Hi everyone
Thanks for the comments - much appreciated.
Poynton: I'm afraid I can't make the Chesterfield DIY meet, as it is my daughter's 22nd birthday on Saturday and I am unlikely to be in any fit state to do anything on Sunday.
The design for the amp sort of evolved into a 1950s retro design, quite by chance. My mother-in-law was having a clearout of her garage and among the stuff to be thrown in the dumpster I found a Ferguson console from 1956. The cabinet was shot to pieces, which was a shame as it had clearly once been of very high quality. I rescued the ivory coloured bakelite knobs, the valves, the dial glass and a few other bits and pieces but there wasn't much left of it after 35 years in the garage with the damp and the insects.
After some careful cleaning and a polish with metal polish wadding, the knobs came up good as new. It was then that the seeds of the design idea started to germinate and the amp you see came to life complete with those old knobs, Fender indicator jewel tapered legs etc.
Here is a close up of the controls with the forest of valves behind. I'll put some pics of the innards soon.
Steve
Thanks for the comments - much appreciated.
Poynton: I'm afraid I can't make the Chesterfield DIY meet, as it is my daughter's 22nd birthday on Saturday and I am unlikely to be in any fit state to do anything on Sunday.
The design for the amp sort of evolved into a 1950s retro design, quite by chance. My mother-in-law was having a clearout of her garage and among the stuff to be thrown in the dumpster I found a Ferguson console from 1956. The cabinet was shot to pieces, which was a shame as it had clearly once been of very high quality. I rescued the ivory coloured bakelite knobs, the valves, the dial glass and a few other bits and pieces but there wasn't much left of it after 35 years in the garage with the damp and the insects.
After some careful cleaning and a polish with metal polish wadding, the knobs came up good as new. It was then that the seeds of the design idea started to germinate and the amp you see came to life complete with those old knobs, Fender indicator jewel tapered legs etc.
Here is a close up of the controls with the forest of valves behind. I'll put some pics of the innards soon.
An externally hosted image should be here but it was not working when we last tested it.
Steve
Here is the progress so far on the works inside.
All the hardware has been mounted on the chassis apart from the heater, bias and preamp transformers. These need their looms prewiring and all their the tags double insulating before they are fastened in their final positions and the cover is fitted.
A few pics below.
It's those little details that count. Bakelite knobs had their red dots restored after the polishing session removed the paint. Red Fender jewel indicator light adds to the retro feel
Here's what the underside looks like with the pre/driver and output stage modules in place.
Here is the PSU detail before all the wiring and caps go in. Mains inlet, on/off switch and fuse holder are mounted next to the mains TX. The two pots to the right are the bias adjusters for each channel.
The two bridge rectifiers mounted on the heat sink will power the output stage and the heater supply for the amp. Heatsink vents through slots on the top plate. The indicator bulb will be powered from a spare 6.3V heater winding on the mains TX.
I can see the finish line approaching and I am getting a bit nervous.
Steve.
All the hardware has been mounted on the chassis apart from the heater, bias and preamp transformers. These need their looms prewiring and all their the tags double insulating before they are fastened in their final positions and the cover is fitted.
A few pics below.
An externally hosted image should be here but it was not working when we last tested it.
It's those little details that count. Bakelite knobs had their red dots restored after the polishing session removed the paint. Red Fender jewel indicator light adds to the retro feel
An externally hosted image should be here but it was not working when we last tested it.
Here's what the underside looks like with the pre/driver and output stage modules in place.
An externally hosted image should be here but it was not working when we last tested it.
Here is the PSU detail before all the wiring and caps go in. Mains inlet, on/off switch and fuse holder are mounted next to the mains TX. The two pots to the right are the bias adjusters for each channel.
The two bridge rectifiers mounted on the heat sink will power the output stage and the heater supply for the amp. Heatsink vents through slots on the top plate. The indicator bulb will be powered from a spare 6.3V heater winding on the mains TX.
I can see the finish line approaching and I am getting a bit nervous.
Steve.
