C354+ Choke Needing a Tester

[Geek]

Hi Guys,

A couple of you here know I had been talking about a bigger & better choke for the ST-70.

I have a sample from my partner and here's the data:
www.classicvalve.ca/docs/C354+_docs.pdf

Anyone interested in giving me 3-rd party FB on it?

They will retail for $25, but a tester can have one for $15 (I'll make up the cost with my supplier) + shipping (~$15... it isn't light).

Only one available for testing now.

Cheers!

[Geek]

Size comparison....

http://geek.scorpiorising.ca/contrib/Ge ... ompare.jpg

[danf]

This is a great idea. I'd jump on this if I had an appropriate project underway - ST-70, Mark III, etc.

[jgf]

I'm interested in being the guinea pig. What sort of testing do you want (besides putting it in a stereo 70 and listening?)

[Geek]

I'm interested in being the guinea pig. What sort of testing do you want (besides putting it in a stereo 70 and listening?)

Thank you!

If you have heard an ST-70 with the stock C354, basically tell me what you hear in change (if any) with the extra inductance and if you want to get more complex, if you find the B+ steadier under use.

Cheers!

[jgf]

Much appreciated. I'll set up at least a voltage test point, and if I can figure out how to rig a probe to deal with the HV, I'll put my scope on it. Maybe I can capture the output to a computer sound interface.

I'll PM you my info.

[jgf]

I jumpered the new C354+ choke into my 70 early this past week, and I'm liking what I'm hearing.. Improved bass and better clarity throughout the range. I haven't done any measurements until this morning (too dang hot!... 90+ degree days) but I got some measurements this morning, just with a dc multimeter. I'll post those soon.

[Geek]

Great news so far, thanks!

[highflyin9]

Very exciting! I may be looking for a couple when you roll them out :)

[EdStiles]

Just a thought... could you build them with with a couple of more Henrys and a higher DCR? My perverted thought process is to decrease the B+ slightly to adjust for the higher AC that is typical today (120-123v locally vs 115v as designed). The higher AC line voltage adds 20-30 volts to the B+ DC voltage, exceeding the rated 525 VDC on most Dynaco caps. The additional Henrys would help the filtering, the higher DCR would drop a few B+ volts.

I rebuild my Dyna Mk IIIs with either a 5 Hy, 200ma or 7 Hy 150ma choke on an extra chassis (and use 30 mfd of Solen 630v caps for the first section, then join sections 1 & 2 togeter). It definitely improves the sound.

[Geek]

Hi,

These are purely as a C354 improvement, hence they must be the same DCR. I'm not getting into custom iron, sorry.

I suggest perhaps a custom choke from Edcor... Hammonds of the current rating will not fit in a Dynaco chassis.

Cheers!

[Geek]

Project has been scrapped. Thanks all for your interest!

[highflyin9]

Hi Geek,

Sorry to bump an old thread, but what was the reason for scrapping the project?

[Geek]

Even drop-shipped straight from the manufacturer, it costed about twice as much as any other ST70 choke