-40%

High Power Custom Tube Amp And EL34,6CA7, 6550 KT88 Pro Built 2 Full Sets Tubes!

$ 1184.24

  • Amplifier Class: AB
  • Audio Inputs: Two-Channel RCA
  • Audio Outputs: Banana Speaker Jacks, RCA
  • Brand: Tubes4 Hifi
  • Color: Brown
  • Country/Region of Manufacture: United States
  • Features: Analog
  • Model: Dynaco ST70 Variant
  • Number of Channels: 2.1
  • Number of Inputs: 4
  • Number of Outputs: 2
  • Power: 44 W
  • Type: Tube Amplifier
  • Year Manufactured: 2023
  • Состояние товара: Б/у

Description

This high-power tube amplifier is a custom-built unit from Tubes4 Hifi, featuring a Dynaco ST70 Variant model. With an audio output of 44 W, it has two-channel RCA audio inputs and RCA and banana speaker jacks for maximum flexibility. The amplifier class is AB, push pull parallel circuit with 2 input channels and 4 outputs The unit is designed with an analog signal path and a brown color aesthetic. It was manufactured in the United States in 2023 and includes many tubes, including EL34, 6CA7, and can run the Big Boy power tubes 6550 & Kt88; the original Dynaco ST70 was an excellent , well designed, high quality Transformers and producedhigh fidelity performance from a relatively easy to understand,simple circuit. But it had a number of flaws that are easy to fix, improve or eliminate . If you follow my modifications, you can transform any Dynaco into a superb, compact super amp, capable of embarrassing much more costly amps, even the big names My story : About 20 years ago , I decided to see if tubes actually did sound as well as tube heads claimed. So I did research on tube, amps, preamps, integrated amps, monoblocks; studied the respected names ( Marantz. Macintosh etc. ) but I seeing Dynaco mentioned as a good quality amp, sold as a kit that c tubeheads all seemed to agree that vintage Dynaco equipment was perfect for a new would be tube aficionado. It readily was relatively eazy to find, of quality obtained was very favorable relative to the cost of acquiring, the designs were well thought out , and easy for a novice to understand, and restore. I soon found many vendors of parts, eefeupgrade kits, vintage hard to find tubes , even copies of old schematics! My first tube amp was a prebuilt Velleman k4040 amp,I knew almost nothing about tubes, but this monster had 8 El34 SED Russian power tubes as a complete set of preamp , phase inverter and z Rectifiers included. But the only number that interested me was the power 80 watts per channel. I had recently purchased a pair of Cerwin-Vega 3 way E 710 98 Db efficiency and s massive power capacity of 200 watts per channel. I bought the amp and set it up, but no sound? The directions rsferred to a “preamp” so CI bought one. I loved that velleman ; but i was forced to sell it because my cat found it fascinating and was always nosing around. It no doubt was attracted to the warmth and orange glow from 8 EL34s and eventually ge was sure to get Burned or shocked. So I hooked up a dynaco ad site. Bought a kit to build and enjoyed it for years, but i felt it could be much better with a few key mods. I had been studying amps & tubes transformers for years. Even as amateur, I spotted serious flaws and came up with a plan to make a good amp superb, I asked the guys at tubes4hifi.co if they could build from the ground up if listed my mods? They agreed. So i pointed all the flaws annd my proposed fixes. 1) it had a terrible chassis that looked cheap even when new 2) input jacks on front cover. Inconvenient 3) the whole top plate had too much stuff. It looked like a train wreck 4) quad cap can unreliable, can’t be high quality if you cram 4 elements in tiny can . It’s also an ugly eyesore 5)Too many exposed circuits 6) circuit board exposed on top easy to damage 7)ugly tube sockets built into chassis face solely to measure bias? 8)Power supply not sufficient, amp needs 200 milliamps to operate. This requires the lone rectifier to be running its maximum capacity 100% of the time, not good. 10) Triode to pentode switch not needed. This amp is designed to use pentodes. Tube designers had reason to have 3 grids in pentode. Let the tube operate as it should. My.solutions: While browsing on ebay , I discovered a guy selling hand made oak Chassis for amps. They were tight in space ,but well built. Bottom plate had plenty holes to cool hot parts.itseemed too small, the custom made a top plate and it allowed only transformers and tubes on top All electronics mounted under fop plate. Eliminated quad cap can. Paralleled rectifiers using 2 Emission labs 274b mesh plate. These are handmade in Czech Republic. They claim to be electrically identical to old Western Electric 274 b .After Buying they remain testing good and have lasted over 20 years. Parallel rectifiers double the current available, and cut the voltage drop from the single rectifier B by 50%. Reduced sag, higher B+ voltage to the tubes, rectifiers last forever, and amp is much more responsive. The sound is stunning, vastly better that original Dynaco ST70. Outdated, and hard to find 7199 tubes replaced by readily available 12AU7. Compact size 14 5 inches wide by 13.5 deep. Can use el34, 6CA7, kt 77, Kt88 and 6550 power tubes What you get: Very lighty used amp , totally rebuilt ffom ground up, ( almost new, It was done 18 months ago. All parts are New /NOS Tubes included 1 matched quad Telefunken EL34 ( real Telefunken, not RFT junk ) $800 -$1000 value. 5 Sylvania/GE “Fatboy” power tubes 2 new PS Vane 274b recitifier 2 cc NOS Sylvania mil spec 5V4G rectifiers 3 Genelex gold lion gold pin Ecc82 preamp tubes 3 Sylvania rebranded as “Baldwin” 12Au7 preamp tubes So you get two complete sets of quality tubes , And a free gift 1 GE JG-6414 . It can sub for 12AU7 type, but be careful. As this tube draws twice thee current of 12AU7 types. And it has a gain factor of 41. Vs 18-22 for the 12AU7 types, Howeved , I tried one innthis smp i n the middle spot oc preamp tubess, and it soundrd te But note; my preamp is dezigned cor 3. X 12AX7 tubes. Buy shen i bought the preamp( bavck in 2003 ,i replla. Rddthe no name junk. 12AX7s with Sylvania Gold brand. 3 mica , gold pin 5751 So these only have a gain of 70 and tend to be vdru relisble long lasting fubes so ic you xo this the gain is 30% less exiting the presmp, so the 6414 worked , and it really had a positive effect impact! But only use it in the v2 ( micdle presmp tube). V1 and v3 ade are phase iverterrs and have liftke ecfect onn thee sound Tve power trans can hanxle the adxirjonL. Currennt draw of 1. 6414 , but not 3 1 3-prong power cord 4 and 8 ohm speaker jacks Its s terrific deal considering the tubed you get! Any questions, message me !!!! I want someone to get fhis geffific zmp. If thr price id an issue messzgd me snd Im sure an agreement can. Be rescbed, Beck ouy my ogher losting! I absolutely guarztee you will bd smazed at yhe sou d quality. Thd matchrd Qjuad of telefunken el34 alone usually sells for $900 -$1000. Two full sets of tubes ( good quality, not junk) is a big value. You wont get an offer like this!