spritzer

Yup, they will fit. I use the Hirschmann clip on probes and they are excellent. They don't like 5A passing through them in an instant but that is to be expected...

Since you are dealing with 600V only mm from the ground plane it would be a good idea to make a small loop on the PSU side of the 5M resistor to make measuring easier. The PSU is regulated at +580V so it should just work.

I do have a new transformer box that needs to be tested so I'll probably report back soon. Now where did I put that T-amp... Let's just put it this way, I know the 009's traits well enough now to know what works for them and what doesn't. Super transparent amps are not an ideal match in my book. For your requirements I'd get a mint 007Mk1 and never look back. Perfect amount of top end and the reward every upgrade to the signal chain.

Yup, that would do it. We really should add a bias test point on one of these PSU's...

Well they are sitting next to the amp but I'm sure it will not be a match I'll like. They will be waiting for my SRA-10S mods (all new active parts).

...and reversed caps and some solder blobs.

Haven't touched the 009's yet.

From those specs the OTL version of the Electra is far better than the WES so I hope we'll see something crazy.

I figured it was time to say a few words about the KGSSHV since I've finally been able to live with a "fully built" unit for a while now. It's always hard to comment on that pile of parts over there... Now I'm a bit biased when it comes to the HV given my involvement in the project but I'm also very hard to please so it should balance out. I also constructed the HV to be as close to my KGSS as is possible and vital parts such as the volume control are the same. The goal with the HV design was to eliminate the slight bloom and the ever so slightly warm nature of the KGSS and I must say this was accomplished without going too far away from what made the KGSS great. The KGSS was always very revealing while being forgiving of less than stellar material and the HV is still like that but now even cleaner sounding when the going gets tough. Even with the 007Mk1 at silly levels it never runs out of steam. This was a particular concern of mine since the onboard heatsinks limit the standing current of the output stage but I'm glad it wasn't a problem. Anybody who thinks the LCD-2's are the bass kings really needs to hear the HV/007 setup. Even in sheer output the Stax wins... What has really stood out for me is the layering and detail retrieval of the HV. Feed it something good and it can dig out miniscule details and revealing slight mic differences. Not sure why this is the case compared to my old KGSS but this is BHSE territory. The extra power and extended frequency response seem to be doing wonders to open up the top end of the 007mk1. Color me very impressed. even if this can be a bit scary at times.

The KT120 is a promising tube and I'm glad Craig dropped the 300B. I'm building a SE amp with 300B's (or rather I have all the parts but no time) but to me it's just a curiosity. I know it will never work as well as a full push-pull circuit but at least it will never be as bad as the A-10... I don't think anybody who's seen inside the EC amps will ever contest the use of less than optimal parts. I'm all for cheap parts that perform well (as in not spending a fortune on Mundorf caps which are just rebadged F&T units for instance) but some of the parts are too cheap and do not hold up with use. Take the Lorlin/Alpha/"who else makes them this week" switches he uses and all the issues they have caused. There will be a full circuit analysis of the LL shortly after the first units ship but seeing how hard some people are pushing IXYS parts as some superior beings (which they aren't) I'm guessing mosfets for the output devices. A truly bad idea compared to excellent BJT's such as the 4686/4686A.

Ahh 6L6 makes a lot more sense. Don't know why he didn't just go with EL34's but then again Craig likes to be a bit different. I do have high hopes for the Electra since the WES is a dud and so is the LL (unless you happen to like a SRM-323 with mosfet output). I just hope Craig has given the assembly monkeys a good thrashing and spent a bit more money for more reliable parts. As for the SE electrostatic amps, you basically have all the issues of a SE amp plus have to deal with a transformer doing the phase splitting and probably some gain. As such it will never be a contender for a TOTL solution but should be fun none the less.

Single ended fed through a transformer is a novelty act, no more than that. Also, is he using 6SL7's as output tubes in the OTL version?

I'm looking at the schematic for the digital inputs but I don't think I understand half of it. Edit. I see Kevin got the service manual.

Long live simple fixes. If anybody wants the full service manual, drop me a line since I do have it.

So if you tap the board and it gets better? If so then the relays probably are acting up and I'd start by replacing them. Those Omron's look to be no longer made but I'm sure they have a pin compatible replacement.

Flux shouldn't cause shorts under any circumstances but it won't do any harm to clean the boards.

Those of us who are truly insane just buy everything in multiples of 100...

All of the PSU's acting up does point to the transformer or something wrong with the ground. They are the only shared elements. That's indeed the rub. There is something to be said about beginners luck....

Yeah, that's not out of the ordinary but the true test is under load to to the heat rise. One thing I wouldn't rule out is a short on the board. One of my HV amp boards is going onto the trash heap since the PCB has a short somewhere.

How much voltage is the transformer putting out? If it runs too hot then it might develop a short and boom, way too much voltage for the parts.

They will fit since the Vishay CMF60's are also 1/2W.

The plan is to introduce a relatively simple amp that can drive any headphone to destruction and be fully Class A. The EF-6 is a nice design for the price but we can't settle for something commercial.. For the transformer, bigger is usually better and with Class A amps you should spec at least double the max current draw. Be vary of the inrush current though.

For the fuse I use 2A slow blow but I use that for pretty much anything smaller than a T2/BH/ESX. Hey... I'm using those cases too.... So exact same setup with an even smaller box (2U) and no heat issues, in fact it runs cooler than my old KGSS. Now take the normal thermal drift of the IXYS parts (the 2SA1968 are much better in this regard) add forced cooling and there will be some very interesting results.

Happy Birthday Gary!!

Happy Birthday Al!!!