Using a cisco network device as the case! Excellent idea, I have some laying around but never thought of doing this.
I zoomed in on that part of the picture as well. Great stuff.
As top plate for one of my amps I used a 19" blind panel from HP. Nice thick, dark grey coated aluminium plate. No cool logo 'though.
Beautiful work, the rectifier could be 6CA4 or (European EZ81), the suffix 4 indicates four electrodes inside. This is a double rectifier for that reason has this number. 6CA7 is american equivalent to EL34.
Oops yes I typo'd it. The rectifier is a 6CA4
All DHT 845 SE
I have some 104D's.
Any problems with Microphonics with the 102D.
I have 100+Db speakers.
Phil
Hi Phil,
I'm coming back to you on this. I've just replaced my original set of 102d with premium matched ones. This new pair is acting differently to the first set. They are drawing more anode current, have higher gain and much more sensitive to vibration as a result. Tapping the chassis and the glass of one has the vibration passing to the speaker. Same setting as before, played even louder, does not provoke a microphonic reaction so not an issue in this case. (Some of my 76 on input duties do the same when tapped but are not excited by the speaker SPL, at my usual listening level, no more than 75db, 55-65db typical.)
Since the new set are 'Premium matched' as opposed to my first test mule pair which were cheap ebay 2nds (even if they don't advertise the fact!), I assume the behaviour of the latest pair is more typical.
tony said:
sad to say, this is a failed design, i can't find tubes that have sections that are equally matched,
and since the cathodes are common to both sections, they do not conduct equally so that
the resulting distortion is audible....i suppose i can tweak this by manipulating filament
voltage to get the transconductance equal on either side, but that will be too much hard work...
so i ditched the septar socket and put in an octal socket instead....
in came the 6AV5 horizontal output tube rated for 11 watts....but in this
amp it is running about 16 watts plate dissipation, 250volts plate at 60mA cathode,
does this ring a bell? yes, it does, it is the operating point for the 2A3....
the power factor of almost 90% and a power draw of about 80watts...
the power traffo is rated for 180VA, so that the power traffo will be
very cool to touch and will last a long long time....
the high power factor is indicative of a very good power supply...
for those interested to design their own SET,
this is how i sized the cathode bias resistor:
for triode mode, grid 1 bias is calculated as follows:
Vg = -(Vpx0.6)/mu
mu equals 4.5 and Vp is 250 volts,
so that Vg is 40volts,
looking for 60mA. Rk, the cathode resistor then becomes,
40/60 = 600ohms, this is achieved with a parallel combination of
1k and 1.5k 5 watt resistors, making for a 600 ohm 10 watt
cathode bias resistor....this resistor dissipates 2.4 watts
so that use of a 10 watt resistor is very much justified...
it would interest you to note the in the actual amplifier,
bias was at 39.5 volts, am i lucky or what? :tmi:
Hi. This is my first post here. I read this forum a long time, and now decided to write. So, I want to present you some of my DIY tube projects.
One of my first amps (~10 years ago):
SE A-class poweramp
Circuit based on SRPP and SE-output, but I don't used chokes. Fail. This amp has so high level of noises.
And pair of last projects:
Headamp (2011) with built-in DAC. Each part (digital, low- and high-voltage analog, heat) of amp has its own power supply (PCB with transformers).
Main concept is 6N23P (ECC88) + 2x 6N6P (7044) + transformer output. DAC based on AD1853+DIR9001.
PP-poweramp (2014). 6SL7 as input and phaseinvertor, 6SN7 as drivers, 5881 as output.
I used Hammond transformers for output and custom-made toroidal transformers + 2x 10H chokes + 2x 5U4G in power supply. Sound much better then Onkyo Integra A-927 that I used to compare.
Some pics of chasis:
It's steel with polymer paint (chasis) and TiN-coating (feet and plate)
I like Ongaku-style design so I tried to make it like Audio Note.
