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[fotios]

Originally Posted by donnyab

Fotios, very nice amp.
where did you source the transformers ?
did you build the chassis yourself, where did you source construction materials ?
tnx

Thanks a lot donny. Transformers and choke are made in Greece, custom ordered in a top workshop: ? ??????? ?. ?. ?????????? & ??? ?? (ask VANGELIS)
Chassis is designed by me with Auto-Cad and then ordered again in a Greek workshop: almek.gr - ?????? (ask DIMITRIS)
Here pictures of transformers, from left to the right:
1) 10H/0.31A Choke 2) 400VA mains transformer with "Belly Band" and 3) M6 core/100Watt output transformer. I ordered in the mains transformer multiple secondary taps for the B+ of output tubes. It is obvious on the picture (400V-420V-440V-460V X 2). It offers the posibility to try different tubes from the currently used 300B/c in the future.
I did enough work on chassis by myself (drilling holes, mounting of support plates and angles etc) but i received all main pieces ready as is shown in a previous picture. All are made from black anodized aluminum.

[PGDO]

Very nice Fotis, if you do have to cover those tubes than this is the way to go. Did you design and make the PCB's yourself?

Regards,
Peter

[fotios]

Originally Posted by PGDO

Very nice Fotis, if you do have to cover those tubes than this is the way to go. Did you design and make the PCB's yourself?

Regards,
Peter

Thanks Peter, you really have a sharp view!
Indeed PCBs are designed and constructed by myself in home. I use exclusively BUNGARD FR4 presensitized PCBs (their photoresist coating is the most smooth from all brands i've tried so far, it is also very durable and non sensitive in small mistakes during processing either over-exposure in UV or too hard developement solution), ink-jet transparencies for artworks, UV light exposure, caustic soda developement solution and HCl acid solution + Perydrol for copper etching.
Here some pictures e.g. of the double sided main amplifier PCB processing:
1) The PCB is etched, drilled and all tracks are tinned with a thick layer of WBT silver solder wire. 2) The PCB from solder side 3) and 4) The PCB firstly is sprayed with green protective laquer and after this solder lugs, collar sleeves (used as spacers) and stampets are soldered on it. All are from silver plated copper, brand ETTINGER. 5) Finally, all parts (except tube bases) are soldered on PCB

[PGDO]

Again wow, nicely done those PCB's, only thing missing now are the schematics.

I will hopefully be posting my own amp pictures sometime this year. Only got one mono block playing so far, my first amp (300B SE) and it won't be anywhere as clean a build as yours, no PCB's, point to point wiring with star ground.

Cheers,
Peter

[fotios]

In the next posts i will show the internal circuits of amplifier.
Filaments and heaters of all tubes are supplied with DC stabilized voltages provided from the PCB shown in the picture. Three separate circuits are used, two of 5V/3A for the filaments of the two 300B and one (in the left side) of 6.3V/3A for the heaters of EF86 and 5687. All rectifiers are ON-SEMI schottky type, capacitors are PANASONIC FM rated at 105C and parallel connected for lower ESR, voltage stabilizers are two NATIONAL LM1084-5V and one LM1084-Adj (for 6.3V), resistors are VISHAY-SFERNICE metal film 1% 0.6W and heatshinks are FISCHER. The 9Vac input voltages are provided from 3 separate secondary windings of power transformer

[fotios]

Originally Posted by PGDO

Again wow, nicely done those PCB's, only thing missing now are the schematics.

I will hopefully be posting my own amp pictures sometime this year. Only got one mono block playing so far, my first amp (300B SE) and it won't be anywhere as clean a build as yours, no PCB's, point to point wiring with star ground.

