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SDS, Supra, MPX tuberolling, the new global, improved thread - Page 2

post #16 of 780
So how many adapters there are? As far as I know, 5687 (outputs/power), 7n7 (gain/driver). Can MPX3 use 6cg7 tubes?

What's the difference between a regular MPX3 SE with an MPX3 SLAM that Earl and others have?

Pardon my questions, as I'm a new guy to this game.
post #17 of 780
HOw many adapters are there...

Ones that are used for an octal base:

6cg7 adapter
5687 adapter
loctal adapter
6350/6463 adapter
ecc Adapter

For a 9 pin mini base (depend on the default pin out/wiring configuration):
octal adapter
5687 adapter (dpending on the default configuration)
6cg7 adapter
6350/6463 adapter
ecc adapter

Those are the main ones. And just to clarify, you can also use the 5687s as gain tubes as well, as well as the loctal tubes (7/14n7, 7/14af7) as output tubes.

The SLAM is a modification that allows the amps to use the 5687s as output tubes. The SE modification is a modfication that is optimized for the output tubes that operate optimally at higher votlages (6BL7GTAs, 6BX7GTs, etc..) With the SE modification you can also use the 5687s, however you need to just keep them at the lower setting.
post #18 of 780
Quote:
Originally Posted by sacd lover
My favorite combo with the SLAM PPX3 remains the RCA 6CG7 for gain with the Tung Sol 5687 D getter x2 for outputs. My other favorite is the Sylvania tall bottle 7N7 for gain .... again with the Tung Sol D getter 5687's for the outputs. I sometimes substitute either the Raytheon 5687wa O getter or the Sylvania 5687wa as the output tubes with the Sylvania tall bottle 7N7 for gain. If you can find the tube .... the National Union gray glass, round plate, tall bottle 7n7 is an excellent match with the Sylvania 5687wa's.

Now new tube alert .... my ECC99 tube socket adapters will arrive tomorrow. The ECC99 is a new production replacement for the 5687. I have heard good things about this tube and hopefully these will live up to their hype. I will be using these as outputs with the typical 6CG7/ 7N7 gain tubes. But the ECC99 adapter ( actually called the ECC adapters) has the same pin out as the 12AX7/ 12AU7/ 12AT7. Therefore, the Singlepowers will be able to use the 12 and ECC series of tubes as well. I will need a third adapter, which I dont have, but for now, I am also going to experiment using one of the ECC adapters with some nos 5814a's for gain with two 5687's as the out tubes. But once I get the third adapter .... I am going to see what I can come up with using only new production tubes; maybe a 12AU7 driving two ECC99's.
Are these adaptors from Mikhail?

Does this mean that any SP amp will be able to use 12AX7/ 12AU7/ 12AT7 tubes with these adaptors?
post #19 of 780
Quote:
Originally Posted by Rob N
Are these adaptors from Mikhail?

Does this mean that any SP amp will be able to use 12AX7/ 12AU7/ 12AT7 tubes with these adaptors?
Yes the ECC adapters are from Mikhail and theoretically the 12 series will work in the SP amps.

I already have some 5814a's = 12au7's. The other tubes may have to much gain. Tubes with a gain/ amplification factor around 15- 20 will work best .... in most cases.
post #20 of 780
Quote:
Originally Posted by PaulDB
So how many adapters there are? As far as I know, 5687 (outputs/power), 7n7 (gain/driver). Can MPX3 use 6cg7 tubes?

What's the difference between a regular MPX3 SE with an MPX3 SLAM that Earl and others have?

Pardon my questions, as I'm a new guy to this game.
The are adapters for using the 6cg7/ loctal 7n7/ 5687 and 6350 .... and now the ECC adapters for the 12 series tubes.

But some of the adapters work with more than one tube.

7n7 adapters can be used the 7af7 and the 12 volt equivalents 14n7 and 14af7.

The 5687 adapter can also use the 7119 and 7044.

The 6350 adapter can also use the 6463.

Here is where people get confused ..... some adapters have the same socket type .... like the 6cg7 and 5687, for example, each with 9 pin mini sockets. But they are wired differently.

Just because the adapter has the same tube socket type does not mean any tube with that type base will work.

Furthermore, some sockets will work fine at 6 or 12 volts like the 7n7 adapter. Some tubes like the 5687 can work at 6 or 12 volts but must be wired for one or the other. In other words .... the there are 6 volt 5687 adapters and 12 volt 5687 adapters.

The MPX3 SLAM SE is fitted with the higher output power transformer borrowed from the Supra model. The SE is then fitted with a high/ low voltage switch so that the amp can run the OUTPUT TUBES at 300 volts or approximately 400 volts. The 300 volt setting is for the output tubes like the 6cg7/ 6sn7/ 7n7/ 5687 and 6350. The 400 volt setting is for the 6bl7gt/ 6bl7gta and 6bx7gt tubes which work best at a higher voltage. The tubes used at 300 volts should not be used at 400 volts .... or kiss the tube goodbye.

All the Singlepower amps continue to run the gain tube at 300 volts.
post #21 of 780
PKFMan23 and sacd lover, you're da men. Your clear explanations are excellent complements to the stunning SP amps, which for some reason come to customers without a user's manual.

Back to the adapters, how would I know which 5687 is 6v, which is 12v? Provided I have a multi-meter, is there a way to find out without having to call SP and ask?

I was told Tung Sol 5687 are among the best 5687s. How about 7n7? And where do you get them?

I feel overwhelmed (and positively so) by the possibilities of tube rolling the SP amps provided to the users. These amps pack lots of value and tons of fun!

Thank you all.
post #22 of 780
Quote:
Originally Posted by PaulDB
PKFMan23 and sacd lover, you're da men. Your clear explanations are excellent complements to the stunning SP amps, which for some reason come to customers without a user's manual.