So not finish with power suply oly , the heater total how many A?, Im think power tranfomer for heater verry inpostan with OTL ampli, so you think to do with AC and DC, and have regulator for it ?
if B+ change AC>DC with Diot the soud verry fast same SS and use Classic music, and pop, rock verry good, if use tube valve for DC = B+, Im think better with Jazz, and voical music.
So all your choice follow your music love.!
Im think you happiness with your way DIY.
When to finish, pleaser send photo more !
if B+ change AC>DC with Diot the soud verry fast same SS and use Classic music, and pop, rock verry good, if use tube valve for DC = B+, Im think better with Jazz, and voical music.
So all your choice follow your music love.!
Im think you happiness with your way DIY.
When to finish, pleaser send photo more !
Guijs said:
Hi everybody,
just here to show how actually ended up the project.
Don' t ask me about eletronic stuff employed cause I' m just a final consumer
. Chassis are inox and the wooden part is Jatobá, while connectors and binding-post are top of Vampire.
It just sounds great and that' s all I can say
I did a PCB for the Firefly guitar amp (see: http://www.ax84.com for lots of discussion on the Firefly).
The amp is a small three tube guitar amp. Great sounding. Here is the chassis:
Here is the PCB before wiring external components (transformers, etc.) and installation in a chassis:
You can read more about the PCB here: http://web.mac.com/calhoun/iWeb/PCB/Firefly PCB.html
I may make the PCB "open source" so to speak (in case others want to modify it and make their own PCB's).
John Calhoun
The amp is a small three tube guitar amp. Great sounding. Here is the chassis:
An externally hosted image should be here but it was not working when we last tested it.
Here is the PCB before wiring external components (transformers, etc.) and installation in a chassis:
An externally hosted image should be here but it was not working when we last tested it.
You can read more about the PCB here: http://web.mac.com/calhoun/iWeb/PCB/Firefly PCB.html
I may make the PCB "open source" so to speak (in case others want to modify it and make their own PCB's).
John Calhoun
My GM70 SET project
This is the pthotos of my monoblock GM70 SET amp project. Named by NoyMark. Sound is fantastic.
http://img158.imageshack.us/my.php?image=dsc08345bz4.jpg
http://img158.imageshack.us/my.php?image=alooooe4.jpg
This is the pthotos of my monoblock GM70 SET amp project. Named by NoyMark. Sound is fantastic.
http://img158.imageshack.us/my.php?image=dsc08345bz4.jpg
http://img158.imageshack.us/my.php?image=alooooe4.jpg
![otl50w1 [640x480].jpg](/community/data/attachments/86/86776-65742adb18dd481355ca9a742a1b4b0e.jpg)
![otl50wpl1 [640x480].jpg](/community/data/attachments/86/86780-9ce8483192ea8765014c147499d26c09.jpg)
Re: artQuake preamplifier
Hi Artquake !
So your Preampli look good, Please tell me how to do with Balance in put, and out put, you have shema for it and all preampli ? because when see it Im think you do same group cable with cold and shield, keep only hot from RCA and out put you do the same in put ? So not use opam, of transfome ?
Please tell me , How the soud XLR with this preamp ?
Thank you !
artquake said:
Hi Artquake !
So your Preampli look good, Please tell me how to do with Balance in put, and out put, you have shema for it and all preampli ? because when see it Im think you do same group cable with cold and shield, keep only hot from RCA and out put you do the same in put ? So not use opam, of transfome ?
Please tell me , How the soud XLR with this preamp ?
Thank you !
GM70 monoblock tube amp
The advantages of my design;
1-Imput(6c45p), Driver(Svetlana 6c4c), Output(gm70) all tubes are triode. Driver and output tubes are working with fixed bias for dynamic sound. This means that, cathode electrolytic caps not used.
2-No any coupling caps used in this amp. Input and driver tube directly connected to each other. Driver tube connected to gm70 by using an interstage transformer.
3-Each tube heaters and anode supplies are independed. Also, all voltages regulated with integrated circuits. Including gm70 anode and heater supply. No choke transformer used. No any audible hum exist even with 96db Tannoys.
4-Power supply transformer is toroidal.
