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Spectral Morn
19-04-2009, 23:41
I was planning on doing some tube rolling in my EAR 864 pre-amplifier, and I was checking to see what Ecc82 and 83 tubes I had. And I found these two white boxes with a valve I know nothing about in them....so I did a bit of looking .....

and found that I have a pair of very rare German valves. These are Siemens 6dj8 types and are called e288c basically about as good an ecc88/6dj8 valve as you can get (also big money to buy). I will post pictures tomorrow (done tonight) and I will have to test them to see if they are okay. These came out of a box of valves my dad had when he used ham radio gear with valves in them.

According to what I have read these may be amazing....Any one got an opinion or experience of these. Can you put them into an amp that uses ecc88/6dj8/6922 tubes....without a problem.

http://i549.photobucket.com/albums/ii364/davros124/SystemSynergy013.jpg

http://i549.photobucket.com/albums/ii364/davros124/SystemSynergy014.jpg


Regards D S D L:)

Spectral Morn
20-04-2009, 16:20
Spent a few hours this afternoon testing signal and some power valves, with my Mighty Mite TC162 tube tester...YIPEEEE it works.

http://i549.photobucket.com/albums/ii364/davros124/Ecofanvalvebuffers--BoostItandBu-64.jpg

Most of the signal tubes ECC83 and ECC88 measured fine (even a white and yellow label Mullard ECC83 were okay :)) one ECC82 was just about okay floating above the middle Question mark Zone.

However 2 EL34's were good on Shorts, Emissions and Grid leakage but had falling levels on the Life test....they dropped fairly quickly into the questionable zone....are these stuffed ? The manual with the tester says bin them....


Regards D S D L

The Grand Wazoo
20-04-2009, 16:42
Neil,
I'm not 100% sure but I think I may also have some of these. I can't check them though till the weekend. I do know I have some pretty obscure ECC88/6DJ8/6922 types I've bought in the past as 'what if?' speculatory purchases.

I've been meaning to try them out in my SP8 for ages, but it sounds so good at the moment, I don't want to rip it apart!

Spectral Morn
20-04-2009, 16:53
Neil,
I'm not 100% sure but I think I may also have some of these. I can't check them though till the weekend. I do know I have some pretty obscure ECC88/6DJ8/6922 types I've bought in the past as 'what if?' speculatory purchases.

I've been meaning to try them out in my SP8 for ages, but it sounds so good at the moment, I don't want to rip it apart!


If you do, they (E288C) are selling in the USA for $300 +. They may be more common here in Europe, but maybe not ? I want to know a bit more before I put them into anything, but from what I have read they appear to be gold dust.

I want to test them too and sadly I have no settings info accept for ECC88,6922,6DJ8's maybe the e288c is the same ? I just don't know :confused:


Regards D S D L

Mike
20-04-2009, 16:59
I want to test them too and sadly I have no settings info accept for ECC88,6922,6DJ8's maybe the e288c is the same ? I just don't know :confused:


Specs HERE (http://www.mif.pg.gda.pl/homepages/frank/sheets/009/e/E288CC.pdf) and HERE (http://www.mif.pg.gda.pl/homepages/frank/sheets/030/e/E288CC.pdf)

Spectral Morn
20-04-2009, 17:09
Thanks Mike but I haven't a clue what that is all about ....I be a bit stupid about such things. The Mighty Mite allows you to set up via an idiots guide (instruction book tells you what to do) so you select any pins needing to be switched out(isolated), filament voltage the load ( selects applied voltage and load resistance, so valve can be tested to its rated current), I also need to know the control grid pin so I can test emission and grid leakage...I need to know those to run a test.

I have a choice of 10 pins for settings A and D see photo close up...here http://theartofsound.net/forum/showthread.php?t=2007.


Can you interpret this for me MIKE....please. What might be the same as an ECC88 (specs)etc I can use settings suggested (in the book) if similar.....

I have got one spec from this pdf, i.e the cathode current which seems to be 40ma, so i know the load now....I still can't figure out the rest.


