Hi, Is there some way to build a tube amp in a metal case, using the case as RF ground, and not have current flow out of the amp through the grounding conductor? (other than isolating that ground fro
For anyone that complained about no signature and no call sign, here it is. Could you give me feedback on the new layout, please? This is what the old layout was: https://ibb.co/HpMdDkY I realise now
Hi Jim, It is similar here in the EU as far as I know. A typical way devices, are constructed here is that the ground (including the case if made of metal) is not used as a normal current path in the
Hi Lukasz, I use a tube amplifier which I have built in 1975 in a no RCD environment. It uses a 3-phase HV power supply as well as single phase small power supplies. The amplifier is of course ground
Hi, It is based on a lm741 op amp (if I remember correctly) steering an N channel mosfet shunt regulator. The reference is two 1% resistors and a multi turn potentiometer (it only moves the voltage b
Indeed I do. I read it a long time ago so I must have forgotten. Thank you for mentioning it. I've managed to modify my custom transformer order as it hasn't been made yet. I changed it to 2x140V (28
Hi, I have a number of parts of a mobile (mounted on a 7 ton truck) Warsaw pact HF military radio. Parts include 1500W HF amplifier (modifiable up to 3.5kW), 3 phase power supplies (HV:3kV,350kV, LV:
What is acceptable? Of course I know "as good as you can make it", but let's say we have a tradeoff to make. What is the most ripple we can tolerate and still consider the amp output good? That's wha
I suspect the original circuit is a series resonate circuit at the ripple frequency. I'm not sure. This is the schematic: https://ibb.co/KzmLW4C The choke/inductor is next to R40 with (Russian letter
Very interesting. Have you ever measured the ripple? If so, what is it? If you haven't, please give some details of the PSU so I can guesstimate it. What AC/DC voltage and current do you use, is it a
Very interesting. I'll check this book out too. Only during the peak power excursions where plate voltage gets close to This amplifier is grid driven. 73, ukasz - SP4IT ______________________________
Hi, I found the full power supply specification in some old documents. This is very surprising ,because usually in manuals there is a note that technical specs are classified. So what did they consid
We are talking about a 3 phase full wave rectifier here so the ripple frequency is 300Hz. After a string of minor problems (including discovering DC blowers with built in drivers do not like strong R
I'm not sure these IMD measurement can be compared between different setups. I measured the same thing using a tinysa spectrum analyser and I got completely different numbers (30dB instead of 26dB).
Hi, Does anyone know how to set the TX delay with Kenwood TS-690s? This radio is very similar to TS-440 so maybe you know the setting for that one? I need to change it for VOX. I heard it is changeab
Thanks for replying. You're 100% correct Thank you for clarifying. This is quite surprising. I've overbuilt my T/R relay box somewhat with these huge open relays, but they do take 20ms (measured) to
I'm currently working on final touches of restoring an old military tube HF amplifier that has very useful mechanical memories. It's constructed in a way that there is no need to retune within the sa
This will be difficult . I can pull at most 4mA at 3.3V on the control lines out of the uC board. That is not a lot of power.... I'm already at over half of that, so realistically ... I can't pull mo
Thank you for replying , but I don't see what the benefit would be. Quite the contrary the way I think about it. With BJT at least the signal has to drive enough current to open the transistor. With
Hi, In certain rigs/amps running at very low power level can result in much worse signal quality for various reasons. Is this the case in tetrode (common cathode) amplifiers ? Let me explain what I'm