Please see post#480 on main circlophone thread. Going through entire thread may be time consuming
, but a good practice and also give you additional information needed to build and troubleshoot if necessary. Make use of 'Search this thread' option also.
Cheers !
Only 2N3019 were from CDIL, I procured it from a local shop here in Bangalore (Vishal electronics, SP Road). You can get ST 2n3019 frm diyaudiocart.com but it's very expensive at 250+rs.
Drivers :You can buy philips nxp Bd140 from DIYAudiocart or 8 audio OR rs components.
Outputs : TIP 35C from RS components OR MJL21194 from 8 audio.
I have used ksa1845 for Q12 and Q13 bought from 8audio.
Bc556b for inputs and other Qs. Procured from DIYAudiocart.
Try to Consolidate all your order with one vendor so that you will save on shipping cost.
Dear Katiyar,
Please see DAC - Elvee's Circlophone - Power Amplifier . diyaudiocart sells PCBs, Parts and assembled boards for Circlophone !
--gannaji
Please see DAC - Elvee's Circlophone - Power Amplifier . diyaudiocart sells PCBs, Parts and assembled boards for Circlophone !
--gannaji
Mr Elvee,
Can I use MBR 745 Schottky diode from Taiwan Semiconductor in the circuit. It has a same forward voltage drop as MBR735 (0.57 to 0.72V). Also for higher voltage version can I use KSA1220A in place of BD140. Original grey colour BD140 is now impossible to get here in India so can I use Original ST make BD140 as driver for lower volrage version of Circlophone. For VAS I am planning to use BF869 with 3.9pf capacitor between C&B. I shall be thankful for your valuable advice. Katiyar
Can I use MBR 745 Schottky diode from Taiwan Semiconductor in the circuit. It has a same forward voltage drop as MBR735 (0.57 to 0.72V). Also for higher voltage version can I use KSA1220A in place of BD140. Original grey colour BD140 is now impossible to get here in India so can I use Original ST make BD140 as driver for lower volrage version of Circlophone. For VAS I am planning to use BF869 with 3.9pf capacitor between C&B. I shall be thankful for your valuable advice. Katiyar
Certainly: the 745 has a higher Vr, which will be wasted here but will do no harm.
In addition, the manufacturing process for MBR7xx series has probably reached its maturity a long time ago, meaning that the only difference is in the marking, driven by market demand.
The 1220A is OK, and you might need to care about the wiring, and possibly add a ferrite bead in the emitter or base, because the Ft is somewhat higher than the original BD140, which could lead to local instabilities.
The ST BD140's might have the opposite problem: in my experience, these ST versions tend to have worse HF performance than the Philips originals, and this could cause poor HF performance: slew-rate and bandwidth mainly, perhaps instabilities too if used in conjunction with high speed OP devices.
This should be checked in reality, and if problems occur, you can simply switch to the 1220A for all versions, which should simplify your orders.
It should be OK, but it depends on many factors, including the speed of other devices.
If instabilities appear for a particular configuration, they can always be cured by increasing (slightly!) the C-B cap
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I have tried to modify Circlophone PCB layout file downloaded from this thread to accommodate the following;
1. To accommodate TO-3 Transistors in out put stage.
2. To accommodate 470pF capacitor C2 between B&C of Transistor Q7
3. To accommodate old TO-126 video transistors e.g. BF469 etc in VAS.
4. To accommodate small capacitaor between C&B of VAS transistors in case Cob is less than 6pF.
4. To accommodate KSC1845 /2sc1845 Transistors Q12 & Q13.
There could still be mistakes in this layout. If any one can debug the same it would be beneficial for the DIY community.
Thanks
1. To accommodate TO-3 Transistors in out put stage.
2. To accommodate 470pF capacitor C2 between B&C of Transistor Q7
3. To accommodate old TO-126 video transistors e.g. BF469 etc in VAS.
4. To accommodate small capacitaor between C&B of VAS transistors in case Cob is less than 6pF.
4. To accommodate KSC1845 /2sc1845 Transistors Q12 & Q13.
There could still be mistakes in this layout. If any one can debug the same it would be beneficial for the DIY community.