Regards D S D L

Barry
20-04-2009, 21:51
I have a pair of very rare German valves. These are Siemens 6dj8 types and are called e288c basically about as good an ecc88/6dj8 valve as you can get (also big money to buy). ... According to what I have read these may be amazing....Any one got an opinion or experience of these. Can you put them into an amp that uses ecc88/6dj8/6922 tubes....without a problem.

Regards D S D L:)

Hi Neil,

Put simply the E288CC has no direct equivalents. It is similar to, but not identical to the E88CC and its variants (6DJ8, 6922, ECC88 etc.). The E288CC has lower gain, higher inter-electrode capacitance and heater current than the E88CC. Since the E288CC has higher absolute limits than the E88CC, you could at least try them in your amp without damage. How they sound that can of course only be found by trying them.

If you are looking for the 'Chateau d'Yquem' of E88CC 'bottles', then you need the 1950s Siemens & Halske CCa, the 1960s Telefunken CCa, or early 1960s Lorentz CCa valves (in decreasing order of desirability). A pair of Siemens CCa went on eBay three weeks ago for £98. I was thinking of bidding for them. Wish I had, they were a bargain, but I have no idea of their provenace; the description just said NOS.

Regards

Barry

Spectral Morn
20-04-2009, 22:09
Hi Barry


Thanks for the info....I would like to test them before trying them. I know my Dad won't remember much about them...if he stopped using them because they had gone off.

Can you interpret the specs at the end of Mike's links ?

The other tubes you list are very expensive in the states £98 looks cheap to me compared to what I read last night. Its like Antiques this end of the audio game.

Regards D S D L

Barry
20-04-2009, 22:38
The Mighty Mite allows you to set up via an idiots guide (instruction book tells you what to do) so you select any pins needing to be switched out(isolated), filament voltage the load ( selects applied voltage and load resistance, so valve can be tested to its rated current), I also need to know the control grid pin so I can test emission and grid leakage...I need to know those to run a test. .....


I have got one spec from this pdf, i.e the cathode current which seems to be 40ma, so i know the load now....I still can't figure out the rest.

Regards D S D L


Neil,

I would suggest setting the anode (pins 1 and 6) voltage to 100V, anode current will then be 30mA. Amplification factor 25. Grid pins are 2 and 7 respectively.

For an anode voltage of 60V, the anode current should be 15mA (not 1.5mA as quoted in the first data sheet).

See how you get on with these settings.

Regards

Barry

Spectral Morn
20-04-2009, 22:49
THanks Barry

2 and 7 are the same for the ecc88/ecc83 and 30/40 ma is a setting...excellent we are getting some where.

Is annode the same as filament ? I need the filament voltage.


Let you know how it works....


Regards D S D L

Barry
21-04-2009, 09:41
THanks Barry

2 and 7 are the same for the ecc88/ecc83 and 30/40 ma is a setting...excellent we are getting some where.

Is annode the same as filament ? I need the filament voltage.


Let you know how it works....


Regards D S D L

Neil, there seems to be some confusion here.

The E288CC and ECC88/ ECC83 are double triodes, that is two separate devices enclosed in a single glass envelope. Does your tester, test each triode separately? The pin connections for the first triode are:

anode, pin 1
grid, pin 2
cathode, pin 3,

and for the second triode:

anode, pin 6
grid, pin 7
cathode, pin 8.

The heaters are attached to pins 4 and 5. Heater voltage is 6.3V (that's what the 'E' means in the nomenclature) and the heater current will be 475mA (roughly 30 -60% more than for the ECC83 and ECC88).

No, the anode is not the same as the filament. I'm trying to find a simple to read guide on vacuum tube parameters, so that you can understand/interpret the data sheets that Mike has sent you. This is not really my field; I'm a 'sandman', to use the current colloquialism and I has been fourty years since I last built a valve amp. If all else fails you could try the 'World Design' forum; the people there seem to be more DIY with valve circuits and will be able to help you.

