Don't know if anyone will be able to help with this.
My Icon Audio headphone amp uses two 6sn7 valves. I'm interested in trying some Mullard ECC32 tubes which I've seen advertised, but I'm unclear whether they will damage the amp.
There is a very good 6sn7 reference thread on Head Fi, which says that 'the current draw (of the ECC32) is 50% higher and this will fry most transformers', and so the ECC32 is not a drop-in replacement. I believe this is because the Ah (heater current) for the ECC32 is 950 mA, but the Ah for a 6sn7 is 600 mA.
I have contacted Icon Audio to ask what the maximum Ah (heater current) capability of the headphone amp is, but didn't get a reply.
The information isn't in the user manual, or anywhere on the web.
My assumption is that if my headphone amp is designed for a tube with a max draw of 600 mA, it may not be able to handle the ECC32. However, I'm not a tube expert. It may be that the transformer in the Icon was built with enough headroom to cope with the extra draw.
Has anyone tried ECC32s in an HP8, or is anyone else able to advise?