Dynaco/VTA ST70 NEW Custom Built ST70 35WPC

NEW Custom
Built VTA Dynaco ST70 35WPC

For Offer is a new custom built, fully assembled and tested VTA (Dynaco)
ST 70 including many audiophile refinements: OFC in all audio circuits,
selected and matched coupling capacitors and tube set, NOS drivers,
triode/pentode selectable, custom biasing ports and more.

1.  Featuring a new 16 gauge
STAINLESS STEEL chassis identical in size, shape and markings to the older
original nickel plated steel frame except it weighs 1.25 pounds more than the
original Dynaco 18 gauge chassis. This upgraded chassis is NON-MAGNETIC and
removes any magnetic interference effects of a steel chassis on the audio
circuitry. 16 gauge stainless steel bottom cover with four hard rubber chassis
supports also included.

2. The new power transformer has a 5/8 inch higher stack lamination and
is rated for 120 volts instead of 115 like the old design. The two tube heater
legs are rated for 5 amps each instead of 3 amps each like the old design. This
beefed up transformer allows the use of 6L6, KT66, KT77, KT88 or
6550 output tubes in place of the standard EL34 tubes for a slightly
different tonal presentation. The transformer sits on 4 neoprene isolation
mounts to prevent any mechanically
generated transformer noise from entering the chassis.

3. The A-470 output transformers are brand new USA made custom production
transformers. They use the same interleaved/layer winding technique as the
original Dynaco cloth lead A-470's and incorporate high quality silicon steel
M-6 grain oriented laminations. They are dimensionally accurate to the original
design, come with a black oxide finish and have 4, 8 and 16 ohm
secondaries (the 4 and 8 ohm outputs have been employed in this amp).

4. The old stock 30, 20, 20, 20 electrolytic quad cap (90 Mfd total)
which had marginal storage capacity for this amp has been replaced by a 80, 40,
30, 20 quad cap for almost double the power storage capacity. In conjunction
with the 88 Mfd to power the driver board this amp has 258 Mfd of power storage
- almost 3 times what the old amp had.

5. The upgraded VTA driver board uses three 12AU7 (or 12BH7 or 6189 or
5963 or 5814) triodes in place of the two mediocre sounding 7199
pentode/triode tubes. Dynaco saved money using a two tube 7199 board design but
made some serious compromises in sound quality. The VTA triple triode board,
however, features a better phase splitter/inverter design with CCS (constant
current source). The VTA driver also uses less feedback for
noticeably better sound than the old design. The older ST-70 design had one
bias control for each channel whereas the VTA board has a separate bias control
for each of the four output tubes. This design allows for individual adjustment
of each output tube bias. Matched pairs or quads of output tubes are not necessary
with this design but are included with this amp to provide even greater
enjoyment.

6. The input jacks are gold plated and have a wider (9/16 of an inch)
spacing to allow for newer design thicker interconnects. The original Dynaco
input board had a 3/8 inch spacing and most replacement ST-70 input mounting
boards have a 1/2 inch spacing. (see photo)

7. The output jacks are modern gold plated binding posts that will accept
banana plugs, spade lugs or bare wire up to 12 gauge. The binding posts that have
been for 8 ohms in this build. The 7 octal tube sockets are high quality
Celanex sockets. These sockets are very durable and more reliable than the
older stock phenolic tube sockets found in the original amps.

9. This design also includes triode/pentode switches to allow a
quick change between these two modes of operation. The switching may be
done while the amp is running to instantly compare the two sonic presentations.

The Completed and tested amp includes the following features:

 Operating and Assembly manual with
pictorial and color photo

 16 gauge Stainless Steel chassis frame
with original markings

Matched Clarity Cap Coupling Capacitors

Upgraded  VTA CCS driver board with
precision capacitors and 5% resistors hand matched

Celanex octal tube sockets

USA made PA-060 power transformer with bottom plate

Isolation mounts for Power transformer

USA made A-470 output transformers

C24-X 240 milliamp choke

1 - multi section (80, 40, 30, 20) quadruple electrolytic capacitor

1 - three lug terminal strip

6 - grounding lugs

gold plated RCA input jacks and output binding posts

Matched power tubes (EL34) and NOS driver tubes

2 - Triode/ultralinear switches with associated parts

This amp delivers incredible dynamics a remarkably low sound floor and
great speed and refinement. Offered hundreds of dollars below the kit price
offered by VTA this is a new fully tested custom built component (no tube set
included allowing buyer specification of final configuration) currently listing
for over $1100 without upgrades.  Shipping only to the contiguous 48 states.
This is a VERY heavy and delicate component and will be professionally packaged
and insured at my cost.

Thank you!.