Regards

Barry

Spectral Morn
21-04-2009, 10:30
Yes you do the test twice...in the case of an ECC83 you test set to 2 and then do it again set to 7. This according to the book that comes with the tester. You just follow the guide...understanding is not required.

Thanks for your help. Its at times like this that my subjective expertise fails and I realize just how little I know about the technical side of things. In your day and I mean no insult based on age you guys learn't about the way things worked built your own kit etc....I never have. I never felt the need to do so...yes I do know some things about the way things work but at a fairly shallow level...oh to have more depth.

Maths, physics, Science and the like were not high on my interests at school I was more into Art, History, Geography , Wood work and Metal Work.....and writing...reading etc.


Regards D S D L

Mike
21-04-2009, 11:11
Is annode the same as filament ? I need the filament voltage.

Filament = Cathode

Plate = Anode

According to Wikipedia that is!... http://en.wikipedia.org/wiki/Triode

Although I've seen the heater referred to as 'filament' also, just to confuse matters!... the second data sheet quotes for Vf and If ('f' meaning filament perhaps?) which are clearly figures for the heater.

What options for 'filament' does your tester have Neil?

More about triodes... http://www.allaboutcircuits.com/vol_3/chpt_13/3.html

That bit would indicate to me that the cathode and filament are one and the same thing in a directly heated triode only. When talking about indirectly heated triodes I'm pretty sure that filament = heater.

Maybe...

Mike
21-04-2009, 12:52
What options for 'filament' does your tester have Neil?

Neil, after peering at the picture of your tester, I'd put money (not too much though :eyebrows:) on the 'filament' control being the heater voltage selector. :)

Probably... :lolsign:

Spectral Morn
21-04-2009, 16:05
Hi Mike

From the instruction book...

"Filament This switch selects the filament voltage applied to the tube under test from 1 to over 50 volts . The twelve position switch selects a range of voltage and the unique design of the filament transformer, the tube under test will load the transformer to obtain the correct voltage for testing." This is switch B on the tester.

Does that help ?



Regards D S D L

Mike
21-04-2009, 16:26
I've just downloaded the manual for your tester Neil. I'll take a look.

Spectral Morn
21-04-2009, 16:32
Hi Mike

I had just taken photos of the manual......great minds think alike...;)


Thanks Mike


Regards D S D L

Mike
21-04-2009, 16:41
Right, I've had a look and now I'm quite certain that the 'filament' control selects the heater voltage!

It gives an example for the 6JE6 which is also a 6.3V heater. Set the filament control to '6'. :)

Spectral Morn
21-04-2009, 17:16
And pin isolation to what Barry suggested 1 and 6 or something else ? In fact maybe if you tell me exactly what to set for all the parts please it will make it easier...:)



Thank you Mike

Barry
21-04-2009, 18:47
Hi Neil,

I think I‘m beginning to understand your confusion. Your ‘tube’ tester is an American make (if British, it would called a ‘valve’ tester). According to both American and British terminology the ‘filament’ is the same as the heater. There are differences in terminology as Mike has pointed out:

Plate (American) = Anode (British).

The use of the term ‘filament’ for cathode stems from the days of directly heated cathode valves where the cathode and heater were one and the same. Such valves are still used today in SET (single ended triode) power amplifiers. Examples are the 300B and the 2A3. SET aficionados claim that directly heated triodes are the most linear audio devices around; but this is deviating somewhat from your query.

The valves you have will almost certainly be indirectly heated devices, and so will have at least:

a heater = ‘filament’,

a cathode, a grid and

an anode = ‘plate’.

