Hi,
I found a pair of monoblock amps that use KT88 output tubes,with ECC 83 as input valve and ECC 82 as a phase splitter .The elderly gentleman who built them back in the 60's says that it is a GEC design.The rectifier is a 5U4G/U52
The transformers are made by Partridge and the only information I have is a connection diagram for the transformer that he gave me.There are no other details other than mentioning that it is part of the F5000 series and has four sections.The gentleman thinks that the model is 5353 but he is not certain.
The choke and mains transformer are also made by Partridge.
The amps have to be restored and I would welcome any information on the amps circuit, etc. and transformers.
Regards
Rajiv
I found a pair of monoblock amps that use KT88 output tubes,with ECC 83 as input valve and ECC 82 as a phase splitter .The elderly gentleman who built them back in the 60's says that it is a GEC design.The rectifier is a 5U4G/U52
The transformers are made by Partridge and the only information I have is a connection diagram for the transformer that he gave me.There are no other details other than mentioning that it is part of the F5000 series and has four sections.The gentleman thinks that the model is 5353 but he is not certain.
The choke and mains transformer are also made by Partridge.
The amps have to be restored and I would welcome any information on the amps circuit, etc. and transformers.
Regards
Rajiv
Hello Rajiv,
Sounds like the "88-50"
have a look at these drawings: 50W from 500V supply using the set of valves you named.
Please use new electrolytic capacitors, if you're trying it out now!
Partridge Transformers were among the absolute best in their day, and rarely, if ever, made 'cheaped out' versions.
Enjoy it, until the temptation to mod it comes on, then enjoy it even more.
Sounds like the "88-50"
have a look at these drawings: 50W from 500V supply using the set of valves you named.
Please use new electrolytic capacitors, if you're trying it out now!
Partridge Transformers were among the absolute best in their day, and rarely, if ever, made 'cheaped out' versions.
Enjoy it, until the temptation to mod it comes on, then enjoy it even more.
Attachments
Hi Rod,
Thank you very much for the information.
I will replace all faulty components before powering it on.How would it compare to a Dynaco Mk III,or similar amp?
Regards
Rajiv
Thank you very much for the information.
I will replace all faulty components before powering it on.How would it compare to a Dynaco Mk III,or similar amp?
Regards
Rajiv
The transformers are a very important part of the performance, and if the rest of the components are comparable quality, it should be at least as good as a Dyna.
Capacitor quality is very important, and Nichicon VR and KX or Panasonic HA or HB or TSUP are recommended electrolytics. I like the LCR components PC/HV/S polypropylene for lower values, or try some Russian surplus on ebay (K40Y-9 PIO, K72 Ftouroplast/teflon)
Capacitor quality is very important, and Nichicon VR and KX or Panasonic HA or HB or TSUP are recommended electrolytics. I like the LCR components PC/HV/S polypropylene for lower values, or try some Russian surplus on ebay (K40Y-9 PIO, K72 Ftouroplast/teflon)
Great find. I am sure you will have fun restoring it.
Found a higher res pic of the schematic here.
GEC schematic
Found a higher res pic of the schematic here.
GEC schematic
i have been on the 88-50 quite a while now and would be interested in the mods if they can sound better with hammonds. could you pls hilite some of those pls.
1 - fixed biased?
2 - ?
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