Dynaco ST-70 Tube Amplifier Chassis For Project/Parts-Read Me
프로젝트/부품 읽기용 다이나코 ST-70 튜브 앰프 섀시
| 상품번호 | 278058369728 |
| 상태 | For parts or not working |
| 거래유형 | 즉시구매 |
| 출고국 | 미국 (US) |
이베이 판매가
$135
약 198,990원
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상품 설명
Dynaco Stereo 70 chassis and Triad power transformer offered for project/parts.
I used this as the basis for trying various Single-ended pentode output tube options.
The VA/driver is for a pentode wired C3g loctal tube running about 10ma on a 300V B+ with a mosfet regulated (150V) screen grid supply, cathode resistor not bypassed. (I have used the same OP and plate and cathode resistor values with 6688 tubes which are much more common; though they will require a 9 pin noval socket mod.)
Output pentodes that share a common basing, 6L6, EL34, EL38 (w/plate cap), etc. were tried out, plug and play style. A simple CCS on the cathode applied a stable 60ma current sink for whichever tube was plugged into the socket.
The output transformer I used was a 5K SE type from Transcendar with UL taps.
A combination of global negative FB and local (schade) plate to grid at the output stage completed the picture.
It's important to note that the Triad transformer (from a Leslie donor amp) will not power a push-pull stereo amp. Sorry. BTW the power transformer runs barely warm under the given load. 750VCT, 6.3v & 5v secondaries. With a 5U4 rectifier you get about 430VDC under load. Last 2 photos show high voltage reading (no load w/ 110v input).
The chassis itself was stripped of its original nickel plating and refinished with a bronze hammertone. This work was done about 30 years ago and the condition of the finish is still remarkably nice and resistant to chipping. A few additional small holes were drilled but overall the metal work is stock.
Sadly I never had a bottom plate for this guy.
Review the pictures; what you see is what you get.
Offered to those experienced with tube equipment. And I will gladly answer your questions.
In other words if this is all Greek to you, please pass this one by.
Guaranteed as described.
Will be carefully packed and promptly shipped.
USPS Ground Advantage.
Tracked and Insured