Your tester can test for ‘shorts’, ‘emission’ and ‘grid leakage’. To explain what these tests do, I’ll quote from F. Langford Smith ‘Radio Designer’s Handbook’, Iliffe 4th edition (1960):

p.91 ‘Shorts and continuity – It is important to ensure that the electrodes such as control and signal grids and suppressors, which do not normally dissipate any power, should not be subjected to any appreciable power dissipation during the shorts and continuity test, otherwise the valve may become damaged as the degassing treatment of these grids during manufacture is normally much lighter than that of electrodes which are required to dissipate power. In addition the cathode current drawn, should not be excessive. It is also important that shorts be checked between the various electrode pin connections and pins designated as no connection, also that the continuity of internal jumper connections between base pins can be checked.’

p.92 ‘It is also essential that in any shorts tester that the cathode-to-grid voltage and filament (heater)-to-grid voltage be kept to a value not exceeding approximately 100 volts.’

I don’t think you will run into any problems here with your tester. Basically if the valve fails the short test, the valve is damaged, either through physical damage to the electrodes, or the glass seals have leaked compromising the vacuum and the valve has become ‘soft’.

p.94 ‘Emission – The purpose of the emission test is to ensure that the cathode emission is adequate to provide the peak and average space currents for the application of the type by a margin which has been found to be satisfactory for good life and performance.’

‘Emission is normally tested by applying a suitable direct positive voltage to all grids connected together with the anode, and measuring the total cathode current.’

‘Because of the very high value of the emission current normally drawn from the cathode, the resulting excessive dissipation of the inner grids and the gas produced as a result of this dissipation and also as a result of ion bombardment of the cathode, the emission test is a damaging test and should be performed as seldom as possible and always very carefully.’

‘In order to avoid damage to the cathode by this test, the applied voltage must be sufficiently large to approach current saturation without drawing sufficient current to damage the valve due to excessive dissipation of the inner grids. At the same time the test must be of sufficient duration to enable the stability of the emission to be indicated without being so long as to give risk of poisoning the emission. A safe value generally accepted for the duration of the emission tests is 3 seconds. During this period the emission should not fall below a value recommended by the valve manufacturer. In general, emission is a minimum reading.’

p.95 ‘Amplifier valves are normally tested for emission with an applied voltage of 30 volts.’

‘Valves having an oxide-coated cathode have a very high degree of emission as compared with other forms of emitters but require very great care during manufacture since they are readily poisoned by certain impurities which may be present in the cathode itself or which may be driven out in the form of gas from the glass enclosure or the other electrodes.’

Grid leakage

p.102 ‘Leakage current is measured with a voltage applied between the grid and each electrode in turn, with the other electrodes floating.’


To obtain all the information you need on the pin connections and value of the various valve parameters this web site is very useful:

http://tdsl.duncanamps.com/tubesearch.php ,

Just enter the name of the valve (ECC88, EF86 etc.) and the various data sheets are returned.

Finally the web site that Nick has suggested is a good one and explains how a valve works and what some of the valve parameters mean.

Apologies for the ‘information overload’.

Barry

Spectral Morn
21-04-2009, 19:06
Thank you Barry for the information...a lot to take in and try and learn.

I have a thread on Audiokarma too and this just came in interesting link http://www.tube-classics.de/indexen.htm. The e288cc is not 100%compatible with Ecc88's, but can be; this is due to higher voltage. It can need twice the current of an Ecc88. So if I fit these will anything go pop or will it just not work ?



Regards D S D L :)

Ali Tait
21-04-2009, 19:36
Barry beat me to it,but yes,in a Directly-Heated Triode (DHT) such as a 300b or 45,the cathode IS the heater or filament.Valves other than DHT's are said to be Indirectly Heated,i.e. the anode,cathode and heater/filament are all separate entities.In regard to your valves,my advice would be to sell them for a large wedge,and buy some nice Siemens/Mullard/Telefunken ecc88's,and pocket the rest of the cash! :)

Barry
21-04-2009, 19:48
I have a thread on Audiokarma too and this just came in interesting link http://www.tube-classics.de/indexen.htm. The e288cc is not 100%compatible with Ecc88's, but can be; this is due to higher voltage. It can need twice the current of an Ecc88. So if I fit these will anything go pop or will it just not work ?