3D-model and result:
One of my first amps (~10 years ago):
SE A-class poweramp
Circuit based on SRPP and SE-output, but I don't used chokes. Fail. This amp has so high level of noises.
And pair of last projects:
Headamp (2011) with built-in DAC. Each part (digital, low- and high-voltage analog, heat) of amp has its own power supply (PCB with transformers).
Main concept is 6N23P (ECC88) + 2x 6N6P (7044) + transformer output. DAC based on AD1853+DIR9001.
PP-poweramp (2014). 6SL7 as input and phaseinvertor, 6SN7 as drivers, 5881 as output.
I used Hammond transformers for output and custom-made toroidal transformers + 2x 10H chokes + 2x 5U4G in power supply. Sound much better then Onkyo Integra A-927 that I used to compare.
Some pics of chasis:
It's steel with polymer paint (chasis) and TiN-coating (feet and plate)
I like Ongaku-style design so I tried to make it like Audio Note.
3D-model and result:
845 twins
Hello,
I decided to list the project I have been working on about one year.
Here they are my little baby-845 twins.
Regards,
Jarek, Poland
Hello,
I decided to list the project I have been working on about one year.
Here they are my little baby-845 twins.
Regards,
Jarek, Poland
Attachments
Hello,
I decided to list the project I have been working on about one year.
Here they are my little baby-845 twins.
Regards,
Jarek, Poland
Looks great!
I like the transformer end bells.
Member
Joined 2009
Paid Member
845 twins
Hello Ian,
Here you have. In my opinion OPT is the key to success in such a project...
Regards,
Jarek
Jarek,
Would you post the schematic for your 845 twins?
Please,
Ian
Hello Ian,
Here you have. In my opinion OPT is the key to success in such a project...
Regards,
Jarek
Attachments
Hi to All , this is my new amp , it's a hybrid one , the first gain stage consists of one PCC85 in LTP configuration followed by a second gain stage which is the triode section of the PCL86 and the pentode section ( of PCL86 ) is the cathode follower to drive the output stage which is a CFP ( compound output stage ) with transistors as drivers and mosfets as output devices .
And some technical characteristics :
Closed loop GAIN = 27dB
NFB = -17dB
POWER : 2 * 65W at 8Ω load
2 * 98W at 4Ω
Output impedance = 66mΩ
DAMPING FACTOR = 122 at 8Ω
HIGH FREQUENCY RESPONSE 260KHZ ( -3dB )
And some technical characteristics :
Closed loop GAIN = 27dB
NFB = -17dB
POWER : 2 * 65W at 8Ω load
2 * 98W at 4Ω
Output impedance = 66mΩ
DAMPING FACTOR = 122 at 8Ω
HIGH FREQUENCY RESPONSE 260KHZ ( -3dB )
Attachments
Hi Junm , thank you very much ! , you have pm .Very nice DIMITRIS...would you share the schematics?...I been looking for a hybrid schematics using a triode pentode tube as prestage....i got some 6F5p...
Thanks...
Hi Estaban , thanks for your comments , it is a very different design from moskido as I describe it before and it sounds detailed and very clean ,Nice Idea, is something than moskido? Could you send the schematics?
Best Regards M A L A K A
Regards ! , ciao PAPARA .
Hi Estaban , thanks for your comments , it is a very different design from moskido as I describe it before and it sounds detailed and very clean ,
Regards ! , ciao PAPARA .
Hello
Could you send the schematics please?
Greetings gabor
Hello guys ! , Dady , Jun and gabor and any one else who interested you can take a look here
http://www.diyaudio.com/forums/tubes-valves/238568-se-hybrid-amp-lunatic-one-3.html ,
soon I will post the schematic ! , best Regards .
http://www.diyaudio.com/forums/tubes-valves/238568-se-hybrid-amp-lunatic-one-3.html ,
soon I will post the schematic ! , best Regards .
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