Dynakit Stereo 70 / ST-70 Stereo Tube Amplifier (7199 version)

ORDERING OPTIONS:

  • Select from several available tube sets
  • Bias Balance Control Option by Dynakit

It is fairly safe to say that most people today would have no idea of how wonderful a Stereo 70 amplifier is capable of sounding like. Isn't the great smooth sound of a time long gone by what you're really after, those sweet tones produced only from tube amplification? Like a musical time machine, this amplifier will take you back to the beginning, like when these amps were new. But there's even more to consider here. All of the components used in this amplifier have greatly improved characteristics over the ones available and used 50 years ago. That makes the sound quality of this amp even better than one would have been then, as a new one 50 years ago.  Take a good close look at this one. Don't cheat yourself out of what you're really wanting; superb sound, high build quality, safe and reliable operation, great looks and that comforting pride of ownership. 

Enjoy the rich smooth tones of analog audio with this 7199 tube version of the Stereo 70 Amplifier. It has that lush signature of even order harmonics that only vacuum tube amplification can produce. It reveals musical qualities with fantastic realism and depth you may have never imagined possible. This amplifier brings the legendary original design up to date with highly improved levels of sound quality, looks and performance. Because of the ST-70's naturally high impedance (470K) it is compatible with virtually any solid state or tube preamp.

Features

  • Mundorf MCap ZN Capacitors - 600v - 5% - Values are .22uf & .1uf - Improves Bass Response
  • Cornell Dubilier Silver Dipped Mica Capacitors - 390pf @ 1000v & 82pf @ 500v Rated - 5% - High Precision 
  • PRP Audio Grade Resistors - High Resolution - 500v Rated - 1% Accuracy - Ultra Low Noise 
  • Bias Circuit Uses Upgraded 100uf Capacitors with Flameproof Metal Oxide Resistors
  • Dynakit PA-060 Power Transformer (120v Windings) - Notice the Increased Lamination Stack
  • Dynakit A-470 Output Transformers - (4,8,16 Ohm Taps) - Grain Oriented Laminations - Interleave Wound
  • Dynakit C-354 Shielded Power Supply Filter Choke - (1.75 Henries, 62 Ohms, 10%) 
  • 9 Brand New High Quality Tube Sockets
  • 600v & 1000v Alpha Wiring Used Throughout the Entire Amp 
  • Genuine Dynakit Multi Section Filter Capacitor - Factory Correct Values 80/40/30/20uf - 525v Rated - (a higher rated cap is available, ask us)
  • New Dynakit Stainless Steel Mirror Finish Chassis (Non-Magnetic) - Beautiful Museum Quality Look
  • Optional Dynakit Perforated Steel Cover / Cage w/ matching badge, available in several color choices
  • Dynakit PC-3 "A" Circuit Board - Made Specifically for 7199 Driver Tubes -
  • Flashback Prevention Safety Diodes Installed at the Rectifier Tube
  • Additional shielding on under chassis components to reduce EMI / interference
  • Careful and detailed wire routing to reduce electromagnetic signal interference (EMI) potential
  • Assembled With Alpha 60/40 rosin core solder - for the Very Best Quality Connections
  • Power Transformer Isolation Bushings Installed - Prevents the Transfer of Mechanical Hum to the Chassis
  • Custom Silver or Gold Plated RCA Input Jacks - Wider Spacing for Larger Modern Input Cables 
  • Original Screw Style Speaker Output Terminals - Vintage Correct - Full Function  (4,8,16 Ohm + Common/Ground) 
  • Heavy Duty Rubber Feet with Steel Bushings
  • Heavy Duty Power Cord
  • Assembled with Great Attention to Detail Using High Quality Parts - 48 hr Minimum Burn in Tested - Sounds Incredible
  • Operates From a Standard Wall Outlet - No Voltage Reducer (Variac) Needed - Built for Today's 120v+ Voltages
  • 6 month limited warranty - see details below
  • Arrives With Bias Preset * - Just Install the Tubes - Simple To Do - Instructions are Included
  • Front Preamp Sockets are Wired for Bias Set Only - Reduces Audio Signal Interference 

A Vintage Vibe with Modern Reliability - The Beautiful Sound of Tubes

So how does it sound? - “Magical” - this is not your average Dynakit Stereo 70 folks. With the addition of it's premium components this amp is very musical with a highly detailed voice and plenty of solid, clean wonderful bass. This amp is absolutely dead quiet - no hum, no buzz, no hiss, no snap-crackle-pop! It sounds like it is supposed to, like you want it to. If you're in search of that "golden age of audio sound” with “stunning vintage looks”, you've just found it. This is your bad boy. This is a 100% brand new amp, a very high quality build, total listening satisfaction. This ST-70 delivers dramatically improved sonics as the result of being carefully and thoughtfully built, all new, from the ground up, with technologically advanced components and high-end parts.