Regards D S D L :)
Hi Neil,

That's an interesting site; just don't ask what the prices are !

Regarding the final sentence - difficult call. The E288CC requires a filament current of 475mA compared with 365mA for the ECC88. The E288CC has lower gain, but in general has higher absolute values than the ECC88, so it's probably more a question of whether your preamp might be damaged by the substitution, rather than the valve. Depends on the design of you amp - I'm not qualified to say. Try running it past the guys at 'World Audio Designs'.

Barry

Spectral Morn
21-04-2009, 20:07
Barry beat me to it,but yes,in a Directly-Heated Triode (DHT) such as a 300b or 45,the cathode IS the heater or filament.Valves other than DHT's are said to be Indirectly Heated,i.e. the anode,cathode and heater/filament are all separate entities.In regard to your valves,my advice would be to sell them for a large wedge,and buy some nice Siemens/Mullard/Telefunken ecc88's,and pocket the rest of the cash! :)

Or buy nothing and pocket the cash..... I don't know on my AudioKarma thread a couple of the guys are having no problem with them and one guy says don't try them because he was told not too...very vague. One guy is using them in an Audio Research p2...he rates them as very good.

Regards D S D L

Ali Tait
22-04-2009, 20:25
One thing about NOS valves is that the price will always go up and up and up and up... Good investment if you don't want to sell them at the moment.I'm always surprised by how much NOS prices have risen,even in just the last four or five years.

Mike
22-04-2009, 21:06
One thing about NOS valves is that the price will always go up and up and up and up... Good investment if you don't want to sell them at the moment.I'm always surprised by how much NOS prices have risen,even in just the last four or five years.

Even better than money in the bank ATM! ;)

The Grand Wazoo
22-04-2009, 21:06
I'm always surprised by how much NOS prices have risen,even in just the last four or five years.

Yer not joking, when I last bought some valves for my Radford amp, I bought a few spare Mullard GZ34's - jeeez I'm glad I did - they were only £14 a pop....... & it wasn't that long ago.

Ali Tait
22-04-2009, 21:10
14 quid?? bet you wish you'd bought a crate..

Spectral Morn
22-04-2009, 21:16
As a KT88 went nova today on my Music reference Rm200 amp this afternoon and I probably need to get a Quad as a replacement. They are Ram labs valves, specially matched by Roger M himself so I doubt if I can slip a pair (of something else) in and it will sound right. I may have to sell these valves to pay for a Quad of Kt88's.

Its crap being out of work....:( You only get 6 months dole and mine is finished now....so needs must.



Regards D S D L

Ali Tait
22-04-2009, 21:27
Neil don't get too hung up on getting valves matched to the nth degree.Even if they are perfectly matched they will drift after a week or two.Whatever valves you get I'd check the bias regularly for the first month or so,depending on use.People pay lots of money for closely matched valves,but it's really not necessary IMHO.

Mike
22-04-2009, 21:29
Why not 'PM' Anthony and see if he can help out in some way, Neil?

Spectral Morn
22-04-2009, 21:31
Good idea Mike. I will. Looks like your digital volt meter will come in handy....except I don't know how to use it :lol: I have never set a valve amp bias before. All the amps I have owned have been auto/self biasing. Anyone care to tell me how to do it ? I know the principals okay...I know what to adjust on the amp and the bias points are on the back of the amp. What do I set the DVM to ? I know I need to allow the amp to warm up and under load (hooked up to speakers) and adjust every couple of hours. Then check again in a few days and then every couple of months.

Is there a place on line that gives a blow by blow instruction how too assuming the doer knows very little. I want to learn...I need to learn.


Regards D S D L

Mike
22-04-2009, 21:48
No manual?

It's normally a very simple job along the lines of; connect the meter to the appropriate test point (these will be provided somewhere on the amp) and adjust a 'pot' until the meter reads whatever is specified. It usually takes no time at all.

