JRS94

Have l-pads already, just thought a tap change could get the l-pad to be "less involved" if the transformer did the work. Jimjimbo, saw your post on enclosing the backs. Don't know which thread you're looking for, but I enclosed mine, used 1/2 in birch plywood. Works fine to my old ears. I did add 2x2 support on the inside. 6 screws per panel and some RTV. Easy to remove later if I ever move to a place with Proper corners. My khorns are mutts anyway, Crites and Volti.

Khorns with Crites Type A crossovers. I want to quiet down my mids a little, Currently wired to 0 and 4 on 3654 transformers, which taps do I move to? Thanks

WHat does the Xilica4080dsp do for you, fancy eq? Looks to be all non rca’s.

Looking at the BMS 4592 mids for my Khorns with Volti Horns and learned about the BMS 4592-6HE apparently has a shorting ring and a bit better harmonic distortion. Anyone heard of or tried these 6HE versions? Thanks

Thanks, that’s what I’m after

Did you find the bms to be a large improvement?

More update, replaced the auto bias board, problem appears solved. 300 hours on the new abb. Also notice that Bob no longer recommends the abb. Will update if anything changes.

I have the Volti horns in my Khorns with the John Allen a55g mids, what did you replace the bms with? I’m interested in upgrading. thanks

Update, swapped to a Weber WS-1 with thermistor, amp has been running well since then. Bias still moves up a bit for no reason with the AB board, but at least the amp turns on and runs. As stated earlier I'm on a variac, keep voltage to 115v as much as possible, House voltage swings from 112v to 124v and back quite often. Bias is set at .450v and swings to .600 at which point I flip the amp over and readjust the AB board. Not optimal but not enough to want to change amps. The ST-120 is great with the khorns.

Yup thanks, Using both Bob and the dynaco forum. Gonna try a Weber ws1. Bob thinks it may be auto bias board related. In contact with Pavel as well.

My VTA ST 120 blows the rectifier tube. Last one was 5ar4 tung sol. Happens Every 3 months or so. Usually takes the fuse too. Amp is running off a variac kept at 115v. Power tubes are kt120, Drivers are 5963 hp branded RCA. I keep bias at 450ma via an internal auto bias board. Speakers are khorns. Any ideas? Thanks

Well, it never held a constant value. Bob knows all about it, it blew the fuse now and is on it's way back to Arizona where it was built. More to come...

My St120 has the auto bias board. Supposed to be set it once and forget it. Only 1 trim pot on the inside. This week it drifted from 0.500 to 0.700vdc. All 4 tubes read the same but 40% increase in a week. Anyone else have this experience?

Thanks , currently using KT 120's, TAD gz34, 3 5963's all supplied by Bob. This bias thing is getting crazy. Amp ran up to 0.900vdc today. More to come.

Amped, Thanks for the contacts, I’ll reach out if it acts up again. Since I opened it up and readjusted the autobias board pot, bias has been steady. Keeping a close eye on it since I have no idea why it ran up. I do like the amp a lot, but this one has been problematic so far. Take care, Joe