Back to the adapters, how would I know which 5687 is 6v, which is 12v? Provided I have a multi-meter, is there a way to find out without having to call SP and ask?

I was told Tung Sol 5687 are among the best 5687s. How about 7n7? And where do you get them?

I feel overwhelmed (and positively so) by the possibilities of tube rolling the SP amps provided to the users. These amps pack lots of value and tons of fun!

Thank you all.
I posted this earlier in this thread regarding 7n7's .... you must have missed my comments.

All 7n7's regardless of branding were made by Sylvania .... except the rare, gray glass, tall bottle, round plate National Union 7n7 from the 1940's.

The Sylvania 7n7's come in three styles; 1) 1940's tall bottle, silver coating at the top of the tube, gt style box plates, 2) early 1950's short bottle, silver coating at the top of the tube, gt style box plates, 3) mid- late 1950's/ early 1960's short bottle, gta type triangular plates, with a chrome top ring or clear top. I believe the gt style box plate tubes sound the best .... but the gta type 7n7 is still a very good tube.

Another good tube you can use with the same adapter is the Sylvania 7af7. The 7af7 tube looks almost identical to the short bottle 7n7 gt type box plate tube. But the 7af7 has a distictive round plate constructon. Again, regardless of the brand the 7af7 was a Sylvania tube. This tubes sound quality is much like the early 1950's short bottle 7n7. But the 7af7 has a lighter, tighter bass and a slightly more forward presentation.



As for the 5687 adapters, you order them specifically for 6 or 12 volt operation. The 5687 is wired differently at heater pins 4 and 5 to determine 6 volt or 12 volt operation. I have both voltages and I distinguish between the adapters by simply putting tape on the 6 volt adapters. Any such system will work if you have multiple adapters with the same tube sockets .... and consequently the same appearance.

Where do you get 7n7's? I will send you a pm.
post #23 of 780
Thread Starter 
Today I received a pair of black Tung Sol round plate 6sn7. They look brand new.
Although I only had half an hour before going to work, I rolled them on my Supra in the gain position with four Sylvania 6bl7 as output.

I will give them a serious listen tonight and post impressions later on.
Can't wait to be back home


I think is my 500 post
post #24 of 780
Quote:
Originally Posted by Vic
Today I received a pair of black Tung Sol round plate 6sn7. They look brand new.
Although I only had half an hour before going to work, I rolled them on my Supra in the gain position with four Sylvania 6bl7 as output.

I will give them a serious listen tonight and post impressions later on.
Can't wait to be back home


I think is my 500 post
IMO the Tungsol round plate is one of the best 6SN7's.

BTW are they oval or round mica?
post #25 of 780
Thread Starter 
Quote:
Originally Posted by Rob N
IMO the Tungsol round plate is one of the best 6SN7's.

BTW are they oval or round mica?
Yes, I was lucky to find them at a really good price; they are practically new and one has the original box; I believe the good price is because they are relabelled, but in my case it doesn't make any difference.

Rob, I will check about the mica when I'll get back home (in a couple of hours).

I suppose you use them mostly as gain tube (although I remember you saying that you also liked in all three positions). What other output tubes do you like them best with?
Have you tried with any output tubes other than 6sn7?
post #26 of 780
New tube alert #2: I am trying out Amperex 7119's as replacements in the output stage for the 5687. The 7119 has the same pin out as the 5687 and if you have a 5687 adapter you plug then right in. The sound of this particular 7119 is very close to my favorite Tung Sol 5687 D getter .... using medium impedence senn 595/ 120 ohm headphones. However, I am not sure how the 7119 wil do with loew impedence headphones. So far, the tube has all the drive and slam you could want.

New tube alert #3: I discovered you can use a tube called the 6GU7 as a direct replacement for the 6CG7. Again, these two tubes have identical pin outs. The 6GU7 is surprisingly a 6 volt version of the highly regarded 12BH7. 12BH7's run around $20-25 each and you can pick this tube up for $5-6. The RCA 6GU7 is the typical warm, smooth RCA sound but the tube has excellent detail and better high frequency extension than the 6CG7 .... which is the 6CG7's only real flaw. The Sylvania 6GU7 is a bright, clean, and very fast and dynamic tube. This tube is great for rock using the SLAM ppx3.

New tube alert #4: I have the ECC adapters now and I am trying out the 5814a / 12au7 tube. I have tried the highly regarded Raytheon ribbed black plate, two mica, D getter 5814a .... and its excellent. This tube has superior tone and is very smooth. But the dynamics are still very good and the bass has good weight and control. I am very impressed with this tube. I have tried the RCA, Raytheon and Sylvania 5814's and they are all good tubes. But the Raytheon .... this one is from 1952 .... is the best so far.

These are initial impressions but these tubes just sound right so I commented. The ECC99's will be going in a MPX3's as the output tubes shortly. By the way, the ECC99 is billed as a replacement for the 5687 but the tube is constructed much like the 7119's and looks nothing like the 5687. The ECC99 is a medium sized small signal tube. I hope the ECC99's sound as good as the 7119. If so, the days of hunting nos 5687's may be over.
post #27 of 780
Thread Starter 
Quote:
Originally Posted by Rob N
IMO the Tungsol round plate is one of the best 6SN7's.

BTW are they oval or round mica?
They definetely are oval mica. Is there a difference in quality between the two?
post #28 of 780
Vic,some say that the round mica ones sound better but I can't hear much of a difference
post #29 of 780
Quote:
Originally Posted by sacd lover
Where do you get 7n7's? I will send you a pm.
Me too?
post #30 of 780
Earl could the same adaptor be used for the 6cg7 & this 6gu7?
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