Bush SRP31 valves? - UK Vintage Radio Repair and Restoration Discussion Forum

Dorian27 · 27th Jul 2018, 3:42 pm

I have a Bush SRP31 and the valves inside are ECL83's but I was watching an engineer on you tube servicing the same model but he said to use ECL86 valves as they gave a much better sound output. Is this correct or not and can I change mine or not, or more to the point, should I.

Thanks for any help.

peter_sol · 27th Jul 2018, 4:05 pm

Early models used ECL83's. Later ones ECL86
They are not plug in compatible
Basically as both amps were designed to give 3 watts output,
the negative feedback being changed for the later models.
So conclusion = no difference.

Dorian27 · 27th Jul 2018, 4:39 pm

Thanks

Sideband · 27th Jul 2018, 7:07 pm

ECL86's were not the best of valves in any case. Most that I have come across have been intermittent or microphonic and new replacements are 'variable' to say the least and expensive. ECL83's are fine if the rest of the circuitry (particularly coupling caps) are in good condition so if there are any waxy caps in there, change them for good polyesters. If either (or both) of the ECL83's need replacement they are cheap (much cheaper than ECL86) and plentiful.

27th Jul 2018, 3:42 pm	#1
Dorian27 Heptode Join Date: Jun 2018 Location: Carmarthenshire, Wales, UK. Posts: 569	Bush SRP31 valves? I have a Bush SRP31 and the valves inside are ECL83's but I was watching an engineer on you tube servicing the same model but he said to use ECL86 valves as they gave a much better sound output. Is this correct or not and can I change mine or not, or more to the point, should I. Thanks for any help.

27th Jul 2018, 4:05 pm	#2
peter_sol Octode Join Date: Aug 2003 Location: Welwyn Garden City, Herts. UK. Posts: 1,906	Re: Bush SRP31 valves? Early models used ECL83's. Later ones ECL86 They are not plug in compatible Basically as both amps were designed to give 3 watts output, the negative feedback being changed for the later models. So conclusion = no difference.

27th Jul 2018, 4:39 pm	#3
Dorian27 Heptode Join Date: Jun 2018 Location: Carmarthenshire, Wales, UK. Posts: 569	Re: Bush SRP31 valves? Thanks

27th Jul 2018, 7:07 pm	#4
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,580	Re: Bush SRP31 valves? ECL86's were not the best of valves in any case. Most that I have come across have been intermittent or microphonic and new replacements are 'variable' to say the least and expensive. ECL83's are fine if the rest of the circuitry (particularly coupling caps) are in good condition so if there are any waxy caps in there, change them for good polyesters. If either (or both) of the ECL83's need replacement they are cheap (much cheaper than ECL86) and plentiful. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....