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Tube Amplifier and Tube pre-Amplifier Builds
- Thread starter radium7
- Start date
New 35 + 35 Watts Dual Mono Tube Amplifier using EL34 tubes. EF86 + ECC81 + 5U4G are other tubes in the amplifier.
Cabinet and Transformers are custom build locally. Dale, Allen Bradley, Amtrans carbon film, Ohmite AG series resistors and Elna cerafine, Vishay, Solen, Mallory 150M capacitors are used. Gold plated connectors.
Cabinet and Transformers are custom build locally. Dale, Allen Bradley, Amtrans carbon film, Ohmite AG series resistors and Elna cerafine, Vishay, Solen, Mallory 150M capacitors are used. Gold plated connectors.
EL34 Parallel Push Pull Monoblocks based on Mullard 520 design.
My Tube Guru used this design in Theatre amplifiers operated in ultra linear mode just like original circuit and for home listening as triode mode.
I modified it to operate in both ultra - linear and triode mode.
Output transformers are from Lundahl, Power and Filament Transformers are custom made locally.
Resistors: Kiwame, Takman, Mills, Halco.
Capacitors: Mundrof, Jupiter Cu Wax caps, Audionote Kaisei.
Connectors: RCA- Cardas, Binding post - WBT,
IEC - Furutech,
Tube sockets - Teflon,
Solid state rectifiers,
Hook up wires - Neotech, Signal - Cardas.
My Tube Guru used this design in Theatre amplifiers operated in ultra linear mode just like original circuit and for home listening as triode mode.
I modified it to operate in both ultra - linear and triode mode.
Output transformers are from Lundahl, Power and Filament Transformers are custom made locally.
Resistors: Kiwame, Takman, Mills, Halco.
Capacitors: Mundrof, Jupiter Cu Wax caps, Audionote Kaisei.
Connectors: RCA- Cardas, Binding post - WBT,
IEC - Furutech,
Tube sockets - Teflon,
Solid state rectifiers,
Hook up wires - Neotech, Signal - Cardas.
Attachments
Great ......
I wondering,How does a mechanical engineer get into this field? ur products are very neatly and beautifully created. well done.
In the early eighties ,when i was a student in Karaikudi Alagappa Polytec , we enjoyed tube amp in a Tea shop named Indian Tea Stall.
I didn't see the Tube Amps after that. One of my collegemate is a great admirer of Tube Amps and we had tried some Tube Amp projects in our college days.
You take me back to my college days... Thanks Professor
I wondering,How does a mechanical engineer get into this field? ur products are very neatly and beautifully created. well done.
In the early eighties ,when i was a student in Karaikudi Alagappa Polytec , we enjoyed tube amp in a Tea shop named Indian Tea Stall.
I didn't see the Tube Amps after that. One of my collegemate is a great admirer of Tube Amps and we had tried some Tube Amp projects in our college days.
You take me back to my college days... Thanks Professor
Hi Radium 7:
You have made one consistent lay-out mistake .............in both amplifiers.
You really should fix it before you consider either amplifier to be completed properly.
I have discussed what follows here twice, in the last few years on HFV.
( 1 ) : You never place the input wiring, starting from the amp's incoming RCA jack, anywhere nearby other wiring with larger fields radiating in close proximity.
( Specifically, the OUTPUT / Speaker wiring's fields, in both layouts, sadly conflict with the lowest signal level - RCA jack - INPUT wiring .)
( 2 ) : You never position the RCA jack onto the chassis such that that wire length / distance from the RCA jack, to the grid of the first ( INPUT ) tube's G1 Control Pin, exceeds 2.5 inches in length. You want to do this to ideally obtain the short signal path.
Better audio performance ........ occurs .......for free. In both cases.
Does this make sense to everyone ? I hope so. Do I need to spell out the reasoning ?? One must "Think" when laying amps out with a new, from-scratch, build !
I liked many other things, pretty much,- - - all else. Fix each of the INPUT wire paths, entry positions and lengths. All else, earned a solid "B++" IMHO. Good job.
Jeff
You have made one consistent lay-out mistake .............in both amplifiers.
You really should fix it before you consider either amplifier to be completed properly.
I have discussed what follows here twice, in the last few years on HFV.