Cheers,
Peter

Thanks again Peter. IMHO, nothing wrong with PCBs, nothing wrong with point to point wiring. The only needed is great care in the arrangement of wires regarding p2p wiring, and great care in the drawing of tracks on PCB. In my case, i sincerelly was newbie in Hi-End tube amplifiers and so i selected the... most complex circuit i found! DC supply for heaters/filaments and the extra 5687 tube that used as driver for the output 300B's and needs separate power supply, add an amazing complexity in the project . So the use of PCBs (i really hate their construction, is a dirty and enervating work) offers some... relief. BTW we had in mind - like you - the use of 300B SE (special edition) which is also equiped with solid carbon plate and the matched pair is considered from the top 300B's. I have read 2-3 reviews about these tubes of TJ, but our budget would be... launched due to the 700$ cost of 300B-SE. So we decided to... stay at the 435$ cost of 300B/c matched pair to the present. Moreover (according to the reviewer opinion) their sound is very close to this of 300B-SE.
Wishes to finish your amplifiers with success and as soon as posible

[nedi]

Picture of my new DAC unit.

[mhouston]

fotios: I have a 300B amp using the TJ Full Music 300B\SE carbon plates. I realised this maybe just a small step-up from your TJs but you won't be disappointed. These tubes produce absolutely beautiful music with no bad habits. I have a spare set too, just in case one fails.

I used a 6SN7 Shuguang 50 years treasure for the driver tube. The parts alone for my amp cots $AU3,500. One of the reasons is 30W Hammond OPTs, Audio Note pure silver inter-stage caps now costing $US340 each and all Mudorf polypropylene M-Caps for PS filtering. The amp is called the Silver Dragon

I would be interested to know what you think of the sound of your amp.

[popilin]

Originally Posted by fotios

Thanks Peter, you really have a sharp view!
Indeed PCBs are designed and constructed by myself in home. I use exclusively BUNGARD FR4 presensitized PCBs (their photoresist coating is the most smooth from all brands i've tried so far, it is also very durable and non sensitive in small mistakes during processing either over-exposure in UV or too hard developement solution), ink-jet transparencies for artworks, UV light exposure, caustic soda developement solution and HCl acid solution + Perydrol for copper etching.
Here some pictures e.g. of the double sided main amplifier PCB processing:
1) The PCB is etched, drilled and all tracks are tinned with a thick layer of WBT silver solder wire. 2) The PCB from solder side 3) and 4) The PCB firstly is sprayed with green protective laquer and after this solder lugs, collar sleeves (used as spacers) and stampets are soldered on it. All are from silver plated copper, brand ETTINGER. 5) Finally, all parts (except tube bases) are soldered on PCB

Very nice work !
A professional work of art, congratulations !

I also make my own PCBs, epoxy-glass sensitized with Positiv 20, and positive photographic. Tell me more about the green mask, please.

[fotios]

Originally Posted by mhouston

fotios: I have a 300B amp using the TJ Full Music 300B\SE carbon plates. I realised this maybe just a small step-up from your TJs but you won't be disappointed. These tubes produce absolutely beautiful music with no bad habits. I have a spare set too, just in case one fails.

I used a 6SN7 Shuguang 50 years treasure for the driver tube. The parts alone for my amp cots $AU3,500. One of the reasons is 30W Hammond OPTs, Audio Note pure silver inter-stage caps now costing $US340 each and all Mudorf polypropylene M-Caps for PS filtering. The amp is called the Silver Dragon

I would be interested to know what you think of the sound of your amp.

Thanks mhouston for comments, i really appreciate very much. Your amplifier is very nice and i am sure that its sound is amazing!
Regarding the sound of my amplifiers... is a true vintage sound. With simple words, it is like the sound of a Chevy Camaro V8 or a Lamborghini V12 compared to the sound of a... turbo sport Nissan or Mitsubishi .
BTW i have a... crazy idea: to build a SET with... four 300B's in... V4 arrangement. I will need a 1.2KVA power transformer to feed the tubes and a... special M6 core/400W output transformer. So i will get: 4X10W= 40Wrms of pure single ended, no feedback, true class A vintage sound .
Yeah... that would be a real "muscle" tube amplifier. Like the old muscle American cars.