It is up and running !

[Audio Al]

Just home from the boat club and found a box in the porch

From Watford valves

Plugged them in , power up and Woo Hoo its up and running

Will do some photos and comments tomorrow after some listening

[Audio Al]

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As promised even though its a bit late Photos

MY Audio Innovations 500 , Pure Class A 25watts per channel

Its BIG,its heavy, it Powerful and it can boogie
Now fitted with a matched quad of Harma EL34/STR Valves
2 E88CC/JJ-Teslas for the phono stage
3 Harma ECC83's

This amp also appears to have the rather nice Hinchley mains & output transformers.

The amp can drive 4 Ohm 8 Ohm and 16 Ohm speakers , it also has a built in phono stage

Well pleased with the outcome , I have had this for a couple of years , Last year Graeme ( Valvebloke ) ( Ampregen ) took it away and repaired what was needed to get it up and running , so a big thumbs up for that

[Idlewithnodrive]

A cracking amp Al, which also sounds fantastic with 6550's. I much preferred them to the EL-34's

[Audio Al]

A cracking amp Al, which also sounds fantastic with 6550's. I much preferred them to the EL-34's

Cheers Mike

I was advised not to use the wide body valves as it may cause over heating due to the close positioning of the valves in the amp , hence sticking with the original slim body type EL34's

[PaulStewart]

Hi Al,

Looks good, I really rate the Harma EL34s I use them in my Art Audio Quintet in triode mode. Only gives me 17 watts a side but with the Monitor Golds in the Lockwoods this is more than adequate. I have to confess to not being a JJ fan, but let us know how they fare long term.

[hard1175]

Hi Al
The audio innovations was my first valve amp many years ago and to this day I still regret selling it.

Bernie

[TheMooN]

It does appear like you may have just enough space between output valves to utilize straight sided 6550's such as winged C's etc, etc, however, were you to push the boat out for Nos GE 6550's , well

[Idlewithnodrive]

I used Winged C's with no probs.

Lovely.

[Spectral Morn]

It does appear like you may have just enough space between output valves to utilize straight sided 6550's such as winged C's etc, etc, however, were you to push the boat out for Nos GE 6550's , well

I seem to recall that 6550's don't work well in this amp, 5881s work fine (my choice for this amp) as do 6L6 but for 6L6 one needs the circuit tweaked.

Fabulous amp, I still have mine. The version with the 3 output taps is the best, later ones were not quiet so
good.

Anthony TD can give you more info re suitability of valves and the changes needed made to the amp to safely run electrically similar but different valves to EL34s.

Regards Neil