( 1 ) : You never place the input wiring, starting from the amp's incoming RCA jack, anywhere nearby other wiring with larger fields radiating in close proximity.
( Specifically, the OUTPUT / Speaker wiring's fields, in both layouts, sadly conflict with the lowest signal level - RCA jack - INPUT wiring .)
( 2 ) : You never position the RCA jack onto the chassis such that that wire length / distance from the RCA jack, to the grid of the first ( INPUT ) tube's G1 Control Pin, exceeds 2.5 inches in length. You want to do this to ideally obtain the short signal path.
Better audio performance ........ occurs .......for free. In both cases.
Does this make sense to everyone ? I hope so. Do I need to spell out the reasoning ?? One must "Think" when laying amps out with a new, from-scratch, build !
I liked many other things, pretty much,- - - all else. Fix each of the INPUT wire paths, entry positions and lengths. All else, earned a solid "B++" IMHO. Good job.
Jeff
Last edited:
RtoR King
Active Member
Radium 7:
Your build is coming along just fine. Specifically the input jacks. I see they are floating ground and using shielded cable to the input stage. That's all you need. Tens of millions of tube and SS amplifiers have been built with the RCA jacks on the rear panel, even mag phono inputs, without any problems.
What DrLowMu does not seem to understand is that the input impedance of the amplifier is most often swamped by the output impedance of the source device. Especially if that source is solid state.
Your build is coming along just fine. Specifically the input jacks. I see they are floating ground and using shielded cable to the input stage. That's all you need. Tens of millions of tube and SS amplifiers have been built with the RCA jacks on the rear panel, even mag phono inputs, without any problems.
What DrLowMu does not seem to understand is that the input impedance of the amplifier is most often swamped by the output impedance of the source device. Especially if that source is solid state.
Sorry for the delayed reply, Thank you for your suggestion. As you said I am using Cardas shielded cable for carrying the signal from back to the front of the amp, I have done this successfully in my previous amplifiers builds.
Today I received my output transformers from Japan. I ordered them for upgrading and building Amplifiers for customers. This is the first time I purchased ISO (Tango) Transformers and very eager to see how its going to sound in my amplifier. These OPts seems to be some low budget models, no they are not. HC-203U and HC-507U both are best OPts, and have very well balanced sound, in many aspects both are closer to their higher end models.
I planned to use FC-12S for 45 tube amplifier. They are good for 45, 46, 71A tube based amps.
I purchased these OPTs through my Friend in Japan. When my friend contacted the sellers, they were surprised that a person from India is purchasing these things because peoples from India rarely buy them may be 1 pairs. Actually I ordered for 5 pair of different models. They told my friend that their younger generation itself not interested in these transformers or tube amps and not even interested in learning about their transformers technologies.
Many ISO OPTs models are readily available in stock. But Hashimoto are order to make with lead time of minimum 15 days. But they delivered them to my friend in 6 days.
My remaining order---1 pair ISO OPT FC-30-3.5SII and 1 pair Custom made Hashimoto for 2A3 tubes parallel single ended design, expect them in 2 months.
I am very happy that I not bought, I had brought some good things here. I have done this with the support of my customers.
I planned to use FC-12S for 45 tube amplifier. They are good for 45, 46, 71A tube based amps.
I purchased these OPTs through my Friend in Japan. When my friend contacted the sellers, they were surprised that a person from India is purchasing these things because peoples from India rarely buy them may be 1 pairs. Actually I ordered for 5 pair of different models. They told my friend that their younger generation itself not interested in these transformers or tube amps and not even interested in learning about their transformers technologies.
Many ISO OPTs models are readily available in stock. But Hashimoto are order to make with lead time of minimum 15 days. But they delivered them to my friend in 6 days.
My remaining order---1 pair ISO OPT FC-30-3.5SII and 1 pair Custom made Hashimoto for 2A3 tubes parallel single ended design, expect them in 2 months.
I am very happy that I not bought, I had brought some good things here. I have done this with the support of my customers.
I got chance to listen and use all the 3 famous Japanese transformer in my amplifiers. Tamura which I bought long time ago for my own 300B tube amp, but not able to complete that amp due to some continuous work.
Amazing
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