We buy the kits direct from Dynakitparts.com. then add our own upgraded features and components that further elevate the performance of these amplifiers, giving you a beautiful, unique and spectacular sounding amplifier.

Tube Options: 

  • Choose from our available tube sets, or buy it with no tubes.
  • You can select "no tubes" and then add your preferred tubes to your order.

Standard Tube Set

(2) NOS 7199 (RCA or equivalent per availability) matched by test results

(2) NessTone EL34/6CA7

(1) Groove Tubes 5AR4/GZ34

Premium Tube Set

(2) NOS 7199 (RCA or equivalent per availability) tested for noise & microphonics and plate current matched

(4) Mullard EL34 New Production - tested for noise & microphonics and plate current matched

(1) Genalex - Gold Lion U77 / GZ34 - fully tested

Audiophile Tube Set

(2) NOS Premium Brand 7199 - tested for noise & microphonics and plate current matched

(4) BLACK SABLE JJ EL34 - tested for noise & microphonics and plate current matched

(1) NOS 5AR4/GZ34 - (RCA, GE, Matsushita, these are selected as available) fully tested

 

The Optional Dynakit Bias Balance Control

This is an upgrade option, it's an additional secondary bias control circuit that equalizes the bias current between each pair of output tubes. Bias is adjusted as usual first using the original 10k bias pots. Then the balance is adjusted, this is for equalizing the current between each pair of output tubes. These secondary balance adjustments are made using the additional balance pots and adjusters which are installed conveniently behind the front octal sockets. The adjuster is very discreet and is accessible at the center holes of the already existing front octal sockets. Full easy to follow bias setting instructions are included.

 

 1. Set the bias initially using the original bias adjusters

2. Set the balance using the additional adjusters located in the center of the front sockets

3. Bias is now set and equally balanced - add this bias balance upgrade by using the dropdown menu when ordering your amplifier

 

     About the Transformers: 

    If there were any more important part of a tube amplifier we'd talk about that here, we saved the best for last. The transformers are the heart and soul of the tube amp, period. Dynaco wasn't messing around when they designed and built their originals. These are the new Dynakit transformers and have been reverse engineered from the original Dynaco designs. Like the originals, these have grain oriented laminations and interleaved windings. These USA made current production genuine Dynakit transformers meet and exceed every aspect of the originals. If there were some sort of "magic" in the use of cloth leads, Dynakit would have used them again here, you can bet that. But, there's no magic in cloth covered lead wire, period. In an apples to apples showdown, these are simply better than those. Modern advancements in materials, methods and technologies used in the production of these transformers has resulted in transformers that operate quieter and run cooler than the originals while providing less distortion, more power with increased reliability. These transformers are in one word, exceptional. Great job Kevin!

    Included with your shipment: 

    Warranty Information Documents (printed on paper)

    The manuals, instructions, pictorials, diagrams, schematics and supplemental documentation are all included on a CD-ROM. 

    This item is covered by a warranty:

    warranty is limited - warranty is for 6 months from the date of purchase, warranty coverage is offered the original purchaser only. Proof of purchase is required to file for an RMA.

    RMA is for warranty work only, it is not for a refund. Issues from abuse, misuse, neglect or external damages are not covered. Signs of tampering or repairs by anyone other than funtastic vintronics voids all warranty coverage.

    Damage from moisture of any kind, electrical surges, lightning and static electricity are not covered. Coverage is limited to replacement of any original components which have failed under normal operating conditions. Faulty components will be replaced with no charge to you for parts or labor. Vacuum tubes/valves are not covered by warranty. Damage caused by faulty tubes is not covered by warranty.

    Shipping both ways is the responsibility of the original owner/purchaser of the unit. You must request an RMA number prior to making any warranty claim. Your RMA must be approved prior to shipping. Please follow appropriate packing methods to prevent shipping / transportation damage. We strongly suggest insuring your shipment for the replacement value of the item being shipped.

      Unpacking your shipment:

        Tubes, Fuse and Fuse Cap are removed for shipment - numbered and boxed, all packed carefully for secure shipping Tube installation instructions with a numbered easy to follow pictorial included.

        *bias will be pre-set but due to variations in AC wall voltages the bias should be checked and adjusted for your location before using the amplifier.

        Each unit is custom, a hand built, made to order unit. Your unit will look identical but wire color and routing may be slightly different from unit to unit, these are hand built custom units. Turnaround time is 3 weeks or less. (most of the time is simply awaiting parts arrival and shipping/travel time). Once purchased, you will be kept informed of your orders progress with occasional email messages direct from funtastic vintronics.com. We want you to know things are under way and going as planned. Prepayment in full is required and includes shipping. The price is comprehensive, meaning no additional fees or surprise charges will occur.  Shipping price also includes shipping insurance for full value. Straightforward simple business here.

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