NOTE 1 - if you have any questions about any of the 3 amps kits listed on this web page just email me at
send email : Bob01605@aol.com
If you want to talk by phone I can email you my phone number for a call.
NOTE 2 - to purchase any amp kit on this web page just let me know by email
send email : Bob01605@aol.com
with the following info:
1 - Which kit? (ST70, ST120, or M125)
2 - Do you want a complete tube set? (ST70 or ST120 only)
3 - Do you want both capacitor upgrades? (ST70 or ST120 only)
4 - Do you want the stepped attenuator kit? (on ST70 or ST120 only)
5 - Do you want the TDR (time delay relay)? (on ST70 or ST120 only)
6 - Your USA or Canada ZIP code to figure shipping charges.
Payments can be made by bank check, money order, or via PayPal.
Payments by check or money order will receive a $25 discount on a SINGLE amp kit (ST70 or ST120)
or a $50 discount on a PAIR of M125 kits.
All wired and tested amps are custom built and shipped out about 2 weeks after receipt of payment.
brand NEW ST70 amplifiers, in KIT or ready to go!
ST70 amplifier features:
1. The new STAINLESS STEEL chassis is identical in size, shape and markings to the older original nickel plated steel frame.
This upgraded chassis is NON-MAGNETIC and removes any magnetic interference effects of a steel chassis on the audio circuitry.
2. The new USA made power transformer has a higher stack lamination than the original Dynaco power transformer 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 (which has a bottom plate like the original PA-060 to prevent EMI from
the transformer from reaching the audio circuitry) allows the use of KT88 output tubes in place of the EL34 tubes for
a slightly different tonal presentation. Four heavy duty neoprene isolation mounts are used to attach the transformer to 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 cloth lead A-470's and incorporate the same high quality M-6 grain oriented laminations.
They are dimensionally accurate to the original design and have a durable heat resistant black epoxy finish.
4. The old stock 30, 20, 20, 20 electrolytic quad cap which had marginal storage capacity for this amp has been replaced by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.
5. The upgraded VTA driver board uses three new 12AU7 or 12BH7 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 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.
Eight quality Sprague 716P "orange drop" coupling caps are included with the board.
6. The input jacks are gold plated and have a wider spacing to allow for newer design thicker interconnects.
7. The output jacks are modern gold plated 5 way binding posts.
8. The 7 octal tube sockets are modern high quality Celanex sockets with cadmium plated pins.
These sockets are very durable and more reliable than the older stock phenolic tube sockets found in the original amps.
9. Includes two triode/pentode switches to allow switching between these two modes of operation.
The switching may be done while the amp is running to compare the two sonic presentations.
"Shipping costs will be invoiced separately after your purchase of an amp kit - 36 pounds for the ST-70 and 45 pounds for the ST-120.
Kits to the USA shipped by UPS Ground or USPS Priority Mail. Shipments to Canada by USPS Priority Mail International ONLY.
Shipments to areas other than the USA and Canada will be shipped with a tracking number by USPS Express Mail International ONLY.
"
$699 + shipping IN KIT FORM with all parts but NO TUBES
$819 + shipping IN KIT FORM with all parts and tubes and EL34 output tubes
$889 + shipping IN KIT FORM with all parts and tubes and KT88 output tubes
$985 + shipping WIRED with NO TUBES
$1105 + shipping WIRED with ALL tubes & EL34 output tubes
$1175 + shipping WIRED with ALL tubes & KT88 output tubes
240 volt operation add $35 to KIT amp price
add capacitor upgrade for $45 (4 Power supply and 4 hand matched Russian K40-Y PIO coupling caps)
A 21 step, stepped attenuator kit to install in place of the unused stereo/mono switch to allow you to use your ST-70 amp without a preamp !
This is a great option if you only have one signal source for your ST-70 like a CD player. The attenuator may also be used WITH A PREAMP.
If you turn the control all the way to the right there is complete pass through of the signal with no attenuation or alteration of the signal.
You may also use the attenuator as a master level control to effectively reduce the gain of the amp.
$50 added to any ST-70 or ST-120 KIT amp
$75 added to any ST-70 or ST-120 WIRED amp
$50 + $5 shipping = $55 for your existing amp
all ST-70 and ST-120 amp kits come with a heavy duty 16 gauge chassis
ST70 amp kit assembled by Bob
the internal wiring with the Triode/Pentode switches
For more information or questions about a KIT or WIRED VTA ST-70 or ST-120 amplifier - - - Email me at Bob01605@aol.com
This is a "time delay relay" board" for tube amps and preamps.
The time delay allows the tube filament heaters to come up before any high voltage is applied. The time delay is nominally about 17 seconds but may be adjusted
for more or less delay at the discretion of the user. There are complete instructions for the assembly and installation of the board.
In a stock ST-70 the board replaces lugs 5, 6 and 7 of the 7 lug terminal strip. In a VTA ST-70/ST-120 tube amp kit, the VTA-TDB replaces the 3 lug terminal strip.
The VTA-TDB may also be easily retrofitted to any VTA ST-70/ST-120 tube amp kit.
The board is 1 7/8 inches wide by 2 1/2 inches long. It takes about 1/2 hour to assemble and is powered by a 6.3 volt AC line taken off V2.
When the board is powered up a RED LED lights up to show that the board has power. About 17 seconds after power is applied, a GREEN LED comes on,
and the relay kicks in to apply high voltage to your amp. Another nice thing is that if you are in an area that has quick ON/OFF/ON power interruptions
the board will automatically reset itself. In other words, if your power goes OFF and then ON again a split second later the board will automatically reset itself
and no high voltage will be applied for another 17 seconds.
This is only a delay board - you still need a solid state or tube rectifier to plug into the rectifer socket. If you use a GZ34 tube rectifier IMHO you can get by without it.
If you use a solid state rectifier like the Weber WZ68, which only has a 3 to 5 second delay, I think it is helpful.
It would also be helpful if you have the quick ON/OFF/ON power interruptions.
This board is primarily intended for those running amps withOUT a tube rectifier, like most of the ST120 amps that Bob is selling with the Weber SS rectifier.
If you have a tube rectifier you already have a slow turn-on. This board is a relay switch that will not apply the high voltage power to the amplifier until after
the tube filaments are warmed up, the board has a 17 second delay and that can be changed by changing one resistor on the board.
This is a very heavy duty industrial relay used for 270vac 3 phase and rated at 8 amps, with 1500v of isolation between the contacts.
Similar delay circuits I evaluated for tube amp use had 240v contacts with 1000v of isolation and were physically larger, this is a great addition to your tube amp.
It can run on 6vAC or 12vDC.
TDR KIT $35 + $5 shipping (or with amplifier kit)
TDR installed into any WIRED ST-70 or ST-120, add $60
Customer Reviews posted on the Internet . . . . . .
