More about the Dynakit Stereo 35 / Dynaco ST-35
- Mirror polished stainless steel non-magnetic chassis
- Dynakit PA-774 power transformer and matched Z-565 output transformers
- Dynakit Adjustable Fixed Bias Control Upgrade (individual tube biasing)
- Dynakit shielded C-354 Filter Choke upgrade
- Dynakit circuit boards with upgraded tube sockets
- (4) New Tung Sol EL84 / 6BQ5 output tubes - plate current matched
- 2) New JJ Electronic 12DW7 / 7247 preamp tubes - gain matched
- Mundorf MCap ZN Capacitors (not shown in all photos)
- Includes PRP 1% Audio Grade Metal Film resistors
- Assembled entirely with Alpha Fry and or Kester 60/40 rosin core solder with Carol and or Alpha brand stranded and solid core wires
- 6 Amp rated power on/off toggle switch added and a custom retro-look power cord
- Amphenol CL90 inrush current suppression / limiter (thermistor) installed
- Operates from a standard 120-125v wall outlet, no need for a variac or bucking transformer (voltage reducer)
- Hand built and thoroughly tested - extensively auditioned for sound & operation quality
- Manuals and all supplemental documentation included on CD-Rom
click the image to zoom / larger view, use your back button to return
Details and Description:
Now, here's the question, do you really want an amplifier that sounds and looks 50 years old? Romantic - yes, nostalgic - sure, practical? - Not really. Keep in mind that an original condition 50 year old tube amp is going to sound 50 years old, not like it did 50 years ago when it was new. If that is really what you want, that's fine, this one probably isn't what you're looking for. This amp is 100% new, and needs nothing, it sounds, works and looks far better than any Stereo 35 ever did 50 years ago.
These Amplifier Kits are purchased direct from Dynakitparts.com. We then add our own upgraded features and components that further elevate the performance giving you a beautiful, unique and spectacular sounding amplifier.
click the image to zoom / larger view, use your back button to return
ST-35 rear view showing optional banana post output terminals ($50.00 extra)
By using higher quality components with a few additional features this amplifier raises the bar. The original Stereo 35 did not use a power supply filter choke. It was proven that the noise floor of the amp could be lowered even further by its use so a Dynakit C-354 shielded choke was installed in place of the ceramic power resistor.
click the image to zoom / larger view, use your back button to return
This amp is absolutely dead quiet, no hiss, no hum, just crystal clear music is all you hear. The original design used a non adjustable cathode bias circuit. This amp now has user adjustable bias, all four output tubes can be individually biased using the innovative and proven Adjustable Fixed Bias Control Upgrade by Dynakit. The original Stereo 35's did not have a power switch so a 6 amp toggle switch is added neatly on the back side of the chassis.
An inrush current limiter (CL90) has been incorporated to regulate and soften the power on process, this feature helps protect the tubes and extends component life. The original Stereo 35 amps have a cadmium plated metal chassis which has a rather dull shineless finish. This new chassis is heavy duty (non-magnetic) type 304 mirror finished stainless steel with durable black epoxy silkscreen lettering. The perforated cover is available finished in Original Brown, Black or we offer custom colors like Dark Metallic Grey and others. Four 1/2" tall rubber feet with steel bushings are installed instead of the small "bumpers" that are supplied with the kit. This is done for better isolation and improved chassis ventilation.
Each channel uses its own discrete amplifier board, these are Dynakit PC-13 boards, they’re made in the USA. These heavy duty boards faithfully reproduce the original and brilliant Dynaco Stereo 35 circuit, layout and color, they're made to military specs using modern materials of the highest quality. The stereo separation this unique design provides is amazing. These circuit boards are populated with special high precision audio grade metal film resistors and excellent sounding high quality audio grade capacitors.
