Thank you! Yes, turret board I made myself.
Jim, the enclosure was bought in Russia. Here - Astra audio .
Amp GM-70SE
Amp GM-70SE
E88CC > KT-88 > GM-70
Ua = 900VDC
Ia = 90mA/1 tube GM-70
Auto bias
Amp GM-70SE
E88CC > KT-88 > GM-70
Ua = 900VDC
Ia = 90mA/1 tube GM-70
Auto bias
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
DIY Amp GM-70
Made By huyhoanghp96
Made By huyhoanghp96
An externally hosted image should be here but it was not working when we last tested it.
Very interesting is it made of lexan (plastic) then painted?PSU Unit
Signal UNIT 1
Signal Unit 2
Hello all.
Not long ago there was over such a project.
With respect to all of Alexander.
https://sites.google.com/site/agalkaaudio/hobbi/riaa-cupid-s-arrow
Not long ago there was over such a project.
With respect to all of Alexander.
https://sites.google.com/site/agalkaaudio/hobbi/riaa-cupid-s-arrow
Attachments
You know,
I think thats a great lookig amp.
The more I look at these images the more it reminds me of Unison research..The 845 comes to mind..
How did you cut/shape the wood?
Do you have any shots of inside?
Regards
M. Gregg
Nice work!
I notice the improvement in your internal wiring it was very good before, now..looks great
What board did you use for the turret tags?
Regards
M. Gregg
This is becoming a series; the 3rd high power 500W Williamson amp on a revamped older chassis using the identical circuit as those previous using a duality power supply B+ at 325V and 650V, this provides a conservative class A 50W and AB1
275W /ch resp. The wiring is about to commence. PCb's completed and tested; lower RHS, bias fail watchdog, logic switching, line softstart; lifted 6.3VDC board; (neg board hidden) The top right is the 1kW pfc module. Many caps have nomex tape to avoid damage to the very thin outer insulation tape that many have nowdays. All grid stoppers are Allen Bradley carbon types.
Tube lineup; 8x EH KT90; 4x 12BY7A diff slam drivers as triodes; 2x ECF80 p/s front end as triode. Output transformers (2x 15kg) Majestic (UK) custom spec wound. 15Hz-75Khz # -3dB. The distortion from the other amps was very low; typ 0.1% at full power 550W in bridge mode.
Later, more on the approach regarding testing. The loop stability and response of the series of amps were designed on the graphical approach; typical of the 1950-60's. Computer emulation used was for optimising the switchmode power supply and number crunching Excel graphics. A USB bus is provided for studio MI interface, to provide a programmable B+ droop for guitar work and standby mode at 150V B+.
This power amp is for those with a proven record in power & system electronics; the 650V B+ with all the Joules, can do considerable damage.
650V is an awkward voltage; many DMM's have a 600V limit; and particular care using the correct probes with digital scopes; and ones own safety approach is paramount.
richy
275W /ch resp. The wiring is about to commence. PCb's completed and tested; lower RHS, bias fail watchdog, logic switching, line softstart; lifted 6.3VDC board; (neg board hidden) The top right is the 1kW pfc module. Many caps have nomex tape to avoid damage to the very thin outer insulation tape that many have nowdays. All grid stoppers are Allen Bradley carbon types.
Tube lineup; 8x EH KT90; 4x 12BY7A diff slam drivers as triodes; 2x ECF80 p/s front end as triode. Output transformers (2x 15kg) Majestic (UK) custom spec wound. 15Hz-75Khz # -3dB. The distortion from the other amps was very low; typ 0.1% at full power 550W in bridge mode.
Later, more on the approach regarding testing. The loop stability and response of the series of amps were designed on the graphical approach; typical of the 1950-60's. Computer emulation used was for optimising the switchmode power supply and number crunching Excel graphics. A USB bus is provided for studio MI interface, to provide a programmable B+ droop for guitar work and standby mode at 150V B+.
This power amp is for those with a proven record in power & system electronics; the 650V B+ with all the Joules, can do considerable damage.
650V is an awkward voltage; many DMM's have a 600V limit; and particular care using the correct probes with digital scopes; and ones own safety approach is paramount.
richy
Attachments
