Stock 5E3 B+ Voltage

[Diablo]

I heard a rumor that MM doesn't use Kraft paper as an insulator in their transformers - they use $20 bills......

I'm all for buying American, but these guys need to drop their prices about 40% to be competitive with other American transformers. The largest cost in a transformer is the steel and the copper, and these materials are just as inexpensive in the US as overseas. I work for a company that sells steel for transformers and motors. I've also toured transformer factories, and understand the build process.

[KingCameron]

Bruce is a good dude!

Yup, go with Bruce...he's helped me many times....a good dude in my book

[KingCameron]

Prices at MM

I heard a rumor that MM doesn't use Kraft paper as an insulator in their transformers - they use $20 bills......

I'm all for buying American, but these guys need to drop their prices about 40% to be competitive with other American transformers. The largest cost in a transformer is the steel and the copper, and these materials are just as inexpensive in the US as overseas. I work for a company that sells steel for transformers and motors. I've also toured transformer factories, and understand the build process.

I know I'm starting to sound like an MM sales guy, but....
They are only expensive if you buy directly from them, in small amounts.

If you want 40% off, go to ebay...or contact a builder like me, who has bought over 10 units from them. We get a big discount for buying lots of items from them and can pass along the savings.
I think MM has tried to structure their ASPs this way to encourage a network of amp guys, and limit the small time buyers coming directly to them....it does not mean all their stuff is expensive, it means you have to be smart about how you buy from them.

Plus, as far as I'm concerned, building amps is an art form...do it right, don't just make it work...this way 40 years from now, some guys will be sitting around figuring out how to repair our old amps

[mbratch]

I find the Sovtek 5Y3 to be way higher in voltage versus any vintage 5Y3.

I've compared the Sovtek with vintage Tung-Sol and Ken-Rad 5Y3 rectifiers and with 3 different power tube sets (new JJs and a couple of vintage sets). The B+ voltage generated by the Sovtek 5Y3 measured consistently at ~40V higher than the other 5Y3's.

I've checked eBay for MM Deluxe PT's and the only ones I've seen so far have all been the FTDP model, which is the 380-0-380.

I have the Mojo MOJO756 PT. The voltages are 384-0-384. With that PT and a vintage 5Y3 all in the Mojo 5E3 kit, I'm getting B+ voltages of around 360 to 365V. Using the Sovtek 5Y3, I'm getting 400 to 405V. My wall voltage is 120VAC.

[Five_E35]

A number of people have said the Sovtek 5Y3 acts more like a 5V4 or even a weak 5AR4. Russian rectifier tubes also don't have a very good track record for reliability, maybe that's why Fender included the bomb-proof rectifier diodes in the RI? Many Russian & eastern block tubes aren't really what they say they are. Some people call the JJ 6V6 a 6VL6 and their EL84 will not physically fit in a vintage AC30. The Sovtek 5881 appears to be the same tube as the tube they sell as 7027a, with a different base & pinout. It takes abuse like no real 5881, so it's probably is closer to a 7027a. The common Sovtek 12AX7WA & WB is closer to a NOS 5751 than a real 12AX7WA.

A 40V difference is about what I get in my 5E3 going from a JAN Sylvania 5Y3WGT & 6V6GTA's(~350-360v) and a small bottle GE 'copper stripe' 5AR4 & NOS 5881's(~395v). There is a significant difference in idle current & I'd guess the 5AR4 with 6V6's would go another 10 volts higher, but I'm not about to try that with the GTA's.

The Tube World web site has good pictures of many NOS tubes that can make identifying relabeled NOS tubes like the Ken-Rad 5Y3 easier. Might be an RCA.

https://www.tubeworld.com/index_high.htm

[Ringwraith]

Is the Mesa Boogie 5Y3 a re-branded Sovtek??
I just scored a bunch of old 5Y3's at a Hamfest & they all produce the same voltage as the Mesa Boogie.

Sean

[mbratch]

I've read that JJ 6V6S tubes are more 6L6-like, but more in terms of sound perhaps. They also spec at a max plate dissipation of 14 watts whereas some modern 6V6's I've looked at spec at 12 watts. I've used them in my 6V6 amps and really like them even compared to NOS 6V6s. I've also used JJ GZ34 (5AR4) tubes without any odd voltages compared to other 5AR4s. I have found JJs all areound to be quite reliable.

