oscar,
But I would know how it performs once I get it from the fabricator. Fingers crossed

Your offset is cool 👍

I would like to know if the position of VAS transistors would affect the response in anyways and where should they be placed

 

[oscargolf]

Du meinst Q5,Q6 ?

 

[oscargolf]

Small tip, for the offset !
Q3,Q4 hfe paired, I measured mine to 1% hfe.
It also makes sense to measure R6,R7.
The value doesn't matter much, but they should be approximately the same.

 

[Vunce]

Hi OSGO,

Do you have a vendor link or data sheet for the Canton capacitor used on your board? I'm not finding any info about them.
Thank you and Happy New Year to all!

 

[aditya]

Du meinst Q5,Q6 ?

Yes 👍

 

[oscargolf]

Hello Vunce,
here are the data of the Canton capacitor !
Manufacturer Arcotronics (now Kemet).
**** expensive but good.

Canton capacitor:
GENERAL TECHNICAL DATA:
Dielectric: polyester film (polyethylene terephthalate).
Plates: aluminium layer deposited by evaporation under vacuum.
Winding: non-inductive type.
Leads: tinned wire.
Protection: plastic case, thermosetting resin filled. Box material is solvent resistant and flame retardant according to UL94.
Marking: Manufacturer’s logo (if requested), capacitance, tolerance, D.C. rated voltage.
Climatic category: 55/105/56 IEC 60068-1 Operating temperature range: -55 to +105°C Upper operating temperature of +125°C is allow ed for a max.operating time of 1000h.
Related documents: IEC 60384-2
Arcotronics:


R60ER4560ZC00J = 5µ6-100DC/63AC V – 5% - RM27.5mm

 

[Vunce]

Thanks OSGO!
Looks like Canton Loudspeaker had these manufactured for their XO's.

 

[oscargolf]

Genau, stimmt....
Ich verwende sie nur in meinen Audioprojekten.