The boards have upgraded tube sockets. The resistors are made by PRP rated at 1% tolerance and specifically designed for high end audio applications, these ensure the signal circuit is quiet and accurate. The capacitor selection consists of (6) Silver Mica, (2) 0.22uf / 250v (4) 0.1uf / 500v, (2) 0.1uf / 100v (Metalized Polypropylene Film). Original capacitance (uf/mfd) values were kept as recommended to avoid creating low-frequency instability. The screening tolerances are tightened up for improved sonics and component voltage ratings are slightly increased for higher reliability. The tighter screening tolerances of the resistors and excellent quality capacitors help give this amp its great ability to reproduce complex musical passages in superb detail while keeping all the magic and smooth musical warmth you want. This approach would not lend itself to guitar amplification but works wonders in HiFi applications. Great sound comes from great circuit design, not magic parts. Having high quality parts in a great circuit simply enhances the already good design. This amp obviously holds great advantage over a new unmodified or original condition ST-35. The warmth, depth and detailed sonic range of this amps soundstage are incredible.
The Bias Control Module: Output is kept in check by the Dynakit Fixed Bias Control Unit. This is an upgraded feature and is not found on the original or new stock Stereo 35 amplifiers. The ST-35 Bias Control Unit (BCU) is a fantastic power circuit modification from Dynakit which permits adjustment and control of the bias setting for each of the 4 (EL84/6BQ5) output tubes via (4) separate “on board” precision adjustment pots. The BCU circuit board has Vishay, Xicon and NTE precision metal film resistors, high quality Nichicon capacitors and Vishay brand trimmers. The BCU board is constructed from type III, 240 degree C rated Brown “Polyimide material with (PTH) plated thru-holes and double sided solder mask. It was carefully designed to “fit in” nicely and also match the amplifier boards in appearance. This is a well engineered and desirable upgrade that greatly extends tube and transformer life while also creating a stable balanced output and overall more efficient operation throughout the amplifier. This tightly balanced and controlled output ensures circuit stability which in turn improves sound quality. The BCU also allows for the use of unmatched output tubes to be used as those can now be individually biased for a balanced draw and output by adjusting the BCU. This Stereo 35 amplifier uses solid state diode rectification as did the original design. The correct 60/40/20/100 multi section power supply filter capacitor is from Dynakit and quality made in the USA.
The heart and soul of any tube amplifier are its transformers. The new PA-774 power transformer and matching Z-565 output transformers are exceptional quality Dynakit transformers that meet or exceed the quality and performance of the originals and they're made in the USA. The Z-565 output transformers use M-6 grain oriented laminations and they are interleaved wound just like the originals. With these new Z-565 transformers, this ST-35 will accommodate a pair of either 4 or 8 ohm speakers making it much more compatible for use with modern speakers than the 8 and 16 ohm design of the original Z565 transformers. The new PA-774 power transformer is wound for today's real world 120v + line voltage as opposed to the originals which were wound for the 112-117v of the early 1960's. A huge and convenient improvement which allows this amp to operate directly from a standard wall outlet without the need of a voltage reducing device. Another big improvement is the fact that the PA-774 incorporates Class "B" insulation & wiring which is better designed to handle significantly higher operating temperatures. Based on findings from a tear down and close inspection of some number of original production Dynaco PA-774 power transformers, it was concluded that all of these old units were of a Class A design with a maximum operating temperature of only 221 degrees Fahrenheit. The new production PA-774 units are designated as "B" classification, a NEMA Class 150 C design having a maximum operating temperature of 302 degrees Fahrenheit. Operating close to or beyond a transformers temperature rating will eventually result in a premature failure of the unit. The bottom line is the new production Dynakit power transformers are designed to handle measurably higher operating temperatures than the original Dynaco power transformers resulting in near zero failures, extended service life and enhanced durability. The power transformer is mounted on rubber isolation bushings.
So what about all the fuss made over those “magic” cloth lead transformers? The truth here is there’s no magic in those cloth lead wires whatsoever. Cloth covered leads simply indicate early manufacture (pre-1970) and for many brands, those old transformers are in fact better quality than their new production counterparts and replacements. This is certainly NOT the case with the new Dynakit transformers which incorporate the latest design advancements in metals, insulation, resins and construction. The results of this well executed transformer design and painstaking production effort are quieter and cooler operating transformers which effortlessly provide increased performance over the originals.
