ClassicTone Customer Service is Excellent!

[big_teee]

Justin:
A 300-0-300 PT with diodes,should do the 420v or so, pretty easy.
I may try that if I ever do another 6v6 build.
A 2 tube bass amp will probably be my next, but not 6v6s.
T
**Sorry, I posted about the same time as Stratz!

[bob p]

Hi Bob.
In defense of people such as myself (first time build and I chose the Mojo Tone Deluxe Reverb kit) Classic Tone lists their 40-18016 as a replacement for the Fender (Schumacher?) 025130 and125P23B PT's.

your link is to an OT, but I found the spec sheet you're referring to. It's spec'd at 660VCT@120mA.

What I have for voltages (at idle) is quite different than their posted voltages.

I promise, this is the last time I'll say it: 20 ma != 120 mA

Tom already brought up the fact that quiescent voltages and load-condition voltages can never be expected to be the same.

Another cruel truth is that if you look at the Tung-Sol and GE 6V6-GTA spec sheets, they don't show any operating conditions in which a pair of 6V6 produces a 120mA load.

That 40-18016 PT lists a B+ voltage of 413V using a 5AR4 with a load of 120mA. Those operating conditions won't come close to being be matched by a 20mA load at idle, and may not be matched by a pair of 6V6 that only present a 70-90 mA load.

I have to confess -- I don't understand why people who are running into high voltage problems insist on sticking with SS rectification, or using something as stiff as a GZ34. Need more drop? Use a 5Y3 or a 5U4. That's got to be the oldest trick in the book.

[Stratz]

your link is to an OT, but I found the spec sheet you're referring to.


I promise, this is the last time I'll say it: 20 ma != 120 mA


I also don't understand why people who are running into high voltage problems insist on sticking with SS rectification, or using something as stiff as a GZ34. Need more drop? Use a 5Y3 or a 5U4.

Sorry about that Bob. I do understand your point.

The reason that I chose the GZ34 (other than the fact that it came with the kit) is because I like it.
My '73 Deluxe Reverb had the 5U4 and it was soft and mushy. The GZ34 is much stiffer just as you say. I own three vintage Marshall's with SS rectifiers and I like the pretty much instant attack.

My original plan for my DR build was to go with a SS rectifier replacement but I dont think that's an option anymore.
Many of the current production 6V6 valves are spec'd for ~ 500v so I'm not worrying about it.

Thanks for your input.
Rob.

[Steve A.]

I guess all threads get hijacked eventually, and this one is no exception. Honestly, I like the way the hijack has gone in this thread, because you and Terry are addressing the same concerns that I've dealt with many times. These are the types of problems that has had everyone banging his head on the desk at one time or another.

Heck, if threads weren't being hijacked this wouldn't be the Music Electronics Forum...

Back in the days of AMPAGE I judged threads positively by how many side trips and diversions they took in their meanderings. A really good thread would touch base on every single issue that was important in life... "Off-topic? No such term found in database, Dave."

You posted good experiences with CT's customer service, for Terry it was not so good...

With CT selling replacement transformers for classic amps I would expect them to put out reasonable voltages when installed in those amps. (You brought up a valid point about tweed deluxes running at much lower B+ voltages than the AB763 so I would only look at the BF/SF Deluxe Reverbs.) As you pointed out there are ways to lower B+ if necessary.

BTW in the early 2000's Bruce Collins mentioned problems he was having with Hammond iron and why he had to switch to another mfg for his custom trannies: their contract specified a tolerance of +/- 20%, not close enough for rock'n'roll or government work...

Steve Ahola

P.S. I've used Bruce's trick of inserting zener diodes between the CT and chassis ground to lower B+ over 50VDC with no discernable negative effects observed besides the obvious loss in total power available.

[Chuck H]

I only browsed the thread, so please forgive if there's a "We already covered that!"

My own experience with Edcor has ben mixed. They can be somewhat curt. I think they're a close knit group (as in family and/or friends) and not all the positions are filled by people who behave professionally WRT customer service. That said... They have made adjustments to their product specs for me on two occasions. The last was a PT I was interested in that didn't offer the primary I required. I asked about whether they could accommodate me and the person on the phone said "Wait a sec and I'll ask." Then, shouting over their shoulder "Hey! Can we..." Then, back to me "Sure we can do that." It was sort of cute really.

My latest experience with them was less amicable. Maybe someone burned the toast that morning. It's alright. Stateside magnetics shops are usually pretty blue collar and I'll wager their employee list is smaller than anyone would expect.

Their products are pretty, full featured and the few transformers I've purchased have performed above expectations. Running quiet and cool with no unexpected considerations to compensate for.

I haven't used any Edcor products for any EL84 builds as yet. I used Hammond for all the PT's and Hammond, Heyboer and Classic tone for OT's. The hitch with the Hammonds was that, at that time, they only had the 115V primary. So all the voltages ran high of spec on American 120V outlets. This was easy enough to calculate for WRT HV but correcting for high filament voltages requires circuit modification. I used the 270EX and a rather large 150R series resistor on the HV rail for 2XEL84 amps for a Vp of about 365. I also built two 4XEL84 models but I can't remember the PT I used for them and I lost the info in a pooter crash. I could probably just pick it off the list at the Hammond site though. The current offering includes a 125V primary tap. I would use that and reduce the sag resistor if/when I build another 2XEL84 order for a little lower Vp and less fuss with the filament supply. I like the 270EX for it's higher current spec. The amps I made with these were designed (and intended) to run balls out full time. The truth is that the DX or DAX (if you're using a 5V tube rectifier) are probably up to the chore and I've used those models too in standard use designs (only sometimes cranked ) with good results.

Regarding the OT's... The Hammond 1608 is the hands down winner for tone. I've also accidentally abused this model in extensive proto and modification work and never managed to blow one up. So that's my first choice. The Heyboers were proprietary, but probably not much different from one of their standard offerings and sounded great too. A little "smoother" tone than the Hammonds, which I actually didn't prefer. YMMV. These were used in builds that didn't get treated to my clumsy prototyping and bench work but these amps are still working well after seven years of frequent cranking. So I'd guess their also quite reliable as the Hammonds are. The Classic tone OT is smaller and boxier sounding. More mids, less chaos, less top and bottom. Only ever used in a self contained "powered reverb" amp that doesn't get cranked into clipping. But I did test it for guitar amp use and if you're after that smaller, boxier kind of tone (hey, some guys like it) then it's a good, inexpensive option.

That's my experience and $.02