EL34 integrated

newbie308

I just picked up this integrated EL34 amplifier off of Ebay. I will undoubtedly do some upgrades such as a Hexfred rectifier, new binding posts, new capacitors, Mills resistors, SED Winged C's, and some Russian 6N3P's. My primary source is vinyl, so I will need a good phono stage to utilize this amplifier. I was wondering if I could use my Dynaco PAS2 as the phono stage until I can get a dedicated phono preamp. The inputs are CD, Tuner, Tape, and AUX. Can I simply connect from the Dynaco's outputs to the Amplifier's AUX inputs?

I'm very excited! I have read the numerous posts regarding SDA's and tube amplification. I have wanted to try this since I started my musical journey a few years ago, but the lack of funds have always prevented me from reaching this goal. This amplifier will fill the spot currently occupied by my Carver TFM-35. I know that this amp is a product of China, and it is not going to sound as good as old American Iron, but it will allow me to "dip my toe into" the world of tubey goodness!

While the tube amp is in use, I want to send my Carver out to be refurbished. I have noticed that it is developing a hum that increases with volume. Any recommendations for this service would be appreciated.

newbie308

Thanks for the words of encouragement! I'm sure it isn't a total POS, but It could probably benefit from some new Edcor output transformers, and a stepped attenuator or Alps potentiometer in lieu of the original carbon potentiometer. Do you have any idea if I can use my Dynaco preamp as a Phono stage?

doctor r

Yes you can use the Dynaco as a phono preamp. You would use the phono input on the Pas2 as normal and then connect the tape out to any line level input on the new amp. Using the tape output will bypass unwanted circuits and should produce a one volt output that is correct for the line level input. The Dynacos volume control will not be in the circuit.

newbie308

Thanks for the information doctor r! I can't wait until this thing gets here! What would you recommend as a good used phono stage? How much should I budget? I am running a Technics SL1200MK2 with a Grado Blue cartridge. Some time in the future I'd like to try the Dennon DL103R, so I would want the pre to accommodate both MM and MC.

newbie308

I was out today looking for a moderately priced quality phono stage. Unfortunately, the only thing I found was a Rega analog to digital converter that doubled as a phono stage for $200 and at the other end of the spectrum was a $4000 AR preamp. The AR preamp was awesome, but completely out of my price range. I'm not a wealthy man, but I like nice things and good sound. I like exceptional sound, too, but maybe in another lifetime I will be able to afford gear at that level!

marvda1

http://www.audiocircle.com/index.php?topic=117743.msg1236037;topicseen#new

polkfarmboy

That lil yaqin would do the trick, I have my eye on one of the Dared MC-7P with the phono stage in them

cnh

Congrats. There is a LOT of German (and American) engineering know how in many of the designs of the Chinese amps above, so yeah, a LOT of value for your money!

Enjoy!

cnh

Dawgfish

Very sweet amp!

newbie308

Marvda1,
I wish that I had seen your post before I went to the gun store this afternoon! Too many hobbies, and that rifle was just calling to me!

doctor r

Sorry for the delay in replying to your question. The price of phono preamps (new) that might be a decent match will start at a minimum of $200.00. If you visit the http://www.needledoctor.com/Online-Store/View-All-Phono-Preamps you can see a large variety of what is available. This will give you some ideas to look for in the used sales such AudioGon if that is a direction you would want to look into. I have heard good comments on the Lehman Black Cube and the Project units. I had a Monolithic Sound unit I liked (needs the extra power supply to be its best). These all appear used with decent frequency so a little patience could pay off (as if any of use have any :rolleyes:). Enjoy

Rick

newbie308

According to the tracking number, this amplifier is due to arrive tomorrow! I have been reviewing the various tubes available on line, and I'm having trouble deciding what I want. The amplifier is equipped with a nice set of Svetlana EL34's, but I wanted a tube amp so that I could tinker with various tube brands. I hear great things about the SED winged C tubes, but the Genalex gold lion KT77 reissues description sound interesting, too! Then there are the Psvane treasures that cost a bit more, but get rave reviews everywhere! I primarily listen to Classic Rock, Blues guitar, and some Heavy Metal. I love to play live performances with good recordings. Once in a while I'll spin some classical during dinner parties, but rarely will I listen critically to the classical music. It tends to be more of a backdrop for special occasions. Can you guys offer some sage advice regarding tubes worth investing in and tubes to avoid? I'd love to get a set of NOS Mullards, but that would cost more than the amp did and beyond my means. Even NOS Sylvania's are exclusively priced for my wallet! This amp is replacing a Carver TFM-35. I have nothing bad to say about the Carver. I just wanted to switch things up a bit. I have read sooooo many posts about how happy fellow Polkies are with their new tube amps that I had to try it my self.