Thanks
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I have assembled the circlophone this Evening,I used project 16's layout. I will upload a photo in due course. It's a 18 volt version, using 2n3501 for vas .All other components as per original schema..Having built/ listened to a number of amps, The one that I most liked was the JLH 69, but sadly can't run it for al time, for thermal and efficiency issues... Then came across the circlophone... The moment it was powered up, the sonically superiority was obvious.. There was no harsh or metallic sibilance, even in average recordings. As someone reviewed exactly, It gives more detailed and dynamic sound even in regular and familiar tracks... I am not an engineer by profession,Hence I never understand specs,But what I always consider is the way I perceive music...Elvee Circlophone did one thing which no other amplifier did,( except JLH69).. That is ,1. you tend to listen to tracks that you normally skip.. 2. You tend to forget that you are listening to your home setup, and you feel like you are in concert hall like liveliness..3.. Most importantly,For the first time ,Music conveyed emotion.You Hear a song,and you will instantly recognise the mood that the song delivers... I don't know if it's psychoacoustics or harmonic profile etc etc,. It just plays music,the way it's supposed to be.. Elvee, I should say, you have set a new benchmark for upcoming amp designs,in terms of musicality....All the magical musicality that the JLH 69 delivered,is now easily available at a higher efficiency.If this is what Mr.Elvee,the designer intended to gift to the diy community, Then I Should say, Mr. Elvee,What you have given to us is not just an amplifier, But an anti depressant,. a. lifetime friend, and a beautiful gift,That is going to Keep your name etched in our memories forever.. This is the most detailed and long review,I have ever done,because,The Designer deserves a standing ovation...Thanks forever for a great amplifier,Mr.Elvee..
The 2SC5200 could be make to work (and members have used successfully), but it is fast (Ft=30MHz), which is going to be mostly wasted, and will make the layout and choice of other components trickier.
They are not really high power either: with a pair, you could push it to ~70W output at most.
In principle, you could parallel a number of pairs, but this will require matching and additional emitter resistors, which is not my preferred solution.
A better alternative is to use very high power devices, like 250~350W.
Their Ft will be <10MHz, which will simplify matters
Thanks for the appraisal: when I designed the C, my goal was to attain class-A-like performance with class-B-like economy and efficiency, together with the ease and convenience of a chip-amp: no matching or adjustment required.
I also wanted to make it accessible to anybody, even if their component sources are limited and of poor quality.
The result of this design work was this ugly little duckling: the Circlophone.
Aesthetically, its topology is rather messy, not pleasing, and for this reason, I had initially decided not to publish it, but after some weeks of extensive tests and abuse, I changed my mind: it was so pleasant, so gallant and well-behaved that I had to offer it, regardless of its somewhat crooked appearance.
I am from Chennai, and I got authentic BEL 2N3501, Presumably NOS.. from a shop in Ritchie street.It was our Linuxguru, who came with me and searched for all the components..Those transistors had the gold plated pins and it looked really premium..I plan to stock the remaining 2N3501, I will be glad to ship you a pair when I got the stock..
Mr.Elvee,
1.What's the min input sensitivity of the circlophone ? I connect the inputs directly to a Ruizu MP3 player...,in order to avoid the usage of A volume pot ...So, in order to get specified output power, what's the input sensitivity required?
2.. Can I replace the C10(4.7 MFD,polar) into 3.3 or 1 MFD Nonpolar film type capacitor?
1.What's the min input sensitivity of the circlophone ? I connect the inputs directly to a Ruizu MP3 player...,in order to avoid the usage of A volume pot ...So, in order to get specified output power, what's the input sensitivity required?
2.. Can I replace the C10(4.7 MFD,polar) into 3.3 or 1 MFD Nonpolar film type capacitor?
In the original Circlo, R16 and R17 determine the gain: ~22x.
Combine this with the PSU voltages, +/-25V, allow a bit of headroom before clipping and this gives you 1V peak input voltage max., or 0.7Vrms.
Of course, this estimation is only valid for the fore-mentioned assumptions: you are free to chose the supply voltages and gain, and the end result could be widely different.
I have no idea about the actual output level of the Ruizou or the supplies of your build...
That said, I am not certain that dispensing completely with a hardware volume control is a good idea, especially with interconnected devices (a completely stable, integrated hardwired system would be another story): you could have unpleasant surprises.
A reasonable tradeoff would be a circlo gain of about twice the theoretical value required, and an adjustable volume pot you adjust once and for all (and each time you need a firmware update)
Sure, you can always use a non-polar instead of a polar one, but if you use 1µF, you might lose some bass
No problem at all, they are good for 100V rails if they need to....