Sovtek tubes are a different story, especially the 5Y3 and 6L6's. My experience with their pre-amp tubes has been OK, but I have had nothing but trouble with Sovtek 6L6's and the 5Y3's. Often the 6L6's have arc'ed and blown fuses. Or, in the case of the 5Y3, make a rattling/jingling noise (in addition to producing incorrect voltages).

I generally don't hesitate to buy a new JJ, but I stay away from Sovteks. YMMV.

I apologize, I'm going OT on the OP.

For proper B+ in a 5E3, I would stay away from Sovtek 5Y3's unless your components are designed to accommodate the overage in voltage compared to other 5Y3's.

[MWJB]

The JJs sound to me like a more "solid" 6V6, not really like a 6L6. After all the JJ6L6 sounds different to most other 6L6s, but it still sounds like 6L6.

6V6GT have been rated at 14W for the better part of the last 50yrs.

"Sovtek" tubes are made in the Reflector, Saratov factory...like EH, RI Tung Sol, GT(R), the new Svetlana (as opposed to SED) etc.

[Five_E35]

There was a small bottle tube Sovtek sold as a 6L6GC that couldn't handle what their 5881 could. Grove Tubes used to sell that tube as a 6V6HD, with the note that it drew more filament current than a real 6V6.

JJ's are reliable and hopefully the new 5AR4 wil be too. FWIW, Victoria is now shipping the 20112 5E3 clone with a JJ 5AR4 and JJ 6V6GT's and call it a 20 watt amp in that configuration. The tube chart now says 5AR4 or 5Y3. I don't know if they've made other circuit changes, such as a larger cathode resistor.

[mbratch]

6V6GT have been rated at 14W for the better part of the last 50yrs.

Most of the data sheets I can find indicate 12W and max plate voltage of 350VDC. Exceptions are the RCA 6V6GTA and the JJ 6V6S.

I haven't found a data sheet for the re-issue Tung-Sol 6V6GT, but I had read in a thread here on the M.E.F. regarding a reply from New Sensor when asked about the re-issue Tung-Sol 6V6GT:

"The Tung-Sol 6V6GT has a maximum plate voltage of 475 volts. It has a plate dissipation of 12 watts. This tube was designed to be used in high plate volt amps such as the Fender Deluxe Reverb."

[MWJB]

The GE 6V6GT/6V6GTA data sheets in your link show 14W max plate dissipation.

I knew that the Russian Reflector has current issues, they'll take mid 400's voltage-wise, but Myles Rose advised me to stay around 19mA in BF Deluxe style amp. Has anyone ever seen figs for the Chines 6V6s.

Yes, they all show 350v max plate dissipation (except for the current production high voltage types) but were often successfully run in amps at way over this. Power tubes are often run at higher voltages that data sheets recommend in popular guitar amps.

In reality, a 6V6 with a real 12W limit would struggle to find a place to live, as even many vintage, cathode biased PP amps run them harder than this.

[mbratch]

The GE 6V6GT/6V6GTA data sheets in your link show 14W max plate dissipation.

Yes, sorry. I was looking at the class A dissipation instead of the max.

Do you have any specs on the new Tung Sol 6V6GT? I'm still curious about that one, being new production. The information I have (12 watts) is second hand.

[MWJB]

Data sheets on Reflector tubes are rare, SED had some but I don't know how well I trust them, don't think they offer a 6V6 anyway.

I would think that the TS would be much the same, dissipation-wise, as the other Reflector made brands (EH etc), but that's an assumption (which I guess I shouldn't really do).

Fender fit the EH to their 5E3 57 Deluxe and I know of another guy who fits Reflector 6V6s to his cathode biased builds & they hold up fine at 430v (uncorrected) at the plate & around 30mA. So if they are just 12W, they can certainly hold up at 12W all day long...which may be the case, or they'll take a bit more. Sorry, more Q's than answers but I reckon the anecdotal evidence tells you more than a data sheet anyway.

[screamingbirdamps]

5e3 power trannys

my origional gave me an under load voltage of 330volts i have built and repaired mojo kits and found their b+ very high, to high lots of distortion and not good.The later black and silver deluxes push the b+ up to 430-450 but thats a different amp design.also measured trannys (origionals)were as follows 5e3 8k a-a later 763 circit 6.6k a-a hope this helps.