doctor r

I will share my experience with new production tubes, with the exception of the Treasures which I have not used. My original EL34 based tube amps initially had pre 2005 (I think that is the date) Svetlana tubes. At that time New Sensor had not won the right to legally use the Svetlana name on their tubes and these were the same as the St Petersburg produced SED winged C tubes. I did not understand the difference and when I replaced them I bought "Svetlana" tubes thinking I was going to have what I started with. Wrong. The "New Sensor" Svetlana tubes did not have to open three dimensional midrange that the now labeled SED Winged C tubes had. The Svetlanas lasted about 100 hours and I sold them on EBay. I then bought Winged C tubes and really enjoyed them. I was always curious so I also ended up trying the Tung Sol EL34B tubes which were a little one dimensional and only lasted about 100 hours, then the New Production Mullards, and each time I returned to the Winged C tubes. The Genlex KT77 were very nice tubes that almost displaced the SEDs. The have a little better extension on top and better bass slam, but ultimately even though they had a nice wide soundstage with my system, the did not project the soundstage depth or third dimmension that I so enjoyed with the SEDs. In summary my opinion would be, and you know what they say about opinions, that you would want to possibly focus on trying some SEDs, and the Genlex KT77s. In addition the Treasure or more recent Psvanes should also be investigated. The Genlex KT77 is the best of the New Sensor production in my experience and FYI they make the Svetlana, Tungsol, New Production Mullard, and Electro Harmonix brand variants all at the same factory in Russia. I had heard that SED may no longer be manufacturing and that would be a loss. These thoughts are all based on the different tube's synergy with my system at the time.

newbie308

Doctor r,
It sounds like you have a good deal of experience with tube integrated amplifiers. Thank you for your thoughtful responses to my questions. Maybe some day I too will be able to offer suggestions and help someone as you have done for me. I will order some SED winged C's to begin with. Then, in a few weeks when my wallet recovers, I will replace the Dynaco Pas 2 preamp with a dedicated phono stage. Eventually, I'd like to try a Summiko Blue point and a Dennon DL103R cartridge.

doctor r

Like I said have some patience with the phono stage. You do need to decide if a MM only stage would be adequate or if you want MM and MC. I think the later since you indicated and interest in the Denon 103R (really low output MC). I find there are a lot of really nice used ones that come available and you will get a lot more quality for your dollar spent. Also it seems to be a piece of equipment that really is not abused by a prior owner and is usually in good order. Scan AudiogoN and Audio Asylum on a regular basis and just research units that come up for sale. I used to cut and paste any piece I had a mild interest in straight to a google search and just read (obviously I need to get a life). I slowly sorted out what might work for me and when I had the funds I would pick it up for a good price second hand. The only piece of equipment I purchased new was my CDP and it actually was a show discounted unit after the Axpona show a number of years ago. You have a good solid start. I was helped by many individuals and enjoy that I can share my experiences. This all started with a pair of Polk Monitor 7b that I bought new around 1979 (which I still have) but that is another story .......

newbie308

Well! My amp arrived last night. I took some time to look it over, and I'm glad that I did! Three of the larger electrolytics are bulging, and are in desperate need of replacement! Most of the capacitors can be replaced easily, but a few of them require me to remove the PCB to access the solder terminals. I want to replace the coupling capacitors as well, but I'm not sure who's capacitor to use! There are sooooo many choices! I ordered the electrolytics last night as well as a few hexfred diodes and an Alps volume pot, but I couldn't decide on the 0.47uf 300V isolation capacitors. I need some better banana jacks, too.

The other problem, once I get the new components installed, will be setting the bias. Never did it before! The tubes were packed separately, and they were not labeled as to where they were, so I definitely need to set the bias. Oh! No schematic or operator's manual was included, so I'm kind of working blind until I trace the circuit out.

newbie308

It has only been a couple of weeks since my new used amp arrived, but I just couldn't wait to tweak it! I replaced all of the electrolytic capacitors because some were clearly on their way out. Then a new Alps 100k ohm blue velvet potentiometer went in place of the crappy old el cheapo stock pot. Next I replaced all of the 1N4007 diodes with Hexfred low noise diodes. I replaced the stock polyetelyne caps with Vishay orange drops, but that is a temporary swap until the NOS PIO Vitamin Q's get here! The cruddy old binding posts were swapped with Pamona laboratory grade gold plated copper binding posts. Finally, the carbon composition resistors were replaced with Vishay mil spec metal film resistors. I cleaned the selector switch with some Caig's, and did the same for the tube sockets as well.

To sum up! The amplifier sounds fantastic! What it lacks in power, it makes up for in detail. The highs are extended and a bit bright, but not fatiguing. I love blues guitar, and I can't believe how good SRV sounds on this system! You can hear when the pick touches the strings like the artist is sitting in the same room with you playing! I've never experienced that before! I heard that bass was an issue for tube amplifiers, but I can not complain about what I'm hearing. I can hear John Paul Jones loud and clear the same goes for Geezer Butler. I need to cue up some Rush and see how the bass sounds when Geddy Lee takes lead!

I've ordered a quad of SED winged C's to replace the Sovtek's that the amp came with and I can't wait to hear what this system sounds like with them. I also ordered some Russian 6n3p's because the RCA 5670's in the amp now are highly microphonic.

Sprags

Was this a 'new' amp?

newbie308

Sprags wrote: »

Was this a 'new' amp?

No. This was an Ebay purchase. I saw the large transformers and figured that even if it were DOA it was not a bad deal for $300! Turns out I was right! The output tubes are early (1997) Svetlana Electron Devices Incorporated EL34's witch are the equivalent to new SED (=C=) and worth half of what I paid for the amp. The tube sockets are ceramic, and the chassis is well made with a nice layout. The big issue was the total lack of information available, but I did find a schematic for it's big brother the T.A.C. 88, and from that I traced the circuit and completed the schematic for this.