I'm planning to build the Angela SE 6SL7->EL34 (triode strapped) amp. Their designs call for GZ37 rectifiers, but as this is to be a low-cost project, I don't want to chase NOS tubes down at high $$.
I'm thinking a 5AR4/GZ34 might be a decent replacement here-- draws 1A less current, but is rated for 160mA Irect compared to the GZ37's 250. So perhaps a 5U4G, rated for 225mA Irect would be preferable, and I have some of those around.
Thanks in advance for any advice.
I'm thinking a 5AR4/GZ34 might be a decent replacement here-- draws 1A less current, but is rated for 160mA Irect compared to the GZ37's 250. So perhaps a 5U4G, rated for 225mA Irect would be preferable, and I have some of those around.
Thanks in advance for any advice.
Check the data sheets out. The 5AR4/GZ34 is rated for a 250 mA. draw. The GZ37 is rated at 275 mA. into a cap. I/P filter and 350 mA. into a choke I/P filter. Also, the GZ37 data sheet says 4 muF. max. for a cap. I/P filter.
The forward drop in a GZ37 is greater than that in a GZ34. So, the B+ rail voltage will be somewhat higher. Current production 5AR4s have improved significantly of late and that's what I'd use.
The forward drop in a GZ37 is greater than that in a GZ34. So, the B+ rail voltage will be somewhat higher. Current production 5AR4s have improved significantly of late and that's what I'd use.
Eli Duttman said:
Which data sheet would that have been? My Mullard data sheet simply gives data using 4uF as a reservoir, but given that the data sheet was from 1958 (and probably an update of an earlier one), perhaps that's not indicative? The peak current ratings suggest that it ought to be equivalent to a GZ34 - it just uses more heater current.
Of course, you could always use a pair of 6CL3/6CK3 or 12CL3/12CK3, which are substantially beefier than GZ34, and in your neck of the woods, probably cheaper.
The 5R4 can deliver plenty of current too. 4 muF. is max. for that type too. Arc over at start up is NOT good.
There are reports about the GZ37 sounding mediocre when used as a substitute for the GZ34. My hunch is that the tube is stressed, even if it does not arc over with a substantial filter cap.
The data sheet I've seen was published by Chelmer Valve.
There are reports about the GZ37 sounding mediocre when used as a substitute for the GZ34. My hunch is that the tube is stressed, even if it does not arc over with a substantial filter cap.
The data sheet I've seen was published by Chelmer Valve.
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