hello, my last amp sound really very nice, its a GM70pp driven by VT25/10Y by Sowter 8424S.
input sennheiser transformer for 6E6P-E and 1rst IT Hammond 126B.
power supply two transformers series 600+500V for 1100VAC
bridge four 5R4WGB, PIO capacitors, hammond 193Q for both channels
then 193M and professional capacitors for each channel
similar way for drivers +B, separate choke cap for each channel.
mounted on tree floor chassis, main HT power supply , filament power supply and HT1 and HT2 filter and amplifier on top.
the last capacitor for HT i moove to near output transformers.
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https://drive.google.com/open?id=0B-0tOlvfRP7sUW9naS01dzZydWM
input sennheiser transformer for 6E6P-E and 1rst IT Hammond 126B.
power supply two transformers series 600+500V for 1100VAC
bridge four 5R4WGB, PIO capacitors, hammond 193Q for both channels
then 193M and professional capacitors for each channel
similar way for drivers +B, separate choke cap for each channel.
mounted on tree floor chassis, main HT power supply , filament power supply and HT1 and HT2 filter and amplifier on top.
the last capacitor for HT i moove to near output transformers.
https://drive.google.com/open?id=0B-0tOlvfRP7sUW9naS01dzZydWM
Attachments
Good afternoon from Greece! Your amplifier is perfect,very beautiful beast! I like more the chassis! Brilliant idea to use dexion as chassis! Please give us more details,like power out,distortion etc.
Hi Claudio,
What a great beast! It reminds me to my 46/814 SE Class A2 amp, 100% DHT. A beast as well, but rather smaller.
If I can make a couple of suggestions:
1. 6e6p is a great driver, try LED or SiC bias. It sounds much better in my experience
2. Go with proper DC (e.g. rod coleman regulators) for the DHT. You will notice a significant improvement in sound. It's worth the extra effort, however you will have to modify your filament supplies.
Any chance of taking some measurements on the amp performance?
Cheers
Ale
What a great beast! It reminds me to my 46/814 SE Class A2 amp, 100% DHT. A beast as well, but rather smaller.
If I can make a couple of suggestions:
1. 6e6p is a great driver, try LED or SiC bias. It sounds much better in my experience
2. Go with proper DC (e.g. rod coleman regulators) for the DHT. You will notice a significant improvement in sound. It's worth the extra effort, however you will have to modify your filament supplies.
Any chance of taking some measurements on the amp performance?
Cheers
Ale
with dummy load 8 ohm and signal generator , bias 75mA each GM70 +B 960V output its
2X24Vrms, the +B fall to 870V same test 27Vrms only one channel
by external +B 1KV from other amp i get 30Vrms.
full power can be obtained by adding capacitors afther the first 10H500mA choke, there its only 6 capacitors 10uF1Kv and on 5R4WGBA bridge two 1.2uF 2K4V, but i like the sweet and powerfull low end i get by this way.
linearity its excellent from 27Hz to 35Khz.
2X24Vrms, the +B fall to 870V same test 27Vrms only one channel
by external +B 1KV from other amp i get 30Vrms.
full power can be obtained by adding capacitors afther the first 10H500mA choke, there its only 6 capacitors 10uF1Kv and on 5R4WGBA bridge two 1.2uF 2K4V, but i like the sweet and powerfull low end i get by this way.
linearity its excellent from 27Hz to 35Khz.
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Thanks for posting that. The vertical design looks good for a small footprint. Would you tell us what the shelf system is?
find in "leroy merlin " in France, made by AR Shelving :Metal con tornillos
the screw one 30X60cm you can solder wire on chassis
upgraded power supply to 1200VAC to get full power 29Vrms/8ohm
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they are triode but different category, 2A3 its very nice tube need only 2.5V 2.5A heater,low rp, easy good output transformer, but few watts, 300B need 5V 1.2A otherwise similar to 2A3, 845 its bigger triode similar to GM70 but less powerfull, need 10V3A NOS tube are out of stock , GM70 available NOS very cheap but need 20V3A , so this its the only problem, 60watts of heater, and very well filtered DC please.
i took away the 150uF (3X470/450V series)becose the 5R4 bridge do not like it flash at start up sometime and really sound very nice with only 6 parallel 10uF1kV oil capacitor
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Disregard my question, I thought you are getting 2x200W RMS. I am getting 24W from a GK-71 SE. from 18 Hz full power.
i made my amplifiers for the sound not the power, the speacker fostex FE208 back loaded horn, need only 15watts, i made also tree GM70 SE and GEC KT88 multipair 120watts
the last SE and this one without capacitor in the signal path ,caps only for power supply and cathode bias, the Sowter IT its really very good, very linear ,
the last SE and this one without capacitor in the signal path ,caps only for power supply and cathode bias, the Sowter IT its really very good, very linear ,
I am redesigning my Gubernator-71 SE, for 30WPC now. I like pentodes more, they are more flexible than triodes. However triodes are good also. What is better in GM-70, no plate caps with HV.
https://www.facebook.com/Wavebourn/...heater¬if_t=like¬if_id=1470606221513780
https://www.facebook.com/Wavebourn/...heater¬if_t=like¬if_id=1470606221513780
I am not usually a fan of SE amps, but I have listened to some of your videos of your Gubernator-71 and I must say, I think it is fantastic. I'm too chicken with very high voltage to try to build something like that.
Wait for my new project, a "Sparrowflock". ;-)
There will be 22 of 6P1P tubes, no more than 35pV of B+
There will be 22 of 6P1P tubes, no more than 35pV of B+
How are you connecting the top plate for the Gubernator-71?
I like your cage idea. How hot does it get?
Here is a link to my version of a GK71 SE amp. It's more of a think piece to try out some different ideas.
Audio ratbag: The heart attack special - 6S17K-V powerdrive GK71 SE amplifier
Mine is running in triode mode now but I may change that eventually.
ray
I like your cage idea. How hot does it get?
Here is a link to my version of a GK71 SE amp. It's more of a think piece to try out some different ideas.
Audio ratbag: The heart attack special - 6S17K-V powerdrive GK71 SE amplifier
Mine is running in triode mode now but I may change that eventually.
ray
The cage does not get hot. Anodes radiate horizontally, almost all heat goes on reflecting stainless steel mirror. Top plate connectors I took from some socket from hot swap PS socket from Sun server, covering by several layers of heat shrink tubing. I run them as pentodes, with local feedback by voltage.
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