Ali Tait
22-04-2009, 21:53
I guess there will be connection points on the amp to plug the leads in from the multimeter.Just set the meter to read milliamps.Dunno which meter you will be using,but just use one of the two lower settings in the "amps" range on the meter dial.Your destructions will tell you what milliamps your amp runs the valves at,and just twiddle the pots to the correct value,and Bob's your relative!
Personally,I'd check the bias around three times a week for the first couple of weeks.But that's just me being paranoid.

Spectral Morn
22-04-2009, 21:58
No manual?

It's normally a very simple job along the lines of; connect the meter to the appropriate test point (these will be provided somewhere on the amp) and adjust a 'pot' until the meter reads whatever is specified. It usually takes no time at all.

For the amp or the DVM ?;)

Yes the amplifier has an instruction manual but the DVM didn't come with one ;)

Out of interest if I wanted to check the fuse at the valve position (its wrapped in paper so I can't see if the element has broke or not) what setting do I select on the DVM. I know you guys might think I am a bit of an idiot about this....I confess I am. It was to easy in the shop to let others do this.

Hi Ali 20m dc or 20 m ac ?


Regards D S D L

Mike
22-04-2009, 22:09
Out of interest if I wanted to check the fuse at the valve position (its wrapped in paper so I can't see if the element has broke or not) what setting do I select on the DVM. I know you guys might think I am a bit of an idiot about this....I confess I am.

Errrr.... erm.... oh, I see!

You might like to start HERE (http://www.doctronics.co.uk/meter.htm). ;)

Ali Tait
22-04-2009, 22:19
A.C. or D.C. refers to voltage.It's amperage or amps you need to measure.There should be a separate section on the dial of your meter for "amps". 1 or 10 amps setting will be fine,the decimal point just moves.

Spectral Morn
22-04-2009, 22:37
This mighty fine DVM see below....

http://i549.photobucket.com/albums/ii364/davros124/SystemSynergy024.jpg

What do I move to where to achieve what you say ? Boy I feel like a total idiot here :doh:



Regards D S D L

Barry
22-04-2009, 23:28
What do I move to where to achieve what you say ? Boy I feel like a total idiot here :doh:

Regards D S D L

If your avatar does you justice, than I'm sure you will have no difficulty getting all the help you need!

Barry

No seriously, if you want to check a fuse:

Plug the black lead into the 'V Ohm' socket,
Plug the red lead into the 'COM' socket,
Set the switch to 'omega'.

If the fuse is OK you will get a low reading (0 Ohms)

Or, set the switch to continuity test (the musical note sign).

In this case if the fuse is OK you will hear a bleep or some other sound.

Mike
23-04-2009, 00:14
Neil, to read the bias current (what is it BTW?) plug the black lead into 'com' (for common) and the red lead into 10A or mA (as appropriate, most likely the mA) and turn the dial to the corresponding position. Either 20m or 200m (most likely 200m).

The meter will then need to be connected to the amp, can you give us pic of the test point(s) and bias adjuster(s) please? :)

Spectral Morn
23-04-2009, 00:49
HI Mike


Yes no problem i will do it tomorrow I am off to bed now...


Regards D S D L

Spectral Morn
23-04-2009, 15:26
Photos of the Music Reference 200 amplifier...sorry these are not better lights poor here today. The fuse above the empty socket was blown. I am amazed the amplifier was still going and making great music from only one valve on that channel. Until I noticed the blown valve glowing bright blue around its bottom inside the glass, you would not have known anything was wrong. Roger M the designer claims bomb proof operation for his kit...seems to be true on this showing.