This is an amp for even the discriminating audiophile. Here's what the renowned tube amp guru Bob Latino had to say a while back about the Stereo 35: "Many feel, and I concur, that this little amp, within its power range, is probably the best sounding all stock power amp that Dynaco ever put out. Only 17.5 watts per channel but, even unmodified, a very clean sounding 17.5 watts. EL84 output tubes, an all triode driver system and a solid state rectifier gave this little amp excellent frequency extension and very low distortion figures." My thoughts are that if Bob Latino says that, and many others agree with him, that you will be convinced as well. This legendary little amp goes beyond its call of duty, it is truly a listening pleasure and it is built to last.
If you would care to read a fantastic and detailed review of the Stereo 35 - CLICK HERE
- If you're undecided here are a few more points to consider regarding Dynaco/Dynakit.
- accessible product support
- affordable and readily available parts
- a great variety of upgrades
- The ongoing and active online community of Dynaco enthusiasts
- ease of repair and service if needed.
- Dynaco and Dynakit products hold a special place in the HiFi Audio industry regarding these important aspects and in fact, are unrivaled by any other brand for support, parts availability and serviceability. You can own, enjoy and use this amp with confidence.
SHIPPING is Fully Insured with Tracking
All insured shipments require an adult signature at the door upon delivery, so plan accordingly please. We do NOT ship to PO box addresses, so you must have a valid physical street address. For safest shipping, all of the tubes, the fuse and fuse cap will be removed and individually boxed, numbered and labeled. A numbered pictorial for quick easy tube installation is included, all you'll need is a screwdriver for removing the cover. Includes the printed Dynakit Stereo 35 assembly and operating manual stamped with the serial number that belongs specifically with this unit along with other supplemental documentation referencing the wiring, transformers, circuit boards, parts, bias instructions etc.
1963 statement from the Dyna Company
The Dynakit Stereo 35 is a dual power amplifier of deceptively simple appearance and circuitry. Behind its seemingly conventional design is an extremely sophisticated circuit configuration representing the most recent advances in power amplifier engineering and construction. This high degree of technical refinement, combined with the conservative use of premium-grade components, has resulted in a typical Dynakit design offering superb performance at low cost. Each of the two channels in the Stereo 35 is rated as a 17.5 watt amplifier. Although not evident from this simple rating, the power stated is available on a continuous basis at any frequency from 20 to 20,000 cycles per second. A music power rating would make the Stereo 35 a 45-watt amplifier, although even this rating would not disclose that full power is available at low distortion throughout the audio spectrum. Nor would such a rating indicate that the Stereo 35, even when driven to power output levels beyond its rating, is able to handle these overloads gracefully, with minimum detriment to the sound. As a result, the Stereo 35 can, if necessary, duplicate the sound intensity of amplifiers with much higher power ratings when called upon to do so. The heart of the Stereo 35 is the special Dynaco Z-565 output transformer, a patented design tailored specifically to this circuit. The transformer is free of resonances, has extended frequency response (from 6 to over 60,000 cycles), and is wound by special techniques on a carefully designed core to insure low distortion over a wide frequency spectrum. Transformers of this calibre have never previously been used in low-cost equipment of moderate power rating.
Turnaround time is 4-5 weeks. (most of the time is awaiting parts arrival) Once purchased, you will be kept informed in a communication loop with updates direct from us. Prepayment in full is required and includes shipping cost. The shipping will be computer calculated at the time of checkout. The list price is comprehensive, meaning no additional fees or surprise charges will occur. This means all tubes, upgrades and features described in this ad are included in the stated price, then shipping is added as you check out/purchase. Shipping price includes insurance for full value.
Each unit is custom, a hand built, made to order unit and wire color / routing may be slightly different from unit to unit, these are hand built custom units.
*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.
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.
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.
This item is covered by a warranty:
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.