5-Interstage and Output transformers are double C core and laminated with 0,05mm thickness for ultimate sound.
When comparing the sound with Tenor OTL 75watts, my amplifier's sound is better.
http://img379.imageshack.us/my.php?image=tenot75wotliletestfd0.jpg
http://img248.imageshack.us/my.php?image=noymarkfiguruzimparalanol4.jpg
http://img248.imageshack.us/my.php?image=miliampermetrezr5.jpg
http://img248.imageshack.us/my.php?image=arkagorunusns6.jpg
http://img379.imageshack.us/my.php?image=anfialttangorunusuyz1.jpg
The advantages of my design;
1-Imput(6c45p), Driver(Svetlana 6c4c), Output(gm70) all tubes are triode. Driver and output tubes are working with fixed bias for dynamic sound. This means that, cathode electrolytic caps not used.
2-No any coupling caps used in this amp. Input and driver tube directly connected to each other. Driver tube connected to gm70 by using an interstage transformer.
3-Each tube heaters and anode supplies are independed. Also, all voltages regulated with integrated circuits. Including gm70 anode and heater supply. No choke transformer used. No any audible hum exist even with 96db Tannoys.
4-Power supply transformer is toroidal.
5-Interstage and Output transformers are double C core and laminated with 0,05mm thickness for ultimate sound.
When comparing the sound with Tenor OTL 75watts, my amplifier's sound is better.
http://img379.imageshack.us/my.php?image=tenot75wotliletestfd0.jpg
http://img248.imageshack.us/my.php?image=noymarkfiguruzimparalanol4.jpg
http://img248.imageshack.us/my.php?image=miliampermetrezr5.jpg
http://img248.imageshack.us/my.php?image=arkagorunusns6.jpg
http://img379.imageshack.us/my.php?image=anfialttangorunusuyz1.jpg
Re: Re: artQuake preamplifier
Hi HDaudio,
Youre right, the XLR-Connectors ar conected like the RCA ones at the moment. But the the Input selector board and volumecontrol-
boards are consisting as balanced. So my next project will be
to make the Input up to the tube balanced, and from the tube output to balanced out. I think on using a National LME49720 .
The link to the schematics you can find between the pictures ...
Best regards
artQuake
HDaudio said:
Hi Artquake !
So your Preampli look good, Please tell me how to do with Balance in put, and out put, you have shema for it and all preampli ? because when see it Im think you do same group cable with cold and shield, keep only hot from RCA and out put you do the same in put ? So not use opam, of transfome ?
Please tell me , How the soud XLR with this preamp ?
Thank you !
Hi HDaudio,
Youre right, the XLR-Connectors ar conected like the RCA ones at the moment. But the the Input selector board and volumecontrol-
boards are consisting as balanced. So my next project will be
to make the Input up to the tube balanced, and from the tube output to balanced out. I think on using a National LME49720 .
The link to the schematics you can find between the pictures ...
Best regards
artQuake
In due to the fact that my signal-cables have a lenght of max. 0.8 m there is no need at the moment to use balanced in/out. On the other hand i do not have any humm on my speakers, so my Preamp layout is well done. I am very happy with the sonic quality of my Preamp/Amp/Speaker - System.
If someone wants to add Balanced in/out to a Pre-Amp it needs really to have a reason to do so.
To your schematics i looked very short .... 250 Volts is to much for a 6H30. You do not have 4 Tubes you have only 2 Tubes in your schematic. A 6H30 is a double Triode.
THIS Schematic of an SRPP Preamp has also only 2 6H30, and i recommend to rebuild it.
Try to open a new thread for your project. IMHO this is the wrong one, to get the answers you wish.
artQuake
If someone wants to add Balanced in/out to a Pre-Amp it needs really to have a reason to do so.
To your schematics i looked very short .... 250 Volts is to much for a 6H30. You do not have 4 Tubes you have only 2 Tubes in your schematic. A 6H30 is a double Triode.
THIS Schematic of an SRPP Preamp has also only 2 6H30, and i recommend to rebuild it.
Try to open a new thread for your project. IMHO this is the wrong one, to get the answers you wish.
artQuake