Rogers HG88 - UK Vintage Radio Repair and Restoration Discussion Forum

dfriedman · 4th Dec 2020, 9:46 pm

Hi to all
Yet - I've a Rogers HG88, no Mk #. Mine has: 2xEF86, 3x ECC83, 4x ECL82, 4x Sil rectifiers over the 2 old sections to create the bridge.
A schematic I obtained of the same as mine has 5x ECC83 - how is that?
An Mk II has 2x EF86 4X ECC83, 4x ECL86, GZ34 - so, this's not my version.
in an 8 page description a HG88 II, the component layout shows 2x EF86, 2x ECC83, 4x ECL86, GZ34. But the schematic here of HG88 II, shows 4x ECC83 - other tubes have the same count. Cannot be mine either.
So what's going on here & what's my version - even that it hasn't got a suffix? Can anyone of you explain this? I've no problem repairing it - have already determined that 2x 500o 3w resistors have gone "dry" + who knows what else...
Dany, Toronto, Canada

vidjoman · 4th Dec 2020, 11:14 pm

Don't forget that an ECC83 has 2 triodes in each glass envelope. It maybe that the drawing shows them as 4 x single sections and it has been labeled as 4 valves. I can't recall seeing any HG88 with 4 ECC83's. The version with 4 x ECL82 would be earlier than any version with ECL86 valves.

GrimJosef · 5th Dec 2020, 10:49 am

Rogers did have a bit of a habit of building different amps and giving them the same name. I think the HG88 might have been the worst in this respect. If the front panel is original and if it has no Mark no on it then I suspect that means it is some sort of Mk I (for obvious reasons no-one ever writes Mk I on anything commercial).

Cheers,

GJ

Silicon · 5th Dec 2020, 4:31 pm

Is it possible that this is a standard HG88 that someone has converted to ECL82 because the ECL86 tube is becoming scarce?

Edward Huggins · 6th Dec 2020, 5:04 pm

I very much doubt that. You can't readily substitute an ECL86 for an ECL82 as the anode load impedence is different. This would mean a change of output transformers - making for a very expensive downgrade!

4th Dec 2020, 9:46 pm	#1
dfriedman Triode Join Date: Mar 2016 Location: Toronto, Ontario, Canada Posts: 18	Rogers HG88 Hi to all Yet - I've a Rogers HG88, no Mk #. Mine has: 2xEF86, 3x ECC83, 4x ECL82, 4x Sil rectifiers over the 2 old sections to create the bridge. A schematic I obtained of the same as mine has 5x ECC83 - how is that? An Mk II has 2x EF86 4X ECC83, 4x ECL86, GZ34 - so, this's not my version. in an 8 page description a HG88 II, the component layout shows 2x EF86, 2x ECC83, 4x ECL86, GZ34. But the schematic here of HG88 II, shows 4x ECC83 - other tubes have the same count. Cannot be mine either. So what's going on here & what's my version - even that it hasn't got a suffix? Can anyone of you explain this? I've no problem repairing it - have already determined that 2x 500o 3w resistors have gone "dry" + who knows what else... Dany, Toronto, Canada

4th Dec 2020, 11:14 pm	#2
vidjoman Dekatron Join Date: Jun 2013 Location: East Sussex, UK. Posts: 3,326	Re: Rogers HG88 Don't forget that an ECC83 has 2 triodes in each glass envelope. It maybe that the drawing shows them as 4 x single sections and it has been labeled as 4 valves. I can't recall seeing any HG88 with 4 ECC83's. The version with 4 x ECL82 would be earlier than any version with ECL86 valves.

5th Dec 2020, 10:49 am	#3
GrimJosef Dekatron Join Date: Sep 2007 Location: Oxfordshire, UK. Posts: 4,311	Re: Rogers HG88 Rogers did have a bit of a habit of building different amps and giving them the same name. I think the HG88 might have been the worst in this respect. If the front panel is original and if it has no Mark no on it then I suspect that means it is some sort of Mk I (for obvious reasons no-one ever writes Mk I on anything commercial). Cheers, GJ __________________ http://www.ampregen.com

5th Dec 2020, 4:31 pm	#4
Silicon Nonode Join Date: Jun 2007 Location: Coulsdon, London, UK. Posts: 2,163	Re: Rogers HG88 Is it possible that this is a standard HG88 that someone has converted to ECL82 because the ECL86 tube is becoming scarce?

6th Dec 2020, 5:04 pm	#5
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,328	Re: Rogers HG88 I very much doubt that. You can't readily substitute an ECL86 for an ECL82 as the anode load impedence is different. This would mean a change of output transformers - making for a very expensive downgrade! __________________ Edward.