Front of amplifier

http://i549.photobucket.com/albums/ii364/davros124/SystemSynergy030.jpg

Close up of bias holeappears to be adjusted via slot screw driver.

http://i549.photobucket.com/albums/ii364/davros124/SystemSynergy025.jpg

Rear of amplifier with tp points ? I assume these are for connecting your DVM during the bias process.

http://i549.photobucket.com/albums/ii364/davros124/SystemSynergy028.jpg

Long shot with writing about bias ratings 40mv +or- 4mv.

http://i549.photobucket.com/albums/ii364/davros124/SystemSynergy029.jpg

This should help. Can you give me exact instructions of what to do ? Thanks. Is it not odd to have only one bias adjusting port. How do you adjust for both valves on each channel, is it done individually, or is it done with them being a pair ? Hence there only being one bias trim adjuster thingy . I would have thought if you set one then do the other by moving the same trim pot, you would stuff the setting for the valve you have just done. Or does this just allow you to check how each valve is reading.

I am getting some valves off Marco....


Regards D S D L

Ali Tait
23-04-2009, 17:33
Ok Neil,not knowing your amp or being familiar with the circuit,I would suggest you need to do the following-On the rear of the amp you have two "TP" sockets on each channel.Connect your meter leads between each channel's TP socket and it's nearest 8-ohm speaker socket i.e. one lead to TP,one to the nearest speaker socket.It doesn't matter which way round,you may just get a negative reading instead of a positive on the meter,this does not matter.Given that you only have one bias pot per channel,I would say you need to switch between both "TP" points on each channel (and it's nearest 8-ohm speaker socket) and twiddle the bias pot with a screwdriver so the readings you get are as near to 40mV and also each other as you can get on each channel.You may not be able to get quite the same reading on each channel,but don't worry about that.If they are quite far out,try swapping the valve pairs in each channel about till you get a good combination that measures as near as you can get them.Don't be anal about it though,near enough really is good enough! Does this make sense? Don't hesitate to ask if you're not sure. :)

Spectral Morn
23-04-2009, 17:38
Hi Ali

Yes thats what I thought but if in doubt always ask.... You must have the speakers attached, so the outputs are under load as well YES/NO and let the amp warm up a bit before doing the test....how long ? Then check again a bit latter.

Is that right.

I used to own a T+A V10 amp, but the bias was set via a built in meter. The access was terrible from holes under the amp. Who thought that was a clever thing :doh:. You had to lift it up (as the access holes where right in the middle of the bottom). I took the top shelf off my table and did it that way but what a real pain. Other than that the valve tester,valve life clock and bias reducer were great ideas all at the push of a button, with a built in screen idiot proof. Sound was good but veiled. Oh yes the fan in the bottom was to loud the other reason why I sold it on. Beautiful looking amp though.

http://www.laser-turntable.com/images/T+A/v10_frontal.gif


Regards D S D L

Ali Tait
23-04-2009, 17:54
I assume this is a push-pull amp yes? In that case,yes DO NOT run the amp without speakers connected,as they form part of the circuit,and you may fry the output transformers if you do so.In similar situations I have (assuming you use banana plugs) plugged the speaker leads in so they just make contact,leaving a little bare banana plug hanging out of the end of the socket,so you can connect your DMM lead to this with a crocodile clip (if you have some!) Failing that,unscrew the nut on the speaker socket to expose the hole drilled through.Plug your DMM lead into this and then tighten down the nut.Then plug your speaker lead in as far as it will go.As for the amp being warm,give it a few minutes before the first reading,then just turn it on and off to get the others once it's warmed up a bit.Croc clips would make the job a lot easier as you could just leave the amp on as you swap the leads around.This is quite safe to do,just try not to burn yourself on the output valves! :)

Spectral Morn
23-04-2009, 18:31
Thanks for the help Ali

I will let you know how I get on when the valves I have ordered today come.



Regards D S D L

Mike
23-04-2009, 18:32
Ah... jolly good!

Ali beat me to it again. All sorted then Neil?

:)

Ali Tait
23-04-2009, 19:21
No worries,glad I could help. :)

Spectral Morn
23-04-2009, 20:40
Thanks for the help Ali and Mike.


I may have questions but I wont know until the valves I have ordered, come next week...Marco came to my rescue,TOP BLOKE :):):)


Regards D S D L

Ali Tait
23-04-2009, 21:10
Nice one.Let us know how you get on. :)