Up for
sale is a professionally restored and fully working pair of vintage Dynaco / Dynakit Mark IV mono block
power amplifiers. These amplifiers deliver 40 watts per channel RMS and can top out at 90 watts per channel.
These units have been serviced and include the requisite updates for units of this vintage. See photos for the updates!
All tubes were tested on a B&K 707 Dyna-Jet and test at NOS levels.
TUBES ARE INCLUDED: GE (Westinghouse branded) 5AR4 / GZ34 rectifiers (new-old-stock), Electro-Harmonix EL34 / 6CA7 brand-new matched quad, RCA 7199’s.
Updated circuitry measures were undertaken to ensure decades of reliable use and include the following:
The original 30/20/20/20 main filter can capacitors were replaced with brand-new C&E manufacturing filter cans.
The wax-paper bias supply capacitors were replaced with new 100µF caps.
The coupling capacitors were replaced with brand-new, top-quality Solen metalized polypropylene fast caps. The capacitance has been increased to 0.22µF and 0.1µF to bring out more bass and low-mid reflex.
The 6.8K filter can resistors have been replaced with 3W metal film resistors.
New power cords with strain relief fittings were installed, replacing the knotted power cords and the decayed rubber bushings.
The internal rectifier diodes have been replaced with fast-switching diodes.
The matched pair of 47K resistors have been replaced with brand-new metal film resistors, 2W.
The bias has been set for the output tubes, using not only the 1.56V biaset terminals, but by measuring actual bias voltage on the grids.
The worn factory input jacks have been replaced.
New fuses installed.
And finally, the mono blocks were burned in for 72h to measure if any further bias adjustments were required.
The bias control potentiometers have been cleaned with DeOxit D5.
This auction is for both amplifiers as described.
Shipping rates vary by your location. Click on the "Shipping and Payments" tab to have a shipping price calculated for you. Want these amps as fast as possible? Expedited shipping services are available for you to choose from if you wish. Just click on the "Shipping and Payments" tab to get a shipping quote.
Shipping discounts are of course considered for multiple auctions/sales.
Customer satisfaction is my top priority, and each item I sell comes with a 14-day warranty period. Check my feedback and bid with confidence—I sell almost exclusively vintage tubes and electronics! Please read below for further details regarding product descriptions/operation-usage/returns.
Conditions of sale:
Payment must be by Paypal. Payment must be made within 48 hours of auction close.
The amplifiers are guaranteed to be as described and are warrantied for 14 days following receipt. If you feel the amplifiers have been described improperly, please communicate with me your concerns. If received in the same condition I’ll issue a refund (buyer though pays return shipping). Please be aware that the silkscreen that is intact adds significant value to vacuum tubes and is easily rubbed off or removed with virtually any solvent or solute, even water alone. Always handle tubes by the pins and the top. Should the tube be returned, the silkscreen must be retained for a full refund.
Shipping:
Shipping will be to customers in the United States only through USPS, double-boxed, well secured and packaged. To receive these two amps in another country, shipping must be handled by eBay's Global Shipping Program (GSP)--I will ship to their facility in Kentucky and eBay will handle the remainder of the shipping process. The parcel will be insured.
International Buyers: are welcome to bid, but must be supported by eBay’s Global Shipping Program (GSP) and not have shipping postal codes in Italy, Poland, Russian Federation, Japan, China, Korea, Taiwan, Vietnam, Singapore, Malaysia, or Hong Kong.
International bidders are responsible for all shipping costs as indicated by the GSP, as well as any customs or importation fees that are required by your location. The GSP will handle all of these fees for you, and ensure that the amps and tubes
will be delivered to you without having to pay any money on delivery.
Additionally, I will not falsify any claims of shipment.
International Buyers: click on the “Shipping and Payments” tab to determine if your country is supported by the GSP, and if it is, you may select your country and eBay will calculate the shipping charges for you.
Should a return be justified the buyer is responsible for all return shipping.
As always, if you have any questions, please contact me prior to bidding. Also please take a look at my other auctions for other quality tubes and audio gear. Shipping discounts will of course be included (details above).
Thank you and good luck!